-- BlockOS installer with onboarding.
-- Generated by tools/build.py from src/installer.lua: every BlockOS file is bundled below,
-- so this single program can be run from Pastebin, GitHub or a disk.

local Version = "1.6.0"
local Files = {}
Files["startup.lua"] = [[
-- Boots BlockOS when it is installed.

if (fs.exists("/blockos/boot.lua")) then
	shell.run("/blockos/boot.lua")
end
]]
Files["blockos/apps/about/app.cfg"] = [[
{ Name = "About BlockOS", Description = "Information about this computer.", Hidden = true, Single = true, Width = 34, Height = 14 }
]]
Files["blockos/apps/about/main.lua"] = [[
-- About BlockOS: version and hardware summary.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Logo = BlockOS.Require("logo")
local Config = BlockOS.Require("config")

local Page = Ui.Page.new()

local function Facts()
	local Free = fs.getFreeSpace("/")
	local Capacity = fs.getCapacity and fs.getCapacity("/")
	return {
		{ "Version", Config.Version() },
		{ "Computer", (os.getComputerLabel() or "Unnamed") .. " #" .. os.getComputerID() },
		{ "Host", _HOST or os.version() },
		{ "Storage", Gfx.FormatSize(Free) .. " free" .. (Capacity and (" of " .. Gfx.FormatSize(Capacity)) or "") },
		{ "Type", (turtle and "Turtle" or (pocket and "Pocket" or "Computer")) .. (term.isColor() and " (Advanced)" or "") }
	}
end

function Page:OnLayout(W, H)
	self:Clear()
	self:Add(Ui.Button.new({
		X = math.floor((W - 20) / 2) + 1, Y = H - 1, W = 20, Text = "Software Update...", Style = "primary",
		OnClick = function() BlockOS.Launch("settings", { "update" }) end
	}))
end

function Page:OnDraw(T, Th)
	local LogoW, LogoH = Logo.Size(Logo.Small)
	Logo.Draw(T, math.floor((self.W - LogoW) / 2) + 1, 2, Logo.Small)
	Gfx.Center(T, LogoH + 3, "BlockOS", Th.Text, Th.WindowBg)
	local Y = LogoH + 5
	for _, Fact in ipairs(Facts()) do
		if (Y >= self.H - 1) then break end
		Gfx.Write(T, 2, Y, Gfx.Pad(Fact[1], 9, "right"), Th.SubText, Th.WindowBg)
		Gfx.Write(T, 12, Y, Gfx.Truncate(Fact[2], self.W - 12), Th.Text, Th.WindowBg)
		Y = Y + 1
	end
end

Page:Run()
]]
Files["blockos/apps/appstore/app.cfg"] = [[
{ Name = "App Store", Description = "Discover and install apps, or install from Pastebin.", Width = 46, Height = 15, Single = true, Icon = { Lines = { " A ", "\131\131\131" }, Fg = "white", Bg = "lightBlue" } }
]]
Files["blockos/apps/appstore/main.lua"] = [=[
-- App Store: browses repository catalogs, installs apps from Pastebin or URLs,
-- and manages installed apps.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Apps = BlockOS.Require("apps")
local Config = BlockOS.Require("config")
local Updater = BlockOS.Require("updater")

local Page = Ui.Page.new()
local Tab = 1
local Catalog = {}
local Loading = false
local Status = ""
local Query = ""
local Selected = nil
local Form = { Code = "", Name = "", Icon = "", Color = 1, Fullscreen = false }
local IconColors = { "blue", "purple", "magenta", "red", "orange", "yellow", "lime", "green", "cyan", "lightBlue", "pink", "gray", "black" }

local function Installed()
	local Result = {}
	for _, App in ipairs(Apps.List(true)) do
		if (not App.System) then
			Result[App.StoreID or App.ID] = App
		end
	end
	return Result
end

local function ResolveUrl(Base, Url)
	if (Url:match("^https?://")) then return Url end
	return Base:gsub("[^/]*$", "") .. Url
end

local function FetchCatalogs()
	Loading = true
	Catalog = {}
	Status = "Loading catalogs..."
	Page:Draw()
	local Errors = 0
	for _, Url in ipairs(Config.Settings().Repositories) do
		local Body = Updater.Get(Url)
		local Data = Body and textutils.unserialise(Body)
		if (type(Data) == "table" and type(Data.Apps) == "table") then
			for _, Entry in ipairs(Data.Apps) do
				if (type(Entry) == "table" and Entry.ID and Entry.Name and type(Entry.Source) == "table") then
					Entry.Repository = Data.Name or Url
					Entry.Base = Url
					table.insert(Catalog, Entry)
				end
			end
		else
			Errors = Errors + 1
		end
	end
	table.sort(Catalog, function(A, B) return A.Name:lower() < B.Name:lower() end)
	Loading = false
	Status = #Catalog .. " apps" .. (Errors > 0 and (", " .. Errors .. " source(s) unavailable") or "")
end

local function DownloadSource(Entry)
	local Source = Entry.Source
	if (Source.Type == "pastebin") then
		return Apps.FetchPastebin(Source.Code)
	elseif (Source.Type == "url") then
		return Apps.Fetch(ResolveUrl(Entry.Base or "", Source.Url))
	elseif (Source.Type == "rom") then
		return "-- Launcher generated by the App Store\nshell.run(" .. string.format("%q", Source.Program) .. ", ...)\n"
	end
	return nil, "Unknown source type"
end

local function InstallEntry(Entry)
	Status = "Downloading " .. Entry.Name .. "..."
	Page:Draw()
	local Source, Err = DownloadSource(Entry)
	if (not Source) then
		Status = ""
		Ui.Alert("Install failed", tostring(Err))
		return
	end
	local Ok, CompileErr = load(Source, "=" .. Entry.ID)
	if (not Ok and not Ui.Confirm("Warning", "This app has a syntax error and may not run:\n" .. tostring(CompileErr), "Install Anyway")) then
		Status = ""
		return
	end
	local Existing = Installed()[Entry.ID]
	Apps.Install({
		ID = Existing and Existing.ID or Entry.ID,
		Name = Entry.Name,
		Description = Entry.Description,
		Author = Entry.Author,
		Category = Entry.Category,
		Version = Entry.Version,
		StoreID = Entry.ID,
		Mode = Entry.Mode,
		Width = Entry.Width,
		Height = Entry.Height,
		Icon = Entry.Icon,
		Source = Entry.Source
	}, Source)
	Status = Entry.Name .. " installed"
	BlockOS.Notify("App Store", Entry.Name .. " is ready in Launchpad.", { AppID = "appstore", Sound = false })
end

local function Filtered()
	local Result = {}
	local Needle = Query:lower()
	for _, Entry in ipairs(Catalog) do
		if (Needle == "" or Entry.Name:lower():find(Needle, 1, true) or (Entry.Category or ""):lower():find(Needle, 1, true)) then
			table.insert(Result, Entry)
		end
	end
	return Result
end

local Build

local function Header(W)
	local TabsW = math.min(W - 2, 44)
	Page:Add(Ui.Tabs.new({
		X = math.floor((W - TabsW) / 2) + 1, Y = 1, W = TabsW, Items = { "Discover", "Installed", "Pastebin", "Sources" }, Selected = Tab,
		OnChange = function(_, Index)
			Tab = Index
			Build()
		end
	}))
end

local function BuildDiscover(W, H)
	local ListW = (W >= 40) and math.floor(W * .45) or W
	local Search = Page:Add(Ui.Input.new({ X = 2, Y = 3, W = ListW - 2, Value = Query, Placeholder = "\16 Search apps" }))
	local List = Page:Add(Ui.List.new({ X = 1, Y = 5, W = ListW, H = H - 6 }))
	local Have = Installed()
	local function Fill()
		local Items = {}
		for _, Entry in ipairs(Filtered()) do
			local Mine = Have[Entry.ID]
			local Label = "GET"
			if (Mine) then
				Label = (Entry.Version and Mine.Version and Updater.Compare(Mine.Version, Entry.Version) < 0) and "UPDATE" or "OPEN"
			end
			local Icon = Entry.Icon or Apps.DefaultIcon(Entry.Name)
			table.insert(Items, {
				Text = Entry.Name,
				Icon = Gfx.Pad(Icon.Lines and Icon.Lines[1] or "", 3),
				IconFg = colors[Icon.Bg] or Icon.Bg or colors.gray,
				Right = Label,
				Entry = Entry
			})
		end
		List:SetItems(Items)
		for Index, Item in ipairs(Items) do
			if (Item.Entry == Selected) then List:Select(Index) end
		end
	end
	Search.OnChange = function(_, Value)
		Query = Value
		Fill()
	end
	local function Act(Entry)
		local Mine = Installed()[Entry.ID]
		if (Mine and not (Entry.Version and Mine.Version and Updater.Compare(Mine.Version, Entry.Version) < 0)) then
			BlockOS.Launch(Mine.ID)
		else
			InstallEntry(Entry)
			Build()
		end
	end
	local Action
	local function ActionText()
		local Mine = Selected and Installed()[Selected.ID]
		if (not Mine) then return "Get" end
		if (Selected.Version and Mine.Version and Updater.Compare(Mine.Version, Selected.Version) < 0) then return "Update" end
		return "Open"
	end
	List.OnSelect = function(_, _, Item)
		Selected = Item.Entry
		if (Action) then
			Action.Enabled = true
			Page:Invalidate()
		end
	end
	List.OnActivate = function(_, _, Item)
		if (ListW == W) then
			local Entry = Item.Entry
			local Choice = Ui.Alert(Entry.Name, (Entry.Description or "") .. "\n\nBy " .. (Entry.Author or "unknown"), { "Close", Item.Right == "GET" and "Get" or (Item.Right == "UPDATE" and "Update" or "Open") })
			if (Choice == 2) then Act(Entry) end
		else
			Act(Item.Entry)
		end
	end
	Fill()
	if (ListW < W) then
		local DetailX = ListW + 2
		local DetailW = W - ListW - 2
		Page:Add(Ui.Canvas.new({
			X = DetailX, Y = 3, W = DetailW, H = H - 6,
			OnDraw = function(Self, T, Th)
				local Entry = Selected
				if (not Entry) then
					Gfx.Write(T, Self.X, Self.Y + 1, Gfx.Truncate(Loading and "Loading..." or "Select an app", Self.W), Th.SubText, Th.WindowBg)
					return
				end
				local Icon = Entry.Icon or Apps.DefaultIcon(Entry.Name)
				local Fg = colors[Icon.Fg] or Icon.Fg or colors.white
				local Bg = colors[Icon.Bg] or Icon.Bg or colors.gray
				for Row = 1, 2 do
					Gfx.Write(T, Self.X, Self.Y + Row - 1, Gfx.Pad(Icon.Lines and Icon.Lines[Row] or "", 3), Fg, Bg)
				end
				Gfx.Write(T, Self.X + 4, Self.Y, Gfx.Truncate(Entry.Name, Self.W - 4), Th.Text, Th.WindowBg)
				Gfx.Write(T, Self.X + 4, Self.Y + 1, Gfx.Truncate((Entry.Category or "App") .. " \7 " .. (Entry.Author or "?"), Self.W - 4), Th.SubText, Th.WindowBg)
				local Lines = Gfx.Wrap(Entry.Description or "", Self.W)
				for Row = 1, math.min(#Lines, Self.H - 5) do
					Gfx.Write(T, Self.X, Self.Y + 2 + Row, Lines[Row], Th.Text, Th.WindowBg)
				end
				Gfx.Write(T, Self.X, Self.Y + Self.H - 1, Gfx.Truncate("Version " .. (Entry.Version or "?") .. " from " .. (Entry.Repository or ""), Self.W), Th.SubText, Th.WindowBg)
			end
		}))
		Action = Page:Add(Ui.Button.new({
			X = W - 9, Y = H - 2, W = 8, Text = ActionText, Style = "primary", Enabled = Selected ~= nil,
			OnClick = function()
				if (Selected) then Act(Selected) end
			end
		}))
	end
end

local function BuildInstalled(W, H)
	local List = Page:Add(Ui.List.new({ X = 1, Y = 3, W = W, H = H - 4 }))
	local Items = {}
	for _, App in ipairs(Apps.List(true)) do
		if (not App.System) then
			table.insert(Items, {
				Text = App.Name,
				Icon = Gfx.Pad(App.Icon.Lines[1], 3),
				IconFg = App.Icon.Bg,
				Right = App.Version or "",
				App = App
			})
		end
	end
	if (#Items == 0) then
		Page:Add(Ui.Label.new({ X = 2, Y = 4, W = W - 2, Text = "No apps installed yet.", Fg = "SubText" }))
	end
	List:SetItems(Items)
	local function Menu(Item, X, Y)
		local App = Item.App
		local Pinned = Apps.IsPinned(App.ID)
		local Options = { "Open", "Open Full Screen", Pinned and "Remove from Dock" or "Keep in Dock", "Edit Source", "-", "Uninstall" }
		local Choice = Options[Ui.ContextMenu(X, Y, Options) or 0]
		if (Choice == "Open") then
			BlockOS.Launch(App.ID)
		elseif (Choice == "Open Full Screen") then
			BlockOS.Launch(App.ID, {}, { Mode = "fullscreen" })
		elseif (Choice == "Keep in Dock" or Choice == "Remove from Dock") then
			Apps.SetPinned(App.ID, not Pinned)
		elseif (Choice == "Edit Source") then
			BlockOS.Launch("editor", { App.Path })
		elseif (Choice == "Uninstall") then
			if (Ui.Confirm("Uninstall", "Remove " .. App.Name .. "?", "Uninstall")) then
				Apps.Uninstall(App.ID)
				Build()
			end
		end
	end
	List.OnActivate = function(_, _, Item) BlockOS.Launch(Item.App.ID) end
	List.OnContext = function(_, _, Item, X, Y)
		if (Item) then Menu(Item, X, Y) end
	end
	Page:Add(Ui.Label.new({ X = 2, Y = H - 1, W = W - 2, Text = "Right-click an app for more options.", Fg = "SubText" }))
end

local function BuildPastebin(W, H)
	local FieldW = math.min(W - 16, 28)
	Page:Add(Ui.Label.new({ X = 2, Y = 3, W = W - 2, Text = "Install any program from Pastebin or a URL as an app.", Fg = "SubText" }))
	Page:Add(Ui.Label.new({ X = 2, Y = 5, Text = "Code / URL" }))
	local Code = Page:Add(Ui.Input.new({ X = 14, Y = 5, W = FieldW, Value = Form.Code, Placeholder = "e.g. aBcD1234" }))
	Code.OnChange = function(_, Value) Form.Code = Value end
	Page:Add(Ui.Label.new({ X = 2, Y = 7, Text = "Name" }))
	local Name = Page:Add(Ui.Input.new({ X = 14, Y = 7, W = FieldW, Value = Form.Name, Placeholder = "My App", MaxLength = 24 }))
	Name.OnChange = function(_, Value) Form.Name = Value end
	Page:Add(Ui.Label.new({ X = 2, Y = 9, Text = "Icon" }))
	local Icon = Page:Add(Ui.Input.new({ X = 14, Y = 9, W = 4, Value = Form.Icon, MaxLength = 3 }))
	Icon.OnChange = function(_, Value) Form.Icon = Value end
	Page:Add(Ui.Canvas.new({
		X = 19, Y = 9, W = 3, H = 1,
		OnDraw = function(Self, T)
			local Text = (#Form.Icon > 0) and Form.Icon or Apps.DefaultIcon(Form.Name ~= "" and Form.Name or "App").Lines[1]
			Gfx.Write(T, Self.X, Self.Y, Gfx.Pad(Text, 3), colors.white, colors[IconColors[Form.Color]])
		end,
		OnEvent = function(_, EventName)
			if (EventName ~= "mouse_click") then return false end
			Form.Color = Form.Color % #IconColors + 1
			return true
		end
	}))
	Page:Add(Ui.Label.new({ X = 23, Y = 9, Text = "\27 click for colour", Fg = "SubText" }))
	Page:Add(Ui.Label.new({ X = 2, Y = 11, Text = "Open as" }))
	Page:Add(Ui.Tabs.new({
		X = 14, Y = 11, W = 22, Items = { "Window", "Full Screen" }, Selected = Form.Fullscreen and 2 or 1,
		OnChange = function(_, Index) Form.Fullscreen = Index == 2 end
	}))
	Page:Add(Ui.Button.new({
		X = W - 11, Y = H - 1, W = 10, Text = "Install", Style = "primary",
		OnClick = function()
			local Input = Form.Code:gsub("^%s+", ""):gsub("%s+$", "")
			if (#Input == 0) then
				Ui.Alert("Install", "Enter a Pastebin code or a URL.")
				return
			end
			local AppName = (#Form.Name > 0) and Form.Name or Input:match("([%w_%-]+)%.?%w*$") or "App"
			Status = "Downloading..."
			Page:Draw()
			local Source, Err
			local SourceInfo
			if (Input:match("^https?://") and not Input:match("pastebin%.com")) then
				Source, Err = Apps.Fetch(Input)
				SourceInfo = { Type = "url", Url = Input }
			else
				Source, Err = Apps.FetchPastebin(Input)
				SourceInfo = { Type = "pastebin", Code = Input }
			end
			Status = ""
			if (not Source) then
				Ui.Alert("Install failed", tostring(Err))
				return
			end
			local Lines = (#Form.Icon > 0) and { Gfx.Pad(Form.Icon, 3), "   " } or Apps.DefaultIcon(AppName).Lines
			local App = Apps.Install({
				Name = AppName,
				Description = "Installed from " .. (SourceInfo.Type == "pastebin" and ("Pastebin " .. Input) or Input),
				Mode = Form.Fullscreen and "fullscreen" or "window",
				Icon = { Lines = Lines, Fg = "white", Bg = IconColors[Form.Color] },
				Source = SourceInfo,
				Version = "1.0"
			}, Source)
			Form = { Code = "", Name = "", Icon = "", Color = Form.Color, Fullscreen = false }
			if (App and Ui.Confirm("Installed", AppName .. " was added to Applications. Open it now?", "Open")) then
				BlockOS.Launch(App.ID)
			end
			Build()
		end
	}))
	Page:SetFocus(Code)
end

local function BuildSources(W, H)
	local Settings = Config.Settings()
	local List = Page:Add(Ui.List.new({ X = 1, Y = 3, W = W, H = H - 5 }))
	local Items = {}
	for Index, Url in ipairs(Settings.Repositories) do
		table.insert(Items, { Text = Url, Icon = "\4", IconFg = "Accent", Index = Index })
	end
	List:SetItems(Items)
	Page:Add(Ui.Button.new({
		X = 2, Y = H - 1, Text = " Add Source ",
		OnClick = function()
			local Url = Ui.Prompt("Add Source", "Catalog URL (catalog.cfg):", "https://")
			if (Url and Url:match("^https?://.+")) then
				table.insert(Settings.Repositories, Url)
				Config.Save("settings")
				Build()
			end
		end
	}))
	Page:Add(Ui.Button.new({
		X = 16, Y = H - 1, Text = " Remove ",
		OnClick = function()
			local Item = List.Items[List.Selected]
			if (Item and Ui.Confirm("Remove Source", Item.Text, "Remove")) then
				table.remove(Settings.Repositories, Item.Index)
				Config.Save("settings")
				Build()
			end
		end
	}))
	Page:Add(Ui.Button.new({
		X = W - 10, Y = H - 1, Text = " Reload ", Style = "primary",
		OnClick = function()
			FetchCatalogs()
			Tab = 1
			Build()
		end
	}))
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Header(W)
	if (Tab == 1) then
		BuildDiscover(W, H)
	elseif (Tab == 2) then
		BuildInstalled(W, H)
	elseif (Tab == 3) then
		BuildPastebin(W, H)
	else
		BuildSources(W, H)
	end
	Page:Add(Ui.Label.new({ X = 1, Y = H, W = W, Text = function() return Status end, Fg = "SubText", Bg = "Panel", Align = "center" }))
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name)
	if (Name == "appstore_refresh") then
		FetchCatalogs()
		Build()
		return true
	elseif (Name == "blockos_apps") then
		if (Tab ~= 3) then Build() end
		return true
	end
	return false
end

os.queueEvent("appstore_refresh")
Page:Run()
]=]
Files["blockos/apps/brocreate/app.cfg"] = [[
{ Name = "Brocreate", Description = "Paint pictures with colours and text characters, and set them as your wallpaper.", Width = 48, Height = 16, Icon = { Lines = { "\7 \7", " \7/" }, Fg = "white", Bg = "magenta" } }
]]
Files["blockos/apps/brocreate/main.lua"] = [[
-- Brocreate: paint pictures with solid colours and text characters, save them and set them as the wallpaper.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")
local Image = BlockOS.Require("image")
local Wallpaper = BlockOS.Require("wallpaper")

local Args = { ... }

local Folder = "/home/Pictures"
local MaxUndo = 30
local MaxSide = 164

local Tools = {
	{ ID = "pen", Label = "Pen", Short = "Pn" },
	{ ID = "line", Label = "Line", Short = "Ln" },
	{ ID = "box", Label = "Box", Short = "Bx" },
	{ ID = "fill", Label = "Fill", Short = "Fl" },
	{ ID = "text", Label = "Text", Short = "Tx" },
	{ ID = "pick", Label = "Pick", Short = "Pk" },
	{ ID = "erase", Label = "Erase", Short = "Er" }
}

-- Palette entries that need dark marks on top.
local Light = { ["0"] = true, ["1"] = true, ["3"] = true, ["4"] = true, ["5"] = true, ["6"] = true, ["8"] = true, ["9"] = true }

local Page = Ui.Page.new()
local State = { Tool = "pen", Ink = "solid", Char = "#", Primary = "f", Secondary = "0", Filled = false }
local View = { ScrollX = 0, ScrollY = 0 }
local Layout = { CX = 1, CY = 2, CW = 1, CH = 1, Swatch = 2 }
local Doc, Stroke, Caret, Hover, CanvasWidget
local Undo, Redo = {}, {}

--
-- Document
--

local function FromImage(Img)
	local NewDoc = { W = Img.W, H = Img.H, Text = {}, Fg = {}, Bg = {}, Base = Img.Rows[1][3]:sub(1, 1) }
	for Y = 1, Img.H do
		local Row = Img.Rows[Y]
		local Text, Fg, Bg = {}, {}, {}
		for X = 1, Img.W do
			Text[X] = Row[1]:sub(X, X)
			Fg[X] = Row[2]:sub(X, X)
			Bg[X] = Row[3]:sub(X, X)
		end
		NewDoc.Text[Y], NewDoc.Fg[Y], NewDoc.Bg[Y] = Text, Fg, Bg
	end
	return NewDoc
end

local function ToImage()
	local Rows = {}
	for Y = 1, Doc.H do
		Rows[Y] = { table.concat(Doc.Text[Y]), table.concat(Doc.Fg[Y]), table.concat(Doc.Bg[Y]) }
	end
	return { W = Doc.W, H = Doc.H, Rows = Rows }
end

local function DisplayName()
	return Doc.Path and fs.getName(Doc.Path) or "Untitled"
end

local function UpdateTitle()
	BlockOS.SetTitle(DisplayName() .. (Doc.Dirty and " *" or ""))
end

local function MarkDirty()
	if (Doc.Dirty) then return end
	Doc.Dirty = true
	UpdateTitle()
end

local function ClampScroll()
	View.ScrollX = math.max(0, math.min(View.ScrollX, Doc.W - Layout.CW))
	View.ScrollY = math.max(0, math.min(View.ScrollY, Doc.H - Layout.CH))
end

local function SetDoc(NewDoc, Path)
	Doc = NewDoc
	Doc.Path = Path
	Doc.Dirty = false
	Undo, Redo = {}, {}
	View.ScrollX, View.ScrollY = 0, 0
	Stroke, Caret, Hover = nil, nil, nil
	UpdateTitle()
	Page:Invalidate()
end

local function PushUndo()
	table.insert(Undo, ToImage())
	if (#Undo > MaxUndo) then table.remove(Undo, 1) end
	Redo = {}
end

local function Restore(Snapshot)
	local Restored = FromImage(Snapshot)
	Restored.Path, Restored.Base = Doc.Path, Doc.Base
	Doc = Restored
	ClampScroll()
	MarkDirty()
end

local function DoUndo()
	if (#Undo == 0) then return end
	table.insert(Redo, ToImage())
	Restore(table.remove(Undo))
end

local function DoRedo()
	if (#Redo == 0) then return end
	table.insert(Undo, ToImage())
	Restore(table.remove(Redo))
end

local function HasCharacters()
	for Y = 1, Doc.H do
		for X = 1, Doc.W do
			if (Doc.Text[Y][X] ~= " ") then return true end
		end
	end
	return false
end

--
-- Painting
--

local function InBounds(X, Y)
	return X >= 1 and Y >= 1 and X <= Doc.W and Y <= Doc.H
end

-- What a cell becomes under the current ink (solid colour, character or eraser).
local function Inked(X, Y, Color)
	if (State.Tool == "erase") then
		return " ", "f", Doc.Base
	elseif (State.Ink == "solid") then
		return " ", Doc.Fg[Y][X], Color
	end
	return State.Char, Color, Doc.Bg[Y][X]
end

local function Plot(X, Y, Color)
	if (not InBounds(X, Y)) then return end
	Doc.Text[Y][X], Doc.Fg[Y][X], Doc.Bg[Y][X] = Inked(X, Y, Color)
end

local function LinePoints(X1, Y1, X2, Y2)
	local Points = {}
	local DX, DY = math.abs(X2 - X1), -math.abs(Y2 - Y1)
	local StepX = (X1 < X2) and 1 or -1
	local StepY = (Y1 < Y2) and 1 or -1
	local Err = DX + DY
	while (true) do
		table.insert(Points, { X1, Y1 })
		if (X1 == X2 and Y1 == Y2) then break end
		local Double = 2 * Err
		if (Double >= DY) then
			Err = Err + DY
			X1 = X1 + StepX
		end
		if (Double <= DX) then
			Err = Err + DX
			Y1 = Y1 + StepY
		end
	end
	return Points
end

local function BoxPoints(X1, Y1, X2, Y2)
	local Points = {}
	local Left, Right = math.max(1, math.min(X1, X2)), math.min(Doc.W, math.max(X1, X2))
	local Top, Bottom = math.max(1, math.min(Y1, Y2)), math.min(Doc.H, math.max(Y1, Y2))
	local EdgeLeft, EdgeRight = math.min(X1, X2), math.max(X1, X2)
	local EdgeTop, EdgeBottom = math.min(Y1, Y2), math.max(Y1, Y2)
	for Y = Top, Bottom do
		for X = Left, Right do
			if (State.Filled or Y == EdgeTop or Y == EdgeBottom or X == EdgeLeft or X == EdgeRight) then
				table.insert(Points, { X, Y })
			end
		end
	end
	return Points
end

local function ShapePoints(Shape)
	if (State.Tool == "line") then
		return LinePoints(Shape.X1, Shape.Y1, Shape.X2, Shape.Y2)
	end
	return BoxPoints(Shape.X1, Shape.Y1, Shape.X2, Shape.Y2)
end

-- Solid ink fills the area of matching background and keeps characters; character ink fills matching cells.
local function Fill(StartX, StartY, Color)
	if (not InBounds(StartX, StartY)) then return false end
	local Solid = State.Ink == "solid"
	local function KeyOf(X, Y)
		if (Solid) then return Doc.Bg[Y][X] end
		return Doc.Text[Y][X] .. Doc.Fg[Y][X] .. Doc.Bg[Y][X]
	end
	local Target = KeyOf(StartX, StartY)
	local Seen = {}
	local Stack = { { StartX, StartY } }
	while (#Stack > 0) do
		local Point = table.remove(Stack)
		local X, Y = Point[1], Point[2]
		local Index = Y * (Doc.W + 1) + X
		if (InBounds(X, Y) and not Seen[Index] and KeyOf(X, Y) == Target) then
			Seen[Index] = true
			if (Solid) then
				Doc.Bg[Y][X] = Color
			else
				Doc.Text[Y][X], Doc.Fg[Y][X] = State.Char, Color
			end
			table.insert(Stack, { X + 1, Y })
			table.insert(Stack, { X - 1, Y })
			table.insert(Stack, { X, Y + 1 })
			table.insert(Stack, { X, Y - 1 })
		end
	end
	return true
end

local function Pick(X, Y, Button)
	if (not InBounds(X, Y)) then return end
	if (Button == 2) then
		State.Secondary = Doc.Bg[Y][X]
	elseif (State.Ink == "char" and Doc.Text[Y][X] ~= " ") then
		State.Primary, State.Char = Doc.Fg[Y][X], Doc.Text[Y][X]
	else
		State.Primary = Doc.Bg[Y][X]
	end
end

--
-- Canvas view
--

-- Page position of image cell 1, 1. Small images are centred, large ones scroll.
local function Origin()
	local OffsetX = (Doc.W <= Layout.CW) and math.floor((Layout.CW - Doc.W) / 2) or -View.ScrollX
	local OffsetY = (Doc.H <= Layout.CH) and math.floor((Layout.CH - Doc.H) / 2) or -View.ScrollY
	return Layout.CX + OffsetX, Layout.CY + OffsetY
end

local function ToCell(PageX, PageY)
	local OriginX, OriginY = Origin()
	return PageX - OriginX + 1, PageY - OriginY + 1
end

local function Pan(DX, DY)
	View.ScrollX = View.ScrollX + DX
	View.ScrollY = View.ScrollY + DY
	ClampScroll()
end

local function BeginStroke(Button, PageX, PageY)
	local X, Y = ToCell(PageX, PageY)
	Hover = { X, Y }
	Caret = nil
	if (Button == 3) then
		Stroke = { Pan = true, LastX = PageX, LastY = PageY }
		return true
	end
	local Color = (Button == 2) and State.Secondary or State.Primary
	local Tool = State.Tool
	if (Tool == "pen" or Tool == "erase") then
		PushUndo()
		Stroke = { LastX = X, LastY = Y, Color = Color }
		Plot(X, Y, Color)
		MarkDirty()
	elseif (Tool == "line" or Tool == "box") then
		Stroke = { Shape = true, X1 = X, Y1 = Y, X2 = X, Y2 = Y, Color = Color }
	elseif (Tool == "fill" and InBounds(X, Y)) then
		PushUndo()
		Fill(X, Y, Color)
		MarkDirty()
	elseif (Tool == "pick") then
		Pick(X, Y, Button)
	elseif (Tool == "text" and InBounds(X, Y)) then
		Caret = { X = X, Y = Y, StartX = X, Color = Color }
	end
	return true
end

local function ContinueStroke(PageX, PageY)
	if (not Stroke) then return false end
	if (Stroke.Pan) then
		Pan(Stroke.LastX - PageX, Stroke.LastY - PageY)
		Stroke.LastX, Stroke.LastY = PageX, PageY
		return true
	end
	local X, Y = ToCell(PageX, PageY)
	Hover = { X, Y }
	if (Stroke.Shape) then
		Stroke.X2, Stroke.Y2 = X, Y
		return true
	end
	for _, Point in ipairs(LinePoints(Stroke.LastX, Stroke.LastY, X, Y)) do
		Plot(Point[1], Point[2], Stroke.Color)
	end
	Stroke.LastX, Stroke.LastY = X, Y
	return true
end

local function EndStroke()
	if (Stroke and Stroke.Shape) then
		PushUndo()
		for _, Point in ipairs(ShapePoints(Stroke)) do
			Plot(Point[1], Point[2], Stroke.Color)
		end
		MarkDirty()
	end
	Stroke = nil
	return true
end

-- Text tool: the whole typing run since the click is one undo step.
local function TypeText(Text)
	if (not Caret) then return false end
	if (not Caret.Pushed) then
		PushUndo()
		Caret.Pushed = true
	end
	for Index = 1, #Text do
		if (InBounds(Caret.X, Caret.Y)) then
			Doc.Text[Caret.Y][Caret.X] = Text:sub(Index, Index)
			Doc.Fg[Caret.Y][Caret.X] = Caret.Color
		end
		Caret.X = math.min(Caret.X + 1, Doc.W + 1)
	end
	MarkDirty()
	return true
end

local function CaretKey(Key)
	if (Key == keys.enter or Key == keys.numPadEnter) then
		Caret.X = Caret.StartX
		Caret.Y = math.min(Caret.Y + 1, Doc.H)
	elseif (Key == keys.backspace) then
		if (Caret.X <= 1) then return true end
		Caret.X = Caret.X - 1
		TypeText(" ")
		Caret.X = Caret.X - 1
	elseif (Key == keys.left or Key == keys.right) then
		Caret.X = math.max(1, math.min(Doc.W, Caret.X + ((Key == keys.left) and -1 or 1)))
	elseif (Key == keys.up or Key == keys.down) then
		Caret.Y = math.max(1, math.min(Doc.H, Caret.Y + ((Key == keys.up) and -1 or 1)))
	else
		return false
	end
	return true
end

local function CanvasKey(Key)
	if (Ui.Modifiers.Ctrl) then return false end
	if (Caret) then return CaretKey(Key) end
	local Step = Ui.Modifiers.Shift and 8 or 1
	if (Key == keys.left) then
		Pan(-Step, 0)
	elseif (Key == keys.right) then
		Pan(Step, 0)
	elseif (Key == keys.up) then
		Pan(0, -Step)
	elseif (Key == keys.down) then
		Pan(0, Step)
	else
		return false
	end
	return true
end

local function DrawCanvas(Self, T, Th)
	Gfx.Fill(T, Self.X, Self.Y, Self.W, Self.H, Th.Panel, Th.SubText, "\127")
	local OriginX, OriginY = Origin()
	local First = math.max(1, Self.X - OriginX + 1)
	local Last = math.min(Doc.W, Self.X + Self.W - OriginX)
	if (First > Last) then return end
	for Y = math.max(1, Self.Y - OriginY + 1), math.min(Doc.H, Self.Y + Self.H - OriginY) do
		T.setCursorPos(OriginX + First - 1, OriginY + Y - 1)
		T.blit(
			table.concat(Doc.Text[Y], "", First, Last),
			table.concat(Doc.Fg[Y], "", First, Last),
			table.concat(Doc.Bg[Y], "", First, Last)
		)
	end
	if (Stroke and Stroke.Shape) then
		for _, Point in ipairs(ShapePoints(Stroke)) do
			local X, Y = Point[1], Point[2]
			local ScreenX, ScreenY = OriginX + X - 1, OriginY + Y - 1
			if (InBounds(X, Y) and Ui.Inside(Self, ScreenX, ScreenY)) then
				T.setCursorPos(ScreenX, ScreenY)
				T.blit(Inked(X, Y, Stroke.Color))
			end
		end
	end
end

local function CaretPos(Self)
	if (not Caret) then return nil end
	local OriginX, OriginY = Origin()
	local X, Y = OriginX + Caret.X - 1, OriginY + Caret.Y - 1
	if (not Ui.Inside(Self, X, Y)) then return nil end
	local Under = InBounds(Caret.X, Caret.Y) and Doc.Bg[Caret.Y][Caret.X] or Doc.Base
	local Color = Caret.Color
	if (Color == Under) then Color = Light[Under] and "f" or "0" end
	return X, Y, 2 ^ tonumber(Color, 16)
end

--
-- Files
--

local function ParseSize(Answer)
	if (not Answer) then return nil end
	local W, H = Answer:match("^%s*(%d+)%s*[xX*, ]%s*(%d+)%s*$")
	W, H = tonumber(W), tonumber(H)
	if (not W or W < 1 or H < 1 or W > MaxSide or H > MaxSide) then
		Ui.Alert("Canvas Size", "Enter a size like 51x19, up to " .. MaxSide .. " on each side.")
		return nil
	end
	return W, H
end

local function DefaultSize()
	if (BlockOS.ScreenSize) then return BlockOS.ScreenSize() end
	return term.getSize()
end

local function BlankDoc(W, H, Base)
	return FromImage(Image.new(W, H, Base))
end

local function SaveTo(Path)
	if (Path:lower():match("%.nfp$") and HasCharacters()) then
		if (not Ui.Confirm("Save as .nfp", ".nfp pictures only keep colours, so characters will be lost.", "Save")) then return false end
	end
	if (not Image.Save(Path, ToImage(), DisplayName())) then
		Ui.Alert("Save Failed", "Could not write " .. Path)
		return false
	end
	Doc.Path = Path
	Doc.Dirty = false
	UpdateTitle()
	local Settings = Config.Settings()
	if (Settings.Wallpaper == "picture" and Settings.WallpaperImage == Path) then
		Wallpaper.Invalidate()
		os.queueEvent("blockos_settings")
	end
	return true
end

local function SaveAs()
	if (not fs.exists(Folder)) then fs.makeDir(Folder) end
	local Path = Ui.PickFile({
		Title = "Save Picture", Save = true,
		Dir = Doc.Path and fs.getDir(Doc.Path) or Folder,
		Name = Doc.Path and fs.getName(Doc.Path) or "Untitled.bimg"
	})
	if (not Path) then return false end
	if (not Image.IsImage(Path)) then Path = Path .. ".bimg" end
	if (fs.isDir(Path) or fs.isReadOnly(Path)) then
		Ui.Alert("Save Picture", "Can't save to " .. Path)
		return false
	end
	if (fs.exists(Path) and Path ~= Doc.Path) then
		if (not Ui.Confirm("Replace", "\"" .. fs.getName(Path) .. "\" already exists. Replace it?", "Replace")) then return false end
	end
	return SaveTo(Path)
end

local function Save()
	if (Doc.Path) then return SaveTo(Doc.Path) end
	return SaveAs()
end

-- Returns true when it is fine to throw the current picture away.
local function ConfirmDiscard()
	if (not Doc.Dirty) then return true end
	local Choice = Ui.Alert("Unsaved Changes", "Save changes to \"" .. DisplayName() .. "\"?", { "Cancel", "Don't Save", "Save" })
	if (Choice == 3) then return Save() end
	return Choice == 2
end

local function OpenPath(Path)
	local Img, Err = Image.Load(Path)
	if (not Img) then
		Ui.Alert("Open Picture", fs.getName(Path) .. ": " .. tostring(Err))
		return false
	end
	SetDoc(FromImage(Img), Path)
	return true
end

local function OpenPicture()
	if (not ConfirmDiscard()) then return end
	local Path = Ui.PickFile({ Title = "Open Picture", Dir = fs.exists(Folder) and Folder or "home" })
	if (Path) then OpenPath(Path) end
end

local function NewPicture()
	if (not ConfirmDiscard()) then return end
	local ScreenW, ScreenH = DefaultSize()
	local W, H = ParseSize(Ui.Prompt("New Picture", "Width x height. The background uses your right-click colour.", ScreenW .. "x" .. ScreenH))
	if (not W) then return end
	local NewDoc = BlankDoc(W, H, State.Secondary)
	SetDoc(NewDoc, nil)
end

local function ResizeCanvas()
	local W, H = ParseSize(Ui.Prompt("Canvas Size", "Width x height. New space uses the background colour.", Doc.W .. "x" .. Doc.H))
	if (not W) then return end
	PushUndo()
	local Resized = BlankDoc(W, H, Doc.Base)
	for Y = 1, math.min(H, Doc.H) do
		for X = 1, math.min(W, Doc.W) do
			Resized.Text[Y][X], Resized.Fg[Y][X], Resized.Bg[Y][X] = Doc.Text[Y][X], Doc.Fg[Y][X], Doc.Bg[Y][X]
		end
	end
	Resized.Path, Resized.Base = Doc.Path, Doc.Base
	Doc = Resized
	Caret = nil
	ClampScroll()
	MarkDirty()
end

local function ClearCanvas()
	PushUndo()
	local Path, Base = Doc.Path, Doc.Base
	Doc = BlankDoc(Doc.W, Doc.H, Base)
	Doc.Path = Path
	Caret = nil
	MarkDirty()
end

local function SetAsWallpaper()
	if ((Doc.Dirty or not Doc.Path) and not Save()) then return end
	local Settings = Config.Settings()
	Settings.Wallpaper = "picture"
	Settings.WallpaperImage = Doc.Path
	Wallpaper.Invalidate()
	Config.Save("settings")
	BlockOS.Notify("Brocreate", "Wallpaper set to " .. DisplayName())
end

local function ChooseChar()
	local Code = Ui.PickChar("Character", State.Char:byte())
	if (Code) then
		State.Char = string.char(Code)
		State.Ink = "char"
	end
end

--
-- Layout
--

local function FileMenu(Self)
	local Options = { "New...", "Open...", "Save", "Save As...", "-", "Set as Wallpaper", "-", "Canvas Size..." }
	local Choice = Options[Ui.ContextMenu(Self.X, Self.Y + 1, Options) or 0]
	if (Choice == "New...") then
		NewPicture()
	elseif (Choice == "Open...") then
		OpenPicture()
	elseif (Choice == "Save") then
		Save()
	elseif (Choice == "Save As...") then
		SaveAs()
	elseif (Choice == "Set as Wallpaper") then
		SetAsWallpaper()
	elseif (Choice == "Canvas Size...") then
		ResizeCanvas()
	end
	Page:Invalidate()
end

local function EditMenu(Self)
	local Options = {
		{ Text = "Undo", Disabled = #Undo == 0 },
		{ Text = "Redo", Disabled = #Redo == 0 },
		"-",
		{ Text = State.Filled and "Shapes: Filled" or "Shapes: Outline" },
		{ Text = "Choose Character..." },
		"-",
		{ Text = "Clear Canvas" }
	}
	local Index = Ui.ContextMenu(Self.X, Self.Y + 1, Options)
	local Choice = Index and Options[Index].Text
	if (Choice == "Undo") then
		DoUndo()
	elseif (Choice == "Redo") then
		DoRedo()
	elseif (Choice == "Shapes: Filled" or Choice == "Shapes: Outline") then
		State.Filled = not State.Filled
	elseif (Choice == "Choose Character...") then
		ChooseChar()
	elseif (Choice == "Clear Canvas") then
		ClearCanvas()
	end
	Page:Invalidate()
end

local function ToolColors(Self, Th)
	if (State.Tool == Self.Tool) then return Th.Accent, Th.AccentFg end
	return Th.Panel, Th.Text
end

local function InkColors(Self, Th)
	if (State.Ink == Self.Ink) then return Th.Accent, Th.AccentFg end
	return Th.ButtonBg, Th.ButtonFg
end

local function StatusText()
	local Size = Doc.W .. "x" .. Doc.H
	if (Caret) then return "Typing \7 " .. Size end
	if (Hover and InBounds(Hover[1], Hover[2])) then
		return Hover[1] .. "," .. Hover[2] .. " \7 " .. Size
	end
	return Size
end

local function DrawPalette(Self, T, Th)
	Gfx.Fill(T, Self.X, Self.Y, Self.W, 1, Th.Panel)
	local Swatch = Layout.Swatch
	for Index = 0, 15 do
		local Hex = string.format("%x", Index)
		local Marks = (Hex == State.Primary and "L" or " ") .. (Hex == State.Secondary and "R" or " ")
		if (Swatch == 1) then
			Marks = (Hex == State.Primary and "L") or (Hex == State.Secondary and "R") or " "
		end
		T.setCursorPos(Self.X + Index * Swatch, Self.Y)
		T.blit(Marks, string.rep(Light[Hex] and "f" or "0", Swatch), string.rep(Hex, Swatch))
	end
end

local function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Layout.CX, Layout.CY = 1, 2
	Layout.CW, Layout.CH = W, math.max(1, H - 3)
	Layout.Swatch = (W >= 34) and 2 or 1
	ClampScroll()

	Page:Add(Ui.Panel.new({ X = 1, Y = 1, W = W, H = 1 }))
	Page:Add(Ui.Button.new({ X = 1, Y = 1, Text = " File ", Style = "plain", Bg = "Panel", Fg = "Text", KeepFocus = true, OnClick = FileMenu }))
	Page:Add(Ui.Button.new({ X = 7, Y = 1, Text = " Edit ", Style = "plain", Bg = "Panel", Fg = "Text", KeepFocus = true, OnClick = EditMenu }))
	local ToolsW = 0
	for _, Tool in ipairs(Tools) do
		ToolsW = ToolsW + #Tool.Label + 1
	end
	local Wide = 13 + ToolsW <= W
	local X = 14
	for _, Tool in ipairs(Tools) do
		local Label = " " .. (Wide and Tool.Label or Tool.Short)
		local Button = Page:Add(Ui.Button.new({
			X = X, Y = 1, W = #Label, Text = Label, Tool = Tool.ID, KeepFocus = true,
			OnClick = function(Self)
				State.Tool = Self.Tool
				Caret, Stroke = nil, nil
			end
		}))
		Button.Colors = ToolColors
		X = X + #Label
	end

	CanvasWidget = Page:Add(Ui.Canvas.new({
		X = Layout.CX, Y = Layout.CY, W = Layout.CW, H = Layout.CH, Focusable = true, KeepFocus = true,
		OnDraw = DrawCanvas,
		OnCursor = CaretPos,
		OnEvent = function(Self, Name, A, B, C)
			if (Name == "mouse_click") then
				return BeginStroke(A, B, C)
			elseif (Name == "mouse_drag") then
				return ContinueStroke(B, C)
			elseif (Name == "mouse_up") then
				return EndStroke()
			elseif (Name == "mouse_scroll") then
				if (Ui.Modifiers.Shift) then
					Pan(A * 2, 0)
				else
					Pan(0, A)
				end
				return true
			elseif (Name == "char") then
				if (Caret) then return TypeText(A) end
				if (State.Ink == "char" and State.Tool ~= "text") then
					State.Char = A
					return true
				end
				return false
			elseif (Name == "paste") then
				return TypeText((A:gsub("[\r\n]", " ")))
			elseif (Name == "key") then
				return CanvasKey(A)
			end
			return false
		end
	}))

	Page:Add(Ui.Canvas.new({
		X = 1, Y = H - 1, W = W, H = 1, KeepFocus = true,
		OnDraw = DrawPalette,
		OnEvent = function(Self, Name, A, B)
			if (Name ~= "mouse_click") then return false end
			local Index = math.floor((B - Self.X) / Layout.Swatch)
			if (Index < 0 or Index > 15) then return true end
			if (A == 2) then
				State.Secondary = string.format("%x", Index)
			else
				State.Primary = string.format("%x", Index)
			end
			return true
		end
	}))

	Page:Add(Ui.Panel.new({ X = 1, Y = H, W = W, H = 1 }))
	local SolidButton = Page:Add(Ui.Button.new({
		X = 1, Y = H, Text = " Solid ", Ink = "solid", KeepFocus = true,
		OnClick = function()
			State.Ink = "solid"
		end
	}))
	SolidButton.Colors = InkColors
	local CharButton = Page:Add(Ui.Button.new({
		X = 9, Y = H, W = 8, Ink = "char", KeepFocus = true,
		Text = function()
			return " Char " .. State.Char .. " "
		end,
		OnClick = function(_, Button)
			if (State.Ink == "char" or Button == 2) then
				ChooseChar()
			end
			State.Ink = "char"
		end
	}))
	CharButton.Colors = InkColors
	if (W >= 20) then
		Page:Add(Ui.Label.new({ X = 18, Y = H, W = W - 18, Align = "right", Fg = "SubText", Bg = "Panel", Text = StatusText }))
	end

	Page:SetFocus(CanvasWidget)
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_close") then
		if (ConfirmDiscard()) then self:Stop() end
		return true
	elseif (Name == "key" and Ui.Modifiers.Ctrl) then
		if (A == keys.s) then
			Save()
		elseif (A == keys.o) then
			OpenPicture()
		elseif (A == keys.n) then
			NewPicture()
		elseif (A == keys.z) then
			DoUndo()
		elseif (A == keys.y) then
			DoRedo()
		else
			return false
		end
		return true
	end
	return false
end

function Page:OnTerminate()
	if (ConfirmDiscard()) then self:Stop() end
end

BlockOS.SetCloseHandler(true)
local Target = Args[1] and (shell and shell.resolve(Args[1]) or Args[1])
if (Target and not Target:find("^/")) then Target = "/" .. Target end
local ScreenW, ScreenH = DefaultSize()
SetDoc(BlankDoc(ScreenW, ScreenH, State.Secondary), nil)
if (Target and fs.exists(Target) and not fs.isDir(Target)) then
	OpenPath(Target)
end
Page:Run()
]]
Files["blockos/apps/btunes/app.cfg"] = [[
{ Name = "bTunes", Description = "Play YouTube, DFPWM links and music files through your speakers.", Width = 40, Height = 14, Single = true, Icon = { Lines = { " \14 ", "\140\140\140" }, Fg = "white", Bg = "red" } }
]]
Files["blockos/apps/btunes/main.lua"] = [[
-- bTunes: plays YouTube, DFPWM links and files on disk through every attached speaker.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")

local Dfpwm = require("cc.audio.dfpwm")

local Args = { ... }

local LibraryPath = "/blockos/data/music.dat"
local ChunkSize = 16 * 1024
local BytesPerSecond = 6000
local SampleRate = 48000
-- Community server that converts YouTube audio to DFPWM (the same one Minux and iPod use).
local DefaultServer = "https://ipod-2to6magyna-uc.a.run.app/"
local ApiVersion = "2.1"

local Library = Config.Read(LibraryPath) or { Tracks = {} }
local Page = Ui.Page.new()
local Tab = 1
local Build
local SearchField

local Search = {
	Query = "",
	Results = {},
	State = "idle",
	RequestUrl = nil,
	Error = nil
}
-- Title lookups for pasted YouTube links, keyed by request URL.
local Lookups = {}

local Player = {
	Queue = {},
	Index = 0,
	State = "stopped",
	Volume = 1,
	Shuffle = false,
	Repeat = false,
	Bytes = 0,
	Total = 0,
	-- Decoded chunks with the clock times the speakers play them, newest last.
	Timeline = {},
	AudioEnd = nil,
	Error = nil
}

local Visual = {
	Modes = { "Bars", "Mirror", "Wave" },
	Window = 1024,
	Count = 0,
	Wanted = 16,
	-- FFT tables, built once.
	Hann = {},
	Reverse = {},
	Cos = {},
	Sin = {},
	-- First FFT bin of each band; band N ends where band N + 1 starts.
	Edges = {},
	Bands = {},
	Peaks = {},
	Wave = nil
}

local function Speakers()
	local List = {}
	for _, Name in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Name) == "speaker") then
			table.insert(List, { Name = Name, Device = peripheral.wrap(Name) })
		end
	end
	return List
end

local function SaveLibrary()
	Config.Write(LibraryPath, Library)
end

local function Server()
	local Url = Library.Server or DefaultServer
	if (Url:sub(-1) ~= "/") then Url = Url .. "/" end
	return Url
end

local function StreamUrl(ID)
	return Server() .. "?v=" .. ApiVersion .. "&id=" .. textutils.urlEncode(ID)
end

local function SearchUrl(Query)
	return Server() .. "?v=" .. ApiVersion .. "&search=" .. textutils.urlEncode(Query)
end

-- Returns the video ID of a YouTube link, or nil for anything else.
local function YouTubeID(Link)
	if (not Link:match("youtube%.com") and not Link:match("youtu%.be")) then return nil end
	return Link:match("youtu%.be/([%w_%-]+)") or Link:match("[?&]v=([%w_%-]+)") or Link:match("/shorts/([%w_%-]+)") or Link:match("/live/([%w_%-]+)")
end

local function IsYouTubePlaylist(Link)
	return (Link:match("youtube%.com") and Link:match("[?&]list=") and not YouTubeID(Link)) and true or false
end

local function FormatTime(Seconds)
	Seconds = math.max(0, math.floor(Seconds))
	return string.format("%d:%02d", math.floor(Seconds / 60), Seconds % 60)
end

local function CloseHandle()
	if (Player.Handle) then
		pcall(Player.Handle.close)
		Player.Handle = nil
	end
end

local function Stop()
	Player.State = "stopped"
	Player.Buffer = nil
	Player.Pending = nil
	Player.RequestUrl = nil
	Player.Timeline = {}
	Player.AudioEnd = nil
	CloseHandle()
	for _, Speaker in ipairs(Speakers()) do
		pcall(Speaker.Device.stop)
	end
end

local Play

local function TrackEnded()
	CloseHandle()
	Player.Buffer = nil
	local Next = Player.Index + 1
	if (Player.Shuffle and #Player.Queue > 1) then
		repeat
			Next = math.random(1, #Player.Queue)
		until Next ~= Player.Index
	end
	if (Next > #Player.Queue) then
		if (not Player.Repeat) then
			Player.State = "stopped"
			return
		end
		Next = 1
	end
	Play(Next)
end

-- Remembers when a chunk the speakers just accepted will be heard, so the visualizer follows the sound.
local function Schedule(Samples)
	local Start = math.max(os.clock(), Player.AudioEnd or 0)
	Player.AudioEnd = Start + #Samples / SampleRate
	table.insert(Player.Timeline, { Samples = Samples, Start = Start, End = Player.AudioEnd })
	while (#Player.Timeline > 3) do
		table.remove(Player.Timeline, 1)
	end
end

-- Pushes decoded audio to speakers until one of them is full.
local function Feed()
	while (Player.State == "playing") do
		if (not Player.Buffer) then
			local Chunk = Player.Handle and Player.Handle.read(ChunkSize)
			if (not Chunk or #Chunk == 0) then
				TrackEnded()
				return
			end
			Player.Bytes = Player.Bytes + #Chunk
			Player.Buffer = Player.Decoder(Chunk)
			Player.Pending = {}
			for _, Speaker in ipairs(Speakers()) do
				Player.Pending[Speaker.Name] = Speaker.Device
			end
			if (next(Player.Pending) == nil) then
				Player.Error = "No speaker attached"
				Stop()
				return
			end
		end
		for Name, Device in pairs(Player.Pending) do
			if (Device.playAudio(Player.Buffer, Player.Volume)) then
				Player.Pending[Name] = nil
			end
		end
		if (next(Player.Pending) ~= nil) then return end
		Schedule(Player.Buffer)
		Player.Buffer = nil
	end
end

local function StartStream(Handle, Total)
	Player.Handle = Handle
	Player.Total = Total or 0
	Player.Bytes = 0
	Player.Decoder = Dfpwm.make_decoder()
	Player.State = "playing"
	Player.Error = nil
	Feed()
end

function Play(Index)
	Stop()
	local Track = Player.Queue[Index]
	if (not Track) then return end
	Player.Index = Index
	Player.Error = nil
	BlockOS.SetTitle("bTunes \7 " .. Track.Name)
	if (Track.Path) then
		local Handle = fs.open(Track.Path, "rb")
		if (not Handle) then
			Player.Error = "Cannot open " .. Track.Path
			return
		end
		StartStream(Handle, fs.getSize(Track.Path))
		return
	end
	if (not http) then
		Player.Error = "HTTP is disabled"
		return
	end
	local Url = Track.ID and StreamUrl(Track.ID) or Track.Url
	Player.State = "loading"
	Player.RequestUrl = Url
	http.request({ url = Url, binary = true })
end

local function PlayList(Tracks, Start)
	Player.Queue = Tracks
	Play(Start or 1)
end

local function TogglePause()
	if (Player.State == "playing") then
		Player.State = "paused"
	elseif (Player.State == "paused") then
		Player.State = "playing"
		Feed()
	elseif (Player.State == "stopped" and #Player.Queue > 0) then
		Play(math.max(1, Player.Index))
	end
end

local function Previous()
	if (#Player.Queue == 0) then return end
	if (Player.Bytes > BytesPerSecond * 3) then
		Play(Player.Index)
	else
		Play(math.max(1, Player.Index - 1))
	end
end

local function ResultTrack(Item)
	return { Name = tostring(Item.name or "Untitled"), Artist = Item.artist and tostring(Item.artist) or nil, ID = tostring(Item.id) }
end

local function RunSearch(Query)
	Query = (Query or ""):gsub("^%s+", ""):gsub("%s+$", "")
	if (#Query == 0) then return end
	if (not http) then
		Search.Error = "HTTP is disabled"
		Build()
		return
	end
	Search.Query = Query
	Search.Results = {}
	Search.Error = nil
	Search.State = "searching"
	Search.RequestUrl = SearchUrl(Query)
	http.request(Search.RequestUrl)
	Build()
end

local function SearchDone(Handle)
	local Body = Handle.readAll()
	pcall(Handle.close)
	Search.State = "idle"
	local Parsed, Results = pcall(textutils.unserialiseJSON, Body or "")
	if (not Parsed or type(Results) ~= "table") then
		Search.Error = "The YouTube server sent an unexpected reply"
		return
	end
	Search.Results = {}
	for _, Item in ipairs(Results) do
		if (type(Item) == "table" and Item.id) then
			local Entry = { Name = tostring(Item.name or "Untitled"), Artist = Item.artist and tostring(Item.artist) or nil }
			if (Item.type == "playlist" and type(Item.playlist_items) == "table") then
				Entry.Tracks = {}
				for _, Song in ipairs(Item.playlist_items) do
					if (type(Song) == "table" and Song.id) then table.insert(Entry.Tracks, ResultTrack(Song)) end
				end
			else
				Entry.ID = tostring(Item.id)
			end
			table.insert(Search.Results, Entry)
		end
	end
	if (#Search.Results == 0) then Search.Error = "No results for \"" .. Search.Query .. "\"" end
end

-- Asks the server for the real title of a pasted YouTube link.
local function LookupTitle(Track)
	if (not http) then return end
	local Url = SearchUrl("https://youtu.be/" .. Track.ID)
	Lookups[Url] = Track
	http.request(Url)
end

local function LookupDone(Track, Handle)
	local Body = Handle.readAll()
	pcall(Handle.close)
	local Parsed, Results = pcall(textutils.unserialiseJSON, Body or "")
	if (not Parsed or type(Results) ~= "table" or type(Results[1]) ~= "table") then return end
	local Match = Results[1]
	for _, Item in ipairs(Results) do
		if (type(Item) == "table" and tostring(Item.id) == Track.ID) then Match = Item end
	end
	if (not Match.name) then return end
	Track.Name = tostring(Match.name)
	Track.Artist = Match.artist and tostring(Match.artist) or nil
	SaveLibrary()
end

-- The tracks a search result stands for: one song, or every song of a playlist.
local function ResultTracks(Entry)
	if (Entry.Tracks) then return Entry.Tracks end
	return { { Name = Entry.Name, Artist = Entry.Artist, ID = Entry.ID } }
end

local function LocalFiles()
	local Files = {}
	local Folders = { "/home/Music", "/home/Downloads" }
	for _, Name in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Name) == "drive" and disk.hasData(Name)) then
			table.insert(Folders, "/" .. disk.getMountPath(Name))
		end
	end
	for _, Folder in ipairs(Folders) do
		if (fs.isDir(Folder)) then
			for _, Name in ipairs(fs.list(Folder)) do
				if (Name:lower():match("%.dfpwm$")) then
					table.insert(Files, { Name = Name:gsub("%.[Dd][Ff][Pp][Ww][Mm]$", ""), Path = fs.combine(Folder, Name), Where = Folder })
				end
			end
		end
	end
	return Files
end

local function TrackList(Y, H, Tracks, Removable)
	local Items = {}
	for Index, Track in ipairs(Tracks) do
		local Playing = Player.Queue[Player.Index] == Track and Player.State ~= "stopped"
		local Source = Track.Path and "disk" or (Track.ID and "yt" or "web")
		table.insert(Items, { Text = Track.Name, Icon = Playing and "\16" or "\14", IconFg = Playing and "Accent" or "SubText", Right = Source, Index = Index })
	end
	local List = Page:Add(Ui.List.new({ X = 1, Y = Y, W = Page.W, H = H, Items = Items }))
	List.OnActivate = function(_, Index) PlayList(Tracks, Index) end
	List.OnContext = function(_, Index, Item, X, CY)
		if (not Item) then return end
		local Options = { "Play", "Play Next" }
		if (Removable) then
			table.insert(Options, "Rename")
			table.insert(Options, "Remove")
		end
		local Choice = Options[Ui.ContextMenu(X, CY, Options) or 0]
		if (Choice == "Play") then
			PlayList(Tracks, Index)
		elseif (Choice == "Play Next") then
			table.insert(Player.Queue, math.min(#Player.Queue + 1, Player.Index + 1), Tracks[Index])
		elseif (Choice == "Rename") then
			local Name = Ui.Prompt("Rename", "Track name:", Tracks[Index].Name)
			if (Name and #Name > 0) then
				Tracks[Index].Name = Name
				SaveLibrary()
				Build()
			end
		elseif (Choice == "Remove") then
			table.remove(Tracks, Index)
			SaveLibrary()
			Build()
		end
	end
	if (#Items == 0) then
		Page:Add(Ui.Label.new({ X = 2, Y = Y + 1, W = Page.W - 2, H = 2, Fg = "SubText",
			Text = Removable and "Your library is empty. Find songs in Search or add a link in Add." or "No .dfpwm files in Music, Downloads or disks." }))
	end
end

local function BuildSearch(Y, H)
	local W = Page.W
	SearchField = Page:Add(Ui.Input.new({ X = 1, Y = Y, W = W - 9, Placeholder = "Search YouTube or paste a link" }))
	SearchField:SetValue(Search.Query)
	SearchField.OnSubmit = function(_, Value) RunSearch(Value) end
	Page:Add(Ui.Button.new({ X = W - 8, Y = Y, W = 9, Text = "Search", Style = "primary", OnClick = function() RunSearch(SearchField.Value) end }))
	local Items = {}
	for Index, Entry in ipairs(Search.Results) do
		local Text = Entry.Name
		if (Entry.Artist and #Entry.Artist > 0) then Text = Text .. " \7 " .. Entry.Artist end
		table.insert(Items, { Text = Text, Icon = Entry.Tracks and "\19" or "\14", IconFg = "SubText", Right = Entry.Tracks and (#Entry.Tracks .. " songs") or "yt", Index = Index })
	end
	local List = Page:Add(Ui.List.new({ X = 1, Y = Y + 1, W = W, H = H - 1, Items = Items }))
	List.OnActivate = function(_, Index)
		local Entry = Search.Results[Index]
		if (not Entry) then return end
		if (Entry.Tracks) then
			PlayList(Entry.Tracks, 1)
			return
		end
		-- Queue the other songs too so next/previous keep working.
		local Queue = {}
		local Start = 1
		for Other, Result in ipairs(Search.Results) do
			if (Result.ID) then
				table.insert(Queue, ResultTracks(Result)[1])
				if (Other == Index) then Start = #Queue end
			end
		end
		PlayList(Queue, Start)
	end
	List.OnContext = function(_, Index, Item, X, CY)
		if (not Item) then return end
		local Entry = Search.Results[Index]
		local Options = { "Play", "Play Next", "Add to Library" }
		local Choice = Options[Ui.ContextMenu(X, CY, Options) or 0]
		if (Choice == "Play") then
			PlayList(ResultTracks(Entry), 1)
		elseif (Choice == "Play Next") then
			for Offset, Track in ipairs(ResultTracks(Entry)) do
				table.insert(Player.Queue, math.min(#Player.Queue + 1, Player.Index + Offset), Track)
			end
		elseif (Choice == "Add to Library") then
			for _, Track in ipairs(ResultTracks(Entry)) do
				table.insert(Library.Tracks, Track)
			end
			SaveLibrary()
			BlockOS.Notify("bTunes", "Added " .. Entry.Name .. " to your library")
		end
	end
	local Message = Search.Error
	if (Search.State == "searching") then
		Message = "Searching..."
	elseif (#Items == 0 and not Message) then
		Message = "Type a song, artist or YouTube link and press Enter."
	end
	if (Message) then
		Page:Add(Ui.Label.new({ X = 2, Y = Y + 2, W = W - 2, H = 2, Fg = "SubText", Text = Message }))
	end
	Page:SetFocus(SearchField)
end

local function NowPlaying(Y)
	local W = Page.W
	Page:Add(Ui.Canvas.new({
		X = 1, Y = Y, W = W, H = 3,
		OnDraw = function(Self, T, Th)
			Gfx.Fill(T, Self.X, Self.Y, Self.W, 3, Th.Panel)
			local Track = Player.Queue[Player.Index]
			local Title = Track and Track.Name or "Not playing"
			if (Player.State == "loading") then Title = "Loading " .. Title .. "..." end
			if (Player.Error) then Title = Player.Error end
			Gfx.Write(T, Self.X + 1, Self.Y, Gfx.Truncate(Title, Self.W - 2), Player.Error and colors.red or Th.PanelFg, Th.Panel)
			local Elapsed = Player.Bytes / BytesPerSecond
			local Total = Player.Total / BytesPerSecond
			local Times = FormatTime(Elapsed) .. "/" .. (Total > 0 and FormatTime(Total) or "--:--")
			local BarW = Self.W - #Times - 3
			local Filled = (Total > 0) and math.floor(BarW * math.min(1, Elapsed / Total)) or 0
			Gfx.Fill(T, Self.X + 1, Self.Y + 1, BarW, 1, Th.Border)
			Gfx.Fill(T, Self.X + 1, Self.Y + 1, Filled, 1, Th.Accent)
			Gfx.Write(T, Self.X + BarW + 2, Self.Y + 1, Times, Th.SubText, Th.Panel)
		end
	}))
	local Controls = {
		{ Text = "\171", Action = Previous },
		{ Text = function() return (Player.State == "playing") and "\149\149" or "\16" end, Action = TogglePause },
		{ Text = "\187", Action = function() if (#Player.Queue > 0) then TrackEnded() end end },
		{ Text = "\143", Action = Stop }
	}
	local X = 2
	for _, Control in ipairs(Controls) do
		Page:Add(Ui.Button.new({ X = X, Y = Y + 2, W = 4, Text = Control.Text, Bg = "Panel", OnClick = Control.Action }))
		X = X + 4
	end
	Page:Add(Ui.Button.new({ X = X + 1, Y = Y + 2, W = 3, Text = function() return Player.Shuffle and "S*" or "S" end, Bg = "Panel", OnClick = function() Player.Shuffle = not Player.Shuffle end }))
	Page:Add(Ui.Button.new({ X = X + 4, Y = Y + 2, W = 3, Text = function() return Player.Repeat and "R*" or "R" end, Bg = "Panel", OnClick = function() Player.Repeat = not Player.Repeat end }))
	local VolumeX = W - 12
	if (VolumeX > X + 8) then
		Page:Add(Ui.Button.new({ X = VolumeX, Y = Y + 2, W = 2, Text = "-", Bg = "Panel", OnClick = function() Player.Volume = math.max(0, Player.Volume - .25) end }))
		Page:Add(Ui.Canvas.new({
			X = VolumeX + 2, Y = Y + 2, W = 6, H = 1,
			OnDraw = function(Self, T, Th)
				local Filled = math.floor(Player.Volume / 3 * Self.W + .5)
				Gfx.Fill(T, Self.X, Self.Y, Self.W, 1, Th.Border)
				Gfx.Fill(T, Self.X, Self.Y, Filled, 1, Th.Accent)
			end
		}))
		Page:Add(Ui.Button.new({ X = VolumeX + 8, Y = Y + 2, W = 2, Text = "+", Bg = "Panel", OnClick = function() Player.Volume = math.min(3, Player.Volume + .25) end }))
	end
end

--
-- Visualizer
--

local function BuildTables()
	local N = Visual.Window
	local Bits = math.floor(math.log(N, 2) + .5)
	for Index = 0, N - 1 do
		local Reversed, Value = 0, Index
		for _ = 1, Bits do
			Reversed = Reversed * 2 + Value % 2
			Value = math.floor(Value / 2)
		end
		Visual.Reverse[Index + 1] = Reversed + 1
		Visual.Hann[Index + 1] = .5 - .5 * math.cos(2 * math.pi * Index / (N - 1))
	end
	for Index = 0, N / 2 - 1 do
		Visual.Cos[Index + 1] = math.cos(2 * math.pi * Index / N)
		Visual.Sin[Index + 1] = -math.sin(2 * math.pi * Index / N)
	end
end

-- Splits roughly 50 Hz to 12 kHz into Count bands spaced evenly in pitch, each at least one bin wide.
local function BuildBands(Count)
	if (#Visual.Reverse == 0) then BuildTables() end
	Visual.Count = Count
	local MaxBin = math.floor(12000 * Visual.Window / SampleRate)
	Visual.Edges = { 1 }
	for Band = 1, Count do
		Visual.Edges[Band + 1] = math.max(Visual.Edges[Band] + 1, math.floor(MaxBin ^ (Band / Count) + .5))
	end
	Visual.Bands, Visual.Peaks = {}, {}
end

-- The samples the speakers are playing right now and where they start.
local function Audible()
	local Now = os.clock()
	for _, Chunk in ipairs(Player.Timeline) do
		if (Now >= Chunk.Start and Now < Chunk.End) then
			local Offset = math.floor((Now - Chunk.Start) * SampleRate) + 1
			return Chunk.Samples, math.max(1, math.min(Offset, #Chunk.Samples - Visual.Window + 1))
		end
	end
	return nil
end

-- Power of each FFT bin (0 is DC) for a Hann-windowed slice of the audio.
local function Spectrum(Samples, Offset)
	local N = Visual.Window
	local Re, Im = {}, {}
	for Index = 1, N do
		local Target = Visual.Reverse[Index]
		Re[Target] = (Samples[Offset + Index - 1] or 0) * Visual.Hann[Index]
		Im[Target] = 0
	end
	local Size = 2
	while (Size <= N) do
		local Half = Size / 2
		local Step = N / Size
		for Start = 1, N, Size do
			for K = 0, Half - 1 do
				local Cos, Sin = Visual.Cos[K * Step + 1], Visual.Sin[K * Step + 1]
				local A, B = Start + K, Start + K + Half
				local TRe = Re[B] * Cos - Im[B] * Sin
				local TIm = Re[B] * Sin + Im[B] * Cos
				Re[B], Im[B] = Re[A] - TRe, Im[A] - TIm
				Re[A], Im[A] = Re[A] + TRe, Im[A] + TIm
			end
		end
		Size = Size * 2
	end
	local Power = {}
	for Bin = 0, N / 2 - 1 do
		Power[Bin] = Re[Bin + 1] * Re[Bin + 1] + Im[Bin + 1] * Im[Bin + 1]
	end
	return Power
end

-- Loudness of one band from 0 to 1 over a 54 dB range, from its loudest bin.
local function BandLevel(Power, Band)
	local Loudest = 0
	for Bin = Visual.Edges[Band], Visual.Edges[Band + 1] - 1 do
		if ((Power[Bin] or 0) > Loudest) then Loudest = Power[Bin] end
	end
	-- A full-scale sine through a Hann window peaks at a quarter of the window length.
	local Amplitude = math.sqrt(Loudest) / (Visual.Window / 4)
	local Decibels = 20 * math.log(Amplitude / 128 + 1e-9, 10)
	return math.max(0, math.min(1, (Decibels + 54) / 54))
end

-- Moves every band towards the audio playing now: bars jump up and fall back slowly.
-- Returns false once everything has settled, so idle frames are not redrawn.
local function Analyze()
	if (Visual.Count ~= Visual.Wanted) then BuildBands(Visual.Wanted) end
	local Samples, Offset = Audible()
	if (Player.State ~= "playing" and Player.State ~= "paused") then Samples = nil end
	Visual.Wave = Samples and { Samples = Samples, Offset = Offset } or nil
	local Moving = Samples ~= nil
	local Power = Samples and Spectrum(Samples, Offset)
	for Band = 1, Visual.Count do
		local Target = Power and BandLevel(Power, Band) or 0
		local Current = Visual.Bands[Band] or 0
		Current = (Target > Current) and Target or math.max(Target, Current - .07)
		Visual.Bands[Band] = Current
		local Peak = Visual.Peaks[Band] or 0
		Visual.Peaks[Band] = (Current >= Peak) and Current or math.max(Current, Peak - .025)
		if (Current > 0 or Visual.Peaks[Band] > 0) then Moving = true end
	end
	return Moving
end

-- Teletext characters split a cell into 2x3 pixels; Bits sets them (1, 2 top row, 4, 8 middle, 16, 32 bottom).
-- The sixth bit cannot be drawn directly, so those cells swap colours instead.
local function Pixels(Bits, On, Off)
	if (Bits >= 32) then
		return string.char(128 + 63 - Bits), Off, On
	end
	return string.char(128 + Bits), On, Off
end

-- Thirds of a cell filled from the bottom (Up) or from the top.
local Thirds = {
	Up = { 0, 48, 60, 63 },
	Down = { 0, 3, 15, 63 }
}
-- A single third, counted from the bottom.
local Slices = { 48, 12, 3 }

local function BarColor(Fraction)
	if (Fraction > .88) then return colors.red end
	if (Fraction > .7) then return colors.orange end
	if (Fraction > .45) then return colors.yellow end
	return colors.lime
end

local function DrawBars(T, Th, X, Y, W, H)
	local Count = Visual.Count
	local Bg = Th.WindowBg
	local BarW = math.max(1, math.floor(W / Count) - 1)
	local Left = X + math.floor((W - Count * (BarW + 1) + 1) / 2)
	for Band = 1, Count do
		local Filled = math.floor((Visual.Bands[Band] or 0) * H * 3 + .5)
		local Peak = math.floor((Visual.Peaks[Band] or 0) * H * 3 + .5)
		local Column = Left + (Band - 1) * (BarW + 1)
		for Row = 1, H do
			local Part = math.max(0, math.min(3, Filled - (Row - 1) * 3))
			local Char, Fg, CellBg = Pixels(Thirds.Up[Part + 1], BarColor(Row / H), Bg)
			local PeakRow = math.ceil(Peak / 3)
			if (Part == 0 and Peak > Filled and PeakRow == Row) then
				Char, Fg, CellBg = Pixels(Slices[Peak - (Row - 1) * 3], Th.Text, Bg)
			end
			Gfx.Write(T, Column, Y + H - Row, string.rep(Char, BarW), Fg, CellBg)
		end
	end
end

-- Low notes in the middle spreading outwards, reflected above and below a centre line.
local function DrawMirror(T, Th, X, Y, W, H)
	local Bg = Th.WindowBg
	local Half = math.floor(H / 2)
	local Center = X + math.floor(W / 2)
	for Column = X, X + W - 1 do
		local Band = math.min(Visual.Count, math.floor(math.abs(Column - Center) * Visual.Count / math.max(1, W / 2)) + 1)
		local Level = Visual.Bands[Band] or 0
		local Filled = math.floor(Level * Half * 3 + .5)
		local Color = (Level > .75) and colors.white or ((Level > .45) and colors.lightBlue or Th.Accent)
		for Row = 1, Half do
			local Part = math.max(0, math.min(3, Filled - (Row - 1) * 3))
			local Char, Fg, CellBg = Pixels(Thirds.Up[Part + 1], Color, Bg)
			Gfx.Write(T, Column, Y + Half - Row, Char, Fg, CellBg)
			Char, Fg, CellBg = Pixels(Thirds.Down[Part + 1], Color, Bg)
			Gfx.Write(T, Column, Y + H - Half + Row - 1, Char, Fg, CellBg)
		end
		if (H % 2 == 1) then
			Gfx.Write(T, Column, Y + Half, (Filled > 0) and " " or "\140", Th.Border, (Filled > 0) and Color or Bg)
		end
	end
end

-- An oscilloscope trace of the samples playing now, joined into a line at 2x3 pixels per cell.
local function DrawWave(T, Th, X, Y, W, H)
	local PixelW, PixelH = W * 2, H * 3
	local Lit = {}
	local Wave = Visual.Wave
	local Previous
	for Pixel = 1, PixelW do
		local Value = 0
		if (Wave) then
			Value = Wave.Samples[Wave.Offset + math.floor((Pixel - 1) * Visual.Window / PixelW)] or 0
		end
		local Height = math.max(1, math.min(PixelH, math.floor((.5 - Value / 256) * (PixelH - 1) + 1.5)))
		local From, To = Height, Height
		if (Previous) then
			From, To = math.min(Previous, Height), math.max(Previous, Height)
		end
		for PY = From, To do
			Lit[(PY - 1) * PixelW + Pixel] = true
		end
		Previous = Height
	end
	for Row = 1, H do
		for Column = 1, W do
			local Bits = 0
			for SubY = 0, 2 do
				for SubX = 0, 1 do
					if (Lit[((Row - 1) * 3 + SubY) * PixelW + (Column - 1) * 2 + SubX + 1]) then
						Bits = Bits + 2 ^ (SubY * 2 + SubX)
					end
				end
			end
			local Char, Fg, CellBg = Pixels(Bits, Wave and Th.Accent or Th.Border, Th.WindowBg)
			Gfx.Write(T, X + Column - 1, Y + Row - 1, Char, Fg, CellBg)
		end
	end
end

local Drawers = { DrawBars, DrawMirror, DrawWave }

local function Visualizer(Y, H)
	local Mode = Library.Visual or 1
	Page:Add(Ui.Tabs.new({
		X = 1, Y = Y, W = Page.W, Items = Visual.Modes, Selected = Mode,
		OnChange = function(_, Index)
			Library.Visual = Index
			SaveLibrary()
			Build()
		end
	}))
	Visual.Wanted = math.max(4, math.min(24, math.floor(Page.W / 2)))
	Page:Add(Ui.Canvas.new({
		X = 1, Y = Y + 1, W = Page.W, H = H - 1,
		OnDraw = function(Self, T, Th)
			if (Visual.Count ~= Visual.Wanted) then BuildBands(Visual.Wanted) end
			Drawers[Mode](T, Th, Self.X, Self.Y, Self.W, Self.H)
			if (Player.State == "stopped" or #Speakers() == 0) then
				Gfx.Center(T, Self.Y + math.floor(Self.H / 2) - 1, (#Speakers() == 0) and "Attach a speaker to play music" or "\14 bTunes", Th.SubText, Th.WindowBg, Self.X, Self.W)
			end
		end,
		OnEvent = function(_, Name)
			if (Name ~= "mouse_click") then return false end
			Library.Visual = Mode % #Visual.Modes + 1
			SaveLibrary()
			Build()
			return true
		end
	}))
end

local function BuildAdd(Y)
	local FieldW = Page.W - 9
	Page:Add(Ui.Label.new({ X = 2, Y = Y, Text = "Name" }))
	local Name = Page:Add(Ui.Input.new({ X = 8, Y = Y, W = FieldW, Placeholder = "Track name" }))
	Page:Add(Ui.Label.new({ X = 2, Y = Y + 2, Text = "URL" }))
	local Url = Page:Add(Ui.Input.new({ X = 8, Y = Y + 2, W = FieldW, Placeholder = "YouTube or .dfpwm link" }))
	Page:Add(Ui.Label.new({ X = 2, Y = Y + 4, W = Page.W - 2, H = 2, Fg = "SubText", Text = "Paste a YouTube video or a link to DFPWM audio. Playlists open in Search." }))
	local function Track()
		local Link = Url.Value:gsub("^%s+", ""):gsub("%s+$", "")
		if (not Link:match("^https?://")) then
			Ui.Alert("bTunes", "Enter an http(s) link.")
			return nil
		end
		if (IsYouTubePlaylist(Link)) then
			Tab = 2
			RunSearch(Link)
			return nil
		end
		local ID = YouTubeID(Link)
		if (ID) then
			if (#Name.Value > 0) then return { Name = Name.Value, ID = ID } end
			local Entry = { Name = "YouTube " .. ID, ID = ID }
			LookupTitle(Entry)
			return Entry
		end
		local Title = (#Name.Value > 0) and Name.Value or (Link:match("([^/]+)%.%w+$") or Link)
		return { Name = Title, Url = Link }
	end
	Page:Add(Ui.Button.new({ X = 2, Y = Y + 7, Text = " Play Now ", OnClick = function()
		local Entry = Track()
		if (Entry) then PlayList({ Entry }, 1) end
	end }))
	Page:Add(Ui.Button.new({ X = 14, Y = Y + 7, Text = " Add to Library ", Style = "primary", OnClick = function()
		local Entry = Track()
		if (not Entry) then return end
		table.insert(Library.Tracks, Entry)
		SaveLibrary()
		Name:SetValue("")
		Url:SetValue("")
		Tab = 1
		Build()
	end }))
	Page:Add(Ui.Button.new({ X = math.max(32, Page.W - 8), Y = Y + 7, Text = " Server ", OnClick = function()
		local Value = Ui.Prompt("YouTube Server", "Streaming server URL:", Server())
		if (not Value) then return end
		Value = Value:gsub("^%s+", ""):gsub("%s+$", "")
		Library.Server = (#Value > 0 and Value ~= DefaultServer) and Value or nil
		SaveLibrary()
	end }))
	Page:SetFocus(Url)
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Page:Add(Ui.Tabs.new({
		X = 1, Y = 1, W = W, Items = { "Library", "Search", "Files", "Add", "Visual" }, Selected = Tab,
		OnChange = function(_, Index)
			Tab = Index
			Build()
		end
	}))
	local BodyH = H - 4
	if (Tab == 1) then
		TrackList(2, BodyH, Library.Tracks, true)
	elseif (Tab == 2) then
		BuildSearch(2, BodyH)
	elseif (Tab == 3) then
		local Files = LocalFiles()
		TrackList(2, BodyH - 1, Files, false)
		Page:Add(Ui.Button.new({ X = W - 9, Y = H - 3, W = 9, Text = "Open...", OnClick = function()
			local Path = Ui.PickFile({ Dir = "/home/Music", Extension = ".dfpwm" })
			if (Path) then PlayList({ { Name = fs.getName(Path), Path = Path } }, 1) end
		end }))
	elseif (Tab == 4) then
		BuildAdd(3)
	else
		Visualizer(2, BodyH)
	end
	NowPlaying(H - 2)
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A, B)
	if (Name == "speaker_audio_empty") then
		if (Player.State == "playing") then Feed() end
		return false
	elseif (Name == "http_success" and A == Player.RequestUrl) then
		Player.RequestUrl = nil
		local Headers = B.getResponseHeaders and B.getResponseHeaders() or {}
		StartStream(B, tonumber(Headers["Content-Length"] or Headers["content-length"] or 0))
		return true
	elseif (Name == "http_failure" and A == Player.RequestUrl) then
		Player.RequestUrl = nil
		Player.State = "stopped"
		Player.Error = "Could not load track"
		return true
	elseif ((Name == "http_success" or Name == "http_failure") and Lookups[A]) then
		local Track = Lookups[A]
		Lookups[A] = nil
		if (Name == "http_success") then
			LookupDone(Track, B)
			Build()
		end
		return true
	elseif (Name == "http_success" and A == Search.RequestUrl) then
		Search.RequestUrl = nil
		SearchDone(B)
		if (Tab == 2) then Build() end
		return true
	elseif (Name == "http_failure" and A == Search.RequestUrl) then
		Search.RequestUrl = nil
		Search.State = "idle"
		Search.Error = "Search failed: " .. tostring(B or "no connection")
		if (Tab == 2) then Build() end
		return true
	elseif (Name == "peripheral" or Name == "peripheral_detach" or Name == "disk" or Name == "disk_eject") then
		if (Tab == 3) then Build() end
		return true
	elseif (Name == "blockos_open" and A) then
		PlayList({ { Name = fs.getName(A), Path = A } }, 1)
		return true
	elseif (Name == "key" and A == keys.space and not (Page.Focus and Page.Focus.Value)) then
		TogglePause()
		return true
	end
	return false
end

function Page:OnTerminate()
	Stop()
	self:Stop()
end

Page:SetInterval(.25, function()
	return Player.State ~= "stopped"
end)

Page:SetInterval(.1, function()
	return Tab == 5 and Analyze()
end)

if (Args[1] and fs.exists(Args[1])) then
	PlayList({ { Name = fs.getName(Args[1]), Path = Args[1] } }, 1)
end
Page:Run()
Stop()
]]
Files["blockos/apps/calculator/app.cfg"] = [[
{ Name = "Calculator", Description = "A four-function calculator with keyboard support.", Width = 22, Height = 14, Icon = { Lines = { "+-=", "x/%" }, Fg = "white", Bg = "orange" } }
]]
Files["blockos/apps/calculator/main.lua"] = [[
-- Calculator: a basic four-function calculator for BlockOS.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")

local Page = Ui.Page.new()
local Display = "0"
local Stored = nil
local Operator = nil
local Fresh = true

local Layout = {
	{ "C", "+/-", "%", "/" },
	{ "7", "8", "9", "*" },
	{ "4", "5", "6", "-" },
	{ "1", "2", "3", "+" },
	{ "0", ".", "<", "=" }
}

local function Format(Value)
	if (Value ~= Value or Value == math.huge or Value == -math.huge) then return "Error" end
	if (Value == math.floor(Value) and math.abs(Value) < 1e15) then
		return string.format("%d", Value)
	end
	return string.format("%.10g", Value)
end

local function Apply(A, B, Op)
	if (Op == "+") then return A + B end
	if (Op == "-") then return A - B end
	if (Op == "*") then return A * B end
	if (Op == "/") then return A / B end
	return B
end

local function Press(Key)
	local Value = tonumber(Display) or 0
	if (Key:match("^%d$")) then
		if (Fresh or Display == "0") then
			Display = Key
		elseif (#Display < 15) then
			Display = Display .. Key
		end
		Fresh = false
	elseif (Key == ".") then
		if (Fresh) then
			Display = "0."
		elseif (not Display:find(".", 1, true)) then
			Display = Display .. "."
		end
		Fresh = false
	elseif (Key == "C") then
		Display, Stored, Operator, Fresh = "0", nil, nil, true
	elseif (Key == "<") then
		Display = Fresh and "0" or Display:sub(1, -2)
		if (Display == "" or Display == "-") then Display = "0" end
	elseif (Key == "+/-") then
		Display = Format(-Value)
	elseif (Key == "%") then
		Display = Format(Value / 100)
		Fresh = true
	elseif (Key == "=") then
		if (Operator and Stored) then
			Display = Format(Apply(Stored, Value, Operator))
		end
		Stored, Operator, Fresh = nil, nil, true
	else
		if (Operator and Stored and not Fresh) then
			Value = Apply(Stored, Value, Operator)
			Display = Format(Value)
		end
		Stored, Operator, Fresh = Value, Key, true
	end
	Page:Invalidate()
end

local function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Page:Add(Ui.Canvas.new({
		X = 1, Y = 1, W = W, H = 3,
		OnDraw = function(Self, T, Th)
			Gfx.Fill(T, Self.X, Self.Y, Self.W, Self.H, Th.Panel)
			local Pending = (Stored and Operator) and (Format(Stored) .. " " .. Operator) or ""
			Gfx.Write(T, Self.X, Self.Y, Gfx.Pad(Pending, Self.W - 1, "right"), Th.SubText, Th.Panel)
			Gfx.Write(T, Self.X, Self.Y + 1, Gfx.Pad(Display, Self.W - 1, "right"), Th.PanelFg, Th.Panel)
		end
	}))
	local CellW = math.max(3, math.floor(W / 4))
	local CellH = math.max(1, math.floor((H - 3) / #Layout))
	for Row, Keys in ipairs(Layout) do
		for Column, Key in ipairs(Keys) do
			local Style = "default"
			if (Column == 4) then Style = "primary" end
			Page:Add(Ui.Button.new({
				X = (Column - 1) * CellW + 1,
				Y = 4 + (Row - 1) * CellH,
				W = (Column == 4) and (W - CellW * 3) or (CellW - 1),
				H = math.max(1, CellH - (CellH > 1 and 1 or 0)),
				Text = Key,
				Style = Style,
				OnClick = function() Press(Key) end
			}))
		end
	end
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A)
	if (Name == "char") then
		if (A:match("^[%d%.%+%-%*/%%=]$")) then
			Press(A)
			return true
		elseif (A == "c") then
			Press("C")
			return true
		end
	elseif (Name == "key") then
		if (A == keys.enter or A == keys.numPadEnter) then
			Press("=")
			return true
		elseif (A == keys.backspace) then
			Press("<")
			return true
		elseif (A == keys.delete) then
			Press("C")
			return true
		end
	end
	return false
end

Page:Run()
]]
Files["blockos/apps/clock/app.cfg"] = [[
{ Name = "Clock", Description = "World time, alarms, stopwatch and timer.", Width = 38, Height = 13, Single = true, Icon = { Lines = { "12:", "00 " }, Fg = "white", Bg = "black" } }
]]
Files["blockos/apps/clock/main.lua"] = [[
-- Clock: big clock, alarms (real or Minecraft time), stopwatch and timer.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")
local Schedule = BlockOS.Require("schedule")

local Page = Ui.Page.new()
local Tab = 1
local Build

local Font = Gfx.Font

local Stopwatch = { Running = false, Start = 0, Elapsed = 0, Laps = {} }
local Timer = { Running = false, Duration = 300000, Remaining = 300000, EndsAt = 0, Fired = false }

local function Now()
	return os.epoch("utc")
end

local function BigWidth(Text)
	local Width = 0
	for Index = 1, #Text do
		local Glyph = Font[Text:sub(Index, Index)]
		Width = Width + (Glyph and #Glyph[1] or 1) + 1
	end
	return Width - 1
end

local function DrawBig(T, X, Y, Text, Color, Bg)
	for Index = 1, #Text do
		local Glyph = Font[Text:sub(Index, Index)]
		if (Glyph) then
			for Row = 1, 5 do
				local Line = Glyph[Row]
				for Column = 1, #Line do
					local Filled = Line:sub(Column, Column) == "#"
					Gfx.Write(T, X + Column - 1, Y + Row - 1, " ", Color, Filled and Color or Bg)
				end
			end
			X = X + #Glyph[1] + 1
		else
			X = X + 2
		end
	end
end

local function CenterBig(T, Y, Text, Color, Bg, W)
	DrawBig(T, math.floor((W - BigWidth(Text)) / 2) + 1, Y, Text, Color, Bg)
end

local function FormatDuration(Milliseconds, Centis)
	local Total = math.max(0, math.floor(Milliseconds / 1000))
	local Hours = math.floor(Total / 3600)
	local Minutes = math.floor(Total / 60) % 60
	local Seconds = Total % 60
	local Text
	if (Hours > 0) then
		Text = string.format("%d:%02d:%02d", Hours, Minutes, Seconds)
	else
		Text = string.format("%02d:%02d", Minutes, Seconds)
	end
	if (Centis) then
		Text = Text .. string.format(".%02d", math.floor(Milliseconds / 10) % 100)
	end
	return Text
end

local function StopwatchTime()
	if (Stopwatch.Running) then
		return Stopwatch.Elapsed + (Now() - Stopwatch.Start)
	end
	return Stopwatch.Elapsed
end

local function TimerRemaining()
	if (Timer.Running) then
		return math.max(0, Timer.EndsAt - Now())
	end
	return Timer.Remaining
end

local function BuildClock(W, H)
	Page:Add(Ui.Canvas.new({
		X = 1, Y = 2, W = W, H = H - 1,
		OnDraw = function(Self, T, Th)
			local Settings = Config.Settings()
			local Text = os.date(Settings.Clock24 and "%H:%M" or "%I:%M")
			CenterBig(T, Self.Y + 1, Text, Th.Accent, Th.WindowBg, W)
			Gfx.Center(T, Self.Y + 7, os.date("%A, %d %B %Y") .. "  " .. os.date(":%S") .. (Settings.Clock24 and "" or os.date(" %p")), Th.Text, Th.WindowBg)
			local Game = textutils.formatTime(os.time(), Settings.Clock24)
			Gfx.Center(T, Self.Y + 9, "Minecraft: Day " .. os.day() .. ", " .. Game, Th.SubText, Th.WindowBg)
			local Hours = os.time()
			local Phase = (Hours >= 6 and Hours < 18) and "\15 Daytime" or "\7 Night"
			Gfx.Center(T, Self.Y + 10, Phase, (Hours >= 6 and Hours < 18) and colors.orange or colors.lightBlue, Th.WindowBg)
		end
	}))
end

local function FormatAlarm(Alarm)
	if (Alarm.Source == "game") then
		return textutils.formatTime(Alarm.Time, true) .. " MC"
	end
	return string.format("%02d:%02d", math.floor(Alarm.Time / 60), Alarm.Time % 60)
end

local function BuildAlarms(W, H)
	local Data = Schedule.Load()
	local List = Page:Add(Ui.List.new({ X = 1, Y = 2, W = W, H = H - 3 }))
	local Items = {}
	for _, Alarm in ipairs(Data.Alarms) do
		table.insert(Items, {
			Text = FormatAlarm(Alarm) .. "  " .. (Alarm.Label or "Alarm"),
			Icon = Alarm.Enabled and "\7" or "o",
			IconFg = Alarm.Enabled and "Accent" or "SubText",
			Right = Alarm.Enabled and "on" or "off",
			Alarm = Alarm
		})
	end
	List:SetItems(Items)
	List.OnActivate = function(_, _, Item)
		Item.Alarm.Enabled = not Item.Alarm.Enabled
		Schedule.Save()
		Build()
	end
	List.OnContext = function(_, _, Item, X, Y)
		if (not Item) then return end
		local Choice = Ui.ContextMenu(X, Y, { Item.Alarm.Enabled and "Turn Off" or "Turn On", "Delete" })
		if (Choice == 1) then
			Item.Alarm.Enabled = not Item.Alarm.Enabled
			Schedule.Save()
		elseif (Choice == 2) then
			Schedule.RemoveAlarm(Item.Alarm.ID)
		end
		Build()
	end
	if (#Items == 0) then
		Page:Add(Ui.Label.new({ X = 2, Y = 3, W = W - 2, Text = "No alarms. Alarms ring while BlockOS is running.", Fg = "SubText", H = 2 }))
	end
	Page:Add(Ui.Button.new({ X = 2, Y = H, Text = " + Add Alarm ", Style = "primary", OnClick = function()
		local Index = Ui.Choose("Alarm clock", { "Real time", "Minecraft time" })
		if (not Index) then return end
		local Text = Ui.Prompt("New Alarm", "Time (HH:MM, 24-hour):", Index == 1 and os.date("%H:%M") or "06:00")
		if (not Text) then return end
		local Hour, Minute = Text:match("^(%d%d?):(%d%d)$")
		if (not Hour or tonumber(Hour) > 23 or tonumber(Minute) > 59) then
			Ui.Alert("New Alarm", "Enter the time as HH:MM.")
			return
		end
		local Label = Ui.Prompt("New Alarm", "Label:", "Alarm") or "Alarm"
		if (Index == 1) then
			Schedule.AddAlarm({ Label = Label, Time = tonumber(Hour) * 60 + tonumber(Minute), Source = "real" })
		else
			Schedule.AddAlarm({ Label = Label, Time = tonumber(Hour) + tonumber(Minute) / 60, Source = "game" })
		end
		Build()
	end }))
	Page:Add(Ui.Label.new({ X = 18, Y = H, W = W - 18, Text = "Double-click toggles", Fg = "SubText" }))
end

local function BuildStopwatch(W, H)
	Page:Add(Ui.Canvas.new({
		X = 1, Y = 2, W = W, H = 6,
		OnDraw = function(Self, T, Th)
			local Text = FormatDuration(StopwatchTime(), false)
			CenterBig(T, Self.Y + 1, Text, Stopwatch.Running and Th.Accent or Th.Text, Th.WindowBg, W)
			Gfx.Center(T, Self.Y + 6, string.format(".%02d", math.floor(StopwatchTime() / 10) % 100), Th.SubText, Th.WindowBg)
		end
	}))
	local Laps = {}
	for Index = #Stopwatch.Laps, 1, -1 do
		table.insert(Laps, { Text = "Lap " .. Index, Right = FormatDuration(Stopwatch.Laps[Index], true) })
	end
	Page:Add(Ui.List.new({ X = 2, Y = 9, W = W - 2, H = math.max(1, H - 10), Items = Laps }))
	Page:Add(Ui.Button.new({ X = 2, Y = H, W = 9, Text = function() return Stopwatch.Running and "Stop" or "Start" end, Style = "primary", OnClick = function()
		if (Stopwatch.Running) then
			Stopwatch.Elapsed = StopwatchTime()
			Stopwatch.Running = false
		else
			Stopwatch.Start = Now()
			Stopwatch.Running = true
		end
	end }))
	Page:Add(Ui.Button.new({ X = 12, Y = H, W = 7, Text = "Lap", OnClick = function()
		if (Stopwatch.Running) then
			table.insert(Stopwatch.Laps, StopwatchTime())
			Build()
		end
	end }))
	Page:Add(Ui.Button.new({ X = 20, Y = H, W = 8, Text = "Reset", OnClick = function()
		Stopwatch = { Running = false, Start = 0, Elapsed = 0, Laps = {} }
		Build()
	end }))
end

local function BuildTimer(W, H)
	Page:Add(Ui.Canvas.new({
		X = 1, Y = 2, W = W, H = 6,
		OnDraw = function(Self, T, Th)
			local Remaining = TimerRemaining()
			CenterBig(T, Self.Y + 1, FormatDuration(Remaining + 999, false), Timer.Running and Th.Accent or Th.Text, Th.WindowBg, W)
		end
	}))
	Page:Add(Ui.Progress.new({ X = 3, Y = 8, W = W - 4, Value = function()
		return Timer.Duration > 0 and (1 - TimerRemaining() / Timer.Duration) or 0
	end }))
	local function Adjust(Delta)
		if (Timer.Running) then return end
		Timer.Remaining = math.max(0, Timer.Remaining + Delta)
		Timer.Duration = Timer.Remaining
	end
	local Presets = { { "-1m", -60000 }, { "+1m", 60000 }, { "+5m", 300000 }, { "+10s", 10000 } }
	local X = 2
	for _, Preset in ipairs(Presets) do
		Page:Add(Ui.Button.new({ X = X, Y = 10, W = 6, Text = Preset[1], OnClick = function() Adjust(Preset[2]) end }))
		X = X + 7
	end
	Page:Add(Ui.Button.new({ X = 2, Y = H, W = 9, Text = function() return Timer.Running and "Pause" or "Start" end, Style = "primary", OnClick = function()
		if (Timer.Running) then
			Timer.Remaining = TimerRemaining()
			Timer.Running = false
		elseif (Timer.Remaining > 0) then
			Timer.EndsAt = Now() + Timer.Remaining
			Timer.Running = true
			Timer.Fired = false
		end
	end }))
	Page:Add(Ui.Button.new({ X = 12, Y = H, W = 8, Text = "Reset", OnClick = function()
		Timer.Running = false
		Timer.Remaining = Timer.Duration
	end }))
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Page:Add(Ui.Tabs.new({
		X = 1, Y = 1, W = W, Items = { "Clock", "Alarms", "Stopwatch", "Timer" }, Selected = Tab,
		OnChange = function(_, Index)
			Tab = Index
			Build()
		end
	}))
	local Builders = { BuildClock, BuildAlarms, BuildStopwatch, BuildTimer }
	Builders[Tab](W, H)
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name)
	if (Name == "blockos_schedule" and Tab == 2) then
		Build()
		return true
	end
	return false
end

Page:SetInterval(.1, function()
	if (Timer.Running and TimerRemaining() <= 0 and not Timer.Fired) then
		Timer.Fired = true
		Timer.Running = false
		Timer.Remaining = 0
		BlockOS.Notify("Timer", "Time's up!", { AppID = "clock", Repeat = 3, Duration = 10 })
	end
	if (Tab == 1) then
		return os.clock() % 1 < .1
	end
	return (Tab == 3 and Stopwatch.Running) or (Tab == 4)
end)

Page:Run()
]]
Files["blockos/apps/devices/app.cfg"] = [[
{ Name = "Devices", Description = "Inspect and control attached peripherals and redstone.", Width = 46, Height = 15, Single = true, Icon = { Lines = { "[\7]", "|||" }, Fg = "cyan", Bg = "black" } }
]]
Files["blockos/apps/devices/main.lua"] = [[
-- Devices: inspect this computer, redstone sides and every attached peripheral, with per-type actions.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")

local Page = Ui.Page.new()
local SelectedID = "computer"
local Build

local TypeIcons = {
	monitor = { "\8", colors.lightBlue }, modem = { "\29", colors.orange }, speaker = { "\14", colors.red },
	drive = { "\22", colors.gray }, printer = { "\127", colors.yellow }, computer = { "\8", colors.cyan },
	turtle = { "\4", colors.lime }, redstone = { "\7", colors.red }
}

local function Entries()
	local List = {
		{ ID = "computer", Text = "This Computer", Icon = "\8", IconFg = colors.cyan },
		{ ID = "redstone", Text = "Redstone", Icon = "\7", IconFg = colors.red }
	}
	local Names = peripheral.getNames()
	table.sort(Names)
	for _, Name in ipairs(Names) do
		local Kind = peripheral.getType(Name)
		local Icon = TypeIcons[Kind] or { "\4", colors.gray }
		table.insert(List, { ID = Name, Text = Name, Icon = Icon[1], IconFg = Icon[2], Kind = Kind })
	end
	return List
end

local function Info(X, Y, W, Lines)
	for Index, Line in ipairs(Lines) do
		Page:Add(Ui.Label.new({ X = X, Y = Y + Index - 1, W = 10, Text = Line[1], Fg = "SubText" }))
		Page:Add(Ui.Label.new({ X = X + 10, Y = Y + Index - 1, W = W - 10, Text = tostring(Line[2]) }))
	end
	return Y + #Lines + 1
end

local function Buttons(X, Y, W, List)
	local BX = X
	for _, Entry in ipairs(List) do
		local Width = #Entry[1] + 2
		if (BX + Width > X + W) then
			BX = X
			Y = Y + 2
		end
		Page:Add(Ui.Button.new({ X = BX, Y = Y, W = Width, Text = Entry[1], Style = Entry[3], OnClick = function()
			local Ok, Err = pcall(Entry[2])
			if (not Ok) then Ui.Alert("Devices", tostring(Err)) end
			Build()
		end }))
		BX = BX + Width + 1
	end
	return Y + 2
end

local Details = {}

function Details.computer(X, Y, W)
	local Uptime = math.floor(os.clock())
	Info(X, Y, W, {
		{ "Label", os.getComputerLabel() or "(none)" },
		{ "ID", os.getComputerID() },
		{ "Kind", (turtle and "Turtle" or (pocket and "Pocket computer" or "Computer")) .. (term.isColor() and ", advanced" or "") },
		{ "Version", _HOST or os.version() },
		{ "Uptime", string.format("%dh %02dm %02ds", math.floor(Uptime / 3600), math.floor(Uptime / 60) % 60, Uptime % 60) },
		{ "World", "Day " .. os.day() .. ", " .. textutils.formatTime(os.time(), true) },
		{ "Storage", Gfx.FormatSize(fs.getFreeSpace("/")) .. " free" },
		{ "Devices", #peripheral.getNames() .. " attached" }
	})
end

function Details.redstone(X, Y, W)
	Page:Add(Ui.Label.new({ X = X, Y = Y, W = W, Text = "Side      In  Out", Fg = "SubText" }))
	for Index, Side in ipairs(redstone.getSides()) do
		local Row = Y + Index
		Page:Add(Ui.Label.new({ X = X, Y = Row, W = 9, Text = Side }))
		local Input = redstone.getAnalogInput(Side)
		Page:Add(Ui.Label.new({ X = X + 10, Y = Row, W = 3, Text = tostring(Input), Fg = (Input > 0) and colors.red or "SubText" }))
		Page:Add(Ui.Toggle.new({ X = X + 14, Y = Row, Value = redstone.getOutput(Side), OnChange = function(_, Value)
			redstone.setOutput(Side, Value)
		end }))
	end
end

local function MonitorDetails(Name, X, Y, W)
	local Monitor = peripheral.wrap(Name)
	local MW, MH = Monitor.getSize()
	Y = Info(X, Y, W, { { "Size", MW .. " x " .. MH }, { "Colour", Monitor.isColor() and "yes" or "no" }, { "Scale", Monitor.getTextScale and Monitor.getTextScale() or "?" } })
	Buttons(X, Y, W, {
		{ "Test Pattern", function()
			local Palette = { colors.red, colors.orange, colors.yellow, colors.lime, colors.cyan, colors.blue, colors.purple, colors.magenta }
			for Row = 1, MH do
				Monitor.setCursorPos(1, Row)
				Monitor.setBackgroundColor(Palette[(Row - 1) % #Palette + 1])
				Monitor.clearLine()
			end
			Monitor.setCursorPos(2, 2)
			Monitor.setTextColor(colors.white)
			Monitor.write("BlockOS")
		end },
		{ "Clear", function()
			Monitor.setBackgroundColor(colors.black)
			Monitor.clear()
		end },
		{ "Scale -", function() Monitor.setTextScale(math.max(.5, Monitor.getTextScale() - .5)) end },
		{ "Scale +", function() Monitor.setTextScale(math.min(5, Monitor.getTextScale() + .5)) end }
	})
end

local function ModemDetails(Name, X, Y, W)
	local Modem = peripheral.wrap(Name)
	local Lines = { { "Type", Modem.isWireless() and "Wireless" or "Wired" }, { "Rednet", rednet.isOpen(Name) and "open" or "closed" } }
	if (not Modem.isWireless() and Modem.getNamesRemote) then
		table.insert(Lines, { "Network", #Modem.getNamesRemote() .. " remote peripherals" })
	end
	Y = Info(X, Y, W, Lines)
	Buttons(X, Y, W, {
		{ rednet.isOpen(Name) and "Close Rednet" or "Open Rednet", function()
			if (rednet.isOpen(Name)) then rednet.close(Name) else rednet.open(Name) end
		end }
	})
end

local function SpeakerDetails(Name, X, Y, W)
	local Speaker = peripheral.wrap(Name)
	Y = Info(X, Y, W, { { "Type", "Speaker" } })
	Buttons(X, Y, W, {
		{ "Chime", function()
			for Index, Pitch in ipairs({ 12, 16, 19, 24 }) do
				Speaker.playNote("chime", 1, Pitch)
				if (Index < 4) then sleep(.15) end
			end
		end },
		{ "Bell", function() Speaker.playNote("bell", 1, 12) end },
		{ "Sound...", function()
			local Sound = Ui.Prompt("Play Sound", "Sound ID:", "entity.experience_orb.pickup")
			if (Sound) then Speaker.playSound(Sound) end
		end },
		{ "Stop", function() Speaker.stop() end }
	})
end

local function DriveDetails(Name, X, Y, W)
	local Lines = { { "Disk", disk.isPresent(Name) and "inserted" or "empty" } }
	if (disk.hasData(Name)) then
		table.insert(Lines, { "Label", disk.getLabel(Name) or "(none)" })
		table.insert(Lines, { "Mount", "/" .. disk.getMountPath(Name) })
		table.insert(Lines, { "Disk ID", tostring(disk.getID(Name)) })
	elseif (disk.hasAudio(Name)) then
		table.insert(Lines, { "Music", disk.getAudioTitle(Name) })
	end
	Y = Info(X, Y, W, Lines)
	local Actions = {}
	if (disk.hasData(Name)) then
		table.insert(Actions, { "Open in Finder", function() BlockOS.Launch("finder", { "/" .. disk.getMountPath(Name) }) end })
	end
	if (disk.hasAudio(Name)) then
		table.insert(Actions, { "Play", function() disk.playAudio(Name) end })
		table.insert(Actions, { "Stop", function() disk.stopAudio(Name) end })
	end
	if (disk.isPresent(Name)) then
		table.insert(Actions, { "Eject", function() disk.eject(Name) end })
	end
	Buttons(X, Y, W, Actions)
end

local function PrinterDetails(Name, X, Y, W)
	local Printer = peripheral.wrap(Name)
	Y = Info(X, Y, W, { { "Ink", Printer.getInkLevel() }, { "Paper", Printer.getPaperLevel() } })
	local function PrintLines(Title, Lines)
		if (not Printer.newPage()) then error("Add ink and paper first.", 0) end
		Printer.setPageTitle(Title)
		local PW, PH = Printer.getPageSize()
		local Row = 1
		for _, Line in ipairs(Lines) do
			for _, Piece in ipairs(Gfx.Wrap(Line, PW)) do
				if (Row > PH) then
					Printer.endPage()
					if (not Printer.newPage()) then return end
					Printer.setPageTitle(Title)
					Row = 1
				end
				Printer.setCursorPos(1, Row)
				Printer.write(Piece)
				Row = Row + 1
			end
		end
		Printer.endPage()
	end
	Buttons(X, Y, W, {
		{ "Test Page", function()
			PrintLines("BlockOS Test", { "BlockOS printer test", "", "Computer #" .. os.getComputerID(), os.date("%Y-%m-%d %H:%M"), "", "If you can read this, printing works." })
		end },
		{ "Print File...", function()
			local Path = Ui.PickFile({ Dir = "/home/Documents" })
			if (not Path) then return end
			local Lines = {}
			local Handle = fs.open(Path, "r")
			for Line in (Handle.readAll() .. "\n"):gmatch("(.-)\n") do
				table.insert(Lines, Line)
			end
			Handle.close()
			PrintLines(fs.getName(Path), Lines)
		end }
	})
end

local function ComputerDetails(Name, X, Y, W)
	local Remote = peripheral.wrap(Name)
	Y = Info(X, Y, W, { { "ID", Remote.getID() }, { "Label", Remote.getLabel() or "(none)" }, { "Running", Remote.isOn() and "yes" or "no" } })
	Buttons(X, Y, W, {
		{ "Turn On", function() Remote.turnOn() end },
		{ "Reboot", function() Remote.reboot() end },
		{ "Shut Down", function() Remote.shutdown() end, "danger" }
	})
end

local function GenericDetails(Name, X, Y, W, H)
	Page:Add(Ui.Label.new({ X = X, Y = Y, W = W, Text = "Methods", Fg = "SubText" }))
	local Items = {}
	local Methods = peripheral.getMethods(Name) or {}
	table.sort(Methods)
	for _, Method in ipairs(Methods) do
		table.insert(Items, { Text = Method .. "()" })
	end
	Page:Add(Ui.List.new({ X = X, Y = Y + 1, W = W, H = math.max(1, H - 2), Items = Items }))
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	local SideW = (W >= 40) and 16 or 0
	local List = Page:Add(Ui.List.new({ X = 1, Y = 1, W = SideW, H = H, Bg = "Panel", SingleClick = true, Visible = SideW > 0 }))
	local Items = Entries()
	List:SetItems(Items)
	local Current
	for Index, Item in ipairs(Items) do
		if (Item.ID == SelectedID) then
			List.Selected = Index
			Current = Item
		end
	end
	if (not Current) then
		SelectedID = "computer"
		Current = Items[1]
		List.Selected = 1
	end
	List.OnActivate = function(_, _, Item)
		SelectedID = Item.ID
		Build()
	end
	local X = SideW + 2
	local ContentW = W - SideW - 2
	local Title = Current.Kind and (Current.Text .. " (" .. Current.Kind .. ")") or Current.Text
	if (SideW == 0) then
		Page:Add(Ui.Button.new({ X = 1, Y = 1, W = W, Text = "\31 " .. Title, Bg = "Panel", OnClick = function()
			local Names = {}
			for _, Item in ipairs(Items) do table.insert(Names, Item.Text) end
			local Index = Ui.Choose("Devices", Names)
			if (Index) then
				SelectedID = Items[Index].ID
				Build()
			end
		end }))
	else
		Page:Add(Ui.Label.new({ X = X, Y = 1, W = ContentW, Text = Title, Fg = "Accent" }))
	end
	local Y = 3
	if (Current.ID == "computer" or Current.ID == "redstone") then
		Details[Current.ID](X, Y, ContentW, H - 2)
	elseif (Current.Kind == "monitor") then
		MonitorDetails(Current.ID, X, Y, ContentW)
	elseif (Current.Kind == "modem") then
		ModemDetails(Current.ID, X, Y, ContentW)
	elseif (Current.Kind == "speaker") then
		SpeakerDetails(Current.ID, X, Y, ContentW)
	elseif (Current.Kind == "drive") then
		DriveDetails(Current.ID, X, Y, ContentW)
	elseif (Current.Kind == "printer") then
		PrinterDetails(Current.ID, X, Y, ContentW)
	elseif (Current.Kind == "computer" or Current.Kind == "turtle") then
		ComputerDetails(Current.ID, X, Y, ContentW)
	else
		GenericDetails(Current.ID, X, Y, ContentW, H - 2)
	end
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name)
	if (Name == "peripheral" or Name == "peripheral_detach" or Name == "disk" or Name == "disk_eject" or Name == "monitor_resize") then
		Build()
		return true
	elseif (Name == "redstone" and SelectedID == "redstone") then
		Build()
		return true
	end
	return false
end

Page:SetInterval(1, function()
	if (SelectedID ~= "computer") then return false end
	Build()
	return true
end)

Page:Run()
]]
Files["blockos/apps/diskcopy/app.cfg"] = [[
{ Name = "DiskCopy", Description = "Copy, back up, erase and clone floppy disks.", Width = 42, Height = 14, Single = true, Icon = { Lines = { "[=]", "[=]" }, Fg = "black", Bg = "lightGray" } }
]]
Files["blockos/apps/diskcopy/main.lua"] = [[
-- DiskCopy: duplicate, back up, restore, erase and label floppy disks, or make an installer disk.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")

local Page = Ui.Page.new()
local Drives = {}
local Progress = 0
local Status = "Insert a disk into a disk drive."
local Busy = false
local DriveList
local Build

local function ScanDrives()
	Drives = {}
	for _, Name in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Name) == "drive") then
			local Entry = { Name = Name, Present = disk.isPresent(Name), HasData = disk.hasData(Name) }
			if (Entry.HasData) then
				Entry.Mount = "/" .. disk.getMountPath(Name)
				Entry.Label = disk.getLabel(Name)
				Entry.Free = fs.getFreeSpace(Entry.Mount)
				Entry.Capacity = fs.getCapacity and fs.getCapacity(Entry.Mount) or nil
			elseif (Entry.Present and disk.hasAudio(Name)) then
				Entry.Audio = disk.getAudioTitle(Name)
			end
			table.insert(Drives, Entry)
		end
	end
end

local function ListFiles(Root, Relative, Into, Exclude)
	Into = Into or {}
	local Dir = fs.combine(Root, Relative or "")
	for _, Name in ipairs(fs.list(Dir)) do
		local Child = fs.combine(Relative or "", Name)
		if (not (Exclude and Exclude[Child])) then
			if (fs.isDir(fs.combine(Root, Child))) then
				table.insert(Into, { Path = Child, Dir = true })
				ListFiles(Root, Child, Into, Exclude)
			else
				table.insert(Into, { Path = Child, Size = fs.getSize(fs.combine(Root, Child)) })
			end
		end
	end
	return Into
end

local function TreeSize(Files)
	local Total = 0
	for _, File in ipairs(Files) do
		Total = Total + (File.Size or 0)
	end
	return Total
end

local function SetProgress(Value, Text)
	Progress = Value
	Status = Text
	Page:Draw()
end

local function CopyTree(Source, Target, Exclude)
	local Files = ListFiles(Source, nil, nil, Exclude)
	local Size = TreeSize(Files)
	if (Size > fs.getFreeSpace(Target)) then
		return false, "Not enough space: needs " .. Gfx.FormatSize(Size) .. ", " .. Gfx.FormatSize(fs.getFreeSpace(Target)) .. " free."
	end
	local Done = 0
	for Index, File in ipairs(Files) do
		local Destination = fs.combine(Target, File.Path)
		if (File.Dir) then
			if (not fs.exists(Destination)) then fs.makeDir(Destination) end
		else
			if (fs.exists(Destination)) then fs.delete(Destination) end
			fs.copy(fs.combine(Source, File.Path), Destination)
			Done = Done + File.Size
		end
		SetProgress(Index / #Files, "Copying " .. File.Path)
		if (Index % 8 == 0) then sleep(0) end
	end
	return true, #Files .. " items, " .. Gfx.FormatSize(Done)
end

local function EraseMount(Mount)
	for _, Name in ipairs(fs.list(Mount)) do
		fs.delete(fs.combine(Mount, Name))
	end
end

local function SelectedDrive()
	local Item = DriveList and DriveList.Items[DriveList.Selected]
	return Item and Item.Drive
end

local function RequireDisk()
	local Drive = SelectedDrive()
	if (not Drive or not Drive.HasData) then
		Ui.Alert("DiskCopy", "Select a drive with a floppy disk in it.")
		return nil
	end
	return Drive
end

local function Run(Task)
	if (Busy) then return end
	Busy = true
	local Ok, Result, Detail = pcall(Task)
	Busy = false
	if (not Ok) then
		Status = "Error: " .. tostring(Result)
	elseif (Result == false) then
		Status = tostring(Detail)
	elseif (Result) then
		Status = tostring(Result)
		Progress = 1
	end
	ScanDrives()
	Build()
end

local Actions = {
	{ Text = "Duplicate", Task = function()
		local Source = RequireDisk()
		if (not Source) then return end
		local Targets, Names = {}, {}
		for _, Drive in ipairs(Drives) do
			if (Drive ~= Source and Drive.HasData) then
				table.insert(Targets, Drive)
				table.insert(Names, (Drive.Label or "Untitled") .. " (" .. Drive.Name .. ")")
			end
		end
		if (#Targets == 0) then
			Ui.Alert("Duplicate", "Insert a second disk into another drive.")
			return
		end
		local Index = Ui.Choose("Copy to", Names)
		if (not Index) then return end
		local Target = Targets[Index]
		if (not Ui.Confirm("Duplicate", "Erase \"" .. (Target.Label or "Untitled") .. "\" and copy \"" .. (Source.Label or "Untitled") .. "\" onto it?", "Duplicate")) then return end
		EraseMount(Target.Mount)
		local Ok, Text = CopyTree(Source.Mount, Target.Mount)
		if (Ok and Source.Label) then disk.setLabel(Target.Name, Source.Label) end
		return Ok and ("Duplicated: " .. Text) or false, Text
	end },
	{ Text = "Back Up", Task = function()
		local Source = RequireDisk()
		if (not Source) then return end
		local Name = (Source.Label or "disk"):gsub("[^%w%-_ ]", "") .. " " .. os.date("%Y-%m-%d %H%M")
		local Target = fs.combine("/home/Backups", Name)
		fs.makeDir(Target)
		local Ok, Text = CopyTree(Source.Mount, Target)
		return Ok and ("Backed up to /" .. Target) or false, Text
	end },
	{ Text = "Restore", Task = function()
		local Target = RequireDisk()
		if (not Target) then return end
		local Folder = Ui.PickFile({ Title = "Restore from folder", Dir = "/home/Backups", Folders = true })
		if (not Folder) then return end
		if (not Ui.Confirm("Restore", "Erase the disk and copy " .. Folder .. " onto it?", "Restore")) then return end
		EraseMount(Target.Mount)
		local Ok, Text = CopyTree(Folder, Target.Mount)
		return Ok and ("Restored: " .. Text) or false, Text
	end },
	{ Text = "Erase", Task = function()
		local Target = RequireDisk()
		if (not Target) then return end
		if (not Ui.Confirm("Erase Disk", "Permanently erase everything on \"" .. (Target.Label or "Untitled") .. "\"?", "Erase")) then return end
		EraseMount(Target.Mount)
		return "Disk erased"
	end },
	{ Text = "Label", Task = function()
		local Drive = SelectedDrive()
		if (not Drive or not Drive.Present) then return end
		local Label = Ui.Prompt("Label Disk", "New label:", Drive.Label or "")
		if (Label == nil) then return end
		disk.setLabel(Drive.Name, #Label > 0 and Label or nil)
		return "Label updated"
	end },
	{ Text = "Installer", Task = function()
		local Target = RequireDisk()
		if (not Target) then return end
		if (not Ui.Confirm("Installer Disk", "Write a BlockOS network installer to this disk? Any computer that boots it can install BlockOS.", "Write")) then return end
		local Repo = Config.Settings().UpdateURL or Config.Repo
		local Script = table.concat({
			"-- BlockOS installer disk",
			"term.clear() term.setCursorPos(1, 1)",
			"print(\"BlockOS installer disk\")",
			"write(\"Install BlockOS on this computer? (y/n) \")",
			"if (read():lower():sub(1, 1) ~= \"y\") then return end",
			"shell.run(\"wget\", \"run\", " .. string.format("%q", Repo .. "install.lua") .. ")"
		}, "\n")
		Config.WriteText(fs.combine(Target.Mount, "startup.lua"), Script .. "\n")
		disk.setLabel(Target.Name, "BlockOS Installer")
		return "Installer disk ready"
	end },
	{ Text = "Eject", Task = function()
		local Drive = SelectedDrive()
		if (Drive) then disk.eject(Drive.Name) end
	end }
}

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	local Items = {}
	for _, Drive in ipairs(Drives) do
		local Text, Right
		if (Drive.HasData) then
			Text = (Drive.Label or "Untitled") .. "  " .. Drive.Mount
			Right = Drive.Capacity and (Gfx.FormatSize(Drive.Capacity - Drive.Free) .. " used") or (Gfx.FormatSize(Drive.Free) .. " free")
		elseif (Drive.Audio) then
			Text, Right = "\14 " .. Drive.Audio, "music"
		else
			Text, Right = "(empty)", ""
		end
		table.insert(Items, { Text = Drive.Name .. ": " .. Text, Icon = "\22", IconFg = Drive.HasData and "Accent" or "SubText", Right = Right, Drive = Drive })
	end
	local Selected = DriveList and DriveList.Selected or 1
	DriveList = Page:Add(Ui.List.new({ X = 1, Y = 1, W = W, H = math.max(3, H - 8), Bg = "Panel" }))
	DriveList:SetItems(Items)
	DriveList.Selected = math.min(math.max(Selected, 1), #Items)
	if (#Items == 0) then
		Page:Add(Ui.Label.new({ X = 2, Y = 2, W = W - 2, H = 2, Bg = "Panel", Fg = "SubText", Text = "No disk drives attached. Place a disk drive next to the computer." }))
	end
	local X, Y = 2, H - 6
	for _, Action in ipairs(Actions) do
		local Width = #Action.Text + 2
		if (X + Width > W + 1) then
			X = 2
			Y = Y + 2
		end
		Page:Add(Ui.Button.new({ X = X, Y = Y, W = Width, Text = Action.Text, Enabled = not Busy, OnClick = function() Run(Action.Task) end }))
		X = X + Width + 1
	end
	Page:Add(Ui.Progress.new({ X = 2, Y = H - 1, W = W - 2, Value = function() return Progress end }))
	Page:Add(Ui.Label.new({ X = 1, Y = H, W = W, Fg = "SubText", Text = function() return " " .. Status end }))
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name)
	if (not Busy and (Name == "disk" or Name == "disk_eject" or Name == "peripheral" or Name == "peripheral_detach")) then
		ScanDrives()
		Progress = 0
		Build()
		return true
	end
	return false
end

ScanDrives()
Page:Run()
]]
Files["blockos/apps/editor/app.cfg"] = [[
{ Name = "Editor", Description = "Code editor with Lua syntax highlighting.", Width = 46, Height = 15, Icon = { Lines = { "</>", "\140\140 " }, Fg = "white", Bg = "purple" } }
]]
Files["blockos/apps/editor/main.lua"] = [=[
-- Editor: a code editor with Lua syntax highlighting, selection, undo, find and run.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")
local Apps = BlockOS.Require("apps")

local Args = { ... }

local Keywords = {}
for Word in ("and break do else elseif end false for function goto if in local nil not or repeat return then true until while"):gmatch("%S+") do
	Keywords[Word] = true
end

local Builtins = {}
for Word in ([[print write read pairs ipairs require type tostring tonumber error assert pcall xpcall select next
	setmetatable getmetatable rawget rawset rawequal load loadstring loadfile dofile unpack sleep table string math
	os io fs term colors colours peripheral rednet http textutils shell multishell window keys turtle coroutine
	parallel settings disk redstone rs vector gps paintutils bit32 bit _G _ENV self BlockOS commands pocket]]):gmatch("%S+") do
	Builtins[Word] = true
end

local Hex = Gfx.Hex

local Doc = {
	Lines = { "" },
	X = 1,
	Y = 1,
	ScrollX = 0,
	ScrollY = 0,
	Path = nil,
	Modified = false,
	Anchor = nil,
	UseTabs = false,
	Undo = {},
	Redo = {}
}

local States = {}
local ValidStates = 0
local Message, MessageTime = nil, 0
local Modifiers = Ui.Modifiers
local Find = ""
local Page = Ui.Page.new()
local Editor

local function Palette(Th)
	if (Th.Dark) then
		return {
			Bg = colors.black, Text = colors.white, Keyword = colors.yellow, String = colors.red,
			Comment = colors.green, Number = colors.purple, Builtin = colors.cyan, Operator = colors.lightGray,
			Gutter = colors.gray, GutterFg = colors.lightGray, Selection = colors.blue
		}
	end
	return {
		Bg = colors.white, Text = colors.black, Keyword = colors.blue, String = colors.red,
		Comment = colors.green, Number = colors.purple, Builtin = colors.cyan, Operator = colors.gray,
		Gutter = colors.lightGray, GutterFg = colors.gray, Selection = colors.lightBlue
	}
end

local function SetMessage(Text)
	Message = Text
	MessageTime = os.clock()
end

local function IsLua()
	return not Doc.Path or Doc.Path:match("%.lua$") ~= nil or not Doc.Path:match("%.%w+$")
end

--
-- Highlighting
--

local function Highlight(Line, State, P)
	local Colors = {}
	local Length = #Line
	local Index = 1
	local function Paint(From, To, Color)
		local Code = Hex[Color]
		for Position = From, math.min(To, Length) do
			Colors[Position] = Code
		end
	end
	if (not IsLua()) then
		Paint(1, Length, P.Text)
		return table.concat(Colors), nil
	end
	if (State) then
		local _, Finish = Line:find(State.Close, 1, true)
		local Color = (State.Kind == "comment") and P.Comment or P.String
		if (not Finish) then
			Paint(1, Length, Color)
			return table.concat(Colors), State
		end
		Paint(1, Finish, Color)
		Index = Finish + 1
		State = nil
	end
	while (Index <= Length) do
		local Char = Line:sub(Index, Index)
		if (Line:sub(Index, Index + 1) == "--") then
			local Level = Line:match("^%[(=*)%[", Index + 2)
			if (Level) then
				local Close = "]" .. Level .. "]"
				local _, Finish = Line:find(Close, Index + 4 + #Level, true)
				if (not Finish) then
					Paint(Index, Length, P.Comment)
					return table.concat(Colors), { Kind = "comment", Close = Close }
				end
				Paint(Index, Finish, P.Comment)
				Index = Finish + 1
			else
				Paint(Index, Length, P.Comment)
				Index = Length + 1
			end
		elseif (Char == "\"" or Char == "'") then
			local Position = Index + 1
			while (Position <= Length) do
				local Next = Line:sub(Position, Position)
				if (Next == "\\") then
					Position = Position + 2
				elseif (Next == Char) then
					break
				else
					Position = Position + 1
				end
			end
			Paint(Index, Position, P.String)
			Index = Position + 1
		elseif (Char == "[" and Line:match("^%[=*%[", Index)) then
			local Level = Line:match("^%[(=*)%[", Index)
			local Close = "]" .. Level .. "]"
			local _, Finish = Line:find(Close, Index + 2 + #Level, true)
			if (not Finish) then
				Paint(Index, Length, P.String)
				return table.concat(Colors), { Kind = "string", Close = Close }
			end
			Paint(Index, Finish, P.String)
			Index = Finish + 1
		elseif (Char:match("%d") or (Char == "." and Line:sub(Index + 1, Index + 1):match("%d"))) then
			local _, Finish = Line:find("^0[xX]%x+", Index)
			if (not Finish) then _, Finish = Line:find("^%d*%.?%d*[eE][%+%-]?%d+", Index) end
			if (not Finish) then _, Finish = Line:find("^%d*%.?%d*", Index) end
			Paint(Index, Finish, P.Number)
			Index = Finish + 1
		elseif (Char:match("[%a_]")) then
			local Start, Finish = Line:find("^[%w_]+", Index)
			local Word = Line:sub(Start, Finish)
			local Color = P.Text
			if (Keywords[Word]) then
				Color = P.Keyword
			elseif (Builtins[Word]) then
				Color = P.Builtin
			end
			Paint(Start, Finish, Color)
			Index = Finish + 1
		else
			Paint(Index, Index, Char:match("[%+%-%*/%%%^#=<>~%.]") and P.Operator or P.Text)
			Index = Index + 1
		end
	end
	return table.concat(Colors), nil
end

local function Invalidate(FromLine)
	ValidStates = math.min(ValidStates, FromLine - 1)
end

local function StateAt(Line, P)
	if (ValidStates < 1) then
		States[1] = nil
		ValidStates = 1
	end
	while (ValidStates < Line) do
		local _, Next = Highlight(Doc.Lines[ValidStates] or "", States[ValidStates], P)
		ValidStates = ValidStates + 1
		States[ValidStates] = Next
	end
	return States[Line]
end

--
-- Text model
--

local function TabWidth()
	return 2
end

local function DisplayWidth(Line, Upto)
	local Width = 0
	for Index = 1, math.min(Upto, #Line) do
		Width = Width + ((Line:sub(Index, Index) == "\t") and TabWidth() or 1)
	end
	return Width
end

local function CharFromDisplay(Line, Column)
	local Width = 0
	for Index = 1, #Line do
		local Step = (Line:sub(Index, Index) == "\t") and TabWidth() or 1
		if (Width + Step > Column) then return Index end
		Width = Width + Step
	end
	return #Line + 1
end

local function Snapshot()
	return { Text = table.concat(Doc.Lines, "\n"), X = Doc.X, Y = Doc.Y }
end

local function Restore(Shot)
	Doc.Lines = {}
	for Line in (Shot.Text .. "\n"):gmatch("(.-)\n") do
		table.insert(Doc.Lines, Line)
	end
	if (#Doc.Lines == 0) then Doc.Lines = { "" } end
	Doc.X, Doc.Y = Shot.X, Shot.Y
	Doc.Anchor = nil
	Invalidate(1)
end

local LastUndoKind, LastUndoTime = nil, 0

local function PushUndo(Kind)
	local Now = os.clock()
	if (Kind == "type" and LastUndoKind == "type" and Now - LastUndoTime < 1.5) then
		LastUndoTime = Now
		return
	end
	table.insert(Doc.Undo, Snapshot())
	if (#Doc.Undo > 100) then table.remove(Doc.Undo, 1) end
	Doc.Redo = {}
	LastUndoKind, LastUndoTime = Kind, Now
end

local function Clamp()
	Doc.Y = math.max(1, math.min(Doc.Y, #Doc.Lines))
	Doc.X = math.max(1, math.min(Doc.X, #Doc.Lines[Doc.Y] + 1))
end

local function SelectionRange()
	if (not Doc.Anchor) then return nil end
	local AX, AY, BX, BY = Doc.Anchor.X, Doc.Anchor.Y, Doc.X, Doc.Y
	if (AY > BY or (AY == BY and AX > BX)) then
		AX, AY, BX, BY = BX, BY, AX, AY
	end
	if (AX == BX and AY == BY) then return nil end
	return AX, AY, BX, BY
end

local function SelectedText()
	local AX, AY, BX, BY = SelectionRange()
	if (not AX) then return nil end
	if (AY == BY) then
		return Doc.Lines[AY]:sub(AX, BX - 1)
	end
	local Parts = { Doc.Lines[AY]:sub(AX) }
	for Line = AY + 1, BY - 1 do
		table.insert(Parts, Doc.Lines[Line])
	end
	table.insert(Parts, Doc.Lines[BY]:sub(1, BX - 1))
	return table.concat(Parts, "\n")
end

local function DeleteSelection()
	local AX, AY, BX, BY = SelectionRange()
	Doc.Anchor = nil
	if (not AX) then return false end
	local Head = Doc.Lines[AY]:sub(1, AX - 1)
	local Tail = Doc.Lines[BY]:sub(BX)
	for _ = AY + 1, BY do
		table.remove(Doc.Lines, AY + 1)
	end
	Doc.Lines[AY] = Head .. Tail
	Doc.X, Doc.Y = AX, AY
	Doc.Modified = true
	Invalidate(AY)
	return true
end

local function InsertText(Text)
	DeleteSelection()
	Text = Text:gsub("\r\n", "\n"):gsub("\r", "\n")
	local Line = Doc.Lines[Doc.Y]
	local Head, Tail = Line:sub(1, Doc.X - 1), Line:sub(Doc.X)
	local Pieces = {}
	for Piece in (Text .. "\n"):gmatch("(.-)\n") do
		table.insert(Pieces, Piece)
	end
	if (#Pieces == 1) then
		Doc.Lines[Doc.Y] = Head .. Pieces[1] .. Tail
		Doc.X = Doc.X + #Pieces[1]
	else
		Doc.Lines[Doc.Y] = Head .. Pieces[1]
		for Index = 2, #Pieces do
			table.insert(Doc.Lines, Doc.Y + Index - 1, Pieces[Index])
		end
		local LastY = Doc.Y + #Pieces - 1
		Doc.X = #Doc.Lines[LastY] + 1
		Doc.Lines[LastY] = Doc.Lines[LastY] .. Tail
		Invalidate(Doc.Y)
		Doc.Y = LastY
	end
	Invalidate(Doc.Y)
	Doc.Modified = true
end

local function ViewSize()
	return Editor.W - Editor.Gutter, Editor.H
end

local function EnsureVisible()
	Clamp()
	local ViewW, ViewH = ViewSize()
	if (Doc.Y <= Doc.ScrollY) then Doc.ScrollY = Doc.Y - 1 end
	if (Doc.Y > Doc.ScrollY + ViewH) then Doc.ScrollY = Doc.Y - ViewH end
	local Column = DisplayWidth(Doc.Lines[Doc.Y], Doc.X - 1)
	if (Column < Doc.ScrollX) then Doc.ScrollX = math.max(0, Column - 4) end
	if (Column >= Doc.ScrollX + ViewW - 1) then Doc.ScrollX = Column - ViewW + 2 end
end

local function SetLines(Text)
	Doc.Lines = {}
	for Line in (Text:gsub("\r\n", "\n") .. "\n"):gmatch("(.-)\n") do
		table.insert(Doc.Lines, Line)
	end
	if (#Doc.Lines > 1 and Doc.Lines[#Doc.Lines] == "") then
		table.remove(Doc.Lines)
	end
	if (#Doc.Lines == 0) then Doc.Lines = { "" } end
	Doc.UseTabs = false
	for _, Line in ipairs(Doc.Lines) do
		if (Line:sub(1, 1) == "\t") then
			Doc.UseTabs = true
			break
		end
	end
	Doc.X, Doc.Y, Doc.ScrollX, Doc.ScrollY = 1, 1, 0, 0
	Doc.Anchor = nil
	Doc.Undo, Doc.Redo = {}, {}
	Doc.Modified = false
	Invalidate(1)
end

local function UpdateTitle()
	BlockOS.SetTitle((Doc.Modified and "\7 " or "") .. (Doc.Path and fs.getName(Doc.Path) or "Untitled"))
end

local function LoadFile(Path)
	local Text = Config.ReadText(Path)
	if (not Text) then
		SetLines("")
		Doc.Path = Path
		SetMessage("New file")
	else
		SetLines(Text)
		Doc.Path = Path
		SetMessage("Opened " .. fs.getName(Path))
	end
	UpdateTitle()
end

local function SaveAs()
	local Path = Ui.PickFile({ Save = true, Dir = Doc.Path and fs.getDir(Doc.Path) or "/home/Documents", Name = Doc.Path and fs.getName(Doc.Path) or "untitled.lua" })
	if (not Path) then return false end
	Doc.Path = Path
	return true
end

local function Save()
	if (not Doc.Path and not SaveAs()) then return false end
	if (fs.isReadOnly(Doc.Path)) then
		Ui.Alert("Save", "This location is read-only.")
		return false
	end
	if (not Config.WriteText(Doc.Path, table.concat(Doc.Lines, "\n") .. "\n")) then
		Ui.Alert("Save", "Could not write " .. Doc.Path)
		return false
	end
	Doc.Modified = false
	SetMessage("Saved " .. fs.getName(Doc.Path))
	UpdateTitle()
	return true
end

-- Returns true when it is safe to discard the current document.
local function ConfirmDiscard()
	if (not Doc.Modified) then return true end
	local Choice = Ui.Alert("Unsaved changes", "Save changes to " .. (Doc.Path and fs.getName(Doc.Path) or "Untitled") .. "?", { "Cancel", "Don't Save", "Save" })
	if (Choice == 3) then return Save() end
	return Choice == 2
end

local function Run()
	if (not Save()) then return end
	BlockOS.Launch(Doc.Path, {}, { Hold = true })
end

local function FindNext(Query, FromStart)
	if (not Query or #Query == 0) then return false end
	local StartY, StartX = Doc.Y, Doc.X
	if (FromStart) then StartY, StartX = 1, 1 end
	for Offset = 0, #Doc.Lines do
		local Line = ((StartY - 1 + Offset) % #Doc.Lines) + 1
		local From = (Offset == 0) and StartX or 1
		local Start, Finish = Doc.Lines[Line]:find(Query, From, true)
		if (Start) then
			Doc.Anchor = { X = Start, Y = Line }
			Doc.X, Doc.Y = Finish + 1, Line
			EnsureVisible()
			return true
		end
	end
	SetMessage("Not found: " .. Query)
	return false
end

local function Indentation(Line)
	return Line:match("^[ \t]*")
end

local function IndentUnit()
	return Doc.UseTabs and "\t" or "  "
end

local function NewLine()
	PushUndo("edit")
	local Line = Doc.Lines[Doc.Y]:sub(1, Doc.X - 1)
	local Indent = Indentation(Doc.Lines[Doc.Y])
	local Trimmed = Line:gsub("%s+$", "")
	if (Trimmed:match("then$") or Trimmed:match("do$") or Trimmed:match("else$") or Trimmed:match("repeat$")
		or Trimmed:match("function%s*[%w_.:]*%b()$") or Trimmed:match("[{(]$")) then
		Indent = Indent .. IndentUnit()
	end
	InsertText("\n" .. Indent)
end

local function Move(Key)
	local Line = Doc.Lines[Doc.Y]
	local _, ViewH = ViewSize()
	if (Key == keys.left) then
		if (Modifiers.Ctrl) then
			local Before = Line:sub(1, Doc.X - 1)
			local Position = Before:find("[%w_]+[^%w_]*$") or 1
			Doc.X = (Position == Doc.X) and math.max(1, Doc.X - 1) or Position
		elseif (Doc.X > 1) then
			Doc.X = Doc.X - 1
		elseif (Doc.Y > 1) then
			Doc.Y = Doc.Y - 1
			Doc.X = #Doc.Lines[Doc.Y] + 1
		end
	elseif (Key == keys.right) then
		if (Modifiers.Ctrl) then
			local _, Finish = Line:find("^[^%w_]*[%w_]*", Doc.X)
			Doc.X = (Finish or #Line) + 1
		elseif (Doc.X <= #Line) then
			Doc.X = Doc.X + 1
		elseif (Doc.Y < #Doc.Lines) then
			Doc.Y = Doc.Y + 1
			Doc.X = 1
		end
	elseif (Key == keys.up or Key == keys.down or Key == keys.pageUp or Key == keys.pageDown) then
		local Column = DisplayWidth(Line, Doc.X - 1)
		local Step = ({ [keys.up] = -1, [keys.down] = 1, [keys.pageUp] = -ViewH, [keys.pageDown] = ViewH })[Key]
		Doc.Y = math.max(1, math.min(#Doc.Lines, Doc.Y + Step))
		Doc.X = CharFromDisplay(Doc.Lines[Doc.Y], Column)
	elseif (Key == keys.home) then
		if (Modifiers.Ctrl) then
			Doc.Y = 1
			Doc.X = 1
		else
			local Indent = #Indentation(Line) + 1
			Doc.X = (Doc.X == Indent) and 1 or Indent
		end
	elseif (Key == keys["end"]) then
		if (Modifiers.Ctrl) then Doc.Y = #Doc.Lines end
		Doc.X = #Doc.Lines[Doc.Y] + 1
	else
		return false
	end
	return true
end

--
-- Commands
--

local Clipboard = nil

local function Copy(Cut)
	local Text = SelectedText()
	if (not Text) then
		Text = Doc.Lines[Doc.Y] .. "\n"
		if (Cut) then
			PushUndo("edit")
			if (#Doc.Lines > 1) then
				table.remove(Doc.Lines, Doc.Y)
			else
				Doc.Lines[1] = ""
			end
			Doc.Modified = true
			Invalidate(Doc.Y)
		end
	elseif (Cut) then
		PushUndo("edit")
		DeleteSelection()
	end
	Clipboard = Text
	BlockOS.TextClipboard = Text
	SetMessage(Cut and "Cut" or "Copied")
end

local function PasteInternal()
	local Text = BlockOS.TextClipboard or Clipboard
	if (not Text) then return end
	PushUndo("edit")
	InsertText(Text)
end

local function UndoStep(Reverse)
	local From, To = Doc.Undo, Doc.Redo
	if (Reverse) then From, To = Doc.Redo, Doc.Undo end
	local Shot = table.remove(From)
	if (not Shot) then return end
	table.insert(To, Snapshot())
	Restore(Shot)
	Doc.Modified = true
	LastUndoKind = nil
end

local function ReplaceAll()
	local Query = Ui.Prompt("Replace", "Find:", Find)
	if (not Query or #Query == 0) then return end
	local Replacement = Ui.Prompt("Replace", "Replace with:", "")
	if (not Replacement) then return end
	PushUndo("edit")
	local Count = 0
	local Pattern = Query:gsub("[%^%$%(%)%%%.%[%]%*%+%-%?]", "%%%0")
	local Safe = Replacement:gsub("%%", "%%%%")
	for Index, Line in ipairs(Doc.Lines) do
		local Updated, Hits = Line:gsub(Pattern, Safe)
		Doc.Lines[Index] = Updated
		Count = Count + Hits
	end
	Find = Query
	Doc.Modified = Count > 0 or Doc.Modified
	Invalidate(1)
	SetMessage("Replaced " .. Count .. " occurrence" .. (Count == 1 and "" or "s"))
end

local function GoToLine()
	local Value = tonumber(Ui.Prompt("Go to Line", "Line number (1-" .. #Doc.Lines .. "):", tostring(Doc.Y)) or "")
	if (Value) then
		Doc.Y = math.floor(Value)
		Doc.X = 1
		Doc.Anchor = nil
		EnsureVisible()
	end
end

local function NewDocument()
	if (not ConfirmDiscard()) then return end
	SetLines("")
	Doc.Path = nil
	UpdateTitle()
end

local function OpenDocument()
	if (not ConfirmDiscard()) then return end
	local Path = Ui.PickFile({ Dir = Doc.Path and fs.getDir(Doc.Path) or "/home/Documents" })
	if (Path) then LoadFile(Path) end
end

local function Close()
	if (ConfirmDiscard()) then
		BlockOS.Quit()
		Page:Stop()
	end
end

local function FileMenu()
	local Options = { "New", "Open...", "Save", "Save As...", "-", "Run", "-", "Close" }
	local OnDesktop = Doc.Path and Apps.HasShortcut(Doc.Path)
	if (Doc.Path) then
		table.insert(Options, 7, OnDesktop and "Remove from Desktop" or "Add to Desktop")
	end
	local Choice = Options[Ui.ContextMenu(1, 2, Options) or 0]
	if (Choice == "New") then
		NewDocument()
	elseif (Choice == "Open...") then
		OpenDocument()
	elseif (Choice == "Save") then
		Save()
	elseif (Choice == "Save As...") then
		if (SaveAs()) then Save() end
	elseif (Choice == "Run") then
		Run()
	elseif (Choice == "Add to Desktop" or Choice == "Remove from Desktop") then
		Apps.SetShortcut(Doc.Path, not OnDesktop)
	elseif (Choice == "Close") then
		Close()
	end
end

local function EditMenu()
	local Options = { "Undo", "Redo", "-", "Cut", "Copy", "Paste", "Select All", "-", "Find...", "Find Next", "Replace...", "Go to Line..." }
	local Choice = Options[Ui.ContextMenu(7, 2, Options) or 0]
	if (Choice == "Undo") then
		UndoStep(false)
	elseif (Choice == "Redo") then
		UndoStep(true)
	elseif (Choice == "Cut" or Choice == "Copy") then
		Copy(Choice == "Cut")
	elseif (Choice == "Paste") then
		PasteInternal()
	elseif (Choice == "Select All") then
		Doc.Anchor = { X = 1, Y = 1 }
		Doc.Y = #Doc.Lines
		Doc.X = #Doc.Lines[Doc.Y] + 1
	elseif (Choice == "Find...") then
		local Query = Ui.Prompt("Find", "Search for:", Find)
		if (Query) then
			Find = Query
			FindNext(Find)
		end
	elseif (Choice == "Find Next") then
		FindNext(Find)
	elseif (Choice == "Replace...") then
		ReplaceAll()
	elseif (Choice == "Go to Line...") then
		GoToLine()
	end
	EnsureVisible()
end

--
-- Editor widget
--

local function DrawEditor(Self, T, Th)
	local P = Palette(Th)
	local Digits = #tostring(#Doc.Lines)
	Self.Gutter = Digits + 2
	local ViewW = Self.W - Self.Gutter
	local AX, AY, BX, BY = SelectionRange()
	for Row = 1, Self.H do
		local LineIndex = Doc.ScrollY + Row
		local Y = Self.Y + Row - 1
		local Line = Doc.Lines[LineIndex]
		if (not Line) then
			Gfx.Fill(T, Self.X, Y, Self.Gutter, 1, P.Gutter)
			Gfx.Fill(T, Self.X + Self.Gutter, Y, ViewW, 1, P.Bg)
		else
			local Number = Gfx.Pad(tostring(LineIndex), Digits, "right") .. " "
			Gfx.Write(T, Self.X, Y, " " .. Number, (LineIndex == Doc.Y) and P.Text or P.GutterFg, P.Gutter)
			local Colors = Highlight(Line, StateAt(LineIndex, P), P)
			local Chars, Fg, Bg = {}, {}, {}
			local BgCode, SelCode = Hex[P.Bg], Hex[P.Selection]
			for Index = 1, #Line do
				local Char = Line:sub(Index, Index)
				local Selected = AX and (LineIndex > AY or (LineIndex == AY and Index >= AX)) and (LineIndex < BY or (LineIndex == BY and Index < BX))
				local Code = Colors:sub(Index, Index)
				if (Code == "") then Code = Hex[P.Text] end
				if (Char == "\t") then
					for _ = 1, TabWidth() do
						table.insert(Chars, " ")
						table.insert(Fg, Code)
						table.insert(Bg, Selected and SelCode or BgCode)
					end
				else
					table.insert(Chars, Char)
					table.insert(Fg, Code)
					table.insert(Bg, Selected and SelCode or BgCode)
				end
			end
			local Text = table.concat(Chars):sub(Doc.ScrollX + 1, Doc.ScrollX + ViewW)
			local FgText = table.concat(Fg):sub(Doc.ScrollX + 1, Doc.ScrollX + ViewW)
			local BgText = table.concat(Bg):sub(Doc.ScrollX + 1, Doc.ScrollX + ViewW)
			local Padding = ViewW - #Text
			T.setCursorPos(Self.X + Self.Gutter, Y)
			T.blit(Text .. string.rep(" ", Padding), FgText .. string.rep(Hex[P.Text], Padding), BgText .. string.rep(BgCode, Padding))
		end
	end
end

local function EditorCursor(Self)
	local Row = Doc.Y - Doc.ScrollY
	if (Row < 1 or Row > Self.H) then return nil end
	local Column = DisplayWidth(Doc.Lines[Doc.Y], Doc.X - 1) - Doc.ScrollX
	if (Column < 0 or Column >= Self.W - Self.Gutter) then return nil end
	local Th = BlockOS.Require("theme").Get()
	return Self.X + Self.Gutter + Column, Self.Y + Row - 1, Palette(Th).Text
end

local function PositionFromMouse(Self, X, Y)
	local LineIndex = math.max(1, math.min(#Doc.Lines, Doc.ScrollY + Y - Self.Y + 1))
	local Column = math.max(0, X - Self.X - Self.Gutter + Doc.ScrollX)
	return CharFromDisplay(Doc.Lines[LineIndex], Column), LineIndex
end

local function EditorEvent(Self, Name, A, B, C)
	if (Name == "mouse_click" or Name == "mouse_drag") then
		local X, Y = PositionFromMouse(Self, B, C)
		if (Name == "mouse_click") then
			if (A == 2) then
				EditMenu()
				return true
			end
			Doc.Anchor = Modifiers.Shift and (Doc.Anchor or { X = Doc.X, Y = Doc.Y }) or { X = X, Y = Y }
		end
		Doc.X, Doc.Y = X, Y
		EnsureVisible()
		return true
	elseif (Name == "mouse_up") then
		if (Doc.Anchor and Doc.Anchor.X == Doc.X and Doc.Anchor.Y == Doc.Y) then
			Doc.Anchor = nil
		end
		return true
	elseif (Name == "mouse_scroll") then
		Doc.ScrollY = math.max(0, math.min(Doc.ScrollY + A * 3, math.max(0, #Doc.Lines - Self.H)))
		return true
	elseif (Name == "char") then
		if (Modifiers.Ctrl) then return true end
		PushUndo((A == " ") and "space" or "type")
		InsertText(A)
		EnsureVisible()
		return true
	elseif (Name == "paste") then
		PushUndo("edit")
		InsertText(A)
		EnsureVisible()
		return true
	elseif (Name == "key") then
		if (Modifiers.Ctrl) then
			if (A == keys.s) then
				Save()
			elseif (A == keys.o) then
				OpenDocument()
			elseif (A == keys.n) then
				NewDocument()
			elseif (A == keys.z) then
				UndoStep(false)
			elseif (A == keys.y) then
				UndoStep(true)
			elseif (A == keys.c or A == keys.x) then
				Copy(A == keys.x)
			elseif (A == keys.a) then
				Doc.Anchor = { X = 1, Y = 1 }
				Doc.Y = #Doc.Lines
				Doc.X = #Doc.Lines[Doc.Y] + 1
			elseif (A == keys.f) then
				local Query = Ui.Prompt("Find", "Search for:", Find)
				if (Query) then
					Find = Query
					FindNext(Find)
				end
			elseif (A == keys.h) then
				ReplaceAll()
			elseif (A == keys.g) then
				GoToLine()
			elseif (A == keys.d) then
				PushUndo("edit")
				table.insert(Doc.Lines, Doc.Y + 1, Doc.Lines[Doc.Y])
				Doc.Y = Doc.Y + 1
				Doc.Modified = true
				Invalidate(Doc.Y)
			elseif (A == keys.q or A == keys.w) then
				Close()
			elseif (not Move(A)) then
				return false
			elseif (not Modifiers.Shift) then
				Doc.Anchor = nil
			end
			EnsureVisible()
			return true
		end
		local Before = { X = Doc.X, Y = Doc.Y }
		if (Move(A)) then
			if (Modifiers.Shift) then
				Doc.Anchor = Doc.Anchor or Before
			else
				Doc.Anchor = nil
			end
		elseif (A == keys.enter or A == keys.numPadEnter) then
			NewLine()
		elseif (A == keys.backspace) then
			PushUndo("delete")
			if (not DeleteSelection()) then
				if (Doc.X > 1) then
					local Line = Doc.Lines[Doc.Y]
					local Unit = IndentUnit()
					if (Line:sub(1, Doc.X - 1):match("^%s+$") and Line:sub(Doc.X - #Unit, Doc.X - 1) == Unit) then
						Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - #Unit - 1) .. Line:sub(Doc.X)
						Doc.X = Doc.X - #Unit
					else
						Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - 2) .. Line:sub(Doc.X)
						Doc.X = Doc.X - 1
					end
				elseif (Doc.Y > 1) then
					local Previous = Doc.Lines[Doc.Y - 1]
					Doc.Lines[Doc.Y - 1] = Previous .. Doc.Lines[Doc.Y]
					table.remove(Doc.Lines, Doc.Y)
					Doc.Y = Doc.Y - 1
					Doc.X = #Previous + 1
				end
				Doc.Modified = true
				Invalidate(Doc.Y)
			end
		elseif (A == keys.delete) then
			PushUndo("delete")
			if (not DeleteSelection()) then
				local Line = Doc.Lines[Doc.Y]
				if (Doc.X <= #Line) then
					Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - 1) .. Line:sub(Doc.X + 1)
				elseif (Doc.Y < #Doc.Lines) then
					Doc.Lines[Doc.Y] = Line .. Doc.Lines[Doc.Y + 1]
					table.remove(Doc.Lines, Doc.Y + 1)
				end
				Doc.Modified = true
				Invalidate(Doc.Y)
			end
		elseif (A == keys.tab) then
			PushUndo("edit")
			InsertText(IndentUnit())
		elseif (A == keys.f3) then
			FindNext(Find)
		elseif (A == keys.f5) then
			Run()
		else
			return false
		end
		EnsureVisible()
		return true
	end
	return false
end

function Page:OnLayout(W, H)
	self:Clear()
	self:Add(Ui.Panel.new({ X = 1, Y = 1, W = W, H = 1, Bg = "Panel" }))
	self:Add(Ui.Button.new({ X = 1, Y = 1, Text = "File", Bg = "Panel", OnClick = function() FileMenu() end }))
	self:Add(Ui.Button.new({ X = 7, Y = 1, Text = "Edit", Bg = "Panel", OnClick = function() EditMenu() end }))
	self:Add(Ui.Button.new({ X = W - 13, Y = 1, W = 6, Text = "Save", Bg = "Panel", OnClick = function() Save() end }))
	self:Add(Ui.Button.new({ X = W - 6, Y = 1, W = 7, Text = "Run \16", Style = "primary", OnClick = function() Run() end }))
	Editor = self:Add(Ui.Canvas.new({
		X = 1, Y = 2, W = W, H = H - 2, Gutter = 3, Focusable = true, KeepFocus = true,
		OnDraw = DrawEditor,
		OnEvent = EditorEvent,
		OnCursor = EditorCursor
	}))
	self:Add(Ui.Canvas.new({
		X = 1, Y = H, W = W, H = 1,
		OnDraw = function(Self, T, Th)
			local Left = " Ln " .. Doc.Y .. ", Col " .. Doc.X .. (Doc.Modified and "  \7 Edited" or "")
			local Right = (IsLua() and "Lua" or "Text") .. " "
			if (Message and os.clock() - MessageTime < 4) then
				Right = Message .. "  " .. Right
			end
			Gfx.Write(T, Self.X, Self.Y, Gfx.Pad(Left, Self.W - #Right) .. Right, Th.SubText, Th.Panel)
		end
	}))
	self:SetFocus(Editor)
	EnsureVisible()
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_close") then
		Close()
		return true
	elseif (Name == "blockos_open" and A) then
		if (ConfirmDiscard()) then LoadFile(A) end
		return true
	end
	return false
end

function Page:OnTerminate()
	Close()
end

local BaseHandle = Page.Handle
function Page:Handle(...)
	BaseHandle(self, ...)
	if (Doc.Modified ~= self.LastModified) then
		self.LastModified = Doc.Modified
		UpdateTitle()
	end
end

BlockOS.SetCloseHandler(true)
if (Args[1]) then
	LoadFile(shell and shell.resolve(Args[1]) or Args[1])
else
	UpdateTitle()
end
Page:SetInterval(1, function()
	return Message ~= nil
end)
Page:Run()
]=]
Files["blockos/apps/finder/app.cfg"] = [[
{ Name = "Finder", Description = "Browse files, folders, disks and apps.", Width = 44, Height = 14, Icon = { Lines = { " :)", "\140\140\140" }, Fg = "white", Bg = "blue" } }
]]
Files["blockos/apps/finder/main.lua"] = [[
-- Finder: file manager with favourites, disks and an Applications view.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Apps = BlockOS.Require("apps")
local Config = BlockOS.Require("config")
local Image = BlockOS.Require("image")
local Wallpaper = BlockOS.Require("wallpaper")

local Args = { ... }

local AppsPath = "apps:"
local Printable = { txt = true, md = true, log = true }
local Current = Args[1] or "/home"
local Back, Forward = {}, {}
local Page = Ui.Page.new()
local Sidebar, Files, PathLabel, Status

BlockOS.Clipboard = BlockOS.Clipboard or {}

local Kinds = {
	lua = { Icon = "\4", Fg = colors.yellow, Name = "Lua script" },
	txt = { Icon = "\7", Fg = colors.lightGray, Name = "Text" },
	md = { Icon = "\7", Fg = colors.lightGray, Name = "Markdown" },
	dfpwm = { Icon = "\14", Fg = colors.red, Name = "DFPWM audio" },
	rec = { Icon = "\7", Fg = colors.red, Name = "Recording" },
	nfp = { Icon = "\127", Fg = colors.pink, Name = "Paint image" },
	bimg = { Icon = "\127", Fg = colors.magenta, Name = "Brocreate picture" },
	ccmd = { Icon = "@", Fg = colors.orange, Name = "ccmd page" },
	json = { Icon = "\7", Fg = colors.orange, Name = "JSON" },
	cfg = { Icon = "\7", Fg = colors.orange, Name = "Config" }
}

local function Normalize(Path)
	if (Path == AppsPath) then return Path end
	return "/" .. fs.combine(Path, "")
end

local function KindOf(Path)
	if (fs.isDir(Path)) then
		return { Icon = "\16", Fg = colors.lightBlue, Name = "Folder" }
	end
	local Extension = Path:match("%.([%w]+)$")
	return Kinds[Extension and Extension:lower() or ""] or { Icon = "\7", Fg = colors.gray, Name = "File" }
end

local function DisplayName(Path)
	if (Path == AppsPath) then return "Applications" end
	if (Path == "/") then return "Computer" end
	if (Path == "/home") then return "Home" end
	return fs.getName(Path)
end

local function UniqueName(Dir, Name)
	if (not fs.exists(fs.combine(Dir, Name))) then return Name end
	local Base, Extension = Name:match("^(.-)(%.[^%.]*)$")
	if (not Base or Base == "") then
		Base, Extension = Name, ""
	end
	local Index = 1
	while (true) do
		local Candidate = Base .. " copy" .. (Index > 1 and (" " .. Index) or "") .. Extension
		if (not fs.exists(fs.combine(Dir, Candidate))) then return Candidate end
		Index = Index + 1
	end
end

local function SidebarItems()
	local Items = {
		{ Text = "Favorites", Header = true },
		{ Text = "Home", Path = "/home", Icon = "\127", IconFg = colors.lightBlue },
		{ Text = "Documents", Path = "/home/Documents", Icon = "\7", IconFg = colors.lightBlue },
		{ Text = "Downloads", Path = "/home/Downloads", Icon = "\25", IconFg = colors.lightBlue },
		{ Text = "Music", Path = "/home/Music", Icon = "\14", IconFg = colors.lightBlue },
		{ Text = "Recordings", Path = "/home/Recordings", Icon = "\7", IconFg = colors.red },
		{ Text = "Pictures", Path = "/home/Pictures", Icon = "\127", IconFg = colors.magenta },
		{ Text = "Locations", Header = true },
		{ Text = "Apps", Path = AppsPath, Icon = "\4", IconFg = colors.purple },
		{ Text = "Computer", Path = "/", Icon = "\8", IconFg = colors.gray }
	}
	for _, Side in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Side) == "drive" and disk.hasData(Side)) then
			local Mount = disk.getMountPath(Side)
			table.insert(Items, { Text = disk.getLabel(Side) or Mount, Path = "/" .. Mount, Icon = "\22", IconFg = colors.gray, Side = Side })
		end
	end
	return Items
end

local Refresh

local function Navigate(Path, SkipHistory)
	Path = Normalize(Path)
	if (Path ~= AppsPath and not fs.isDir(Path)) then
		BlockOS.Open(Path)
		return
	end
	if (not SkipHistory and Path ~= Current) then
		table.insert(Back, Current)
		Forward = {}
	end
	Current = Path
	Refresh()
end

local function OpenItem(Item)
	if (not Item) then return end
	if (Item.App) then
		BlockOS.Launch(Item.App.ID)
	elseif (Item.IsDir) then
		Navigate(Item.Path)
	else
		BlockOS.Open(Item.Path)
	end
end

function Refresh()
	local Items = {}
	if (Current == AppsPath) then
		for _, App in ipairs(Apps.List()) do
			table.insert(Items, {
				Text = App.Name,
				Icon = Gfx.Pad(App.Icon.Lines[1], 3),
				IconFg = App.Icon.Bg,
				Right = App.System and "System" or "Installed",
				App = App
			})
		end
	else
		if (not fs.isDir(Current)) then Current = "/" end
		local Names = fs.list(Current)
		table.sort(Names, function(A, B) return A:lower() < B:lower() end)
		local Dirs, Plain = {}, {}
		for _, Name in ipairs(Names) do
			local Path = fs.combine(Current, Name)
			local Kind = KindOf(Path)
			local Entry = { Text = Name, Icon = Kind.Icon, IconFg = Kind.Fg, Path = "/" .. Path, IsDir = fs.isDir(Path) }
			if (Entry.IsDir) then
				Entry.Right = "--"
				table.insert(Dirs, Entry)
			else
				Entry.Right = Gfx.FormatSize(fs.getSize(Path))
				table.insert(Plain, Entry)
			end
		end
		for _, Entry in ipairs(Dirs) do table.insert(Items, Entry) end
		for _, Entry in ipairs(Plain) do table.insert(Items, Entry) end
	end
	Files:SetItems(Items)
	local SideItems = SidebarItems()
	Sidebar:SetItems(SideItems, true)
	Sidebar.Selected = 0
	for Index, Item in ipairs(SideItems) do
		if (Item.Path == Current) then Sidebar.Selected = Index end
	end
	PathLabel.Text = DisplayName(Current)
	if (Current == AppsPath) then
		Status.Text = #Items .. " apps"
	else
		Status.Text = #Items .. " items, " .. Gfx.FormatSize(fs.getFreeSpace(Current)) .. " free" .. (fs.isReadOnly(Current) and ", read-only" or "")
	end
	BlockOS.SetTitle(DisplayName(Current))
	Page:Invalidate()
end

local function Paste(Dir)
	local Clip = BlockOS.Clipboard
	if (not Clip.Path or not fs.exists(Clip.Path) or Dir == AppsPath) then return end
	local Target = fs.combine(Dir, UniqueName(Dir, fs.getName(Clip.Path)))
	local Ok, Err = pcall(function()
		if (Clip.Cut) then
			fs.move(Clip.Path, Target)
			Apps.MoveShortcuts(Clip.Path, Target)
		else
			fs.copy(Clip.Path, Target)
		end
	end)
	if (not Ok) then
		Ui.Alert("Paste failed", tostring(Err))
	end
	if (Clip.Cut) then BlockOS.Clipboard = {} end
	Refresh()
end

local function NewItem(Folder)
	if (Current == AppsPath or fs.isReadOnly(Current)) then return end
	local Name = Ui.Prompt(Folder and "New Folder" or "New File", "Name:", Folder and "untitled folder" or "untitled.txt")
	if (not Name or #Name == 0) then return end
	local Path = fs.combine(Current, UniqueName(Current, Name))
	if (Folder) then
		fs.makeDir(Path)
	else
		local Handle = fs.open(Path, "w")
		if (Handle) then Handle.close() end
	end
	Refresh()
end

local function DeleteItem(Item)
	if (not Item or not Item.Path or fs.isReadOnly(Item.Path)) then return end
	if (Ui.Confirm("Delete", "Delete \"" .. fs.getName(Item.Path) .. "\"? This cannot be undone.", "Delete")) then
		local Ok, Err = pcall(fs.delete, Item.Path)
		if (Ok) then
			Apps.MoveShortcuts(Item.Path, nil)
		else
			Ui.Alert("Delete failed", tostring(Err))
		end
		Refresh()
	end
end

local function GetInfo(Item)
	if (Item.App) then
		local App = Item.App
		Ui.Alert(App.Name, (App.Description or "No description.") .. "\n\nID: " .. App.ID .. "\nLocation: " .. App.Dir)
		return
	end
	local Path = Item.Path
	local Lines = { "Kind: " .. KindOf(Path).Name, "Where: " .. fs.getDir(Path) }
	if (not Item.IsDir) then
		table.insert(Lines, "Size: " .. Gfx.FormatSize(fs.getSize(Path)))
	end
	if (fs.attributes) then
		local Ok, Attributes = pcall(fs.attributes, Path)
		if (Ok and Attributes.modified and Attributes.modified > 0) then
			table.insert(Lines, "Modified: " .. os.date("%Y-%m-%d %H:%M", math.floor(Attributes.modified / 1000)))
		end
	end
	table.insert(Lines, fs.isReadOnly(Path) and "Read-only" or "Writable")
	Ui.Alert(fs.getName(Path), table.concat(Lines, "\n"))
end

local function SetWallpaper(Path)
	if (not Image.Load(Path)) then
		Ui.Alert("Set as Wallpaper", fs.getName(Path) .. " is not a picture BlockOS can read.")
		return
	end
	local Settings = Config.Settings()
	Settings.Wallpaper = Wallpaper.Picture.ID
	Settings.WallpaperImage = "/" .. fs.combine(Path, "")
	Wallpaper.Invalidate()
	Config.Save("settings")
end

local function AppMenu(Item, X, Y)
	local App = Item.App
	local Pinned = Apps.IsPinned(App.ID)
	local OnDesktop = Apps.HasShortcut(Apps.AppShortcut(App.ID))
	local Options = { "Open", "Open Full Screen", "-", Pinned and "Remove from Dock" or "Keep in Dock", OnDesktop and "Remove from Desktop" or "Add to Desktop", "Add to Login Items", "Get Info" }
	if (not App.System) then
		table.insert(Options, "-")
		table.insert(Options, "Uninstall")
	end
	local Choice = Options[Ui.ContextMenu(X, Y, Options) or 0]
	if (Choice == "Open") then
		BlockOS.Launch(App.ID)
	elseif (Choice == "Open Full Screen") then
		BlockOS.Launch(App.ID, {}, { Mode = "fullscreen" })
	elseif (Choice == "Keep in Dock" or Choice == "Remove from Dock") then
		Apps.SetPinned(App.ID, not Pinned)
	elseif (Choice == "Add to Desktop" or Choice == "Remove from Desktop") then
		Apps.SetShortcut(Apps.AppShortcut(App.ID), not OnDesktop)
	elseif (Choice == "Add to Login Items") then
		local Settings = Config.Settings()
		table.insert(Settings.StartupApps, App.ID)
		Config.Save("settings")
	elseif (Choice == "Get Info") then
		GetInfo(Item)
	elseif (Choice == "Uninstall") then
		if (Ui.Confirm("Uninstall", "Remove " .. App.Name .. " from this computer?", "Uninstall")) then
			Apps.Uninstall(App.ID)
			Refresh()
		end
	end
end

local function FileMenu(Item, X, Y)
	local ReadOnly = Current == AppsPath or fs.isReadOnly(Current)
	local HasClip = BlockOS.Clipboard.Path ~= nil
	if (not Item) then
		local Options = {
			{ Text = "New Folder", Disabled = ReadOnly },
			{ Text = "New File", Disabled = ReadOnly },
			{ Text = "Paste", Disabled = ReadOnly or not HasClip },
			"-",
			{ Text = "Open in Terminal" },
			{ Text = "Refresh" }
		}
		local Index = Ui.ContextMenu(X, Y, Options)
		local Choice = Index and Options[Index].Text
		if (Choice == "New Folder") then
			NewItem(true)
		elseif (Choice == "New File") then
			NewItem(false)
		elseif (Choice == "Paste") then
			Paste(Current)
		elseif (Choice == "Open in Terminal") then
			BlockOS.Launch("terminal", { Current })
		elseif (Choice == "Refresh") then
			Refresh()
		end
		return
	end
	if (Item.App) then
		AppMenu(Item, X, Y)
		return
	end
	local Locked = fs.isReadOnly(Item.Path)
	local OnDesktop = Apps.HasShortcut(Item.Path)
	local Options = {
		{ Text = "Open" },
		{ Text = "Edit", Disabled = Item.IsDir },
		{ Text = "Run", Disabled = Item.IsDir },
		"-",
		{ Text = "Rename", Disabled = Locked },
		{ Text = "Duplicate", Disabled = ReadOnly },
		{ Text = "Copy" },
		{ Text = "Cut", Disabled = Locked },
		{ Text = "Paste", Disabled = ReadOnly or not HasClip },
		"-",
		{ Text = OnDesktop and "Remove from Desktop" or "Add to Desktop" },
		{ Text = "Get Info" },
		{ Text = "Delete", Disabled = Locked }
	}
	local Extension = (fs.getName(Item.Path):match("%.(%w+)$") or ""):lower()
	if (not Item.IsDir and Printable[Extension]) then
		table.insert(Options, 4, { Text = "Print" })
	end
	if (not Item.IsDir and Image.IsImage(Item.Path)) then
		table.insert(Options, 4, { Text = "Set as Wallpaper" })
	end
	local Index = Ui.ContextMenu(X, Y, Options)
	local Choice = Index and Options[Index].Text
	if (Choice == "Open") then
		OpenItem(Item)
	elseif (Choice == "Edit") then
		BlockOS.Launch(Apps.EditorFor(Item.Path), { Item.Path })
	elseif (Choice == "Run") then
		BlockOS.Launch(Item.Path, {}, { Hold = true })
	elseif (Choice == "Print") then
		BlockOS.Launch("print", { Item.Path })
	elseif (Choice == "Set as Wallpaper") then
		SetWallpaper(Item.Path)
	elseif (Choice == "Add to Desktop" or Choice == "Remove from Desktop") then
		Apps.SetShortcut(Item.Path, not OnDesktop)
	elseif (Choice == "Rename") then
		local Name = Ui.Prompt("Rename", "New name:", fs.getName(Item.Path))
		if (Name and #Name > 0 and Name ~= fs.getName(Item.Path)) then
			local Target = fs.combine(fs.getDir(Item.Path), Name)
			if (fs.exists(Target)) then
				Ui.Alert("Rename", "An item with that name already exists.")
			else
				fs.move(Item.Path, Target)
				Apps.MoveShortcuts(Item.Path, Target)
			end
		end
		Refresh()
	elseif (Choice == "Duplicate") then
		fs.copy(Item.Path, fs.combine(Current, UniqueName(Current, fs.getName(Item.Path))))
		Refresh()
	elseif (Choice == "Copy" or Choice == "Cut") then
		BlockOS.Clipboard = { Path = Item.Path, Cut = Choice == "Cut" }
	elseif (Choice == "Paste") then
		Paste(Item.IsDir and Item.Path or Current)
	elseif (Choice == "Get Info") then
		GetInfo(Item)
	elseif (Choice == "Delete") then
		DeleteItem(Item)
	end
end

local function GoUp()
	if (Current == AppsPath or Current == "/") then return end
	Navigate("/" .. fs.getDir(Current))
end

function Page:OnLayout(W, H)
	self:Clear()
	local SideW = (W >= 34) and 12 or 0
	self:Add(Ui.Panel.new({ X = 1, Y = 1, W = W, H = 1, Bg = "Panel" }))
	self:Add(Ui.Button.new({ X = 1, Y = 1, W = 3, Text = "\17", Bg = "Panel", OnClick = function()
		if (#Back > 0) then
			table.insert(Forward, Current)
			Current = table.remove(Back)
			Refresh()
		end
	end }))
	self:Add(Ui.Button.new({ X = 4, Y = 1, W = 3, Text = "\16", Bg = "Panel", OnClick = function()
		if (#Forward > 0) then
			table.insert(Back, Current)
			Current = table.remove(Forward)
			Refresh()
		end
	end }))
	self:Add(Ui.Button.new({ X = 7, Y = 1, W = 3, Text = "\24", Bg = "Panel", OnClick = GoUp }))
	PathLabel = self:Add(Ui.Label.new({ X = 11, Y = 1, W = W - 18, Text = "", Bg = "Panel", Fg = "PanelFg" }))
	self:Add(Ui.Button.new({ X = W - 6, Y = 1, W = 3, Text = "+", Bg = "Panel", OnClick = function() NewItem(true) end }))
	self:Add(Ui.Button.new({ X = W - 3, Y = 1, W = 3, Text = "\15", Bg = "Panel", OnClick = function() FileMenu(nil, W - 3, 2) end }))
	Sidebar = self:Add(Ui.List.new({ X = 1, Y = 2, W = SideW, H = H - 2, Bg = "Panel", Focusable = false, SingleClick = true, Visible = SideW > 0 }))
	Sidebar.RenderItem = function(_, T, Th, Item, X, Y, Width, Selected, RowBg, RowFg)
		if (Item.Header) then
			Gfx.Write(T, X, Y, Gfx.Pad(Item.Text, Width), Th.SubText, Th.Panel)
			return
		end
		Gfx.Write(T, X, Y, " " .. (Item.Icon or " ") .. " " .. Gfx.Truncate(Item.Text, Width - 4), Selected and RowFg or Th.PanelFg, RowBg)
		if (not Selected) then
			Gfx.Write(T, X + 1, Y, Item.Icon or " ", Item.IconFg or Th.PanelFg, RowBg)
		end
	end
	Sidebar.OnActivate = function(_, _, Item)
		if (Item.Header) then return end
		Navigate(Item.Path)
	end
	Sidebar.OnContext = function(_, _, Item, X, Y)
		if (Item and Item.Side) then
			local Choice = Ui.ContextMenu(X, Y, { "Open", "Eject" })
			if (Choice == 1) then
				Navigate(Item.Path)
			elseif (Choice == 2) then
				disk.eject(Item.Side)
			end
		end
	end
	Files = self:Add(Ui.List.new({ X = SideW + 1, Y = 2, W = W - SideW, H = H - 2 }))
	Files.OnActivate = function(_, _, Item) OpenItem(Item) end
	Files.OnContext = function(_, _, Item, X, Y) FileMenu(Item, X, Y) end
	Status = self:Add(Ui.Label.new({ X = 1, Y = H, W = W, Text = "", Bg = "Panel", Fg = "SubText", Align = "center" }))
	self:SetFocus(Files)
	Refresh()
end

function Page:OnEvent(Name, A)
	if (Name == "key") then
		if (A == keys.backspace) then
			GoUp()
			return true
		elseif (A == keys.delete) then
			DeleteItem(Files.Items[Files.Selected])
			return true
		end
	elseif (Name == "disk" or Name == "disk_eject" or Name == "blockos_apps" or Name == "peripheral" or Name == "peripheral_detach") then
		Refresh()
		return true
	elseif (Name == "blockos_open") then
		Navigate(A)
		return true
	end
	return false
end

Current = Normalize(Current)
Page:Run()
]]
Files["blockos/apps/launchpad/app.cfg"] = [[
{ Name = "Launchpad", Description = "All of your apps in one place.", Builtin = "launchpad", Icon = { Lines = { "\7\7\7", "\7\7\7" }, Fg = "white", Bg = "gray" } }
]]
Files["blockos/apps/messages/app.cfg"] = [[
{ Name = "Messages", Description = "Chat with other BlockOS computers over rednet, with encrypted rooms.", Width = 46, Height = 15, Single = true, Icon = { Lines = { "...", "/  " }, Fg = "white", Bg = "green" } }
]]
Files["blockos/apps/messages/main.lua"] = [[
-- Messages: Enchat-style chat rooms between BlockOS computers over rednet.
-- Rooms with a key are end-to-end encrypted; /dm opens a direct conversation.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Chat = BlockOS.Require("chat")

local Page = Ui.Page.new()
local ActiveID = nil
local Scroll = 0
local Rooms, Input, MessageView

local NickColors = { colors.red, colors.orange, colors.green, colors.cyan, colors.blue, colors.purple, colors.magenta, colors.brown }

local function NickColor(Nick)
	local Hash = 0
	for Index = 1, #Nick do
		Hash = (Hash * 17 + Nick:byte(Index)) % 251
	end
	return NickColors[Hash % #NickColors + 1]
end

local function Active()
	return ActiveID and Chat.Rooms[ActiveID]
end

local function RoomTitle(Room)
	if (Room.Target) then return "@" .. Room.Name:gsub("^@", "") end
	return "#" .. Room.Name
end

local function SetActive(ID)
	ActiveID = ID
	Scroll = 0
	local Room = Active()
	if (Room) then
		Room.Unread = 0
		BlockOS.SetTitle("Messages \7 " .. RoomTitle(Room))
	end
end

local function System(Text)
	local Room = Active()
	if (not Room) then return end
	table.insert(Room.Messages, { Kind = "system", Text = Text, Time = os.epoch("utc") })
end

local Refresh

local function JoinPrompt()
	local Name = Ui.Prompt("Join Room", "Room name:", "")
	if (not Name or #Name == 0) then return end
	Name = Name:gsub("^#", ""):gsub("%s+", "-"):lower()
	local Key = Ui.Prompt("Join Room", "Room key (leave empty for a public room):", "", "\7")
	if (Key == nil) then return end
	local Room = Chat.Join(Name, Key)
	SetActive(Room.ID)
	Refresh()
end

local Help = {
	"/join <room> [key]  join or create a room",
	"/leave              leave this room",
	"/nick <name>        change your nickname",
	"/me <action>        send an action",
	"/dm <computer id>   start a direct message",
	"/who                list people online",
	"/clear              clear this room's history"
}

local function RunCommand(Text)
	local Command, Rest = Text:match("^/(%S+)%s*(.*)$")
	Command = (Command or ""):lower()
	local Room = Active()
	if (Command == "join") then
		local Name, Key = Rest:match("^#?(%S+)%s*(.*)$")
		if (not Name) then
			JoinPrompt()
			return
		end
		local NewRoom = Chat.Join(Name:lower(), Key)
		SetActive(NewRoom.ID)
	elseif (Command == "leave") then
		if (Room) then
			Chat.Leave(Room.ID)
			SetActive(Chat.Order[1])
		end
	elseif (Command == "nick") then
		if (#Rest > 0) then
			Chat.SetNick(Rest:sub(1, 20))
			System("You are now known as " .. Rest:sub(1, 20))
			Chat.Presence()
		end
	elseif (Command == "me") then
		if (Room and #Rest > 0) then Chat.Send(Room.ID, Rest, "me") end
	elseif (Command == "dm") then
		local Target = tonumber(Rest)
		if (not Target or Target == os.getComputerID()) then
			System("Usage: /dm <computer id>")
			return
		end
		local NewRoom = Chat.Join("@" .. Target, nil, Target)
		SetActive(NewRoom.ID)
	elseif (Command == "who") then
		if (Room) then
			local Names = {}
			for _, User in ipairs(Chat.OnlineUsers(Room)) do
				table.insert(Names, User.Nick .. " (#" .. User.ID .. ")")
			end
			System((#Names > 0) and ("Online: " .. table.concat(Names, ", ")) or "Nobody else is here yet.")
		end
	elseif (Command == "clear") then
		if (Room) then
			Room.Messages = {}
			Chat.Save()
		end
	else
		for _, Line in ipairs(Help) do
			System(Line)
		end
	end
	Refresh()
end

local function Send(Text)
	Text = Text:gsub("^%s+", ""):gsub("%s+$", "")
	if (#Text == 0) then return end
	if (Text:sub(1, 1) == "/") then
		RunCommand(Text)
		return
	end
	local Room = Active()
	if (not Room) then return end
	local Ok, Err = Chat.Send(Room.ID, Text)
	if (not Ok) then
		System("Not sent: " .. tostring(Err))
	end
	Scroll = 0
	Refresh()
end

-- Builds wrapped display lines: each is a list of { Text, Color } segments.
local function RenderLines(Room, Width, Th)
	local Lines = {}
	for _, Message in ipairs(Room.Messages) do
		local Stamp = os.date("%H:%M", math.floor((Message.Time or 0) / 1000)) .. " "
		local Prefix, PrefixColor, Body, BodyColor
		if (Message.Kind == "system") then
			Prefix, PrefixColor, Body, BodyColor = "", Th.SubText, Message.Text, Th.SubText
		elseif (Message.Kind == "me") then
			Prefix, PrefixColor, Body, BodyColor = "* " .. Message.Nick .. " ", NickColor(Message.Nick), Message.Text, Th.Text
		else
			Prefix = Message.Nick .. ": "
			PrefixColor = Message.Self and Th.Accent or NickColor(Message.Nick)
			Body, BodyColor = Message.Text, Th.Text
		end
		if (Message.Failed) then
			Body = Body .. " (!)"
		end
		local Wrapped = Gfx.Wrap(Prefix .. Body, Width - #Stamp)
		for Index, Line in ipairs(Wrapped) do
			local Segments = { { Index == 1 and Stamp or string.rep(" ", #Stamp), Th.SubText } }
			if (Index == 1 and #Prefix > 0) then
				table.insert(Segments, { Line:sub(1, #Prefix), PrefixColor })
				table.insert(Segments, { Line:sub(#Prefix + 1), BodyColor })
			else
				table.insert(Segments, { Line, BodyColor })
			end
			table.insert(Lines, Segments)
		end
	end
	return Lines
end

function Refresh()
	local Items = {}
	local Selected = 0
	for Index, ID in ipairs(Chat.Order) do
		local Room = Chat.Rooms[ID]
		table.insert(Items, {
			Text = RoomTitle(Room),
			Icon = Room.Key and "\4" or " ",
			IconFg = colors.orange,
			Right = (Room.Unread > 0) and tostring(Room.Unread) or "",
			ID = ID
		})
		if (ID == ActiveID) then Selected = Index end
	end
	if (Rooms) then
		Rooms:SetItems(Items, true)
		Rooms.Selected = Selected
	end
	Page:Invalidate()
end

function Page:OnLayout(W, H)
	self:Clear()
	local SideW = (W >= 36) and 13 or 0
	Rooms = self:Add(Ui.List.new({ X = 1, Y = 1, W = SideW, H = H - 1, Bg = "Panel", SingleClick = true, Focusable = false, Visible = SideW > 0 }))
	Rooms.OnActivate = function(_, _, Item)
		SetActive(Item.ID)
		Refresh()
	end
	Rooms.OnContext = function(_, _, Item, X, Y)
		local Options = { "Join Room..." }
		if (Item) then
			table.insert(Options, "Leave " .. Item.Text)
		end
		local Choice = Ui.ContextMenu(X, Y, Options)
		if (Choice == 1) then
			JoinPrompt()
		elseif (Choice == 2) then
			Chat.Leave(Item.ID)
			SetActive(Chat.Order[1])
			Refresh()
		end
	end
	self:Add(Ui.Button.new({ X = 1, Y = H, W = math.max(SideW, 1), Text = "+ Join", Bg = "Panel", Visible = SideW > 0, OnClick = JoinPrompt }))
	local MainX = SideW + 1
	local MainW = W - SideW
	self:Add(Ui.Canvas.new({
		X = MainX, Y = 1, W = MainW, H = 1,
		OnDraw = function(Self, T, Th)
			local Room = Active()
			Gfx.Fill(T, Self.X, Self.Y, Self.W, 1, Th.Panel)
			if (not Room) then return end
			local Online = #Chat.OnlineUsers(Room)
			local Title = " " .. RoomTitle(Room) .. (Room.Key and " \4" or "")
			local Info = Room.Target and "direct " or (Online .. " online ")
			Gfx.Write(T, Self.X, Self.Y, Gfx.Truncate(Title, Self.W - #Info), Th.PanelFg, Th.Panel)
			Gfx.Write(T, Self.X + Self.W - #Info, Self.Y, Info, Th.SubText, Th.Panel)
		end,
		OnEvent = function(_, Name)
			if (Name ~= "mouse_click" or SideW > 0) then return false end
			local Names = {}
			for _, ID in ipairs(Chat.Order) do
				table.insert(Names, RoomTitle(Chat.Rooms[ID]))
			end
			table.insert(Names, "+ Join Room...")
			local Index = Ui.Choose("Rooms", Names)
			if (Index == #Names) then
				JoinPrompt()
			elseif (Index) then
				SetActive(Chat.Order[Index])
				Refresh()
			end
			return true
		end
	}))
	MessageView = self:Add(Ui.Canvas.new({
		X = MainX, Y = 2, W = MainW, H = H - 2,
		OnDraw = function(Self, T, Th)
			local Room = Active()
			if (not Chat.OpenModems()) then
				Gfx.Write(T, Self.X + 1, Self.Y, Gfx.Truncate("No modem attached. Attach a wireless or ender modem.", Self.W - 2), colors.red, Th.WindowBg)
			end
			if (not Room) then return end
			local Lines = RenderLines(Room, Self.W - 1, Th)
			local MaxScroll = math.max(0, #Lines - Self.H)
			Scroll = math.min(Scroll, MaxScroll)
			local First = #Lines - Self.H - Scroll + 1
			for Row = 1, Self.H do
				local Segments = Lines[First + Row - 1]
				if (Segments) then
					local X = Self.X + 1
					for _, Segment in ipairs(Segments) do
						Gfx.Write(T, X, Self.Y + Row - 1, Segment[1], Segment[2], Th.WindowBg)
						X = X + #Segment[1]
					end
				end
			end
			if (#Room.Messages == 0) then
				Gfx.Center(T, Self.Y + math.floor(Self.H / 2), "Say hello to " .. RoomTitle(Room), Th.SubText, Th.WindowBg, Self.X, Self.W)
			end
		end,
		OnEvent = function(_, Name, A)
			if (Name == "mouse_scroll") then
				Scroll = math.max(0, Scroll - A * 2)
				return true
			end
			return false
		end
	}))
	Input = self:Add(Ui.Input.new({ X = MainX, Y = H, W = MainW, Placeholder = "Message (/help for commands)", MaxLength = 400 }))
	Input.OnSubmit = function(Self, Value)
		Self:SetValue("")
		Send(Value)
	end
	self:SetFocus(Input)
	Refresh()
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_chat") then
		local Room = Active()
		if (Room and A == Room.ID and BlockOS.IsFocused()) then
			Room.Unread = 0
		end
		Refresh()
		return true
	elseif (Name == "peripheral" or Name == "peripheral_detach") then
		return true
	elseif (Name == "key" and (A == keys.pageUp or A == keys.pageDown)) then
		Scroll = math.max(0, Scroll + ((A == keys.pageUp) and 5 or -5))
		return true
	end
	return false
end

Chat.Load()
Chat.OpenModems()
if (not Chat.Nick) then
	local Nick = Ui.Prompt("Welcome to Messages", "Choose a nickname others will see:", Chat.GetNick())
	if (Nick and #Nick > 0) then
		Chat.SetNick(Nick:sub(1, 20))
	else
		Chat.SetNick(Chat.GetNick())
	end
end
SetActive(Chat.Order[1])
Page:SetInterval(15, function() return true end)
Page:Run()
]]
Files["blockos/apps/network/app.cfg"] = [[
{ Name = "Network", Description = "Find nearby BlockOS computers on a GPS map.", Width = 46, Height = 16, Single = true, Icon = { Lines = { "\7 \7", " \2 " }, Fg = "white", Bg = "cyan" } }
]]
Files["blockos/apps/network/main.lua"] = [[
-- Network: finds nearby BlockOS computers over rednet and places them on a map using GPS.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")
local Presence = BlockOS.Require("presence")

local Page = Ui.Page.new()
local Settings = Config.Settings()

local ScanSeconds = 3
local RescanSeconds = 30
local RelocateSeconds = 60
local Scales = { 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000 }
-- Terminal cells are about one and a half times taller than they are wide.
local CellAspect = 1.5

local State = {
	Computers = {},
	Self = nil,
	Status = "idle",
	Message = nil,
	Selected = nil,
	Scale = nil,
	ScanTimer = nil
}
local Markers = {}
local Build

local function Distance(Entry)
	if (not (State.Self and Entry.Position)) then return math.huge end
	return (Presence.Bearing(State.Self, Entry.Position))
end

local function Sorted()
	local List = {}
	for _, Entry in pairs(State.Computers) do
		table.insert(List, Entry)
	end
	table.sort(List, function(A, B)
		local DA, DB = Distance(A), Distance(B)
		if (DA ~= DB) then return DA < DB end
		return A.ID < B.ID
	end)
	return List
end

local function FormatDistance(Blocks)
	if (Blocks == math.huge) then return "?" end
	if (Blocks < 1000) then return string.format("%dm", math.floor(Blocks + .5)) end
	return string.format("%.1fkm", Blocks / 1000)
end

local function Scan()
	if (State.Status ~= "idle") then return end
	if (not Presence.OpenModems()) then
		State.Message = "No modem attached"
		Build()
		return
	end
	State.Message = nil
	if (not Presence.LocatedAt or os.clock() - Presence.LocatedAt > RelocateSeconds) then
		State.Status = "locating"
		Page:Draw()
		Presence.Locate(2)
	end
	State.Self = Presence.Position
	State.Computers = {}
	State.Status = "scanning"
	Presence.Scan()
	State.ScanTimer = os.startTimer(ScanSeconds)
	Build()
end

local function StatusText()
	if (State.Status == "locating") then return "Locating with GPS..." end
	if (State.Status == "scanning") then return "Scanning..." end
	if (State.Message) then return State.Message end
	local Count = 0
	for _ in pairs(State.Computers) do Count = Count + 1 end
	local Text = (Count == 1) and "1 computer nearby" or (Count .. " computers nearby")
	if (State.Self) then
		return Text .. string.format(" \7 you %d, %d, %d", State.Self.X, State.Self.Y, State.Self.Z)
	end
	return Text .. " \7 no GPS"
end

local function DetailText()
	local Entry = State.Selected and State.Computers[State.Selected]
	if (not Entry) then
		return Settings.NetworkVisible ~= false and "Select a computer for details." or "This computer is hidden from others."
	end
	local Parts = { "#" .. Entry.ID .. " " .. Presence.Name(Entry) }
	if (Entry.User) then table.insert(Parts, Entry.User) end
	if (State.Self and Entry.Position) then
		local Blocks, Direction = Presence.Bearing(State.Self, Entry.Position)
		table.insert(Parts, FormatDistance(Blocks) .. " " .. Direction)
		local Rise = Entry.Position.Y - State.Self.Y
		table.insert(Parts, "y" .. ((Rise >= 0) and "+" or "") .. Rise)
	elseif (Entry.Position) then
		table.insert(Parts, string.format("%d, %d, %d", Entry.Position.X, Entry.Position.Y, Entry.Position.Z))
	else
		table.insert(Parts, "no GPS")
	end
	return table.concat(Parts, " \7 ")
end

-- The point the map is centred on: this computer, or the middle of everyone else.
local function MapCentre()
	if (State.Self) then return State.Self end
	local SumX, SumZ, Count = 0, 0, 0
	for _, Entry in pairs(State.Computers) do
		if (Entry.Position) then
			SumX = SumX + Entry.Position.X
			SumZ = SumZ + Entry.Position.Z
			Count = Count + 1
		end
	end
	if (Count == 0) then return nil end
	return { X = SumX / Count, Y = 0, Z = SumZ / Count }
end

local function FitScale(Centre, W, H)
	local Needed = 1
	for _, Entry in pairs(State.Computers) do
		if (Entry.Position) then
			local DX = math.abs(Entry.Position.X - Centre.X) / math.max(1, W / 2 - 2)
			local DZ = math.abs(Entry.Position.Z - Centre.Z) / math.max(1, (H / 2 - 1) * CellAspect)
			Needed = math.max(Needed, DX, DZ)
		end
	end
	for _, Scale in ipairs(Scales) do
		if (Scale >= Needed) then return Scale end
	end
	return Scales[#Scales]
end

local function Zoom(Step)
	local Current = State.Scale or State.FittedScale or 1
	local Index = 1
	for Position, Scale in ipairs(Scales) do
		if (Scale <= Current) then Index = Position end
	end
	State.Scale = Scales[math.max(1, math.min(#Scales, Index + Step))]
end

local function DrawMap(Self, T, Th)
	local W, H = Self.W, Self.H
	Gfx.Fill(T, Self.X, Self.Y, W, H, Th.Panel)
	Markers = {}
	local Centre = MapCentre()
	if (not Centre) then
		local Hint = "No GPS signal. Build a GPS cluster (four computers running gps host) to see where everyone is."
		if (State.Message) then
			Hint = "Attach a wireless or ender modem to find nearby computers."
		end
		local Lines = Gfx.Wrap(Hint, W - 2)
		local Top = Self.Y + math.max(0, math.floor((H - #Lines) / 2))
		for Row, Line in ipairs(Lines) do
			if (Top + Row - 1 < Self.Y + H) then
				Gfx.Center(T, Top + Row - 1, Line, Th.SubText, Th.Panel, Self.X, W)
			end
		end
		return
	end
	State.FittedScale = FitScale(Centre, W, H)
	local Scale = State.Scale or State.FittedScale
	local MidX = Self.X + math.floor(W / 2)
	local MidY = Self.Y + math.floor(H / 2)
	for Row = 0, H - 1 do
		for Column = 0, W - 1 do
			if ((Self.X + Column - MidX) % 6 == 0 and (Self.Y + Row - MidY) % 3 == 0) then
				Gfx.Write(T, Self.X + Column, Self.Y + Row, "+", Th.Border, Th.Panel)
			end
		end
	end
	Gfx.Write(T, Self.X, Self.Y, "\24N", Th.SubText, Th.Panel)
	local Legend = "\140\140\140\140\140\140 " .. FormatDistance(Scale * 6)
	Gfx.Write(T, Self.X, Self.Y + H - 1, Legend, Th.SubText, Th.Panel)

	local function Plot(Position, Char, Fg, Bg, Label, ID)
		local X = MidX + math.floor((Position.X - Centre.X) / Scale + .5)
		local Y = MidY + math.floor((Position.Z - Centre.Z) / (Scale * CellAspect) + .5)
		local Outside = X < Self.X or X >= Self.X + W or Y < Self.Y or Y >= Self.Y + H
		X = math.max(Self.X, math.min(Self.X + W - 1, X))
		Y = math.max(Self.Y, math.min(Self.Y + H - 1, Y))
		Gfx.Write(T, X, Y, Outside and "\4" or Char, Outside and Th.SubText or Fg, Bg or Th.Panel)
		if (Label and X + 2 + #Label <= Self.X + W) then
			Gfx.Write(T, X + 1, Y, " " .. Label, Th.SubText, Th.Panel)
		end
		if (ID) then table.insert(Markers, { X = X, Y = Y, ID = ID }) end
	end

	for _, Entry in ipairs(Sorted()) do
		if (Entry.Position) then
			local Selected = Entry.ID == State.Selected
			Plot(Entry.Position, Entry.Turtle and "T" or "\7", Selected and Th.AccentFg or Th.Text, Selected and Th.Accent or nil, Gfx.Truncate(Presence.Name(Entry), 10), Entry.ID)
		end
	end
	if (State.Self) then
		Plot(State.Self, "\2", Th.Accent, nil, "You")
	end
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Page:Add(Ui.Panel.new({ X = 1, Y = 1, W = W, H = 1, Bg = "Panel" }))
	Page:Add(Ui.Button.new({ X = 1, Y = 1, W = 6, Text = "Scan", Style = "primary", OnClick = Scan }))
	Page:Add(Ui.Label.new({ X = 8, Y = 1, W = W - 14, Text = StatusText, Fg = "SubText", Bg = "Panel" }))
	Page:Add(Ui.Button.new({ X = W - 5, Y = 1, W = 3, Text = "-", Bg = "Panel", OnClick = function() Zoom(1) end }))
	Page:Add(Ui.Button.new({ X = W - 2, Y = 1, W = 3, Text = "+", Bg = "Panel", OnClick = function() Zoom(-1) end }))

	local BodyH = math.max(3, H - 3)
	local ListW = (W >= 38) and 16 or 0
	local MapW = W - ((ListW > 0) and ListW + 1 or 0)
	Page:Add(Ui.Canvas.new({
		X = 1, Y = 2, W = MapW, H = BodyH,
		OnDraw = DrawMap,
		OnEvent = function(Self, Name, A, B, C)
			if (Name == "mouse_click") then
				for _, Marker in ipairs(Markers) do
					if (math.abs(Marker.X - B) <= 1 and Marker.Y == C) then
						State.Selected = Marker.ID
						Build()
						return true
					end
				end
			elseif (Name == "mouse_scroll") then
				Zoom(A)
				return true
			end
			return false
		end
	}))
	if (ListW > 0) then
		local Items = {}
		local Selected = 0
		for Index, Entry in ipairs(Sorted()) do
			table.insert(Items, {
				Text = Presence.Name(Entry), ID = Entry.ID,
				Icon = Entry.Turtle and "T" or "\7", IconFg = Entry.Position and "Accent" or "SubText",
				Right = FormatDistance(Distance(Entry))
			})
			if (Entry.ID == State.Selected) then Selected = Index end
		end
		local List = Page:Add(Ui.List.new({ X = MapW + 2, Y = 2, W = ListW, H = BodyH, Items = Items, Bg = "Panel" }))
		List.Selected = Selected
		List.OnSelect = function(_, _, Item)
			if (Item) then State.Selected = Item.ID end
		end
		if (#Items == 0 and State.Status == "idle") then
			Page:Add(Ui.Label.new({ X = MapW + 3, Y = 3, W = ListW - 2, H = 4, Fg = "SubText", Bg = "Panel", Text = "No other computers answered." }))
		end
	end

	Page:Add(Ui.Label.new({ X = 1, Y = H - 1, W = W, Text = DetailText }))
	Page:Add(Ui.Toggle.new({
		X = 1, Y = H, Value = Settings.NetworkVisible ~= false,
		OnChange = function(_, Value)
			Settings.NetworkVisible = Value
			Config.Save("settings")
		end
	}))
	Page:Add(Ui.Label.new({ X = 6, Y = H, W = W - 5, Text = "Let other computers find this one", Fg = "SubText" }))
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A, B, C)
	if (Name == "rednet_message" and C == Presence.Protocol) then
		local Entry = Presence.Parse(A, B)
		if (not Entry or A == os.getComputerID()) then return false end
		State.Computers[Entry.ID] = Entry
		Build()
		return true
	elseif (Name == "timer" and A == State.ScanTimer) then
		State.ScanTimer = nil
		State.Status = "idle"
		Build()
		return true
	elseif (Name == "peripheral" or Name == "peripheral_detach") then
		Build()
		return true
	end
	return false
end

Page:SetInterval(RescanSeconds, function()
	Scan()
	return false
end)

Page:Resize()
Scan()
Page:Run()
]]
Files["blockos/apps/notes/app.cfg"] = [[
{ Name = "Notes", Description = "Quick notes and plain text files with word wrap and autosave.", Width = 44, Height = 14, Single = true, Icon = { Lines = { "\140\140\140", "\140\140 " }, Fg = "black", Bg = "yellow" } }
]]
Files["blockos/apps/notes/main.lua"] = [[
-- Notes: a notepad with a list of notes, word wrap and autosave. Also opens .txt files.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")

local Args = { ... }

local Folder = "/home/Notes"
local SaveDelay = 1.5

local Page = Ui.Page.new()
local Notes = {}
local Doc = nil
local Rows = {}
local Layout = { SideW = 0, EX = 1, EY = 2, EW = 10, EH = 5 }
local Build

local function SplitLines(Text)
	local Lines = {}
	for Line in ((Text or ""):gsub("\r", "") .. "\n"):gmatch("(.-)\n") do
		table.insert(Lines, Line)
	end
	if (#Lines == 0) then Lines[1] = "" end
	return Lines
end

local function TitleOf(Lines, Path)
	for _, Line in ipairs(Lines) do
		local Trimmed = Line:match("^%s*(.-)%s*$")
		if (#Trimmed > 0) then return Trimmed end
	end
	return Path and fs.getName(Path):gsub("%.txt$", "") or "New Note"
end

local function Modified(Path)
	local Ok, Attributes = pcall(fs.attributes, Path)
	return Ok and Attributes and Attributes.modified or 0
end

local function LoadNotes()
	if (not fs.exists(Folder)) then fs.makeDir(Folder) end
	Notes = {}
	for _, Name in ipairs(fs.list(Folder)) do
		local Path = "/" .. fs.combine(Folder, Name)
		if (Name:match("%.txt$") and not fs.isDir(Path)) then
			local Lines = SplitLines(Config.ReadText(Path))
			table.insert(Notes, { Path = Path, Title = TitleOf(Lines, Path), Modified = Modified(Path) })
		end
	end
	table.sort(Notes, function(A, B) return A.Modified > B.Modified end)
	if (Doc and Doc.Path and not Doc.Path:find("^" .. Folder .. "/")) then
		table.insert(Notes, 1, { Path = Doc.Path, Title = fs.getName(Doc.Path), External = true })
	end
end

local function WordCount()
	local Count = 0
	for _, Line in ipairs(Doc.Lines) do
		for _ in Line:gmatch("%S+") do Count = Count + 1 end
	end
	return Count
end

local function Save()
	if (not Doc or not Doc.Dirty) then return true end
	local Ok = Config.WriteText(Doc.Path, table.concat(Doc.Lines, "\n"))
	if (Ok) then
		Doc.Dirty = false
		for _, Note in ipairs(Notes) do
			if (Note.Path == Doc.Path and not Note.External) then
				Note.Title = TitleOf(Doc.Lines, Doc.Path)
			end
		end
	end
	return Ok
end

local function Open(Path)
	Save()
	Doc = { Path = Path, Lines = SplitLines(Config.ReadText(Path)), X = 1, Y = 1, Scroll = 0, GoalX = nil, Dirty = false }
	BlockOS.SetTitle(fs.getName(Path))
end

local function NewNote()
	Save()
	local Path = "/" .. fs.combine(Folder, "Note " .. os.date("%Y-%m-%d %H%M%S") .. ".txt")
	Config.WriteText(Path, "")
	Open(Path)
	LoadNotes()
end

--
-- Word wrap
--

-- Splits a line into visual rows, breaking after the last space that fits.
local function Segments(Text, Width)
	local Starts = { 1 }
	local Position = 1
	while (#Text - Position + 1 >= Width) do
		local Chunk = Text:sub(Position, Position + Width - 1)
		local Break = Chunk:match("^.*() ")
		if (Break and Break > 1) then
			Position = Position + Break
		else
			Position = Position + Width
		end
		table.insert(Starts, Position)
	end
	return Starts
end

local function Rewrap()
	Rows = {}
	local Width = math.max(4, Layout.EW)
	for Index, Line in ipairs(Doc.Lines) do
		local Starts = Segments(Line, Width)
		for Part, Start in ipairs(Starts) do
			local Stop = Starts[Part + 1] and (Starts[Part + 1] - 1) or (#Line + 1)
			table.insert(Rows, { Line = Index, Start = Start, Stop = Stop, Last = Starts[Part + 1] == nil })
		end
	end
end

local function CursorRow()
	for Index, Row in ipairs(Rows) do
		if (Row.Line == Doc.Y and Doc.X >= Row.Start and Doc.X <= Row.Stop) then
			return Index, Row
		end
	end
	return #Rows, Rows[#Rows]
end

local function EnsureVisible()
	local Index = CursorRow()
	if (Index <= Doc.Scroll) then
		Doc.Scroll = Index - 1
	elseif (Index > Doc.Scroll + Layout.EH) then
		Doc.Scroll = Index - Layout.EH
	end
	Doc.Scroll = math.max(0, math.min(Doc.Scroll, math.max(0, #Rows - 1)))
end

local function Changed()
	Doc.Dirty = true
	Doc.LastEdit = os.clock()
	Doc.GoalX = nil
	Rewrap()
	EnsureVisible()
end

--
-- Editing
--

local function Insert(Text)
	local Line = Doc.Lines[Doc.Y]
	Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - 1) .. Text .. Line:sub(Doc.X)
	Doc.X = Doc.X + #Text
	Changed()
end

local function NewLine()
	local Line = Doc.Lines[Doc.Y]
	local Indent = Line:match("^([%-%*] )") or ""
	Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - 1)
	table.insert(Doc.Lines, Doc.Y + 1, Indent .. Line:sub(Doc.X))
	Doc.Y = Doc.Y + 1
	Doc.X = #Indent + 1
	Changed()
end

local function Backspace()
	if (Doc.X > 1) then
		local Line = Doc.Lines[Doc.Y]
		Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - 2) .. Line:sub(Doc.X)
		Doc.X = Doc.X - 1
	elseif (Doc.Y > 1) then
		local Previous = Doc.Lines[Doc.Y - 1]
		Doc.Lines[Doc.Y - 1] = Previous .. Doc.Lines[Doc.Y]
		table.remove(Doc.Lines, Doc.Y)
		Doc.Y = Doc.Y - 1
		Doc.X = #Previous + 1
	else
		return
	end
	Changed()
end

local function Delete()
	local Line = Doc.Lines[Doc.Y]
	if (Doc.X <= #Line) then
		Doc.Lines[Doc.Y] = Line:sub(1, Doc.X - 1) .. Line:sub(Doc.X + 1)
	elseif (Doc.Y < #Doc.Lines) then
		Doc.Lines[Doc.Y] = Line .. Doc.Lines[Doc.Y + 1]
		table.remove(Doc.Lines, Doc.Y + 1)
	else
		return
	end
	Changed()
end

local function MoveVertical(Step)
	local Index, Row = CursorRow()
	local Target = Rows[Index + Step]
	if (not Target) then
		Doc.X = (Step < 0) and 1 or (#Doc.Lines[Doc.Y] + 1)
		return
	end
	Doc.GoalX = Doc.GoalX or (Doc.X - Row.Start)
	Doc.Y = Target.Line
	Doc.X = math.min(Target.Start + Doc.GoalX, Target.Stop)
end

local function MoveHorizontal(Step)
	Doc.GoalX = nil
	if (Step < 0) then
		if (Doc.X > 1) then
			Doc.X = Doc.X - 1
		elseif (Doc.Y > 1) then
			Doc.Y = Doc.Y - 1
			Doc.X = #Doc.Lines[Doc.Y] + 1
		end
	elseif (Doc.X <= #Doc.Lines[Doc.Y]) then
		Doc.X = Doc.X + 1
	elseif (Doc.Y < #Doc.Lines) then
		Doc.Y = Doc.Y + 1
		Doc.X = 1
	end
end

local function HandleKey(Key)
	local Ctrl = Ui.Modifiers.Ctrl
	if (Ctrl and Key == keys.s) then
		Save()
	elseif (Ctrl and Key == keys.n) then
		NewNote()
		Build()
		return true
	elseif (Key == keys.enter or Key == keys.numPadEnter) then
		NewLine()
	elseif (Key == keys.backspace) then
		Backspace()
	elseif (Key == keys.delete) then
		Delete()
	elseif (Key == keys.tab) then
		Insert("  ")
	elseif (Key == keys.left or Key == keys.right) then
		MoveHorizontal(Key == keys.left and -1 or 1)
	elseif (Key == keys.up or Key == keys.down) then
		MoveVertical(Key == keys.up and -1 or 1)
	elseif (Key == keys.pageUp or Key == keys.pageDown) then
		for _ = 1, Layout.EH - 1 do
			MoveVertical(Key == keys.pageUp and -1 or 1)
		end
	elseif (Key == keys.home or Key == keys["end"]) then
		local _, Row = CursorRow()
		Doc.X = (Key == keys.home) and Row.Start or Row.Stop
		Doc.GoalX = nil
	else
		return false
	end
	EnsureVisible()
	return true
end

--
-- Layout
--

local function SelectNote(Path)
	Open(Path)
	Rewrap()
	Build()
end

local function DeleteCurrent()
	if (not Doc) then return end
	local Title = TitleOf(Doc.Lines, Doc.Path)
	if (not Ui.Confirm("Delete Note", "Delete \"" .. Gfx.Truncate(Title, 20) .. "\"?", "Delete")) then return end
	fs.delete(Doc.Path)
	Doc = nil
	LoadNotes()
	if (#Notes == 0) then
		NewNote()
	else
		Open(Notes[1].Path)
	end
	Rewrap()
	Build()
end

local Editor

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Layout.SideW = (W >= 36) and 14 or 0
	Layout.EX = Layout.SideW + 2
	Layout.EY = 2
	Layout.EW = W - Layout.SideW - 2
	Layout.EH = H - 2
	Rewrap()
	EnsureVisible()

	Page:Add(Ui.Canvas.new({
		X = 1, Y = 1, W = W, H = 1,
		OnDraw = function(Self, T, Th)
			Gfx.Fill(T, Self.X, Self.Y, Self.W, 1, Th.Panel)
		end
	}))
	Page:Add(Ui.Button.new({ X = 1, Y = 1, Text = " + New ", Style = "plain", Bg = "Panel", OnClick = function()
		NewNote()
		Rewrap()
		Build()
	end }))
	Page:Add(Ui.Button.new({ X = 9, Y = 1, Text = " Delete ", Style = "plain", Bg = "Panel", OnClick = DeleteCurrent }))
	if (W >= 34) then
		Page:Add(Ui.Button.new({ X = 18, Y = 1, Text = " Print ", Style = "plain", Bg = "Panel", OnClick = function()
			Save()
			if (Doc.Path) then BlockOS.Launch("print", { Doc.Path }) end
		end }))
	end
	if (Layout.SideW == 0) then
		Page:Add(Ui.Button.new({ X = W - 7, Y = 1, W = 7, Text = "Notes \31", Style = "plain", Bg = "Panel", OnClick = function()
			local Names = {}
			for _, Note in ipairs(Notes) do table.insert(Names, Note.Title) end
			local Index = Ui.Choose("Notes", Names)
			if (Index) then SelectNote(Notes[Index].Path) end
		end }))
	end

	if (Layout.SideW > 0) then
		local Items = {}
		local Selected = 1
		for Index, Note in ipairs(Notes) do
			local Title = (Doc and Note.Path == Doc.Path) and TitleOf(Doc.Lines, Doc.Path) or Note.Title
			table.insert(Items, { Text = Title, Path = Note.Path })
			if (Doc and Note.Path == Doc.Path) then Selected = Index end
		end
		local List = Page:Add(Ui.List.new({ X = 1, Y = 2, W = Layout.SideW, H = H - 1, Bg = "Panel", SingleClick = true }))
		List:SetItems(Items)
		List.Selected = Selected
		List.OnActivate = function(_, _, Item)
			if (Item and (not Doc or Item.Path ~= Doc.Path)) then
				SelectNote(Item.Path)
			else
				Page:SetFocus(Editor)
			end
		end
	end

	Editor = Page:Add(Ui.Canvas.new({
		X = Layout.EX, Y = Layout.EY, W = Layout.EW, H = Layout.EH, Focusable = true, KeepFocus = true,
		OnDraw = function(Self, T, Th)
			for Offset = 1, Self.H do
				local Row = Rows[Doc.Scroll + Offset]
				local Text = ""
				local Fg = Th.Text
				if (Row) then
					Text = Doc.Lines[Row.Line]:sub(Row.Start, Row.Last and #Doc.Lines[Row.Line] or Row.Stop)
					if (Row.Line == 1) then Fg = Th.Accent end
				end
				Gfx.Write(T, Self.X, Self.Y + Offset - 1, Gfx.Pad(Text, Self.W), Fg, Th.WindowBg)
			end
		end,
		OnCursor = function(Self, Th)
			local Index, Row = CursorRow()
			local Y = Index - Doc.Scroll
			if (Y < 1 or Y > Self.H) then return nil end
			return Self.X + Doc.X - Row.Start, Self.Y + Y - 1, Th.Text
		end,
		OnEvent = function(Self, Name, A, B, C)
			if (Name == "char") then
				Insert(A)
				return true
			elseif (Name == "paste") then
				Insert((A:gsub("[\r\n]", " ")))
				return true
			elseif (Name == "key") then
				return HandleKey(A)
			elseif (Name == "mouse_click" or Name == "mouse_drag") then
				local Row = Rows[Doc.Scroll + C - Self.Y + 1] or Rows[#Rows]
				Doc.Y = Row.Line
				Doc.X = math.max(Row.Start, math.min(Row.Start + B - Self.X, Row.Stop))
				Doc.GoalX = nil
				return true
			elseif (Name == "mouse_scroll") then
				Doc.Scroll = math.max(0, math.min(Doc.Scroll + A * 2, math.max(0, #Rows - Self.H)))
				return true
			end
			return false
		end
	}))

	Page:Add(Ui.Label.new({
		X = Layout.EX, Y = H, W = Layout.EW, Fg = "SubText",
		Text = function()
			local Words = WordCount()
			return (Doc.Dirty and "Edited" or "Saved") .. " \7 " .. Words .. (Words == 1 and " word" or " words")
		end
	}))
	Page:SetFocus(Editor)
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_close") then
		Save()
		self:Stop()
		return true
	elseif (Name == "blockos_open" and A and fs.exists(A)) then
		Open(A)
		LoadNotes()
		Build()
		return true
	end
	return false
end

function Page:OnTerminate()
	Save()
	self:Stop()
end

-- Autosave a moment after typing stops.
Page:SetInterval(1, function()
	if (Doc and Doc.Dirty and os.clock() - (Doc.LastEdit or 0) >= SaveDelay) then
		Save()
		return true
	end
	return false
end)

BlockOS.SetCloseHandler(true)
local Target = Args[1] and (shell and shell.resolve(Args[1]) or Args[1])
if (Target and not Target:find("^/")) then Target = "/" .. Target end
if (Target and fs.exists(Target) and not fs.isDir(Target)) then
	Open(Target)
	LoadNotes()
else
	LoadNotes()
	if (#Notes == 0) then
		NewNote()
	else
		Open(Notes[1].Path)
	end
end
Page:Run()
Save()
]]
Files["blockos/apps/print/app.cfg"] = [[
{ Name = "Print", Description = "Print text files on an attached printer.", Width = 44, Height = 16, Single = true, Icon = { Lines = { " \131 ", "\143\143\143" }, Fg = "gray", Bg = "white" } }
]]
Files["blockos/apps/print/main.lua"] = [[
-- Print: lays text files out on printed pages and sends them to an attached printer.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")

local Args = { ... }

-- Every CC printer page is 25 characters by 21 lines.
local PageW, PageH = 25, 21

local Page = Ui.Page.new()
local Doc = { Path = nil, Pages = {}, Title = "" }
local Copies = 1
local Shown = 1
local Scroll = 0
local PrinterName = nil
local Status = nil
local Busy = false
local TitleField
local Build

local function Printers()
	local List = {}
	for _, Name in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Name) == "printer") then
			table.insert(List, { Name = Name, Device = peripheral.wrap(Name) })
		end
	end
	return List
end

local function CurrentPrinter()
	local List = Printers()
	for _, Printer in ipairs(List) do
		if (Printer.Name == PrinterName) then return Printer end
	end
	if (List[1]) then PrinterName = List[1].Name end
	return List[1]
end

-- Wraps one line to the page width, breaking at spaces where possible and keeping indentation.
local function WrapLine(Line, Width)
	local Rows = {}
	Line = Line:gsub("\t", "  ")
	while (#Line > Width) do
		local Space = Line:sub(1, Width + 1):match(".*() ")
		if (Space and Space > 1) then
			table.insert(Rows, Line:sub(1, Space - 1))
			Line = Line:sub(Space + 1)
		else
			table.insert(Rows, Line:sub(1, Width))
			Line = Line:sub(Width + 1)
		end
	end
	table.insert(Rows, Line)
	return Rows
end

local function Paginate(Text)
	local Pages = {}
	local Current = {}
	Text = Text:gsub("\r\n?", "\n")
	for Line in (Text .. "\n"):gmatch("(.-)\n") do
		for _, Row in ipairs(WrapLine(Line, PageW)) do
			if (#Current == PageH) then
				table.insert(Pages, Current)
				Current = {}
			end
			table.insert(Current, Row)
		end
	end
	-- Drop trailing blank lines so a final newline does not cost a sheet of paper.
	while (#Current > 0 and Current[#Current]:match("^%s*$")) do
		table.remove(Current)
	end
	if (#Current > 0 or #Pages == 0) then table.insert(Pages, Current) end
	return Pages
end

local function Load(Path)
	local Handle = Path and fs.exists(Path) and not fs.isDir(Path) and fs.open(Path, "r")
	if (not Handle) then
		Status = Path and ("Cannot open " .. fs.getName(Path)) or nil
		return false
	end
	local Text = Handle.readAll() or ""
	Handle.close()
	Doc.Path = Path
	Doc.Pages = Paginate(Text)
	Doc.Title = (fs.getName(Path):gsub("%.[^%.]+$", ""))
	Shown, Scroll = 1, 0
	Status = nil
	BlockOS.SetTitle("Print \7 " .. fs.getName(Path))
	return true
end

-- Two short lines: ink and paper levels, or why there are none.
local function PrinterStatus(Printer)
	if (not Printer) then return "No printer", "attached" end
	local Ok, Ink = pcall(Printer.Device.getInkLevel)
	local _, Paper = pcall(Printer.Device.getPaperLevel)
	if (not Ok) then return "Not responding", "" end
	return "Ink " .. tostring(Ink), "Paper " .. tostring(Paper)
end

local function PrintDocument()
	if (Busy or #Doc.Pages == 0) then return end
	local Printer = CurrentPrinter()
	if (not Printer) then
		Status = "Attach a printer next to the computer or over a wired modem."
		return
	end
	local Device = Printer.Device
	local Title = (#TitleField.Value > 0) and TitleField.Value or Doc.Title
	local Total = #Doc.Pages * Copies
	local Done = 0
	Busy = true
	for _ = 1, Copies do
		for Index, Lines in ipairs(Doc.Pages) do
			if (not Device.newPage()) then
				if (Device.getPaperLevel() == 0) then
					Status = "Out of paper. Add paper to the printer and try again."
				elseif (Device.getInkLevel() == 0) then
					Status = "Out of ink. Add a dye to the printer and try again."
				else
					Status = "The output tray is full. Take the printed pages out."
				end
				Busy = false
				return
			end
			Device.setPageTitle((#Doc.Pages > 1) and (Title .. " " .. Index .. "/" .. #Doc.Pages) or Title)
			for Row, Line in ipairs(Lines) do
				Device.setCursorPos(1, Row)
				Device.write(Line)
			end
			if (not Device.endPage()) then
				Status = "The output tray is full. Take the printed pages out."
				Busy = false
				return
			end
			Done = Done + 1
			Status = "Printing page " .. Done .. " of " .. Total .. "..."
			Page:Draw()
		end
	end
	Busy = false
	Status = "Printed " .. Total .. ((Total == 1) and " page." or " pages.")
	BlockOS.Notify("Print", Title .. " \7 " .. Total .. ((Total == 1) and " page" or " pages"), { Sound = false })
end

local function ChooseFile()
	local Path = Ui.PickFile({ Title = "Print", Dir = Doc.Path and fs.getDir(Doc.Path) or "/home" })
	if (Path and Load(Path)) then
		Build()
	elseif (Path) then
		Build()
	end
end

local function ChoosePrinter(X, Y)
	local List = Printers()
	if (#List == 0) then return end
	local Options = {}
	for _, Printer in ipairs(List) do
		table.insert(Options, { Text = Printer.Name })
	end
	local Index = Ui.ContextMenu(X, Y, Options)
	if (Index) then PrinterName = List[Index].Name end
end

local function DrawPreview(Self, T, Th)
	Gfx.Fill(T, Self.X, Self.Y, Self.W, Self.H, Th.Panel)
	local Lines = Doc.Pages[Shown]
	if (not Lines) then
		local Message = Gfx.Wrap("Choose a text file to print, or right-click one in Finder and pick Print.", Self.W - 4)
		for Row, Line in ipairs(Message) do
			Gfx.Write(T, Self.X + 2, Self.Y + Row, Line, Th.SubText, Th.Panel)
		end
		return
	end
	local PaperX = Self.X + math.max(0, math.floor((Self.W - PageW) / 2))
	for Row = 1, math.min(Self.H, PageH - Scroll) do
		local Line = Lines[Row + Scroll] or ""
		Gfx.Write(T, PaperX, Self.Y + Row - 1, Gfx.Pad(Line, PageW), colors.black, colors.white)
	end
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	local SideW = 16
	local PreviewW = math.max(PageW + 2, W - SideW - 1)
	local SideX = PreviewW + 2
	local Narrow = SideX + SideW - 1 > W

	Page:Add(Ui.Panel.new({ X = 1, Y = 1, W = W, H = 1, Bg = "Panel" }))
	Page:Add(Ui.Label.new({ X = 2, Y = 1, W = W - 12, Bg = "Panel", Text = function()
		return Doc.Path and fs.getName(Doc.Path) or "No document"
	end }))
	Page:Add(Ui.Button.new({ X = W - 8, Y = 1, W = 9, Text = "Open...", Bg = "Panel", OnClick = ChooseFile }))

	Page:Add(Ui.Canvas.new({
		X = 1, Y = 2, W = Narrow and W or PreviewW, H = H - 1,
		OnDraw = DrawPreview,
		OnEvent = function(_, Name, A)
			if (Name == "mouse_scroll") then
				Scroll = math.max(0, math.min(PageH - (H - 1), Scroll + A * 2))
				return true
			end
			return false
		end
	}))
	if (Narrow) then
		Page:Add(Ui.Button.new({ X = W - 8, Y = H, W = 9, Text = "Print", Style = "primary", OnClick = PrintDocument }))
		return
	end

	Page:Add(Ui.Label.new({ X = SideX, Y = 2, Text = "Printer", Fg = "SubText" }))
	local PickPrinter
	PickPrinter = Page:Add(Ui.Button.new({ X = SideX, Y = 3, W = SideW, Text = function()
		local Printer = CurrentPrinter()
		return Gfx.Truncate(Printer and Printer.Name or "None", SideW - 3) .. " \31"
	end, OnClick = function() ChoosePrinter(PickPrinter.X, PickPrinter.Y + 1) end }))
	Page:Add(Ui.Label.new({ X = SideX, Y = 4, W = SideW, Fg = "SubText", Text = function()
		return (PrinterStatus(CurrentPrinter()))
	end }))
	Page:Add(Ui.Label.new({ X = SideX, Y = 5, W = SideW, Fg = "SubText", Text = function()
		return select(2, PrinterStatus(CurrentPrinter()))
	end }))

	Page:Add(Ui.Label.new({ X = SideX, Y = 6, Text = "Title", Fg = "SubText" }))
	TitleField = Page:Add(Ui.Input.new({ X = SideX, Y = 7, W = SideW, Value = Doc.Title, Placeholder = "Page title", MaxLength = 30 }))

	Page:Add(Ui.Label.new({ X = SideX, Y = 9, Text = "Copies", Fg = "SubText" }))
	Page:Add(Ui.Button.new({ X = SideX + 8, Y = 9, W = 3, Text = "-", OnClick = function() Copies = math.max(1, Copies - 1) end }))
	Page:Add(Ui.Label.new({ X = SideX + 11, Y = 9, W = 3, Align = "center", Text = function() return tostring(Copies) end }))
	Page:Add(Ui.Button.new({ X = SideX + 14, Y = 9, W = 2, Text = "+", OnClick = function() Copies = math.min(64, Copies + 1) end }))

	Page:Add(Ui.Button.new({ X = SideX, Y = 11, W = 3, Text = "\17", OnClick = function()
		Shown = math.max(1, Shown - 1)
		Scroll = 0
	end }))
	Page:Add(Ui.Label.new({ X = SideX + 3, Y = 11, W = SideW - 6, Align = "center", Text = function()
		return "Page " .. math.min(Shown, #Doc.Pages) .. "/" .. #Doc.Pages
	end }))
	Page:Add(Ui.Button.new({ X = SideX + SideW - 3, Y = 11, W = 3, Text = "\16", OnClick = function()
		Shown = math.min(#Doc.Pages, Shown + 1)
		Scroll = 0
	end }))

	Page:Add(Ui.Button.new({ X = SideX, Y = 13, W = SideW, Text = "Print", Style = "primary", OnClick = PrintDocument }))
	Page:Add(Ui.Label.new({ X = SideX, Y = 14, W = SideW, H = math.max(1, H - 13), Fg = "SubText", Text = function()
		return Status or ""
	end }))
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A)
	if (Name == "peripheral" or Name == "peripheral_detach") then
		return true
	elseif (Name == "blockos_open" and A) then
		if (Load(A)) then Build() end
		return true
	end
	return false
end

Load(Args[1])
Page:Run()
]]
Files["blockos/apps/recorder/app.cfg"] = [[
{ Name = "Recorder", Description = "Record the screen and play recordings back.", Width = 40, Height = 13, Single = true, Icon = { Lines = { " \7 ", "REC" }, Fg = "red", Bg = "black" } }
]]
Files["blockos/apps/recorder/main.lua"] = [=[
-- Recorder: captures the BlockOS screen into .rec files, plays them back,
-- and can export a recording as a standalone player program.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")

local Args = { ... }

local Folder = "/home/Recordings"
local MaxFrames = 2000

local Page = Ui.Page.new()
local Recording = nil
local Options = { Hide = true, Countdown = true, Fps = 8 }
local Build

local function Serialise(Value)
	local Ok, Text = pcall(textutils.serialise, Value, { compact = true })
	if (Ok) then return Text end
	return textutils.serialise(Value)
end

local function ListRecordings()
	if (not fs.exists(Folder)) then fs.makeDir(Folder) end
	local Items = {}
	for _, Name in ipairs(fs.list(Folder)) do
		if (Name:match("%.rec$")) then
			local Path = fs.combine(Folder, Name)
			table.insert(Items, { Text = Name:gsub("%.rec$", ""), Right = Gfx.FormatSize(fs.getSize(Path)), Icon = "\7", IconFg = colors.red, Path = "/" .. Path })
		end
	end
	table.sort(Items, function(A, B) return A.Text > B.Text end)
	return Items
end

local function Capture()
	local Frame = BlockOS.Capture()
	local Now = os.epoch("utc")
	local Changed = {}
	local Any = false
	for Y, Line in ipairs(Frame.Lines) do
		local Previous = Recording.Last[Y]
		if (not Previous or Previous[1] ~= Line[1] or Previous[2] ~= Line[2] or Previous[3] ~= Line[3]) then
			Changed[Y] = Line
			Recording.Last[Y] = Line
			Any = true
		end
	end
	if (Any) then
		table.insert(Recording.Frames, { T = Now - Recording.Started, Lines = Changed })
	end
	Recording.W, Recording.H = Frame.W, Frame.H
end

local function StopRecording()
	if (not Recording) then return end
	Page:ClearInterval(Recording.Interval)
	BlockOS.SetRecording(false)
	local Data = {
		Version = 1,
		W = Recording.W,
		H = Recording.H,
		Duration = os.epoch("utc") - Recording.Started,
		Frames = Recording.Frames
	}
	Recording = nil
	if (#Data.Frames == 0) then return end
	local Path = fs.combine(Folder, "Recording " .. os.date("%Y-%m-%d %H%M%S") .. ".rec")
	Config.WriteText(Path, Serialise(Data))
	BlockOS.Notify("Recorder", "Saved " .. fs.getName(Path), { AppID = "recorder", Sound = false })
	Build()
end

local function StartRecording()
	if (Recording) then return end
	if (Options.Countdown) then
		for Count = 3, 1, -1 do
			BlockOS.Notify("Recorder", "Recording starts in " .. Count .. "...", { Sound = false, Duration = 1 })
			sleep(1)
		end
	end
	Recording = { Frames = {}, Last = {}, Started = os.epoch("utc") }
	BlockOS.SetRecording(true)
	if (Options.Hide) then BlockOS.Minimize() end
	Capture()
	Recording.Interval = Page:SetInterval(1 / Options.Fps, function()
		if (not Recording) then return false end
		Capture()
		if (#Recording.Frames >= MaxFrames) then StopRecording() end
		return true
	end)
	Build()
end

local function LoadRecording(Path)
	local Data = textutils.unserialise(Config.ReadText(Path) or "")
	if (type(Data) ~= "table" or type(Data.Frames) ~= "table") then return nil end
	return Data
end

-- Plays a recording full screen; any click or key other than space stops it.
local function Play(Path)
	local Data = LoadRecording(Path)
	if (not Data) then
		Ui.Alert("Recorder", "This file is not a valid recording.")
		return
	end
	BlockOS.SetFullscreen(true)
	sleep(0)
	local T = term.current()
	local W, H = T.getSize()
	local Screen = window.create(T, 1, 1, W, H, true)
	Screen.setBackgroundColor(colors.black)
	Screen.clear()
	local Paused = false
	local Index = 1
	local Clock = 0
	local Last = os.epoch("utc")
	local Timer = os.startTimer(0)
	while (Index <= #Data.Frames) do
		local Event = table.pack(os.pullEventRaw())
		local Name = Event[1]
		if (Name == "terminate" or Name == "mouse_click" or (Name == "key" and Event[2] ~= keys.space)) then
			break
		elseif (Name == "key" and Event[2] == keys.space) then
			Paused = not Paused
			Last = os.epoch("utc")
		elseif (Name == "timer" and Event[2] == Timer) then
			local Now = os.epoch("utc")
			if (not Paused) then Clock = Clock + (Now - Last) end
			Last = Now
			while (Index <= #Data.Frames and Data.Frames[Index].T <= Clock) do
				for Y, Line in pairs(Data.Frames[Index].Lines) do
					if (Y <= H) then
						Screen.setCursorPos(1, Y)
						Screen.blit(Line[1]:sub(1, W), Line[2]:sub(1, W), Line[3]:sub(1, W))
					end
				end
				Index = Index + 1
			end
			Timer = os.startTimer(.05)
		end
	end
	sleep(.5)
	Screen.setVisible(false)
	BlockOS.SetFullscreen(false)
	sleep(0)
	Page:Resize()
	Page:Draw()
end

local PlayerTemplate = [[
-- BlockOS recording player (exported by Recorder)
local Data = textutils.unserialise(%q)
local W, H = term.getSize()
term.setBackgroundColor(colors.black)
term.clear()
local Start = os.epoch("utc")
for _, Frame in ipairs(Data.Frames) do
	local Wait = Frame.T - (os.epoch("utc") - Start)
	if (Wait > 0) then sleep(Wait / 1000) end
	for Y, Line in pairs(Frame.Lines) do
		if (Y <= H) then
			term.setCursorPos(1, Y)
			term.blit(Line[1]:sub(1, W), Line[2]:sub(1, W), Line[3]:sub(1, W))
		end
	end
end
term.setCursorPos(1, H)
]]

local function Export(Item)
	local Data = Config.ReadText(Item.Path)
	if (not Data) then return end
	local Target = Item.Path:gsub("%.rec$", "") .. " player.lua"
	Config.WriteText(Target, string.format(PlayerTemplate, Data))
	Ui.Alert("Export", "Saved a standalone player to " .. Target .. ". Run it on any advanced computer.")
	Build()
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	Page:Add(Ui.Canvas.new({
		X = 1, Y = 1, W = W, H = 4,
		OnDraw = function(Self, T, Th)
			Gfx.Fill(T, Self.X, Self.Y, Self.W, Self.H, Th.Panel)
			local Color = Recording and colors.red or colors.gray
			Gfx.Fill(T, Self.X + 2, Self.Y + 1, 4, 2, Recording and colors.red or Th.WindowBg)
			Gfx.Write(T, Self.X + 3, Self.Y + 1, "\7\7", Recording and colors.white or colors.red, Recording and colors.red or Th.WindowBg)
			if (Recording) then
				local Seconds = math.floor((os.epoch("utc") - Recording.Started) / 1000)
				Gfx.Write(T, Self.X + 8, Self.Y + 1, string.format("Recording %d:%02d", math.floor(Seconds / 60), Seconds % 60), Color, Th.Panel)
				Gfx.Write(T, Self.X + 8, Self.Y + 2, #Recording.Frames .. " frames \7 click to stop", Th.SubText, Th.Panel)
			else
				Gfx.Write(T, Self.X + 8, Self.Y + 1, "Record Screen", Th.PanelFg, Th.Panel)
				Gfx.Write(T, Self.X + 8, Self.Y + 2, Gfx.Truncate("Stop from the REC item in the menu bar", Self.W - 9), Th.SubText, Th.Panel)
			end
		end,
		OnEvent = function(_, Name)
			if (Name ~= "mouse_click") then return false end
			if (Recording) then StopRecording() else StartRecording() end
			return true
		end
	}))
	Page:Add(Ui.Checkbox.new({ X = 2, Y = 6, Text = "Hide window", Value = Options.Hide, OnChange = function(_, Value) Options.Hide = Value end }))
	Page:Add(Ui.Checkbox.new({ X = 18, Y = 6, Text = "Countdown", Value = Options.Countdown, OnChange = function(_, Value) Options.Countdown = Value end }))
	local List = Page:Add(Ui.List.new({ X = 1, Y = 8, W = W, H = H - 8 }))
	List:SetItems(ListRecordings())
	List.OnActivate = function(_, _, Item) Play(Item.Path) end
	List.OnContext = function(_, _, Item, X, Y)
		if (not Item) then return end
		local Choices = { "Play", "Export Player", "Rename", "Show in Finder", "-", "Delete" }
		local Choice = Choices[Ui.ContextMenu(X, Y, Choices) or 0]
		if (Choice == "Play") then
			Play(Item.Path)
		elseif (Choice == "Export Player") then
			Export(Item)
		elseif (Choice == "Rename") then
			local Name = Ui.Prompt("Rename", "Name:", Item.Text)
			if (Name and #Name > 0) then
				local Target = fs.combine(Folder, Name .. ".rec")
				if (not fs.exists(Target)) then fs.move(Item.Path, Target) end
				Build()
			end
		elseif (Choice == "Show in Finder") then
			BlockOS.Launch("finder", { Folder })
		elseif (Choice == "Delete") then
			if (Ui.Confirm("Delete", "Delete \"" .. Item.Text .. "\"?", "Delete")) then
				fs.delete(Item.Path)
				Build()
			end
		end
	end
	if (#List.Items == 0) then
		Page:Add(Ui.Label.new({ X = 2, Y = 9, W = W - 2, Text = "No recordings yet.", Fg = "SubText" }))
	end
	Page:Add(Ui.Label.new({ X = 1, Y = H, W = W, Bg = "Panel", Fg = "SubText", Text = " Double-click to play \7 space pauses" }))
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_recorder_stop") then
		StopRecording()
		return true
	elseif (Name == "blockos_open" and A) then
		Play(A)
		return true
	end
	return false
end

function Page:OnTerminate()
	StopRecording()
	self:Stop()
end

Page:SetInterval(1, function() return Recording ~= nil end)

if (Args[1] and fs.exists(Args[1])) then
	Play(Args[1])
end
Page:Run()
StopRecording()
]=]
Files["blockos/apps/reminders/app.cfg"] = [[
{ Name = "Reminders", Description = "Lists and reminders with due-time notifications.", Width = 44, Height = 14, Single = true, Icon = { Lines = { "\7\140\140", "\7\140\140" }, Fg = "orange", Bg = "white" } }
]]
Files["blockos/apps/reminders/main.lua"] = [[
-- Reminders: smart lists, custom lists, due times and priorities.
-- Quick entry: "Buy bread !! @ tomorrow 9:00" sets priority 2 and a due time.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Schedule = BlockOS.Require("schedule")

local Page = Ui.Page.new()
local Data = Schedule.Load()
local Current = { Kind = "smart", ID = "today" }
local Build

local Smart = {
	{ ID = "today", Name = "Today", Icon = "\15", Color = colors.blue },
	{ ID = "scheduled", Name = "Scheduled", Icon = "\4", Color = colors.red },
	{ ID = "all", Name = "All", Icon = "\7", Color = colors.gray },
	{ ID = "done", Name = "Completed", Icon = "x", Color = colors.green }
}

local function EndOfToday()
	local Now = Schedule.Now()
	local Today = os.date("!*t", Now)
	return Now - (Today.hour * 3600 + Today.min * 60 + Today.sec) + 86399
end

local function Matches(Reminder)
	if (Current.Kind == "list") then
		return Reminder.List == Current.ID and not Reminder.Done
	end
	if (Current.ID == "done") then return Reminder.Done end
	if (Reminder.Done) then return false end
	if (Current.ID == "today") then
		return Reminder.Due ~= nil and Reminder.Due <= EndOfToday()
	elseif (Current.ID == "scheduled") then
		return Reminder.Due ~= nil
	end
	return true
end

local function Visible()
	local Result = {}
	for _, Reminder in ipairs(Data.Reminders) do
		if (Matches(Reminder)) then
			table.insert(Result, Reminder)
		end
	end
	table.sort(Result, function(A, B)
		if ((A.Due ~= nil) ~= (B.Due ~= nil)) then return A.Due ~= nil end
		if (A.Due and B.Due and A.Due ~= B.Due) then return A.Due < B.Due end
		if ((A.Priority or 0) ~= (B.Priority or 0)) then return (A.Priority or 0) > (B.Priority or 0) end
		return A.ID < B.ID
	end)
	return Result
end

local function CountFor(Kind, ID)
	local Saved = Current
	Current = { Kind = Kind, ID = ID }
	local Count = #Visible()
	Current = Saved
	return Count
end

local function CurrentName()
	if (Current.Kind == "list") then return Current.ID end
	for _, Entry in ipairs(Smart) do
		if (Entry.ID == Current.ID) then return Entry.Name end
	end
	return ""
end

local function QuickAdd(Text)
	Text = Text:gsub("^%s+", ""):gsub("%s+$", "")
	if (#Text == 0) then return end
	local Due
	local Title, DueText = Text:match("^(.-)%s*@%s*(.+)$")
	if (Title) then
		Due = Schedule.ParseDue(DueText)
		if (not Due) then
			Ui.Alert("Reminders", "Could not understand \"" .. DueText .. "\". Try \"in 10m\", \"14:30\", \"tomorrow 9:00\" or \"2026-11-02 08:00\".")
			return
		end
		Text = Title
	end
	local Bangs = Text:match("(!+)%s*$")
	local Priority = 0
	if (Bangs) then
		Priority = math.min(3, #Bangs)
		Text = Text:gsub("%s*!+%s*$", "")
	end
	if (not Due and Current.Kind == "smart" and Current.ID == "today") then
		Due = EndOfToday() - 59
	end
	Schedule.AddReminder({
		Title = Text,
		Due = Due,
		Priority = Priority,
		List = (Current.Kind == "list") and Current.ID or (Data.Lists[1] or "Personal")
	})
end

local function EditMenu(Reminder, X, Y)
	local Options = { Reminder.Done and "Mark Incomplete" or "Mark Complete", "Rename...", "Set Due...", "Clear Due", "Priority...", "Move to List...", "Notes...", "-", "Delete" }
	local Choice = Options[Ui.ContextMenu(X, Y, Options) or 0]
	if (Choice == "Mark Complete" or Choice == "Mark Incomplete") then
		Reminder.Done = not Reminder.Done
	elseif (Choice == "Rename...") then
		Reminder.Title = Ui.Prompt("Rename", "Title:", Reminder.Title) or Reminder.Title
	elseif (Choice == "Set Due...") then
		local Text = Ui.Prompt("Due", "When? (in 10m, 14:30, tomorrow 9:00)", "")
		local Due = Text and Schedule.ParseDue(Text)
		if (Due) then
			Reminder.Due = Due
			Reminder.Notified = false
		elseif (Text) then
			Ui.Alert("Due", "That time was not understood.")
		end
	elseif (Choice == "Clear Due") then
		Reminder.Due = nil
	elseif (Choice == "Priority...") then
		local Index = Ui.Choose("Priority", { "None", "Low (!)", "Medium (!!)", "High (!!!)" }, (Reminder.Priority or 0) + 1)
		if (Index) then Reminder.Priority = Index - 1 end
	elseif (Choice == "Move to List...") then
		local Index = Ui.Choose("Move to", Data.Lists)
		if (Index) then Reminder.List = Data.Lists[Index] end
	elseif (Choice == "Notes...") then
		Reminder.Notes = Ui.Prompt("Notes", Reminder.Title, Reminder.Notes or "") or Reminder.Notes
	elseif (Choice == "Delete") then
		Schedule.RemoveReminder(Reminder.ID)
		Build()
		return
	end
	Schedule.Save()
	Build()
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	local SideW = (W >= 36) and 14 or 0
	local Sidebar = Page:Add(Ui.List.new({ X = 1, Y = 1, W = SideW, H = H - 1, Bg = "Panel", SingleClick = true, Focusable = false, Visible = SideW > 0 }))
	local Entries = {}
	local Selected = 0
	for _, Entry in ipairs(Smart) do
		table.insert(Entries, { Text = Entry.Name, Icon = Entry.Icon, IconFg = Entry.Color, Right = tostring(CountFor("smart", Entry.ID)), Kind = "smart", ID = Entry.ID })
		if (Current.Kind == "smart" and Current.ID == Entry.ID) then Selected = #Entries end
	end
	table.insert(Entries, { Text = "My Lists", Header = true })
	for _, Name in ipairs(Data.Lists) do
		table.insert(Entries, { Text = Name, Icon = "\7", IconFg = colors.orange, Right = tostring(CountFor("list", Name)), Kind = "list", ID = Name })
		if (Current.Kind == "list" and Current.ID == Name) then Selected = #Entries end
	end
	Sidebar:SetItems(Entries)
	Sidebar.Selected = Selected
	Sidebar.OnActivate = function(_, _, Item)
		if (Item.Header) then return end
		Current = { Kind = Item.Kind, ID = Item.ID }
		Build()
	end
	Sidebar.OnContext = function(_, _, Item, X, Y)
		local Options = { "New List..." }
		if (Item and Item.Kind == "list") then
			table.insert(Options, "Rename List...")
			table.insert(Options, "Delete List")
		end
		local Choice = Options[Ui.ContextMenu(X, Y, Options) or 0]
		if (Choice == "New List...") then
			local Name = Ui.Prompt("New List", "Name:", "")
			if (Name and #Name > 0) then
				table.insert(Data.Lists, Name)
				Schedule.Save()
				Current = { Kind = "list", ID = Name }
			end
		elseif (Choice == "Rename List...") then
			local Name = Ui.Prompt("Rename List", "Name:", Item.ID)
			if (Name and #Name > 0) then
				for Index, Existing in ipairs(Data.Lists) do
					if (Existing == Item.ID) then Data.Lists[Index] = Name end
				end
				for _, Reminder in ipairs(Data.Reminders) do
					if (Reminder.List == Item.ID) then Reminder.List = Name end
				end
				Current = { Kind = "list", ID = Name }
				Schedule.Save()
			end
		elseif (Choice == "Delete List") then
			if (Ui.Confirm("Delete List", "Delete \"" .. Item.ID .. "\" and its reminders?", "Delete")) then
				for Index = #Data.Lists, 1, -1 do
					if (Data.Lists[Index] == Item.ID) then table.remove(Data.Lists, Index) end
				end
				for Index = #Data.Reminders, 1, -1 do
					if (Data.Reminders[Index].List == Item.ID) then table.remove(Data.Reminders, Index) end
				end
				Current = { Kind = "smart", ID = "all" }
				Schedule.Save()
			end
		end
		Build()
	end
	Page:Add(Ui.Button.new({ X = 1, Y = H, W = math.max(SideW, 1), Text = "+ List", Bg = "Panel", Visible = SideW > 0, OnClick = function()
		local Name = Ui.Prompt("New List", "Name:", "")
		if (Name and #Name > 0) then
			table.insert(Data.Lists, Name)
			Schedule.Save()
			Current = { Kind = "list", ID = Name }
			Build()
		end
	end }))

	local MainX = SideW + 2
	local MainW = W - SideW - 2
	local Items = Visible()
	Page:Add(Ui.Label.new({ X = MainX, Y = 1, W = MainW - 4, Text = CurrentName(), Fg = "Accent" }))
	Page:Add(Ui.Label.new({ X = MainX + MainW - 4, Y = 1, W = 4, Text = tostring(#Items), Fg = "SubText", Align = "right" }))
	local List = Page:Add(Ui.List.new({ X = MainX, Y = 3, W = MainW, H = H - 4 }))
	local Rows = {}
	for _, Reminder in ipairs(Items) do
		table.insert(Rows, { Reminder = Reminder })
	end
	List:SetItems(Rows)
	List.RenderItem = function(_, T, Th, Item, X, Y, Width, IsSelected, RowBg, RowFg)
		local Reminder = Item.Reminder
		local Box = Reminder.Done and "\7" or "o"
		Gfx.Write(T, X, Y, Box, Reminder.Done and Th.Accent or Th.SubText, RowBg)
		local Bang = string.rep("!", Reminder.Priority or 0)
		local Due = Reminder.Due and Schedule.FormatDue(Reminder.Due) or ""
		local Overdue = Reminder.Due and not Reminder.Done and Reminder.Due < Schedule.Now()
		local TitleW = Width - 2 - #Due - 1
		local Title = (#Bang > 0 and (Bang .. " ") or "") .. Reminder.Title .. (Reminder.Notes and " \26" or "")
		Gfx.Write(T, X + 2, Y, Gfx.Truncate(Title, TitleW), IsSelected and RowFg or (Reminder.Done and Th.SubText or Th.Text), RowBg)
		if (#Due > 0) then
			Gfx.Write(T, X + Width - #Due, Y, Due, IsSelected and RowFg or (Overdue and colors.red or Th.SubText), RowBg)
		end
	end
	List.OnActivate = function(_, _, Item)
		Item.Reminder.Done = not Item.Reminder.Done
		Schedule.Save()
		Build()
	end
	List.OnContext = function(_, _, Item, X, Y)
		if (Item) then EditMenu(Item.Reminder, X, Y) end
	end
	if (#Rows == 0) then
		Page:Add(Ui.Label.new({ X = MainX, Y = 4, W = MainW, H = 2, Text = "No reminders. Type below to add one.", Fg = "SubText" }))
	end
	local Entry = Page:Add(Ui.Input.new({ X = MainX, Y = H, W = MainW, Placeholder = "+ New reminder  (!! priority, @ in 10m)" }))
	Entry.OnSubmit = function(Self, Value)
		QuickAdd(Value)
		Self:SetValue("")
		Build()
	end
	Page:SetFocus(Entry)
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name)
	if (Name == "blockos_schedule") then
		if (not (self.Focus and self.Focus.Value and #self.Focus.Value > 0)) then
			Build()
		end
		return true
	end
	return false
end

Page:Run()
]]
Files["blockos/apps/savannah/app.cfg"] = [[
{ Name = "Savannah", Description = "Browse ccinternet websites with tabs, favourites, history and find on page.", Width = 50, Height = 16, Single = true, Icon = { Lines = { " \15 ", "~~~" }, Fg = "yellow", Bg = "orange" } }
]]
Files["blockos/apps/savannah/main.lua"] = [=[
-- Savannah: the BlockOS web browser for ccinternet (https://github.com/tamayaren/ccinternet).
-- Tabs, favourites, history, find on page, local site previews (local://) and the built-in
-- savannah:// pages. Network requests run as background tasks so the window stays responsive.
-- Args: an address (ccmd://site.com, domain://) or a path to a local .ccmd page.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")
local Theme = BlockOS.Require("theme")
local Ccmd = BlockOS.Require("ccinternet/ccmd")
local Layout = BlockOS.Require("ccinternet/layout")
local Image = BlockOS.Require("ccinternet/image")
local Protocol = BlockOS.Require("ccinternet/protocol")
local Site = BlockOS.Require("ccinternet/site")
local Tasks = BlockOS.Load("/blockos/lib/tasks.lua")

local Args = { ... }
local Page = Ui.Page.new()

local C = {
	DataPath = "/blockos/data/savannah.dat",
	StartPage = "savannah://start",
	MaxHistory = 150,
	MaxTabHistory = 30,
	CachedPages = 8,
	MaxRedirects = 5,
	MaxUpload = 125000,
	MaxImages = 64,
	MaxField = 256,
	MaxMatches = 200,
	MessageTime = 3
}

-- Everything the window shows lives here (CC limits how many locals a file may have).
local S = {
	Tabs = {},
	Current = 1,
	Data = nil,
	Transport = nil,
	Sites = {},     -- local site key -> Site object
	Images = {},    -- absolute image URL -> picture | false
	ImageCount = 0,
	Find = nil,     -- { Query, Matches, Index } while the find bar is open
	Message = nil,
	MessageAt = 0,
	W = {}          -- widgets
}

local Nav = {}
local Internal = {}
local View = {}

--
-- Saved data: settings, favourites, history and known local sites.
--

local function DefaultHost()
	local Host = settings and settings.get("ccinternet.host")
	if (type(Host) == "string" and Host ~= "") then return Host end
	return Protocol.DefaultHost
end

local function LoadData()
	local Data = Config.Read(C.DataPath)
	if (type(Data) ~= "table") then Data = {} end
	if (type(Data.Host) ~= "string" or Data.Host == "") then Data.Host = DefaultHost() end
	if (type(Data.Home) ~= "string" or Data.Home == "") then Data.Home = C.StartPage end
	if (type(Data.Favourites) ~= "table") then
		Data.Favourites = {
			{ Title = "Domains", Url = "domain://" },
			{ Title = "Directory", Url = "domain://directory" }
		}
	end
	if (type(Data.History) ~= "table") then Data.History = {} end
	if (type(Data.Sites) ~= "table") then Data.Sites = {} end
	S.Data = Data
end

local function SaveData()
	Config.Write(C.DataPath, S.Data)
end

local function Say(Text)
	S.Message = Text
	S.MessageAt = os.clock()
	Page:Invalidate()
end

local function SafeUrl(Url)
	return (tostring(Url):gsub("[%(%)%s]", function(Char) return string.format("%%%02X", Char:byte()) end))
end

local function LinkSource(Text, Url)
	return "[" .. Ccmd.Escape((tostring(Text):gsub("[%[%]\n]", ""))) .. "](" .. SafeUrl(Url) .. ")"
end

--
-- Tabs
--

function Nav.Tab()
	return S.Tabs[S.Current]
end

function Nav.NewTabState()
	return { History = {}, Index = 0, Scroll = 0, State = {}, Title = "New Tab" }
end

function Nav.FavouriteIndex(Url)
	for Index, Entry in ipairs(S.Data.Favourites) do
		if (Entry.Url == Url) then return Index end
	end
	return nil
end

--
-- Requests
--

function Nav.LocalSite(Key)
	local Root = S.Data.Sites[Key]
	if (not Root) then return nil end
	if (not S.Sites[Key] or S.Sites[Key].Root ~= "/" .. fs.combine(Root, "")) then
		S.Sites[Key] = Site.New(Root)
	end
	return S.Sites[Key]
end

-- Picks a short name for a local folder, reusing the one it already has.
function Nav.SiteKey(Root)
	Root = "/" .. fs.combine(Root, "")
	for Key, Known in pairs(S.Data.Sites) do
		if ("/" .. fs.combine(Known, "") == Root) then return Key end
	end
	local Base = Root == "/" and "computer" or fs.getName(Root):lower():gsub("[^%w%-]+", "-"):gsub("^%-+", ""):gsub("%-+$", "")
	if (Base == "") then Base = "site" end
	local Key, Number = Base, 1
	while (S.Data.Sites[Key]) do
		Number = Number + 1
		Key = Base .. "-" .. Number
	end
	S.Data.Sites[Key] = Root
	SaveData()
	return Key
end

local function Response(Status, Source, Headers)
	Headers = Headers or {}
	Headers["Content-Type"] = Headers["Content-Type"] or "text/ccmd"
	return { Status = Status, Headers = Headers, Body = Source }
end

-- Sends one request (no redirects). May block, so it runs inside a task.
function Nav.Request(Parsed, Method, Body, Options)
	if (Parsed.Scheme == "savannah") then
		return Internal.Handle(Method, Parsed, Body)
	elseif (Parsed.Scheme == "local") then
		local Server = Nav.LocalSite(Parsed.Host)
		if (not Server or not fs.isDir(Server.Root)) then
			return Response(404, Site.Message("Folder not found", "Savannah no longer knows where the local site \"" .. Parsed.Host .. "\" is. Open one of its pages again from Finder or File > Open File.", "red"))
		end
		if (Options and Options.Refresh) then Server:Refresh() end
		return Server:Request(Method, Parsed, Body, "local://" .. Parsed.Host)
	elseif (Parsed.Scheme == "ccmd" or Parsed.Scheme == "domain") then
		return S.Transport.Send(Method, Protocol.FormatUrl(Parsed), { Accept = Options and Options.Accept or "text/ccmd" }, Body, Options)
	end
	return nil, Parsed.Scheme .. ":// addresses are not supported."
end

-- Requests a page and follows redirects. Returns the response, the final parsed URL and a problem.
function Nav.Fetch(Tab, Parsed, Method, Body)
	local Result, Problem
	for _ = 1, C.MaxRedirects + 1 do
		Result, Problem = Nav.Request(Parsed, Method, Body, {
			Refresh = true,
			OnProgress = function(Received, Total)
				if (Tab.Loading) then
					Tab.Loading.Received, Tab.Loading.Total = Received, Total
					Page:Invalidate()
				end
			end
		})
		if (not Result) then break end
		local Location = Result.Headers and Result.Headers.Location
		if (Result.Status < 300 or Result.Status >= 400 or type(Location) ~= "string") then break end
		local Next = Protocol.ParseUrl(Location, Parsed)
		if (not Next) then break end
		Parsed, Method, Body = Next, "GET", nil
	end
	return Result, Parsed, Problem
end

local function TextDocument(Title, Text)
	local Lines = {}
	for Line in (tostring(Text):gsub("\r", "") .. "\n"):gmatch("(.-)\n") do
		Lines[#Lines + 1] = { { Text = (Line:gsub("\t", "    "):gsub("[%z\1-\8\11-\31]", "?")) } }
	end
	local Th = Theme.Get()
	return {
		Title = Title, Location = "/", Meta = {}, Inputs = {}, Forms = {}, Errors = {},
		Blocks = { { Type = "text", Align = "left", Lines = Lines } },
		Background = Gfx.ToBlit(Th.WindowBg), TextColor = Gfx.ToBlit(Th.Text), LinkColor = "3"
	}
end

function Nav.ConnectError(Url, Problem)
	Problem = tostring(Problem or "Unknown error")
	local Text
	if (Problem:find("No modem")) then
		Text = "Savannah can't open the page because this computer isn't connected to the internet.\n\nAttach a wireless or ender modem and try again."
	elseif (Problem:find("Could not find")) then
		Text = "Savannah can't find the ccinternet core named \"" .. S.Data.Host .. "\".\n\nCheck that the core is running and in range, or pick another server in Settings."
	elseif (Problem:find("did not answer")) then
		Text = "The server stopped answering.\n\nIt may be busy or out of range. Try again in a moment."
	else
		Text = Problem
	end
	return Site.Message("Can't open the page", Text, "red", { { "Try again", Url }, { "Settings", "savannah://settings" } })
end

-- Turns a response into a document.
function Nav.Interpret(Result, Parsed)
	local Type = (Result.Headers["Content-Type"] or ""):lower()
	local Name = Parsed.Path:match("[^/]*$")
	if (Name == "") then Name = Parsed.Host end
	if (type(Result.Body) ~= "string") then
		return Ccmd.Parse(Site.Message("Empty response", "The server sent nothing back (status " .. Result.Status .. ")."))
	end
	if (Type == "text/ccmd" or (Type == "" and Parsed.Path:lower():match("%.ccmd$"))) then
		return Ccmd.Parse(Result.Body)
	end
	local Kind = Type:match("^image/(%w+)")
	if (Kind and Image.Extensions[Kind]) then
		local Key = Protocol.FormatUrl(Parsed)
		S.Images[Key] = Image.Parse(Result.Body, Kind) or false
		local Doc = TextDocument(Name, "")
		Doc.Blocks = { { Type = "break" }, { Type = "image", Src = Key, Align = "center", Alt = Name } }
		return Doc
	end
	if (Type:match("^text/")) then return TextDocument(Result.Headers.Title or Name, Result.Body) end
	local Doc = Ccmd.Parse(Site.Message(Name, "This is a " .. Gfx.FormatSize(#Result.Body) .. " file (" .. (Type ~= "" and Type or "unknown type") .. ").", "yellow"))
	table.insert(Doc.Blocks, { Type = "break" })
	table.insert(Doc.Blocks, { Type = "button", Text = "Download", Href = "savannah://save", Align = "center", Color = "b", TextColor = "0" })
	return Doc
end

--
-- Showing pages
--

local function CollectImages(Blocks, Into)
	for _, Block in ipairs(Blocks) do
		if (Block.Type == "image") then Into[#Into + 1] = Block.Src end
		if (Block.Type == "form") then CollectImages(Block.Blocks, Into) end
	end
	return Into
end

function Nav.ImageKey(Tab, Src)
	local Parsed = Tab.Parsed and Protocol.ParseUrl(Src, Tab.Parsed)
	return Parsed and Protocol.FormatUrl(Parsed), Parsed
end

-- Lays the tab's page out for the current view size.
function Nav.Rebuild(Tab)
	if (not Tab.Doc or not S.ViewW) then return end
	Tab.Page = Layout.Build(Tab.Doc, S.ViewW, S.ViewH, {
		State = Tab.State,
		Focus = Tab.Focus,
		Images = function(Src)
			local Key = Nav.ImageKey(Tab, Src)
			if (not Key) then return false end
			return S.Images[Key]
		end
	})
	Tab.Built = S.ViewW .. "x" .. S.ViewH
	Tab.Scroll = math.max(0, math.min(Tab.Scroll, Tab.Page.MaxScroll))
	if (S.Find and Tab == Nav.Tab()) then Nav.FindMatches(false) end
	Page:Invalidate()
end

function Nav.UpdateTitle()
	local Tab = Nav.Tab()
	if (not Tab) then return end
	local Title = Tab.Loading and "Loading..." or (Tab.Doc and Tab.Title) or "Savannah"
	BlockOS.SetTitle(Title)
end

function Nav.LoadImages(Tab)
	if (Tab.ImageTask or not Tab.Doc) then return end
	local Pending, Seen = {}, {}
	for _, Src in ipairs(CollectImages(Tab.Doc.Blocks, {})) do
		local Key, Parsed = Nav.ImageKey(Tab, Src)
		if (Key and S.Images[Key] == nil and not Seen[Key]) then
			Seen[Key] = true
			Pending[#Pending + 1] = { Key = Key, Parsed = Parsed }
		end
	end
	if (#Pending == 0) then return end
	if (S.ImageCount + #Pending > C.MaxImages) then
		S.Images, S.ImageCount = {}, 0
	end
	local Task
	Task = Tasks.Spawn(function()
		for _, Item in ipairs(Pending) do
			local Ok, Result = pcall(Nav.Request, Item.Parsed, "GET", nil, { Accept = "image/*", Timeout = 5 })
			local Picture = false
			if (Ok and Result and Result.Status == 200 and type(Result.Body) == "string") then
				local Kind = (Result.Headers["Content-Type"] or ""):match("^image/(%w+)") or Item.Parsed.Path
				Picture = Image.Parse(Result.Body, Kind) or false
			end
			S.Images[Item.Key] = Picture
			S.ImageCount = S.ImageCount + 1
			Nav.Rebuild(Tab)
		end
	end, function()
		Tab.ImageTask = nil
	end)
	if (not Task.Done) then Tab.ImageTask = Task end
end

-- Puts a document in a tab. Keep holds the scroll position (reload, back and forward).
function Nav.Show(Tab, Doc, Result, Url, Scroll)
	Tab.Doc, Tab.Response, Tab.Url = Doc, Result, Url
	Tab.Parsed = Protocol.ParseUrl(Url)
	Tab.State, Tab.Focus, Tab.Selected = {}, nil, nil
	Tab.Scroll = Scroll or 0
	Tab.Title = Doc.Title or "Untitled"
	Tab.Status = Result and Result.Status or 0
	Tab.Problems = #Doc.Errors
	Nav.Rebuild(Tab)
	if (Scroll and Tab.Page) then Tab.Scroll = math.min(Scroll, Tab.Page.MaxScroll) end
	if (Tab == Nav.Tab()) then Nav.UpdateTitle() end
	Nav.LoadImages(Tab)
end

function Nav.Remember(Url, Title)
	local Scheme = Url:match("^(%a+)://")
	if (Scheme == "savannah") then return end
	local History = S.Data.History
	local Visits = 0
	for Index = #History, 1, -1 do
		if (History[Index].Url == Url) then
			Visits = History[Index].Visits or 1
			table.remove(History, Index)
		end
	end
	table.insert(History, 1, { Url = Url, Title = Title, Time = os.epoch("utc"), Visits = Visits + 1 })
	while (#History > C.MaxHistory) do table.remove(History) end
	SaveData()
end

function Nav.Finish(Tab, Result, Parsed, Problem, Opts)
	local Url = Protocol.FormatUrl(Parsed)
	local Doc
	if (not Result) then
		Doc = Ccmd.Parse(Nav.ConnectError(Url, Problem))
		Result = { Status = 0, Headers = {}, Body = nil }
	else
		Doc = Nav.Interpret(Result, Parsed)
	end
	if (Opts.Replace and Tab.History[Tab.Index]) then
		local Entry = Tab.History[Tab.Index]
		Entry.Url, Entry.Response, Entry.Title = Url, Result, Doc.Title
	else
		for Index = #Tab.History, Tab.Index + 1, -1 do Tab.History[Index] = nil end
		Tab.History[#Tab.History + 1] = { Url = Url, Response = Result, Title = Doc.Title, Scroll = 0 }
		while (#Tab.History > C.MaxTabHistory) do table.remove(Tab.History, 1) end
		Tab.Index = #Tab.History
		for Index = 1, #Tab.History - C.CachedPages do Tab.History[Index].Response = nil end
	end
	Nav.Show(Tab, Doc, Result, Url, Opts.Scroll)
	if (Result.Status > 0 and Result.Status < 400) then Nav.Remember(Url, Doc.Title) end
end

function Nav.Stop(Tab)
	if (Tab.Task) then
		Tasks.Cancel(Tab.Task)
		Tab.Task = nil
	end
	Tab.Loading = nil
	Nav.UpdateTitle()
	Page:Invalidate()
end

-- Opens an address in a tab. Opts: Method, Body, Absolute (ignore the current page),
-- Replace (reload in place) and Scroll.
function Nav.Go(Tab, Target, Opts)
	Opts = Opts or {}
	Target = tostring(Target or ""):gsub("^%s+", ""):gsub("%s+$", "")
	if (Target == "") then return end
	if (Opts.Absolute or not Tab.Parsed) then
		local Path = Target:match("^file://(/.*)$") or Target
		if (not Path:find("://", 1, true) and Path:find("/", 1, true) and fs.exists(Path)) then
			Nav.OpenLocal(Tab, Path)
			return
		end
	end
	local Parsed = Protocol.ParseUrl(Target, (not Opts.Absolute) and Tab.Parsed or nil)
	if (not Parsed) then
		Say("That address could not be read")
		return
	end
	if (Parsed.Scheme == "savannah" and Parsed.Host == "save") then
		Nav.SavePage(Tab)
		return
	end
	Nav.Stop(Tab)
	if (Tab.History[Tab.Index]) then Tab.History[Tab.Index].Scroll = Tab.Scroll end
	Tab.Loading = { Received = 0, Total = 0, Started = os.clock(), Url = Protocol.FormatUrl(Parsed) }
	Tab.Focus, Tab.Selected = nil, nil
	Nav.UpdateTitle()
	local Task
	Task = Tasks.Spawn(function()
		return Nav.Fetch(Tab, Parsed, Opts.Method or "GET", Opts.Body)
	end, function(Ok, Result, Final, Problem)
		Tab.Task, Tab.Loading = nil, nil
		if (not Ok) then Result, Final, Problem = nil, Parsed, Result end
		Nav.Finish(Tab, Result, Final or Parsed, Problem, Opts)
		Nav.UpdateTitle()
		Page:Invalidate()
	end)
	if (not Task.Done) then Tab.Task = Task end
	Page:Invalidate()
end

function Nav.OpenLocal(Tab, Path)
	Path = "/" .. fs.combine(Path, "")
	if (fs.isDir(Path)) then
		local Root = Site.FindRoot(fs.combine(Path, "index.ccmd"))
		Nav.Go(Tab, "local://" .. Nav.SiteKey(Root) .. "/", { Absolute = true })
		return
	end
	local Root = Site.FindRoot(Path)
	local Key = Nav.SiteKey(Root)
	local Server = Nav.LocalSite(Key)
	Server:Refresh()
	local Address = Server:Address(Path) or "/"
	if (Server:Resolve(Address) ~= Server:SitePath(Path)) then Address = Server:SitePath(Path) or "/" end
	Nav.Go(Tab, "local://" .. Key .. Protocol.Escape(Address), { Absolute = true })
end

function Nav.GoHistory(Tab, Index)
	local Entry = Tab.History[Index]
	if (not Entry) then return end
	Nav.Stop(Tab)
	if (Tab.History[Tab.Index]) then Tab.History[Tab.Index].Scroll = Tab.Scroll end
	Tab.Index = Index
	if (Entry.Response) then
		local Parsed = Protocol.ParseUrl(Entry.Url)
		Nav.Show(Tab, Nav.Interpret(Entry.Response, Parsed), Entry.Response, Entry.Url, Entry.Scroll)
	else
		Nav.Go(Tab, Entry.Url, { Absolute = true, Replace = true, Scroll = Entry.Scroll })
	end
end

function Nav.Reload(Tab)
	if (Tab.Loading) then
		Nav.Stop(Tab)
		return
	end
	if (not Tab.Url) then return end
	if (Tab.Doc) then
		for _, Src in ipairs(CollectImages(Tab.Doc.Blocks, {})) do
			local Key = Nav.ImageKey(Tab, Src)
			if (Key) then S.Images[Key] = nil end
		end
	end
	Nav.Go(Tab, Tab.Url, { Absolute = true, Replace = true, Scroll = Tab.Scroll })
end

function Nav.OpenTab(Target, Background)
	local Tab = Nav.NewTabState()
	table.insert(S.Tabs, Tab)
	if (not Background) then S.Current = #S.Tabs end
	View.Relayout()
	Nav.Go(Tab, Target or C.StartPage, { Absolute = true })
	if (not Background and not Target) then Page:SetFocus(S.W.Address) end
	return Tab
end

function Nav.CloseTab(Index)
	local Tab = S.Tabs[Index or S.Current]
	if (not Tab) then return end
	Nav.Stop(Tab)
	if (Tab.ImageTask) then Tasks.Cancel(Tab.ImageTask) end
	table.remove(S.Tabs, Index or S.Current)
	if (#S.Tabs == 0) then
		BlockOS.Quit()
		Page:Stop()
		return
	end
	S.Current = math.max(1, math.min(S.Current, #S.Tabs))
	View.Relayout()
	Nav.UpdateTitle()
end

function Nav.SelectTab(Index)
	if (not S.Tabs[Index]) then return end
	S.Current = Index
	if (S.Find) then Nav.FindMatches(true) end
	Nav.UpdateTitle()
	Page:SetFocus(S.W.View)
	Page:Invalidate()
end

function Nav.ToggleFavourite(Tab)
	if (not Tab.Url or Tab.Url:match("^savannah://")) then return end
	local Index = Nav.FavouriteIndex(Tab.Url)
	if (Index) then
		table.remove(S.Data.Favourites, Index)
		Say("Removed from Favourites")
	else
		table.insert(S.Data.Favourites, { Title = Tab.Title or Tab.Url, Url = Tab.Url })
		Say("Added to Favourites")
	end
	SaveData()
end

function Nav.SavePage(Tab)
	local Body = Tab.Response and Tab.Response.Body
	if (type(Body) ~= "string") then
		Say("Nothing to save")
		return
	end
	local Name = Tab.Parsed and Tab.Parsed.Path:match("[^/]+$")
	if (not Name or Name == "") then
		Name = ((Tab.Parsed and Tab.Parsed.Host ~= "" and Tab.Parsed.Host) or "page"):gsub("[^%w%-]", "_") .. ".ccmd"
	elseif (not Name:find("%.")) then
		Name = Name .. ".ccmd"
	end
	if (not fs.exists("/home/Downloads")) then fs.makeDir("/home/Downloads") end
	local Path = Ui.PickFile({ Title = "Save Page As", Save = true, Dir = "/home/Downloads", Name = Name })
	if (not Path) then return end
	local Handle = fs.open(Path, "wb")
	if (not Handle) then
		Ui.Alert("Save", "Could not write " .. Path)
		return
	end
	Handle.write(Body)
	Handle.close()
	Say("Saved " .. fs.getName(Path))
end

--
-- Forms
--

-- Reads a local file or folder into { [relative path] = contents } for a file field.
local function ReadLocal(Path)
	local Files, Total, Count = {}, 0, 0
	local function Add(Full, Name)
		local Data = Site.ReadFile(Full)
		if (not Data) then return end
		Files[Name] = Data
		Total = Total + #Data
		Count = Count + 1
	end
	local function Walk(Dir, Prefix)
		for _, Name in ipairs(fs.list(Dir)) do
			local Full = fs.combine(Dir, Name)
			if (fs.isDir(Full)) then
				if (Name:sub(1, 1) ~= ".") then Walk(Full, Prefix .. Name .. "/") end
			else
				Add(Full, Prefix .. Name)
			end
		end
	end
	if (fs.isDir(Path)) then Walk(Path, "") else Add(Path, fs.getName(Path)) end
	if (Count == 0) then return nil, "There are no files there." end
	return Files, Total, Count
end

function Nav.Submit(Tab, FormIndex, Button)
	local Form = Tab.Doc and Tab.Doc.Forms[FormIndex]
	if (not Form) then return end
	local Fields = Ccmd.FormFields(Tab.Doc, FormIndex, Tab.State, Button)
	local Action = Form.Action or Tab.Url
	if (Form.Method == "GET") then
		local Parsed = Protocol.ParseUrl(Action, Tab.Parsed)
		if (not Parsed) then return end
		Parsed.Query = Protocol.EncodeQuery(Fields)
		Nav.Go(Tab, Protocol.FormatUrl(Parsed), { Absolute = true })
	else
		Nav.Go(Tab, Action, { Method = "POST", Body = Fields })
	end
end

function Nav.FocusInput(Tab, Input)
	Tab.Focus = Input and Input.Id or nil
	Nav.Rebuild(Tab)
	if (not Input) then return end
	local Region = Layout.InputRegion(Tab.Page, Input.Id)
	if (Region) then Tab.Scroll = Layout.ScrollTo(Tab.Page, Region.Y, Tab.Scroll) end
end

function Nav.NextField(Tab, Input, Wrap)
	local Found, First = false, nil
	for _, Other in ipairs(Tab.Doc.Inputs) do
		local Typable = Other.Form == Input.Form and (Other.Kind == "text" or Other.Kind == "password")
		if (Typable and not First) then First = Other end
		if (Found and Typable) then return Other end
		if (Other == Input) then Found = true end
	end
	if (Wrap and First ~= Input) then return First end
	return nil
end

function Nav.ChooseFiles(Tab, Input, X, Y)
	local Choice = Ui.ContextMenu(X, Y, { "Choose File...", "Choose Folder...", { Text = "Clear", Disabled = Tab.State[Input.Id] == nil } })
	local Path
	if (Choice == 1) then
		Path = Ui.PickFile({ Title = "Choose File", Dir = "/home" })
	elseif (Choice == 2) then
		Path = Ui.PickFile({ Title = "Choose Folder", Dir = "/home", Folders = true })
	elseif (Choice == 3) then
		Tab.State[Input.Id] = nil
	end
	if (Path) then
		local Files, Total, Count = ReadLocal(Path)
		if (not Files) then
			Ui.Alert("Upload", Total)
		elseif (Total > C.MaxUpload) then
			Ui.Alert("Upload", "That is " .. Gfx.FormatSize(Total) .. ". A site holds about " .. Gfx.FormatSize(C.MaxUpload) .. ".")
		else
			Tab.State[Input.Id] = Files
			Say(Count .. (Count == 1 and " file" or " files") .. " ready")
		end
	end
	Nav.Rebuild(Tab)
end

-- Follows a link, presses a button or starts editing a field. X, Y place menus.
function Nav.Activate(Tab, Region, NewTab, X, Y)
	if (Region.Kind == "link" or (Region.Kind == "button" and Region.Button.Href)) then
		local Href = Region.Href or Region.Button.Href
		if (NewTab) then
			local Parsed = Protocol.ParseUrl(Href, Tab.Parsed)
			if (Parsed) then
				Nav.OpenTab(Protocol.FormatUrl(Parsed), true)
				Say("Opened in a new tab")
			end
		else
			Nav.Go(Tab, Href)
		end
	elseif (Region.Kind == "button" and Region.Button.Form) then
		Nav.Submit(Tab, Region.Button.Form, Region.Button)
	elseif (Region.Kind == "input") then
		if (Region.Input.Kind == "file") then
			Nav.ChooseFiles(Tab, Region.Input, X or 2, Y or 2)
		else
			Nav.FocusInput(Tab, Region.Input)
		end
	end
end

-- Typing into the focused field. Returns true when handled.
function Nav.EditField(Tab, Name, A)
	local Input
	for _, Other in ipairs(Tab.Doc.Inputs) do
		if (Other.Id == Tab.Focus) then Input = Other end
	end
	if (not Input) then
		Tab.Focus = nil
		return false
	end
	local Value = Tab.State[Input.Id]
	if (type(Value) ~= "string") then Value = Input.Value or "" end
	if (Name == "char" or Name == "paste") then
		if (Ui.Modifiers.Ctrl) then return true end
		Value = (Value .. A:gsub("[\r\n]", "")):sub(1, C.MaxField)
	elseif (Name == "key") then
		if (A == keys.backspace) then
			Value = Value:sub(1, -2)
		elseif (A == keys.enter or A == keys.numPadEnter) then
			local Next = Nav.NextField(Tab, Input, false)
			if (Next) then
				Nav.FocusInput(Tab, Next)
			elseif (Input.Form) then
				Tab.Focus = nil
				Nav.Submit(Tab, Input.Form, nil)
			else
				Nav.FocusInput(Tab, nil)
			end
			return true
		elseif (A == keys.tab) then
			Nav.FocusInput(Tab, Nav.NextField(Tab, Input, true))
			return true
		elseif (A == keys.up or A == keys.down) then
			Nav.FocusInput(Tab, nil)
			return false
		else
			return true
		end
	else
		return false
	end
	Tab.State[Input.Id] = Value
	Nav.Rebuild(Tab)
	return true
end

--
-- Find on page
--

function Nav.FindMatches(Jump)
	local Find, Tab = S.Find, Nav.Tab()
	Find.Matches = {}
	local Query = Find.Query:lower()
	if (Query == "" or not Tab or not Tab.Page) then
		Find.Index = 0
		return
	end
	for Row, Line in ipairs(Tab.Page.Rows) do
		local Text = Line[1]:lower()
		local From = 1
		while (#Find.Matches < C.MaxMatches) do
			local Start, Finish = Text:find(Query, From, true)
			if (not Start) then break end
			Find.Matches[#Find.Matches + 1] = { Y = Row, X1 = Start, X2 = Finish }
			From = Finish + 1
		end
	end
	if (Jump or Find.Index > #Find.Matches or Find.Index < 1) then
		Find.Index = #Find.Matches > 0 and 1 or 0
		if (Jump) then Nav.FindStep(0) end
	end
end

function Nav.FindStep(Step)
	local Find, Tab = S.Find, Nav.Tab()
	if (not Find or #Find.Matches == 0) then return end
	Find.Index = (Find.Index - 1 + Step) % #Find.Matches + 1
	local Match = Find.Matches[Find.Index]
	Tab.Scroll = Layout.ScrollTo(Tab.Page, Match.Y, Tab.Scroll)
	Page:Invalidate()
end

function Nav.OpenFind()
	if (not S.Find) then
		S.Find = { Query = "", Matches = {}, Index = 0 }
		View.Relayout()
	end
	Page:SetFocus(S.W.FindField)
	S.W.FindField:SelectAll()
end

function Nav.CloseFind()
	S.Find = nil
	View.Relayout()
end

--
-- Built-in savannah:// pages
--

-- Wraps a built-in page. Leading spaces become non-breaking spaces so paragraphs keep
-- their margin (ccmd removes indentation shared by every line of a paragraph).
function Internal.Source(Title, Body)
	local Th = Theme.Get()
	for Index, Line in ipairs(Body) do
		Body[Index] = Line:gsub("^( +)", function(Spaces) return string.rep("\160", #Spaces) end)
	end
	return table.concat({
		"--", "title: " .. Title, "location: /",
		"background: " .. (Th.Dark and "black" or "white"),
		"text-color: " .. (Th.Dark and "white" or "black"),
		"link-color: " .. (Th.Dark and "lightBlue" or "blue"),
		"--",
		table.concat(Body, "\n")
	}, "\n")
end

local function Heading(Body, Text)
	Body[#Body + 1] = "<br/>"
	Body[#Body + 1] = "<p text-color=\"gray\">"
	Body[#Body + 1] = " " .. Ccmd.Escape(Text)
	Body[#Body + 1] = "</p>"
end

local function ShortUrl(Url)
	return (Url:gsub("^ccmd://", ""))
end

function Internal.Start()
	local Body = {
		"<br/>",
		"<p alignment=\"center\">",
		"{orange}\15{/} {yellow}Savannah{/}",
		"{gray}Browse the ccinternet{/}",
		"</p>"
	}
	Heading(Body, "Favourites")
	Body[#Body + 1] = "<p>"
	if (#S.Data.Favourites == 0) then
		Body[#Body + 1] = "  {gray}Press * in the toolbar to add the page you are on.{/}"
	end
	for _, Entry in ipairs(S.Data.Favourites) do
		Body[#Body + 1] = "  {orange}\4{/} " .. LinkSource(Entry.Title, Entry.Url)
	end
	Body[#Body + 1] = "</p>"
	local Frequent = {}
	for _, Entry in ipairs(S.Data.History) do
		if (not Nav.FavouriteIndex(Entry.Url)) then Frequent[#Frequent + 1] = Entry end
	end
	table.sort(Frequent, function(A, B) return (A.Visits or 1) > (B.Visits or 1) end)
	if (#Frequent > 0) then
		Heading(Body, "Frequently Visited")
		Body[#Body + 1] = "<p>"
		for Index = 1, math.min(6, #Frequent) do
			local Entry = Frequent[Index]
			Body[#Body + 1] = "  {gray}\7{/} " .. LinkSource(Entry.Title or Entry.Url, Entry.Url) .. " {gray}" .. Ccmd.Escape(ShortUrl(Entry.Url)) .. "{/}"
		end
		Body[#Body + 1] = "</p>"
	end
	Heading(Body, "Explore")
	Body[#Body + 1] = "<p>"
	Body[#Body + 1] = "  " .. LinkSource("Every site", "domain://directory") .. "   " .. LinkSource("Get a domain", "domain://") .. "   " .. LinkSource("History", "savannah://history")
	Body[#Body + 1] = "</p>"
	return Internal.Source("Start Page", Body)
end

function Internal.Favourites()
	local Body = { "<br/>", "<p alignment=\"center\">", "{orange}\4{/} Favourites", "</p>", "<br/>", "<p>" }
	if (#S.Data.Favourites == 0) then
		Body[#Body + 1] = " {gray}No favourites yet. Press * in the toolbar to add the page you are on.{/}"
	end
	for Index, Entry in ipairs(S.Data.Favourites) do
		Body[#Body + 1] = " " .. LinkSource(Entry.Title, Entry.Url) .. "  {gray}" .. Ccmd.Escape(ShortUrl(Entry.Url)) .. "{/}  " .. LinkSource("Remove", "savannah://favourites?remove=" .. Index)
	end
	Body[#Body + 1] = "</p>"
	return Internal.Source("Favourites", Body)
end

function Internal.History()
	local Body = { "<br/>", "<p alignment=\"center\">", "History", "</p>" }
	local Day
	if (#S.Data.History == 0) then
		Body[#Body + 1] = "<br/>"
		Body[#Body + 1] = "<p alignment=\"center\">"
		Body[#Body + 1] = "{gray}Pages you visit show up here.{/}"
		Body[#Body + 1] = "</p>"
	end
	for _, Entry in ipairs(S.Data.History) do
		local Seconds = math.floor((Entry.Time or 0) / 1000)
		local Date = os.date("%A %d %B", Seconds)
		if (Date ~= Day) then
			if (Day) then Body[#Body + 1] = "</p>" end
			Heading(Body, Date)
			Body[#Body + 1] = "<p>"
			Day = Date
		end
		Body[#Body + 1] = " {gray}" .. os.date("%H:%M", Seconds) .. "{/} " .. LinkSource(Entry.Title or Entry.Url, Entry.Url) .. " {gray}" .. Ccmd.Escape(ShortUrl(Entry.Url)) .. "{/}"
	end
	if (Day) then
		Body[#Body + 1] = "</p>"
		Body[#Body + 1] = "<br/>"
		Body[#Body + 1] = "<button text=\"Clear History\" href=\"savannah://history?clear=yes\" color=\"red\" text-color=\"white\"/>"
	end
	return Internal.Source("History", Body)
end

function Internal.Settings(Message)
	local A = Ccmd.Attribute
	local Body = { "<br/>", "<p alignment=\"center\">", "Settings", "</p>", "<br/>" }
	if (Message) then
		Body[#Body + 1] = "<p alignment=\"center\">"
		Body[#Body + 1] = "{lime}" .. Ccmd.Escape(Message) .. "{/}"
		Body[#Body + 1] = "</p>"
		Body[#Body + 1] = "<br/>"
	end
	local Rest = {
		"<form action=\"savannah://settings\" method=\"POST\">",
		"<input name=\"host\" label=\" Server name\" width=\"22\" value=\"" .. A(S.Data.Host) .. "\" placeholder=\"" .. Protocol.DefaultHost .. "\"/>",
		"<p text-color=\"gray\">",
		" The ccinternet core to use. Keep ccinternet unless",
		" you were told the name of another internet.",
		"</p>",
		"<br/>",
		"<input name=\"home\" label=\" Home page  \" width=\"22\" value=\"" .. A(S.Data.Home) .. "\" placeholder=\"" .. C.StartPage .. "\"/>",
		"<br/>",
		"<button text=\"Save\" alignment=\"center\"/>",
		"</form>",
		"<br/>",
		"<p text-color=\"gray\">",
		" Local sites Savannah knows about:",
		"</p>",
		"<p>"
	}
	for _, Line in ipairs(Rest) do Body[#Body + 1] = Line end
	local Keys = {}
	for Key in pairs(S.Data.Sites) do Keys[#Keys + 1] = Key end
	table.sort(Keys)
	if (#Keys == 0) then Body[#Body + 1] = " {gray}None yet. Open a .ccmd page from Finder.{/}" end
	for _, Key in ipairs(Keys) do
		Body[#Body + 1] = " " .. LinkSource(Key, "local://" .. Key .. "/") .. " {gray}" .. Ccmd.Escape(S.Data.Sites[Key]) .. "{/} " .. LinkSource("Forget", "savannah://settings?forget=" .. Key)
	end
	Body[#Body + 1] = "</p>"
	return Internal.Source("Settings", Body)
end

local function Redirect(Url)
	return { Status = 303, Headers = { Location = Url }, Body = nil }
end

function Internal.Handle(Method, Parsed, Body)
	local Name = Parsed.Host ~= "" and Parsed.Host or "start"
	local Params = Parsed.Params
	if (Name == "start") then
		return Response(200, Internal.Start())
	elseif (Name == "favourites" or Name == "bookmarks") then
		local Index = tonumber(Params.remove)
		if (Index and S.Data.Favourites[Index]) then
			table.remove(S.Data.Favourites, Index)
			SaveData()
			return Redirect("savannah://favourites")
		end
		return Response(200, Internal.Favourites())
	elseif (Name == "history") then
		if (Params.clear) then
			S.Data.History = {}
			SaveData()
			return Redirect("savannah://history")
		end
		return Response(200, Internal.History())
	elseif (Name == "settings") then
		if (Method == "POST" and type(Body) == "table") then
			local Host = type(Body.host) == "string" and Body.host:gsub("^%s+", ""):gsub("%s+$", "") or ""
			local Home = type(Body.home) == "string" and Body.home:gsub("^%s+", ""):gsub("%s+$", "") or ""
			S.Data.Host = Host ~= "" and Host or Protocol.DefaultHost
			S.Data.Home = Home ~= "" and Home or C.StartPage
			S.Transport = Protocol.NetworkTransport(S.Data.Host)
			SaveData()
			return Redirect("savannah://settings?saved=yes")
		end
		if (Params.forget and S.Data.Sites[Params.forget]) then
			S.Data.Sites[Params.forget] = nil
			S.Sites[Params.forget] = nil
			SaveData()
			return Redirect("savannah://settings")
		end
		return Response(200, Internal.Settings(Params.saved and "Settings saved."))
	elseif (Name == "source") then
		local Target = Params.url and Protocol.ParseUrl(Params.url)
		if (not Target or Target.Scheme == "savannah") then
			return Response(400, Site.Message("No source", "There is no page source to show."))
		end
		local Result, Problem = Nav.Request(Target, "GET", nil, {})
		if (not Result) then return Response(502, Nav.ConnectError(Params.url, Problem)) end
		return { Status = 200, Headers = { ["Content-Type"] = "text/plain", Title = "Source of " .. ShortUrl(Params.url) }, Body = tostring(Result.Body or "") }
	end
	return Response(404, Site.Message("Not found", "savannah://" .. Name .. " is not a Savannah page.", "red", { { "Start Page", C.StartPage } }))
end

--
-- Drawing
--

function View.DisplayUrl(Tab)
	local Url = (Tab.Loading and Tab.Loading.Url) or Tab.Url or ""
	if (Url == C.StartPage or Url == C.StartPage .. "/") then return "" end
	local Source = Url:match("^savannah://source%?(.*)$")
	if (Source) then return "Source: " .. ShortUrl(Protocol.DecodeQuery(Source).url or "") end
	return ShortUrl(Url)
end

function View.Progress(Tab)
	local Loading = Tab.Loading
	if (not Loading) then return nil end
	if (Loading.Total and Loading.Total > 0) then return 0.2 + 0.8 * Loading.Received / Loading.Total end
	local Time = os.clock() - Loading.Started
	return 0.1 + 0.7 * (1 - math.exp(-Time / 2))
end

function View.DrawAddress(Self, T, Th, P)
	if (P.Focus == Self) then
		Ui.Input.Draw(Self, T, Th, P)
		return
	end
	local Tab = Nav.Tab()
	local Text = View.DisplayUrl(Tab)
	local Fg = Th.InputFg
	if (Text == "") then
		Text, Fg = "Enter an address", Th.SubText
	elseif (#Text > Self.W - 2) then
		Text = "\171" .. Text:sub(-(Self.W - 3))
	end
	local Line = Gfx.Pad(Text, Self.W, "center")
	local Progress = View.Progress(Tab)
	local Filled = Progress and math.floor(Self.W * Progress + .5) or 0
	Gfx.Write(T, Self.X, Self.Y, Line, Fg, Th.InputBg)
	if (Filled > 0) then
		Gfx.Write(T, Self.X, Self.Y, Line:sub(1, Filled), Th.AccentFg, Th.Accent)
	end
end

function View.DrawTabs(Self, T, Th)
	local Count = #S.Tabs
	local X = Self.X
	for Index, Tab in ipairs(S.Tabs) do
		local Width = math.floor(Self.W * Index / Count) - math.floor(Self.W * (Index - 1) / Count)
		local Active = Index == S.Current
		local Bg = Active and Th.WindowBg or Th.Panel
		local Fg = Active and Th.Text or Th.SubText
		local Label = Tab.Loading and "Loading..." or Tab.Title or "New Tab"
		Gfx.Write(T, X, Self.Y, Gfx.Pad(" " .. Label, Width - 2), Fg, Bg)
		Gfx.Write(T, X + Width - 2, Self.Y, "\215 ", Active and Th.Text or Th.SubText, Bg)
		if (Index > 1) then Gfx.Write(T, X, Self.Y, "\149", Th.Border, Bg) end
		X = X + Width
	end
end

function View.TabsEvent(Self, Name, A, X)
	if (Name ~= "mouse_click") then return Name == "mouse_scroll" end
	local Count = #S.Tabs
	local Offset = X - Self.X
	for Index = 1, Count do
		local Right = math.floor(Self.W * Index / Count)
		if (Offset < Right) then
			if (A == 3 or Offset >= Right - 2) then
				Nav.CloseTab(Index)
			else
				Nav.SelectTab(Index)
			end
			return true
		end
	end
	return true
end

local function Blit(T, X, Y, Text, Fg, Bg)
	T.setCursorPos(X, Y)
	T.blit(Text, Fg, Bg)
end

-- Repaints part of a content row with new colours (selection and find highlights).
local function Mark(T, Self, P, Scroll, Y, X1, X2, Fg, Bg)
	local Row = P.Rows[Y]
	local ScreenY = Y - Scroll
	if (not Row or ScreenY < 1 or ScreenY > P.ViewH) then return end
	X1, X2 = math.max(1, X1), math.min(P.ViewW, X2)
	if (X2 < X1) then return end
	local Text = Row[1]:sub(X1, X2)
	Blit(T, Self.X + P.ViewX + X1 - 2, Self.Y + P.ViewY + ScreenY - 2, Text, string.rep(Fg, #Text), string.rep(Bg, #Text))
end

function View.DrawPage(Self, T, Th)
	local Tab = Nav.Tab()
	if (Tab.Doc and Tab.Built ~= S.ViewW .. "x" .. S.ViewH) then Nav.Rebuild(Tab) end
	local P = Tab.Page
	local Region
	if (not P) then
		Gfx.Fill(T, Self.X, Self.Y, Self.W, Self.H, Th.WindowBg)
	else
		local Blank = { string.rep(" ", P.ViewW), string.rep("0", P.ViewW), string.rep(P.Background, P.ViewW) }
		for Y = 1, P.ViewH do
			local Row = P.Rows[Tab.Scroll + Y] or Blank
			Blit(T, Self.X + P.ViewX - 1, Self.Y + P.ViewY + Y - 2, Row[1], Row[2], Row[3])
		end
		if (S.Find) then
			for Index, Match in ipairs(S.Find.Matches) do
				local Current = Index == S.Find.Index
				Mark(T, Self, P, Tab.Scroll, Match.Y, Match.X1, Match.X2, "f", Current and "1" or "4")
			end
		end
		Region = Tab.Selected and P.Regions[Tab.Selected]
		if (Region) then Mark(T, Self, P, Tab.Scroll, Region.Y, Region.X1, Region.X2, "f", "4") end
		if (P.Bar) then
			for Index, Row in ipairs(P.Bar.Rows) do
				Blit(T, Self.X, Self.Y + Index - 1, Row[1], Row[2], Row[3])
			end
		end
		if (P.MaxScroll > 0) then
			local Track = P.ViewH
			local Thumb = math.max(1, math.floor(Track * Track / #P.Rows))
			local ThumbY = math.floor((Track - Thumb) * Tab.Scroll / P.MaxScroll + .5)
			Gfx.Fill(T, Self.X + Self.W - 1, Self.Y + P.ViewY - 1 + ThumbY, 1, Thumb, Th.SubText)
		end
	end
	-- Status pill in the bottom-left corner, like a link preview.
	local Status
	if (Tab.Loading) then
		Status = "Loading " .. View.DisplayUrl(Tab) .. (Tab.Loading.Total > 1 and (" " .. Tab.Loading.Received .. "/" .. Tab.Loading.Total) or "")
	elseif (S.Message and os.clock() - S.MessageAt < C.MessageTime) then
		Status = S.Message
	elseif (Region and (Region.Href or (Region.Button and Region.Button.Href))) then
		local Parsed = Protocol.ParseUrl(Region.Href or Region.Button.Href, Tab.Parsed)
		Status = Parsed and ShortUrl(Protocol.FormatUrl(Parsed))
	elseif (Tab.Problems and Tab.Problems > 0 and Tab.Url and Tab.Url:match("^local://")) then
		Status = Tab.Problems .. (Tab.Problems == 1 and " problem" or " problems") .. " on this page"
	end
	if (Status) then
		Status = " " .. Gfx.Truncate(Status, Self.W - 4) .. " "
		Gfx.Write(T, Self.X, Self.Y + Self.H - 1, Status, Th.PanelFg or Th.Text, Th.Panel)
	end
end

function View.PageCursor(Self)
	local Tab = Nav.Tab()
	local P = Tab.Page
	if (not Tab.Focus or not P) then return nil end
	local Region = Layout.InputRegion(P, Tab.Focus)
	if (not Region) then return nil end
	local X, Y = Layout.RegionPosition(P, Region, Tab.Scroll)
	if (not X) then return nil end
	local Value = Tab.State[Region.Input.Id]
	if (Value == nil) then Value = Region.Input.Value end
	local Shown, Placeholder = Layout.InputText(Region.Input, Value)
	local Offset = Placeholder and 0 or math.min(#Shown, Region.X2 - Region.X1 + 1)
	local Column = math.min(X + Offset, P.ViewX + P.ViewW - 1)
	local Colour = 2 ^ (tonumber(Region.Input.TextColor, 16) or 15)
	return Self.X + Column - 1, Self.Y + Y - 1, Colour
end

function View.Scroll(Tab, By)
	if (not Tab.Page) then return end
	Tab.Scroll = math.max(0, math.min(Tab.Page.MaxScroll, Tab.Scroll + By))
end

function View.SelectRegion(Tab, Step)
	local Regions = Tab.Page and Tab.Page.Regions
	if (not Regions or #Regions == 0) then return end
	local Index = (Tab.Selected or (Step > 0 and 0 or #Regions + 1)) + Step
	if (Index < 1) then Index = #Regions end
	if (Index > #Regions) then Index = 1 end
	Tab.Selected = Index
	Tab.Scroll = Layout.ScrollTo(Tab.Page, Regions[Index].Y, Tab.Scroll)
end

function View.LinkMenu(Tab, Region, X, Y)
	local Href = Region.Href or (Region.Button and Region.Button.Href)
	local Parsed = Href and Protocol.ParseUrl(Href, Tab.Parsed)
	if (not Parsed) then return end
	local Url = Protocol.FormatUrl(Parsed)
	local Options = { "Open Link", "Open Link in New Tab", "-", "Add Link to Favourites", "Copy Link" }
	local Choice = Options[Ui.ContextMenu(X, Y, Options) or 0]
	if (Choice == "Open Link") then
		Nav.Go(Tab, Url, { Absolute = true })
	elseif (Choice == "Open Link in New Tab") then
		Nav.OpenTab(Url, true)
		Say("Opened in a new tab")
	elseif (Choice == "Add Link to Favourites") then
		if (not Nav.FavouriteIndex(Url)) then
			table.insert(S.Data.Favourites, { Title = Region.Kind == "button" and Region.Button.Text or Url, Url = Url })
			SaveData()
		end
		Say("Added to Favourites")
	elseif (Choice == "Copy Link") then
		BlockOS.TextClipboard = Url
		Say("Link copied")
	end
end

function View.PageMenu(Tab, X, Y)
	local Options = {
		{ Text = "Back", Disabled = Tab.Index <= 1 },
		{ Text = "Forward", Disabled = Tab.Index >= #Tab.History },
		{ Text = Tab.Loading and "Stop" or "Reload" },
		"-",
		{ Text = "View Source", Disabled = not Tab.Url or Tab.Url:match("^savannah://") ~= nil },
		{ Text = "Save Page As...", Disabled = not (Tab.Response and Tab.Response.Body) },
		{ Text = "Find on Page..." }
	}
	local Index = Ui.ContextMenu(X, Y, Options)
	local Choice = Index and Options[Index].Text
	if (Choice == "Back") then
		Nav.GoHistory(Tab, Tab.Index - 1)
	elseif (Choice == "Forward") then
		Nav.GoHistory(Tab, Tab.Index + 1)
	elseif (Choice == "Reload" or Choice == "Stop") then
		Nav.Reload(Tab)
	elseif (Choice == "View Source") then
		View.ViewSource(Tab)
	elseif (Choice == "Save Page As...") then
		Nav.SavePage(Tab)
	elseif (Choice == "Find on Page...") then
		Nav.OpenFind()
	end
end

function View.ViewSource(Tab)
	if (not Tab.Url or Tab.Url:match("^savannah://")) then return end
	Nav.OpenTab("savannah://source?" .. Protocol.EncodeQuery({ url = Tab.Url }))
end

function View.PageEvent(Self, Name, A, B, C)
	local Tab = Nav.Tab()
	if (Name == "mouse_click") then
		local P = Tab.Page
		local Region = P and Layout.Hit(P, B - Self.X + 1, C - Self.Y + 1, Tab.Scroll)
		if (A == 2) then
			if (Region and (Region.Kind == "link" or (Region.Kind == "button" and Region.Button.Href))) then
				View.LinkMenu(Tab, Region, B, C)
			else
				View.PageMenu(Tab, B, C)
			end
		elseif (Region) then
			if (Tab.Focus and (Region.Kind ~= "input" or Region.Input.Id ~= Tab.Focus)) then Nav.FocusInput(Tab, nil) end
			Tab.Selected = nil
			Nav.Activate(Tab, Region, A == 3, B, C)
		else
			Tab.Selected = nil
			if (Tab.Focus) then Nav.FocusInput(Tab, nil) end
		end
		return true
	elseif (Name == "mouse_scroll") then
		View.Scroll(Tab, A * 3)
		return true
	elseif (not Tab.Doc) then
		return false
	end
	if (Tab.Focus and (Name == "char" or Name == "paste" or Name == "key")) then
		if (Nav.EditField(Tab, Name, A)) then return true end
	end
	if (Name == "char" and A == " " and not Ui.Modifiers.Ctrl) then
		View.Scroll(Tab, S.ViewH - 1)
		return true
	elseif (Name ~= "key" or Ui.Modifiers.Ctrl) then
		return false
	end
	local Height = Tab.Page and Tab.Page.ViewH or S.ViewH
	if (A == keys.up) then View.Scroll(Tab, -1)
	elseif (A == keys.down) then View.Scroll(Tab, 1)
	elseif (A == keys.pageUp) then View.Scroll(Tab, 1 - Height)
	elseif (A == keys.pageDown) then View.Scroll(Tab, Height - 1)
	elseif (A == keys.home) then View.Scroll(Tab, -math.huge)
	elseif (A == keys["end"]) then View.Scroll(Tab, math.huge)
	elseif (A == keys.tab) then View.SelectRegion(Tab, Ui.Modifiers.Shift and -1 or 1)
	elseif ((A == keys.enter or A == keys.numPadEnter) and Tab.Selected and Tab.Page and Tab.Page.Regions[Tab.Selected]) then
		local Region = Tab.Page.Regions[Tab.Selected]
		local X, Y = Layout.RegionPosition(Tab.Page, Region, Tab.Scroll)
		Tab.Selected = nil
		Nav.Activate(Tab, Region, false, X and (Self.X + X - 1), Y and (Self.Y + Y - 1))
	elseif (A == keys.backspace) then Nav.GoHistory(Tab, Tab.Index - 1)
	else
		return false
	end
	return true
end

--
-- Menus and shortcuts
--

function View.Menu()
	local Tab = Nav.Tab()
	local IsFavourite = Tab.Url and Nav.FavouriteIndex(Tab.Url)
	local IsInternal = not Tab.Url or Tab.Url:match("^savannah://") ~= nil
	local Options = {
		{ Text = "New Tab", Key = "tab" },
		{ Text = "Open File...", Key = "open" },
		{ Text = "Save Page As...", Key = "save", Disabled = not (Tab.Response and Tab.Response.Body) },
		"-",
		{ Text = IsFavourite and "Remove from Favourites" or "Add to Favourites", Key = "fav", Disabled = IsInternal },
		{ Text = "Favourites", Key = "favourites" },
		{ Text = "History", Key = "history" },
		"-",
		{ Text = "Find on Page...", Key = "find" },
		{ Text = "View Source", Key = "source", Disabled = IsInternal },
		"-",
		{ Text = "Home", Key = "home" },
		{ Text = "Set as Home Page", Key = "sethome", Disabled = not Tab.Url },
		{ Text = "Settings", Key = "settings" },
		{ Text = "Close Tab", Key = "close" }
	}
	if (Tab.Url and Tab.Url:match("^local://") and Tab.Parsed) then
		table.insert(Options, 4, { Text = "Edit Page", Key = "edit" })
	end
	local W = Page.W
	local Index = Ui.ContextMenu(W - 22, 2, Options)
	local Key = Index and Options[Index].Key
	if (Key == "tab") then
		Nav.OpenTab()
	elseif (Key == "open") then
		local Path = Ui.PickFile({ Title = "Open File", Dir = "/home" })
		if (Path) then Nav.OpenLocal(Tab, Path) end
	elseif (Key == "save") then
		Nav.SavePage(Tab)
	elseif (Key == "edit") then
		View.EditPage(Tab)
	elseif (Key == "fav") then
		Nav.ToggleFavourite(Tab)
	elseif (Key == "favourites") then
		Nav.Go(Tab, "savannah://favourites", { Absolute = true })
	elseif (Key == "history") then
		Nav.Go(Tab, "savannah://history", { Absolute = true })
	elseif (Key == "find") then
		Nav.OpenFind()
	elseif (Key == "source") then
		View.ViewSource(Tab)
	elseif (Key == "home") then
		Nav.Go(Tab, S.Data.Home, { Absolute = true })
	elseif (Key == "sethome") then
		S.Data.Home = Tab.Url
		SaveData()
		Say("Home page set")
	elseif (Key == "settings") then
		Nav.Go(Tab, "savannah://settings", { Absolute = true })
	elseif (Key == "close") then
		Nav.CloseTab()
	end
end

-- Opens the file behind a local page in CCDream (or Editor when CCDream is not installed).
function View.EditPage(Tab)
	local Server = Nav.LocalSite(Tab.Parsed.Host)
	local File = Server and Server:Resolve(Tab.Parsed.Path)
	local Real = File and Server:RealPath(File)
	if (not Real) then
		Say("No file for this page")
		return
	end
	local Apps = BlockOS.Require("apps")
	BlockOS.Launch(Apps.Get("ccdream") and "ccdream" or "editor", { Real })
end

local Shortcuts = {
	[keys.l] = function() Page:SetFocus(S.W.Address) end,
	[keys.t] = function() Nav.OpenTab() end,
	[keys.n] = function() Nav.OpenTab() end,
	[keys.w] = function() Nav.CloseTab() end,
	[keys.r] = function() Nav.Reload(Nav.Tab()) end,
	[keys.f] = function() Nav.OpenFind() end,
	[keys.d] = function() Nav.ToggleFavourite(Nav.Tab()) end,
	[keys.s] = function() Nav.SavePage(Nav.Tab()) end,
	[keys.o] = function()
		local Path = Ui.PickFile({ Title = "Open File", Dir = "/home" })
		if (Path) then Nav.OpenLocal(Nav.Tab(), Path) end
	end,
	[keys.u] = function() View.ViewSource(Nav.Tab()) end,
	[keys.h] = function() Nav.Go(Nav.Tab(), "savannah://history", { Absolute = true }) end,
	[keys.left] = function() Nav.GoHistory(Nav.Tab(), Nav.Tab().Index - 1) end,
	[keys.right] = function() Nav.GoHistory(Nav.Tab(), Nav.Tab().Index + 1) end,
	[keys.tab] = function() Nav.SelectTab(S.Current % #S.Tabs + 1) end,
	[keys.q] = function()
		BlockOS.Quit()
		Page:Stop()
	end
}
for Number = 1, 9 do
	Shortcuts[keys[({ "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" })[Number]]] = function()
		Nav.SelectTab(Number == 9 and #S.Tabs or Number)
	end
end

--
-- Window layout
--

local function ToolButton(X, Text, OnClick, Enabled)
	return Ui.Button.new({ X = X, Y = 1, W = 3, Text = Text, Bg = "Panel", Fg = "PanelFg", OnClick = OnClick, Enabled = Enabled })
end

function Page:OnLayout(W, H)
	self:Clear()
	local Tab = Nav.Tab()
	local Top = #S.Tabs > 1 and 3 or 2
	local Bottom = S.Find and 1 or 0
	S.ViewW, S.ViewH = W, math.max(1, H - Top + 1 - Bottom)
	self:Add(Ui.Panel.new({ X = 1, Y = 1, W = W, H = 1, Bg = "Panel" }))
	S.W.Back = self:Add(ToolButton(1, "\17", function() Nav.GoHistory(Nav.Tab(), Nav.Tab().Index - 1) end))
	S.W.Forward = self:Add(ToolButton(4, "\16", function() Nav.GoHistory(Nav.Tab(), Nav.Tab().Index + 1) end))
	S.W.Address = self:Add(Ui.Input.new({ X = 8, Y = 1, W = math.max(6, W - 20), Placeholder = "Enter an address" }))
	S.W.Address.Draw = View.DrawAddress
	S.W.Address.OnFocus = function(Self)
		Self:SetValue(Nav.Tab().Url or "")
		if (Self.Value == C.StartPage or Self.Value == C.StartPage .. "/") then Self:SetValue("") end
		Self:SelectAll()
		Self.JustFocused = true
	end
	S.W.Address.Event = function(Self, P, Name, ...)
		if (Name == "mouse_click" and Self.JustFocused) then
			Self.JustFocused = false
			return true
		end
		Self.JustFocused = false
		return Ui.Input.Event(Self, P, Name, ...)
	end
	S.W.Address.OnSubmit = function(Self)
		local Value = Self.Value
		self:SetFocus(S.W.View)
		Nav.Go(Nav.Tab(), Value, { Absolute = true })
	end
	S.W.Reload = self:Add(ToolButton(W - 11, "@", function() Nav.Reload(Nav.Tab()) end))
	S.W.Star = self:Add(ToolButton(W - 8, "*", function() Nav.ToggleFavourite(Nav.Tab()) end))
	self:Add(ToolButton(W - 5, "+", function() Nav.OpenTab() end))
	self:Add(ToolButton(W - 2, "=", function() View.Menu() end))
	if (Top == 3) then
		self:Add(Ui.Canvas.new({ X = 1, Y = 2, W = W, H = 1, OnDraw = View.DrawTabs, OnEvent = View.TabsEvent }))
	end
	S.W.View = self:Add(Ui.Canvas.new({
		X = 1, Y = Top, W = W, H = S.ViewH, Focusable = true, KeepFocus = true,
		OnDraw = View.DrawPage, OnEvent = View.PageEvent, OnCursor = View.PageCursor
	}))
	if (S.Find) then
		local Y = H
		self:Add(Ui.Panel.new({ X = 1, Y = Y, W = W, H = 1, Bg = "Panel" }))
		self:Add(Ui.Label.new({ X = 2, Y = Y, Text = "Find", Bg = "Panel", Fg = "PanelFg" }))
		S.W.FindField = self:Add(Ui.Input.new({ X = 7, Y = Y, W = math.max(4, W - 28), Value = S.Find.Query, Placeholder = "Search this page" }))
		S.W.FindField.OnChange = function(Self)
			S.Find.Query = Self.Value
			Nav.FindMatches(true)
		end
		S.W.FindField.OnSubmit = function() Nav.FindStep(Ui.Modifiers.Shift and -1 or 1) end
		self:Add(Ui.Label.new({
			X = W - 20, Y = Y, W = 9, Bg = "Panel", Fg = "SubText", Align = "right",
			Text = function()
				if (S.Find.Query == "") then return "" end
				if (#S.Find.Matches == 0) then return "No match" end
				return S.Find.Index .. " of " .. #S.Find.Matches
			end
		}))
		self:Add(ToolButton(W - 10, "\30", function() Nav.FindStep(-1) end)).Y = Y
		self:Add(ToolButton(W - 7, "\31", function() Nav.FindStep(1) end)).Y = Y
		self:Add(Ui.Button.new({ X = W - 4, Y = Y, W = 4, Text = "\215", Bg = "Panel", Fg = "PanelFg", OnClick = function() Nav.CloseFind() end }))
	end
	if (Tab and Tab.Doc) then Nav.Rebuild(Tab) end
	self:SetFocus(S.W.View)
end

function View.Relayout()
	local Focus = Page.Focus
	local WasFind = Focus and Focus == S.W.FindField
	Page:OnLayout(Page.W, Page.H)
	if (WasFind and S.Find) then Page:SetFocus(S.W.FindField) end
end

local BaseDraw = Page.Draw
function Page:Draw()
	local Tab = Nav.Tab()
	if (Tab and S.W.Back) then
		S.W.Back.Enabled = Tab.Index > 1
		S.W.Forward.Enabled = Tab.Index < #Tab.History
		S.W.Reload.Text = Tab.Loading and "\215" or "@"
		local Favourite = Tab.Url and Nav.FavouriteIndex(Tab.Url)
		S.W.Star.Fg = Favourite and "Accent" or "PanelFg"
	end
	BaseDraw(self)
end

-- Background events also reach here while a dialog is open, so requests keep running.
local BaseBackground = Page.Background
function Page:Background(Name, ...)
	if (Tasks.Dispatch(Name, ...)) then self.Dirty = true end
	BaseBackground(self, Name, ...)
end

local BaseHandle = Page.Handle
function Page:Handle(Name, A, ...)
	if (Name == "key" and Ui.Modifiers.Ctrl and not Ui.Modifiers.Shift and Shortcuts[A]) then
		local Address = self.Focus == S.W.Address or self.Focus == S.W.FindField
		if (not (Address and (A == keys.left or A == keys.right))) then
			Shortcuts[A]()
			self.Dirty = true
			return
		end
	end
	if (Name == "char" and Ui.Modifiers.Ctrl) then return end
	BaseHandle(self, Name, A, ...)
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_open" and A) then
		Nav.OpenTab(A)
		return true
	elseif (Name == "blockos_settings" and Theme.Get().Dark ~= S.Dark) then
		S.Dark = Theme.Get().Dark
		for _, Tab in ipairs(S.Tabs) do
			if (Tab.Url and Tab.Url:match("^savannah://") and not Tab.Loading) then Nav.Reload(Tab) end
		end
		return true
	end
	return false
end

-- Redraws while something animates (the loading bar) or a message is showing.
Page:SetInterval(0.25, function()
	for _, Tab in ipairs(S.Tabs) do
		if (Tab.Loading) then return true end
	end
	if (S.Message and os.clock() - S.MessageAt < C.MessageTime + 0.3) then return true end
	return false
end)

LoadData()
S.Dark = Theme.Get().Dark
S.Transport = Protocol.NetworkTransport(S.Data.Host)
math.randomseed(os.epoch("utc") + os.getComputerID())
S.Tabs[1] = Nav.NewTabState()
View.Relayout()
Nav.Go(S.Tabs[1], Args[1] or S.Data.Home, { Absolute = true })
Page:Run()
]=]
Files["blockos/apps/settings/app.cfg"] = [[
{ Name = "Settings", Description = "Personalise BlockOS and manage your computer.", Width = 46, Height = 15, Single = true, Icon = { Lines = { " \15 ", "   " }, Fg = "white", Bg = "gray" } }
]]
Files["blockos/apps/settings/main.lua"] = [[
-- Settings: appearance, storage, dock, users, notifications, network, login items and software update.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Theme = BlockOS.Require("theme")
local Config = BlockOS.Require("config")
local Apps = BlockOS.Require("apps")
local Users = BlockOS.Require("users")
local Wallpaper = BlockOS.Require("wallpaper")
local Updater = BlockOS.Require("updater")
local Screensaver = BlockOS.Require("screensaver")

local Args = { ... }

local Settings = Config.Settings()
local Page = Ui.Page.new()
local Build

local Sections = {
	{ ID = "general", Name = "General", Icon = "\15" },
	{ ID = "storage", Name = "Storage", Icon = "\127" },
	{ ID = "appearance", Name = "Appearance", Icon = "\4" },
	{ ID = "dock", Name = "Dock", Icon = "\22" },
	{ ID = "lockscreen", Name = "Lock Screen", Icon = "\8" },
	{ ID = "users", Name = "Users & Login", Icon = "\2" },
	{ ID = "notifications", Name = "Notifications", Icon = "\7" },
	{ ID = "network", Name = "Network", Icon = "\29" },
	{ ID = "startup", Name = "Login Items", Icon = "\16" },
	{ ID = "update", Name = "Software Update", Icon = "\24" }
}

local Current = 1
for Index, Section in ipairs(Sections) do
	if (Section.ID == Args[1]) then Current = Index end
end

local UpdateProgress = nil
local UpdateMessage = nil
local PreviewFrame = 0
local WallpaperColours = {
	colors.white, colors.lightGray, colors.gray, colors.black, colors.blue,
	colors.cyan, colors.green, colors.purple, colors.red, colors.orange
}
local DarkText = { [colors.white] = true, [colors.lightGray] = true, [colors.yellow] = true, [colors.cyan] = true }
-- Storage usage from the last scan, so switching sections does not walk the disk again.
local Usage = nil

local function Save()
	Config.Save("settings")
end

local function Row(Y, Label, Content)
	Page:Add(Ui.Label.new({ X = Page.ContentX, Y = Y, Text = Label }))
	return Content
end

local function Swatches(X, Y, Choices, Get, Set)
	return Page:Add(Ui.Canvas.new({
		X = X, Y = Y, W = #Choices * 2, H = 1,
		OnDraw = function(Self, T)
			for Index, Color in ipairs(Choices) do
				local Mark = (Color == Get()) and "\7" or " "
				Gfx.Write(T, Self.X + (Index - 1) * 2, Self.Y, Mark .. " ", DarkText[Color] and colors.black or colors.white, Color)
			end
		end,
		OnEvent = function(Self, Name, _, MouseX)
			if (Name ~= "mouse_click") then return false end
			local Color = Choices[math.floor((MouseX - Self.X) / 2) + 1]
			if (Color) then Set(Color) end
			return true
		end
	}))
end

local function ToggleRow(Y, Label, Key, After)
	local X = Page.ContentX
	Page:Add(Ui.Toggle.new({
		X = X, Y = Y, Value = Settings[Key],
		OnChange = function(_, Value)
			Settings[Key] = Value
			Save()
			if (After) then After(Value) end
		end
	}))
	Page:Add(Ui.Label.new({ X = X + 5, Y = Y, W = Page.ContentW - 5, Text = Label }))
end

local function ChoiceRow(Y, Label, Key, Items, Values, Default)
	local X = Page.ContentX
	local Selected = 1
	for Index, Value in ipairs(Values) do
		if (Value == (Settings[Key] or Default)) then Selected = Index end
	end
	Page:Add(Ui.Label.new({ X = X, Y = Y, Text = Label }))
	Page:Add(Ui.Tabs.new({
		X = X + 11, Y = Y, W = math.min(20, Page.ContentW - 11), Items = Items, Selected = Selected,
		OnChange = function(_, Index)
			Settings[Key] = Values[Index]
			Save()
		end
	}))
end

local Builders = {}

function Builders.general(X, Y, W)
	local Label = Page:Add(Ui.Input.new({ X = X + 11, Y = Y, W = math.min(20, W - 18), Value = os.getComputerLabel() or "" }))
	Row(Y, "Name", Label)
	Page:Add(Ui.Button.new({ X = X + W - 6, Y = Y, W = 6, Text = "Set", OnClick = function()
		os.setComputerLabel(#Label.Value > 0 and Label.Value or nil)
		BlockOS.Notify("Settings", "Computer name updated.", { Sound = false })
	end }))
	Page:Add(Ui.Label.new({ X = X, Y = Y + 2, Text = "Clock" }))
	Page:Add(Ui.Tabs.new({
		X = X + 11, Y = Y + 2, W = math.min(22, W - 11), Items = { "Real time", "Minecraft" }, Selected = Settings.ClockSource == "game" and 2 or 1,
		OnChange = function(_, Index)
			Settings.ClockSource = (Index == 2) and "game" or "real"
			Save()
		end
	}))
	ToggleRow(Y + 4, "24-hour time", "Clock24")
	ToggleRow(Y + 6, "Show seconds", "ShowSeconds")
	local Free = fs.getFreeSpace("/")
	local Capacity = fs.getCapacity and fs.getCapacity("/") or nil
	Page:Add(Ui.Label.new({ X = X, Y = Y + 8, W = W, Fg = "SubText", Text = "Computer #" .. os.getComputerID() .. " \7 " .. (_HOST or os.version()) }))
	if (Capacity) then
		Page:Add(Ui.Label.new({ X = X, Y = Y + 9, Text = "Storage", Fg = "SubText" }))
		Page:Add(Ui.Progress.new({ X = X + 9, Y = Y + 9, W = W - 9, Value = 1 - Free / Capacity }))
		Page:Add(Ui.Label.new({ X = X, Y = Y + 10, W = W, Fg = "SubText", Text = Gfx.FormatSize(Free) .. " free of " .. Gfx.FormatSize(Capacity) }))
	end
end

function Builders.appearance(X, Y, W, H)
	Page:Add(Ui.Label.new({ X = X, Y = Y, Text = "Mode" }))
	Page:Add(Ui.Tabs.new({
		X = X + 11, Y = Y, W = math.min(16, W - 11), Items = { "Light", "Dark" }, Selected = Settings.Theme == "dark" and 2 or 1,
		OnChange = function(_, Index)
			Settings.Theme = (Index == 2) and "dark" or "light"
			Save()
		end
	}))
	Page:Add(Ui.Label.new({ X = X, Y = Y + 1, Text = "Accent" }))
	Swatches(X + 11, Y + 1, Theme.Accents, function() return Settings.Accent end, function(Color)
		Settings.Accent = Color
		Save()
	end)
	ChoiceRow(Y + 2, "Menu bar", "TopbarStyle", { "Solid", "Clear", "Blur" }, { "solid", "clear", "blur" }, "solid")
	Page:Add(Ui.Label.new({ X = X, Y = Y + 4, Text = "Wallpaper" }))
	local Items = {}
	local Selected = 1
	for Index, Entry in ipairs(Wallpaper.List) do
		table.insert(Items, { Text = Entry.Name, ID = Entry.ID })
		if (Entry.ID == Settings.Wallpaper) then Selected = Index end
	end
	if (Settings.WallpaperImage) then
		table.insert(Items, { Text = Wallpaper.Picture.Name, ID = Wallpaper.Picture.ID })
		if (Settings.Wallpaper == Wallpaper.Picture.ID) then Selected = #Items end
	end
	local ListW = math.min(14, W - 2)
	local ListH = math.max(2, math.min(#Items, H - 6))
	local List = Page:Add(Ui.List.new({ X = X, Y = Y + 5, W = ListW, H = ListH, Items = Items, Bg = "Panel" }))
	List:Select(Selected)
	List.OnSelect = function(_, _, Item)
		Settings.Wallpaper = Item.ID
		Save()
	end
	local PreviewW = W - ListW - 1
	if (PreviewW >= 8) then
		Page:Add(Ui.Canvas.new({
			X = X + ListW + 1, Y = Y + 5, W = PreviewW, H = ListH,
			OnDraw = function(Self, T)
				Wallpaper.Draw(T, Self.X, Self.Y, Self.W, Self.H, Settings.Wallpaper, Settings.WallpaperColor, Settings.WallpaperImage)
			end
		}))
	end
	local ColourY = Y + 5 + ListH
	if (ColourY < Y + H) then
		local Coloured = Wallpaper.Coloured and Wallpaper.Coloured[Settings.Wallpaper]
		Page:Add(Ui.Label.new({ X = X, Y = ColourY, Text = "Colour", Fg = Coloured and "Text" or "SubText" }))
		Swatches(X + 7, ColourY, WallpaperColours, function()
			return Settings.WallpaperColor
		end, function(Color)
			Settings.WallpaperColor = Color
			if (not Coloured) then Settings.Wallpaper = "solid" end
			Save()
		end)
	end
end

-- Size in bytes of a file, or of everything inside a folder.
local function SizeOf(Path)
	if (not fs.exists(Path)) then return 0 end
	if (not fs.isDir(Path)) then return fs.getSize(Path) end
	local Total = 0
	for _, Name in ipairs(fs.list(Path)) do
		Total = Total + SizeOf(fs.combine(Path, Name))
	end
	return Total
end

-- Splits the computer's own drive into categories and measures every app.
local function ScanStorage()
	local Categories = {
		{ Name = "System", Color = colors.blue, Size = 0 },
		{ Name = "Apps", Color = colors.orange, Size = SizeOf("/blockos/userapps") },
		{ Name = "Home", Color = colors.lime, Size = SizeOf("/home") },
		{ Name = "Data", Color = colors.purple, Size = SizeOf("/blockos/data") },
		{ Name = "Other", Color = colors.lightGray, Size = 0 }
	}
	local Skip = { blockos = true, home = true }
	for _, Name in ipairs(fs.list("/")) do
		if (not Skip[Name] and fs.getDrive(Name) == "hdd") then
			local Size = SizeOf(Name)
			if (Name == "startup.lua") then
				Categories[1].Size = Categories[1].Size + Size
			else
				Categories[5].Size = Categories[5].Size + Size
			end
		end
	end
	local Own = { data = true, userapps = true }
	for _, Name in ipairs(fs.list("/blockos")) do
		if (not Own[Name]) then
			Categories[1].Size = Categories[1].Size + SizeOf(fs.combine("/blockos", Name))
		end
	end
	local Used = 0
	for _, Category in ipairs(Categories) do
		Used = Used + Category.Size
	end
	local AppSizes = {}
	for _, App in ipairs(Apps.List(true)) do
		if (App.Builtin ~= "launchpad") then
			table.insert(AppSizes, { App = App, Size = SizeOf(App.Dir) })
		end
	end
	table.sort(AppSizes, function(A, B) return A.Size > B.Size end)
	local Free = fs.getFreeSpace("/")
	local Capacity = fs.getCapacity and fs.getCapacity("/") or nil
	return {
		Categories = Categories,
		Apps = AppSizes,
		Used = Used,
		Free = Free,
		Capacity = (type(Capacity) == "number" and Capacity > 0) and Capacity or (Used + Free)
	}
end

function Builders.storage(X, Y, W, H)
	if (not Usage) then
		Page:Add(Ui.Label.new({ X = X, Y = Y, W = W, Text = "Measuring...", Fg = "SubText" }))
		Page:Draw()
		Usage = ScanStorage()
		Build()
		return
	end
	Page:Add(Ui.Canvas.new({
		X = X, Y = Y, W = W, H = 1,
		OnDraw = function(Self, T, Th)
			Gfx.Fill(T, Self.X, Self.Y, Self.W, 1, Th.Border)
			local Left = Self.X
			local Total = 0
			for _, Category in ipairs(Usage.Categories) do
				Total = Total + Category.Size
				-- Rounds the running total so small categories never push the bar past its end.
				local Right = Self.X + math.floor(Self.W * math.min(1, Total / Usage.Capacity) + .5)
				if (Category.Size > 0 and Right <= Left) then Right = Left + 1 end
				Right = math.min(Right, Self.X + Self.W)
				Gfx.Fill(T, Left, Self.Y, Right - Left, 1, Category.Color)
				Left = Right
			end
		end
	}))
	Page:Add(Ui.Label.new({ X = X, Y = Y + 1, W = W, Fg = "SubText", Text = Gfx.FormatSize(Usage.Used) .. " used, " .. Gfx.FormatSize(Usage.Free) .. " free of " .. Gfx.FormatSize(Usage.Capacity) }))
	Page:Add(Ui.Canvas.new({
		X = X, Y = Y + 2, W = W, H = 2,
		OnDraw = function(Self, T, Th)
			local CX, CY = Self.X, Self.Y
			for _, Category in ipairs(Usage.Categories) do
				local Text = Category.Name .. " " .. Gfx.FormatSize(Category.Size)
				if (CX > Self.X and CX + #Text + 2 > Self.X + Self.W) then
					CX, CY = Self.X, CY + 1
				end
				if (CY >= Self.Y + Self.H) then break end
				Gfx.Write(T, CX, CY, "\7", Category.Color, Th.WindowBg)
				Gfx.Write(T, CX + 1, CY, Gfx.Truncate(Text, Self.X + Self.W - CX - 1), Th.Text, Th.WindowBg)
				CX = CX + #Text + 3
			end
		end
	}))
	local Heading = (W >= 25) and (Gfx.Pad("Apps by size", W - 11) .. "\7 installed") or "Apps by size"
	Page:Add(Ui.Label.new({ X = X, Y = Y + 4, W = W, Text = Heading, Fg = "SubText" }))
	local Items = {}
	for _, Entry in ipairs(Usage.Apps) do
		table.insert(Items, {
			Text = Entry.App.Name .. (Entry.App.System and "" or " \7"),
			Icon = Gfx.Pad(Entry.App.Icon.Lines[1], 3), IconFg = Entry.App.Icon.Bg,
			Right = Gfx.FormatSize(Entry.Size), App = Entry.App
		})
	end
	local List = Page:Add(Ui.List.new({ X = X, Y = Y + 5, W = W, H = math.max(1, H - 7), Items = Items, Bg = "Panel" }))
	local ButtonY = Y + H - 1
	Page:Add(Ui.Button.new({ X = X, Y = ButtonY, Text = " Refresh ", OnClick = function()
		Usage = nil
		Build()
	end }))
	local function Uninstall()
		local Item = List.Items[List.Selected]
		if (not Item) then return end
		if (Item.App.System) then
			Ui.Alert("Storage", Item.App.Name .. " comes with BlockOS and cannot be removed.")
			return
		end
		if (Ui.Confirm("Uninstall", "Remove " .. Item.App.Name .. " and free " .. Item.Right .. "?", "Uninstall")) then
			Apps.Uninstall(Item.App.ID)
			Usage = nil
			Build()
		end
	end
	Page:Add(Ui.Button.new({ X = X + 10, Y = ButtonY, Text = " Uninstall ", Style = "danger", OnClick = Uninstall }))
	List.OnContext = function(_, Index, _, MX, MY)
		if (Index and Ui.ContextMenu(MX, MY, { "Uninstall" }) == 1) then Uninstall() end
	end
end

function Builders.dock(X, Y, W, H)
	ChoiceRow(Y, "Size", "DockSize", { "Small", "Large" }, { "small", "large" }, "small")
	ChoiceRow(Y + 1, "Style", "DockStyle", { "Solid", "Clear" }, { "solid", "transparent" }, "solid")
	ToggleRow(Y + 3, "Animations", "Animations")
	local List = Page:Add(Ui.List.new({ X = X, Y = Y + 5, W = W, H = math.max(1, H - 8), Bg = "Panel" }))
	local function Fill()
		local Items = {}
		for Index, ID in ipairs(Settings.Dock) do
			local App = Apps.Get(ID)
			if (App) then
				table.insert(Items, { Text = App.Name, Icon = Gfx.Pad(App.Icon.Lines[1], 3), IconFg = App.Icon.Bg, Index = Index })
			end
		end
		List:SetItems(Items, true)
	end
	Fill()
	local function MoveSelected(Step)
		local Item = List.Items[List.Selected]
		if (not Item) then return end
		local Target = Item.Index + Step
		if (Target < 1 or Target > #Settings.Dock) then return end
		Settings.Dock[Item.Index], Settings.Dock[Target] = Settings.Dock[Target], Settings.Dock[Item.Index]
		Save()
		Fill()
		List:Select(List.Selected + Step)
	end
	local ButtonY = Y + H - 2
	Page:Add(Ui.Button.new({ X = X, Y = ButtonY, W = 3, Text = "\24", OnClick = function() MoveSelected(-1) end }))
	Page:Add(Ui.Button.new({ X = X + 4, Y = ButtonY, W = 3, Text = "\25", OnClick = function() MoveSelected(1) end }))
	Page:Add(Ui.Button.new({ X = X + 8, Y = ButtonY, Text = " Remove ", OnClick = function()
		local Item = List.Items[List.Selected]
		if (Item) then
			table.remove(Settings.Dock, Item.Index)
			Save()
			Fill()
		end
	end }))
	Page:Add(Ui.Button.new({ X = X + 18, Y = ButtonY, Text = " Add App ", Style = "primary", OnClick = function()
		local Choices, Names = {}, {}
		for _, App in ipairs(Apps.List()) do
			if (not Apps.IsPinned(App.ID)) then
				table.insert(Choices, App)
				table.insert(Names, App.Name)
			end
		end
		if (#Names == 0) then return end
		local Index = Ui.Choose("Add to Dock", Names)
		if (Index) then
			table.insert(Settings.Dock, Choices[Index].ID)
			Save()
			Fill()
		end
	end }))
end

function Builders.lockscreen(X, Y, W, H)
	Page:Add(Ui.Label.new({ X = X, Y = Y, W = W, Text = "Screensaver colours", Fg = "SubText" }))
	local Items = {}
	local Selected = 1
	for Index, Entry in ipairs(Screensaver.Palettes) do
		table.insert(Items, { Text = Entry.Name, ID = Entry.ID })
		if (Entry.ID == (Settings.LockColors or "accent")) then Selected = Index end
	end
	local ListW = math.min(15, W - 2)
	local ListH = math.max(2, math.min(#Items, H - 4))
	local List = Page:Add(Ui.List.new({ X = X, Y = Y + 1, W = ListW, H = ListH, Items = Items, Bg = "Panel" }))
	List:Select(Selected)
	List.OnSelect = function(_, _, Item)
		Settings.LockColors = Item.ID
		Save()
	end
	local PreviewW = W - ListW - 1
	if (PreviewW >= 6) then
		local Canvas = Screensaver.NewCanvas(PreviewW, ListH)
		Page:Add(Ui.Canvas.new({
			X = X + ListW + 1, Y = Y + 1, W = PreviewW, H = ListH,
			OnDraw = function(Self, T)
				Screensaver.Render(Canvas, PreviewFrame * Screensaver.Speed * 4, Settings.LockColors)
				Screensaver.Blit(T, Canvas, Self.X, Self.Y)
			end
		}))
	end
	Page:Add(Ui.Button.new({ X = X, Y = Y + ListH + 2, Text = " Lock Now ", Style = "primary", OnClick = function() BlockOS.Lock() end }))
end

function Builders.users(X, Y, W)
	local User = Users.Primary()
	if (not User) then return end
	Page:Add(Ui.Canvas.new({
		X = X, Y = Y, W = 3, H = 2,
		OnDraw = function(Self, T)
			Gfx.Fill(T, Self.X, Self.Y, 3, 2, User.Color or colors.blue)
			Gfx.Write(T, Self.X + 1, Self.Y, User.Name:sub(1, 1):upper(), colors.white, User.Color or colors.blue)
		end
	}))
	Page:Add(Ui.Label.new({ X = X + 4, Y = Y, W = W - 4, Text = User.Name }))
	Page:Add(Ui.Label.new({ X = X + 4, Y = Y + 1, W = W - 4, Text = "Administrator", Fg = "SubText" }))
	Page:Add(Ui.Button.new({ X = X, Y = Y + 3, Text = " Rename ", OnClick = function()
		local Name = Ui.Prompt("Rename", "New name:", User.Name)
		if (Name and #Name > 0) then
			Users.Update(User.Name, { Name = Name })
			Build()
		end
	end }))
	Page:Add(Ui.Button.new({ X = X + 10, Y = Y + 3, Text = " Change Password ", OnClick = function()
		if (User.HasPassword) then
			local Old = Ui.Prompt("Change Password", "Current password:", "", "\7")
			if (not Old) then return end
			if (not Users.Verify(User.Name, Old)) then
				Ui.Alert("Change Password", "That password is incorrect.")
				return
			end
		end
		local New = Ui.Prompt("Change Password", "New password (empty for none):", "", "\7")
		if (not New) then return end
		local Again = Ui.Prompt("Change Password", "Confirm new password:", "", "\7")
		if (Again ~= New) then
			Ui.Alert("Change Password", "The passwords do not match.")
			return
		end
		Users.SetPassword(User.Name, New)
		Ui.Alert("Change Password", "Password updated.")
		Build()
	end }))
	ToggleRow(Y + 5, "Log in automatically", "AutoLogin")
	Page:Add(Ui.Label.new({ X = X, Y = Y + 7, Text = "Lock after" }))
	local Options = { 0, 1, 5, 15 }
	local Selected = 1
	for Index, Minutes in ipairs(Options) do
		if (Minutes == Settings.IdleLock) then Selected = Index end
	end
	Page:Add(Ui.Tabs.new({
		X = X + 11, Y = Y + 7, W = math.min(24, W - 11), Items = { "Never", "1m", "5m", "15m" }, Selected = Selected,
		OnChange = function(_, Index)
			Settings.IdleLock = Options[Index]
			Save()
		end
	}))
	Page:Add(Ui.Button.new({ X = X, Y = Y + 9, Text = " Lock Screen Now ", Style = "primary", OnClick = function() BlockOS.Lock() end }))
end

function Builders.notifications(X, Y, W, H)
	ToggleRow(Y, "Show notifications", "Notifications")
	ToggleRow(Y + 2, "Play a sound on speakers", "NotificationSound")
	Page:Add(Ui.Button.new({ X = X, Y = Y + 4, Text = " Send Test ", OnClick = function()
		BlockOS.Notify("Hello from BlockOS", "Notifications are working.", { AppID = "settings", Args = { "notifications" } })
	end }))
	Page:Add(Ui.Label.new({ X = X, Y = Y + 6, Text = "Recent", Fg = "SubText" }))
	local Items = {}
	for _, Entry in ipairs(BlockOS.Notifications and BlockOS.Notifications() or {}) do
		table.insert(Items, { Text = Entry.Title .. ": " .. Entry.Text })
	end
	Page:Add(Ui.List.new({ X = X, Y = Y + 7, W = W, H = math.max(1, H - 8), Items = Items, Bg = "Panel" }))
end

function Builders.network(X, Y, W)
	local Chat = BlockOS.Require("chat")
	Chat.Load()
	Page:Add(Ui.Label.new({ X = X, Y = Y, W = W, Text = "Computer ID: " .. os.getComputerID() }))
	local Row = Y + 2
	local Found = false
	for _, Name in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Name) == "modem") then
			Found = true
			local Modem = peripheral.wrap(Name)
			local Kind = Modem.isWireless() and "Wireless modem" or "Wired modem"
			local Open = rednet.isOpen(Name)
			Page:Add(Ui.Label.new({ X = X, Y = Row, W = W - 10, Text = Kind .. " (" .. Name .. ")" }))
			Page:Add(Ui.Button.new({ X = X + W - 8, Y = Row, W = 8, Text = Open and "Close" or "Open", OnClick = function()
				if (rednet.isOpen(Name)) then rednet.close(Name) else rednet.open(Name) end
				Build()
			end }))
			Row = Row + 1
		end
	end
	if (not Found) then
		Page:Add(Ui.Label.new({ X = X, Y = Row, W = W, H = 2, Text = "No modems attached. Attach a wireless or ender modem to use Messages and Turtles.", Fg = "SubText" }))
		Row = Row + 2
	end
	Row = Row + 1
	Page:Add(Ui.Label.new({ X = X, Y = Row, Text = "Nickname" }))
	local Nick = Page:Add(Ui.Input.new({ X = X + 10, Y = Row, W = math.min(18, W - 18), Value = Chat.GetNick(), MaxLength = 20 }))
	Page:Add(Ui.Button.new({ X = X + W - 6, Y = Row, W = 6, Text = "Set", OnClick = function()
		if (#Nick.Value > 0) then
			Chat.SetNick(Nick.Value)
			BlockOS.Notify("Messages", "Nickname set to " .. Nick.Value, { Sound = false })
		end
	end }))
	ToggleRow(Row + 2, "Visible in the Network app", "NetworkVisible")
end

function Builders.startup(X, Y, W, H)
	Page:Add(Ui.Label.new({ X = X, Y = Y, W = W, Text = "Open these apps when you log in:", Fg = "SubText" }))
	local List = Page:Add(Ui.List.new({ X = X, Y = Y + 1, W = W, H = H - 5, Bg = "Panel" }))
	local Items = {}
	for Index, ID in ipairs(Settings.StartupApps) do
		local App = Apps.Get(ID)
		table.insert(Items, { Text = App and App.Name or ID, Index = Index })
	end
	List:SetItems(Items)
	Page:Add(Ui.Button.new({ X = X, Y = Y + H - 3, Text = " Add ", Style = "primary", OnClick = function()
		local Choices, Names = {}, {}
		for _, App in ipairs(Apps.List()) do
			if (App.Builtin ~= "launchpad") then
				table.insert(Choices, App)
				table.insert(Names, App.Name)
			end
		end
		local Index = Ui.Choose("Add Login Item", Names)
		if (Index) then
			table.insert(Settings.StartupApps, Choices[Index].ID)
			Save()
			Build()
		end
	end }))
	Page:Add(Ui.Button.new({ X = X + 7, Y = Y + H - 3, Text = " Remove ", OnClick = function()
		local Item = List.Items[List.Selected]
		if (Item) then
			table.remove(Settings.StartupApps, Item.Index)
			Save()
			Build()
		end
	end }))
end

function Builders.update(X, Y, W, H)
	local State = Updater.State
	local Lines = {
		"Installed: BlockOS " .. Config.Version()
	}
	if (State.Latest) then
		table.insert(Lines, "Latest: BlockOS " .. tostring(State.Latest.Version))
	end
	local Status = ({
		idle = "Not checked yet.",
		checking = "Checking for updates...",
		available = "An update is available.",
		uptodate = "BlockOS is up to date.",
		downloading = "Downloading update...",
		ready = "Update installed. Restart to finish.",
		error = "Error: " .. tostring(State.Error)
	})[State.Status] or ""
	table.insert(Lines, UpdateMessage or Status)
	for Index, Line in ipairs(Lines) do
		Page:Add(Ui.Label.new({ X = X, Y = Y + Index - 1, W = W, Text = Line, Fg = (Index == #Lines) and "Accent" or "Text" }))
	end
	local ButtonY = Y + #Lines + 1
	Page:Add(Ui.Button.new({ X = X, Y = ButtonY, Text = " Check Now ", OnClick = function()
		UpdateMessage = nil
		Updater.State.Status = "checking"
		Build()
		Page:Draw()
		Updater.Check()
		Build()
	end }))
	if (State.Status == "available" and State.Latest) then
		Page:Add(Ui.Button.new({ X = X + 13, Y = ButtonY, Text = " Update Now ", Style = "primary", OnClick = function()
			UpdateProgress = 0
			Build()
			local Ok, Err = Updater.Apply(State.Latest, function(Done, Total, Path)
				UpdateProgress = Total > 0 and Done / Total or 1
				UpdateMessage = "Downloading " .. Path
				Build()
				Page:Draw()
			end)
			UpdateProgress = nil
			UpdateMessage = Ok and "Update installed. Restart to finish." or ("Update failed: " .. tostring(Err))
			Build()
		end }))
	elseif (State.Status == "ready") then
		Page:Add(Ui.Button.new({ X = X + 13, Y = ButtonY, Text = " Restart ", Style = "primary", OnClick = function() BlockOS.Restart() end }))
	end
	if (UpdateProgress) then
		Page:Add(Ui.Progress.new({ X = X, Y = ButtonY + 2, W = W, Value = UpdateProgress }))
	end
	local OptionsY = ButtonY + 4
	ToggleRow(OptionsY, "Check automatically", "AutoUpdate")
	ToggleRow(OptionsY + 2, "Install in the background", "AutoInstall")
	if (OptionsY + 4 < Y + H) then
		Page:Add(Ui.Label.new({ X = X, Y = OptionsY + 4, Text = "Channel", Fg = "SubText" }))
		local Url = Page:Add(Ui.Input.new({ X = X + 8, Y = OptionsY + 4, W = W - 8, Value = Settings.UpdateURL }))
		Url.OnSubmit = function(_, Value)
			Settings.UpdateURL = Value
			Save()
			BlockOS.Notify("Software Update", "Update channel saved.", { Sound = false })
		end
	end
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	local SideW = (W >= 40) and 16 or 0
	Page.ContentX = SideW + 2
	Page.ContentW = W - SideW - 3
	local Sidebar = Page:Add(Ui.List.new({ X = 1, Y = 1, W = SideW, H = H, Bg = "Panel", SingleClick = true, Visible = SideW > 0 }))
	local Items = {}
	for _, Section in ipairs(Sections) do
		table.insert(Items, { Text = Section.Name, Icon = Section.Icon, IconFg = "Accent" })
	end
	Sidebar:SetItems(Items)
	Sidebar.Selected = Current
	Sidebar.OnActivate = function(_, Index)
		Current = Index
		UpdateMessage = nil
		Build()
	end
	local Section = Sections[Current]
	if (SideW == 0) then
		Page:Add(Ui.Button.new({ X = 1, Y = 1, W = W, Text = "\31 " .. Section.Name, Bg = "Panel", OnClick = function()
			local Names = {}
			for _, Entry in ipairs(Sections) do table.insert(Names, Entry.Name) end
			local Index = Ui.Choose("Settings", Names, Current)
			if (Index) then
				Current = Index
				Build()
			end
		end }))
	else
		Page:Add(Ui.Label.new({ X = Page.ContentX, Y = 1, W = Page.ContentW, Text = Section.Name, Fg = "Accent" }))
	end
	Builders[Section.ID](Page.ContentX, 3, Page.ContentW, H - 3)
	BlockOS.SetTitle("Settings \7 " .. Section.Name)
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A)
	if (Name == "blockos_open" and A) then
		for Index, Section in ipairs(Sections) do
			if (Section.ID == A) then Current = Index end
		end
		Build()
		return true
	elseif (Name == "blockos_settings" or Name == "peripheral" or Name == "peripheral_detach") then
		local ID = Sections[Current].ID
		if (ID ~= "general" and ID ~= "storage") then Build() end
		return true
	end
	return false
end

Page:SetInterval(.1, function()
	PreviewFrame = PreviewFrame + 1
	return Sections[Current].ID == "lockscreen"
end)

Page:Run()
]]
Files["blockos/apps/terminal/app.cfg"] = [[
{ Name = "Terminal", Description = "A CraftOS shell in a window.", Width = 42, Height = 13, Icon = { Lines = { ">_ ", "   " }, Fg = "lime", Bg = "black" } }
]]
Files["blockos/apps/terminal/main.lua"] = [[
-- Terminal: an interactive CraftOS shell inside a BlockOS window.

local Args = { ... }

if (Args[1] and fs.isDir(Args[1])) then
	shell.setDir(Args[1])
end

term.setBackgroundColor(colors.black)
term.clear()
term.setCursorPos(1, 1)
term.setTextColor(colors.lime)
print("BlockOS " .. (BlockOS.Version or "") .. " Terminal")
term.setTextColor(colors.lightGray)
print("Type 'help' for commands and 'exit' to close.")
term.setTextColor(colors.white)

shell.run("/rom/programs/shell.lua")
]]
Files["blockos/apps/turtles/app.cfg"] = [[
{ Name = "Turtles", Description = "Remote control and monitor turtles running the BlockOS agent.", Width = 46, Height = 15, Single = true, Icon = { Lines = { "[o]", "/ \\" }, Fg = "yellow", Bg = "green" } }
]]
Files["blockos/apps/turtles/main.lua"] = [=[
-- Turtles: discover, pair with and remote-control turtles running the BlockOS agent.
-- On a turtle it can also drive the local turtle directly.
-- Scripts in /home/Turtles can be sent to a turtle and run there.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Config = BlockOS.Require("config")

local Protocol = "blockos_turtle"
local DataPath = "/blockos/data/turtles.dat"
local ScriptDir = "/home/Turtles"

local Page = Ui.Page.new()
local Known = Config.Read(DataPath) or {}
local Selected = nil
local Message = ""
local Seq = 0
local View = "control"
local ScriptName = nil
local Build

-- Written to ScriptDir the first time it is opened, as starting points.
local Examples = {
	["tunnel.lua"] = [[
-- Digs a tunnel 2 high. Args: length (default 10)
local Length = tonumber(...) or 10

local function Forward()
	while (not turtle.forward()) do
		if (not turtle.dig()) then turtle.attack() end
	end
end

for Step = 1, Length do
	Forward()
	while (turtle.detectUp()) do turtle.digUp() end
end
print("Tunnel done: " .. Length .. " blocks")
]],
	["stairs.lua"] = [[
-- Digs a staircase going down. Args: depth (default 8)
local Depth = tonumber(...) or 8

for Step = 1, Depth do
	while (turtle.detect()) do turtle.dig() end
	turtle.forward()
	turtle.digUp()
	turtle.digDown()
	if (not turtle.down()) then
		print("Blocked at step " .. Step)
		return
	end
end
print("Stairs done: " .. Depth .. " steps")
]],
	["floor.lua"] = [[
-- Places a floor below the turtle from its inventory. Args: width length (default 5 5)
local Args = { ... }
local Width = tonumber(Args[1]) or 5
local Length = tonumber(Args[2]) or 5

local function PlaceDown()
	if (turtle.detectDown()) then return true end
	for Slot = 1, 16 do
		if (turtle.getItemCount(Slot) > 0) then
			turtle.select(Slot)
			if (turtle.placeDown()) then return true end
		end
	end
	return false
end

local function Forward()
	while (not turtle.forward()) do
		if (not turtle.dig()) then turtle.attack() end
	end
end

for Row = 1, Width do
	for Step = 1, Length do
		if (not PlaceDown()) then
			print("Out of blocks")
			return
		end
		if (Step < Length) then Forward() end
	end
	if (Row < Width) then
		local Turn = (Row % 2 == 1) and turtle.turnRight or turtle.turnLeft
		Turn()
		Forward()
		Turn()
	end
end
print("Floor done")
]]
}

local NewScript = [[
-- Describe what this script does here. Args: none
local Args = { ... }

turtle.forward()
]]

local KeyActions = {
	[keys.w] = "forward", [keys.s] = "back", [keys.a] = "turnLeft", [keys.d] = "turnRight",
	[keys.r] = "up", [keys.f] = "down", [keys.q] = "dig", [keys.e] = "place", [keys.x] = "attack"
}

local function SaveKnown()
	local Stored = {}
	for ID, Entry in pairs(Known) do
		if (ID ~= "local") then
			Stored[ID] = { Label = Entry.Label }
		end
	end
	Config.Write(DataPath, Stored)
end

local function OpenModems()
	local Any = false
	for _, Side in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Side) == "modem") then
			if (not rednet.isOpen(Side)) then rednet.open(Side) end
			Any = true
		end
	end
	return Any
end

local function LocalStatus()
	local Inventory = {}
	for Slot = 1, 16 do
		local Detail = turtle.getItemDetail(Slot)
		if (Detail) then Inventory[Slot] = { Name = Detail.name, Count = Detail.count } end
	end
	return {
		Label = os.getComputerLabel() or "This turtle",
		ID = os.getComputerID(),
		Fuel = turtle.getFuelLevel(),
		FuelLimit = turtle.getFuelLimit(),
		Slot = turtle.getSelectedSlot(),
		Inventory = Inventory
	}
end

local function LocalRequest(Cmd, Args)
	local Reply = {}
	if (Cmd == "action") then
		local Fn = turtle[Args.Name]
		local Ok, Result, Detail = pcall(Fn)
		Reply.Ok = Ok and Result ~= false
		if (not Reply.Ok) then Reply.Error = tostring(Detail or Result or "failed") end
	elseif (Cmd == "select") then
		Reply.Ok = turtle.select(Args.Slot)
	elseif (Cmd == "refuel") then
		Reply.Ok = false
		for Slot = 1, 16 do
			if (turtle.getItemCount(Slot) > 0) then
				turtle.select(Slot)
				Reply.Ok = turtle.refuel() or Reply.Ok
			end
		end
		if (not Reply.Ok) then Reply.Error = "Nothing to burn" end
	elseif (Cmd == "run") then
		local Words = {}
		for Word in tostring(Args.Command):gmatch("%S+") do table.insert(Words, Word) end
		local Program = table.remove(Words, 1)
		Reply.Ok = BlockOS.Launch(Program or "", Words, { Hold = true }) ~= nil
		if (not Reply.Ok) then Reply.Error = "Program not found" end
	elseif (Cmd == "script") then
		local Words = {}
		for Word in tostring(Args.Args or ""):gmatch("%S+") do table.insert(Words, Word) end
		Reply.Ok = BlockOS.Launch("/" .. fs.combine(ScriptDir, Args.Name), Words, { Hold = true }) ~= nil
		if (not Reply.Ok) then Reply.Error = "Script not found" end
	elseif (Cmd == "locate") then
		local X, Y, Z = gps.locate(1)
		Reply.Ok = X ~= nil
		Reply.Error = X and nil or "No GPS signal"
		if (X) then Known["local"].Position = { X = X, Y = Y, Z = Z } end
	else
		Reply.Ok = true
	end
	Reply.Status = LocalStatus()
	return Reply
end

local function Request(ID, Cmd, Args, Retried)
	if (ID == "local") then
		local Reply = LocalRequest(Cmd, Args or {})
		Known["local"].Status = Reply.Status
		return Reply
	end
	if (not OpenModems()) then return nil, "No modem attached" end
	Seq = Seq + 1
	local Mine = Seq
	rednet.send(ID, { Cmd = Cmd, Args = Args or {}, Seq = Mine }, Protocol)
	local Deadline = os.clock() + 4
	while (os.clock() < Deadline) do
		local Sender, Reply = rednet.receive(Protocol, math.max(.05, Deadline - os.clock()))
		if (Sender == ID and type(Reply) == "table" and Reply.Re == Mine) then
			if (Reply.Status and Known[ID]) then
				Known[ID].Status = Reply.Status
				Known[ID].Label = Reply.Status.Label
			end
			if (Reply.Error == "pin" and not Retried) then
				local Pin = Ui.Prompt("Pair Turtle", "Enter the PIN shown on turtle #" .. ID .. ":", "")
				if (not Pin) then return nil, "Not paired" end
				local Paired = Request(ID, "pair", { Pin = Pin }, true)
				if (not Paired or not Paired.Ok) then return nil, Paired and Paired.Error or "Pairing failed" end
				return Request(ID, Cmd, Args, true)
			end
			return Reply
		end
	end
	return nil, "Turtle #" .. ID .. " did not respond"
end

local function Send(Cmd, Args)
	if (not Selected) then return end
	local Reply, Err = Request(Selected, Cmd, Args)
	if (not Reply) then
		Message = Err
	elseif (Cmd == "script" and Reply.Error == "Unknown command") then
		Message = "Update the agent: reinstall BlockOS on the turtle"
	elseif (not Reply.Ok) then
		Message = tostring(Reply.Error or "Failed")
	elseif (Cmd == "script") then
		Message = "Running " .. Args.Name
	else
		Message = (Cmd == "action" and Args.Name or Cmd) .. ": ok"
	end
	Page:Invalidate()
end

local function Scan()
	if (not OpenModems()) then
		Message = "Attach a modem to find turtles"
		return
	end
	Message = "Scanning..."
	Page:Draw()
	local IDs = { rednet.lookup(Protocol) }
	for _, ID in ipairs(IDs) do
		Known[ID] = Known[ID] or { Label = "turtle-" .. ID }
	end
	SaveKnown()
	Message = #IDs .. " turtle(s) found"
	Build()
end

local function Status()
	local Entry = Selected and Known[Selected]
	return Entry and Entry.Status
end

local function BuildControls(X, Y, W, H)
	Page:Add(Ui.Canvas.new({
		X = X, Y = Y, W = W, H = 2,
		OnDraw = function(Self, T, Th)
			local Info = Status()
			local Entry = Known[Selected]
			local Title = (Entry and Entry.Label or "?") .. ((Selected ~= "local") and (" #" .. tostring(Selected)) or "")
			Gfx.Write(T, Self.X, Self.Y, Gfx.Truncate(Title, Self.W), Th.Text, Th.WindowBg)
			if (not Info) then
				Gfx.Write(T, Self.X, Self.Y + 1, "Press Refresh to connect", Th.SubText, Th.WindowBg)
				return
			end
			local Fuel = Info.Fuel
			if (Fuel == "unlimited") then
				Gfx.Write(T, Self.X, Self.Y + 1, "Fuel: unlimited", Th.SubText, Th.WindowBg)
			else
				local BarW = Self.W - 6
				local Ratio = (tonumber(Info.FuelLimit) or 0) > 0 and math.min(1, Fuel / Info.FuelLimit) or 0
				Gfx.Write(T, Self.X, Self.Y + 1, "Fuel ", Th.SubText, Th.WindowBg)
				Gfx.Fill(T, Self.X + 5, Self.Y + 1, BarW, 1, Th.Border)
				Gfx.Fill(T, Self.X + 5, Self.Y + 1, math.max(Fuel > 0 and 1 or 0, math.floor(BarW * Ratio)), 1, (Ratio < .1) and colors.red or colors.orange)
				Gfx.Write(T, Self.X + 6, Self.Y + 1, tostring(Fuel), colors.black, (Ratio > .1) and colors.orange or Th.Border)
			end
		end
	}))
	Page:Add(Ui.Canvas.new({
		X = X, Y = Y + 3, W = 16, H = 4,
		OnDraw = function(Self, T, Th)
			local Info = Status()
			for Slot = 1, 16 do
				local Column = (Slot - 1) % 4
				local Row = math.floor((Slot - 1) / 4)
				local Item = Info and Info.Inventory and Info.Inventory[Slot]
				local Active = Info and Info.Slot == Slot
				local Bg = Active and Th.Accent or Th.Panel
				local Text = Item and tostring(Item.Count) or ""
				Gfx.Write(T, Self.X + Column * 4, Self.Y + Row, Gfx.Pad(Text, 3, "center"), Active and Th.AccentFg or Th.PanelFg, Bg)
			end
		end,
		OnEvent = function(Self, Name, Button, MX, MY)
			if (Name ~= "mouse_click") then return false end
			local Column = math.floor((MX - Self.X) / 4)
			local Row = MY - Self.Y
			local Slot = Row * 4 + Column + 1
			if (Slot >= 1 and Slot <= 16) then
				Send("select", { Slot = Slot })
				local Info = Status()
				local Item = Info and Info.Inventory and Info.Inventory[Slot]
				if (Item) then Message = "Slot " .. Slot .. ": " .. Item.Count .. "x " .. Item.Name:gsub("^minecraft:", "") end
			end
			return true
		end
	}))
	local PadX = X + 17
	local Pad = {
		{ { "Up", "up" }, { "\30", "forward" }, { "Dig", "dig" } },
		{ { "\17", "turnLeft" }, { "\31", "back" }, { "\16", "turnRight" } },
		{ { "Dn", "down" }, { "Plc", "place" }, { "Atk", "attack" } }
	}
	if (W >= 29) then
		for Row, Buttons in ipairs(Pad) do
			for Column, Entry in ipairs(Buttons) do
				local Action = Entry[2]
				Page:Add(Ui.Button.new({
					X = PadX + (Column - 1) * 4, Y = Y + 3 + Row - 1, W = 3, Text = Entry[1],
					Style = (Row == 1 and Column == 2) and "primary" or "default",
					OnClick = function() Send("action", { Name = Action }) end
				}))
			end
		end
	end
	local Row2 = Y + 8
	local Extra = {
		{ "\24Dig", "digUp" }, { "\25Dig", "digDown" }, { "\24Plc", "placeUp" }, { "\25Plc", "placeDown" }, { "Suck", "suck" }, { "Drop", "drop" }
	}
	local BX = X
	for _, Entry in ipairs(Extra) do
		if (BX + #Entry[1] + 1 <= X + W) then
			local Action = Entry[2]
			Page:Add(Ui.Button.new({ X = BX, Y = Row2, Text = Entry[1], W = #Entry[1] + 1, OnClick = function() Send("action", { Name = Action }) end }))
			BX = BX + #Entry[1] + 2
		end
	end
	local Bottom = Y + H - 1
	Page:Add(Ui.Button.new({ X = X, Y = Bottom, Text = " Refresh ", OnClick = function() Send("status") end }))
	Page:Add(Ui.Button.new({ X = X + 10, Y = Bottom, Text = " Fuel ", OnClick = function() Send("refuel") end }))
	Page:Add(Ui.Button.new({ X = X + 17, Y = Bottom, Text = " Run ", Style = "primary", OnClick = function()
		local Command = Ui.Prompt("Run on Turtle", "Program and arguments (e.g. excavate 3, tunnel 10):", "")
		if (Command and #Command > 0) then Send("run", { Command = Command }) end
	end }))
	if (X + 29 <= X + W) then
		Page:Add(Ui.Button.new({ X = X + 23, Y = Bottom, Text = " Stop ", Style = "danger", OnClick = function() Send("stop") end }))
	end
end

-- Absolute, so the Editor does not resolve it against its own working directory.
local function ScriptPath(Name)
	return "/" .. fs.combine(ScriptDir, Name)
end

local function ListScripts()
	if (not fs.exists(ScriptDir)) then
		for Name, Source in pairs(Examples) do
			Config.WriteText(ScriptPath(Name), Source)
		end
	end
	local Names = {}
	for _, Name in ipairs(fs.list(ScriptDir)) do
		if (not fs.isDir(ScriptPath(Name))) then table.insert(Names, Name) end
	end
	table.sort(Names)
	return Names
end

-- The first comment line of a script, shown as its description.
local function Describe(Name)
	local Source = Name and Config.ReadText(ScriptPath(Name))
	local First = Source and Source:match("^%-%-+%s*([^\n]*)")
	return First or ""
end

local function RunScript(Name, ScriptArgs)
	local Source = Config.ReadText(ScriptPath(Name))
	if (not Source) then
		Message = "Cannot read " .. Name
		return
	end
	Send("script", { Name = Name, Source = Source, Args = ScriptArgs })
end

local function BuildScripts(X, Y, W, H)
	local Names = ListScripts()
	if (not ScriptName or not fs.exists(ScriptPath(ScriptName))) then ScriptName = Names[1] end
	local Items = {}
	local Index = 0
	for _, Name in ipairs(Names) do
		table.insert(Items, { Text = Name, Icon = "\16", IconFg = "Accent", Right = Gfx.FormatSize(fs.getSize(ScriptPath(Name))), Name = Name })
		if (Name == ScriptName) then Index = #Items end
	end
	local List = Page:Add(Ui.List.new({ X = X, Y = Y, W = W, H = math.max(1, H - 3), Items = Items, Bg = "Panel" }))
	List.Selected = Index
	List:EnsureVisible()
	local ArgsField
	List.OnSelect = function(_, _, Item)
		ScriptName = Item.Name
	end
	List.OnActivate = function(_, _, Item)
		RunScript(Item.Name, ArgsField.Value)
	end
	List.OnContext = function(_, _, Item, MX, MY)
		if (not Item) then return end
		local Choice = Ui.ContextMenu(MX, MY, { "Run", "Edit", "Rename", "Delete" })
		if (Choice == 1) then
			RunScript(Item.Name, ArgsField.Value)
		elseif (Choice == 2) then
			BlockOS.Launch("editor", { ScriptPath(Item.Name) })
		elseif (Choice == 3) then
			local Name = Ui.Prompt("Rename Script", "New name:", Item.Name)
			if (Name and #Name > 0 and not fs.exists(ScriptPath(Name))) then
				fs.move(ScriptPath(Item.Name), ScriptPath(Name))
				ScriptName = Name
				Build()
			end
		elseif (Choice == 4 and Ui.Confirm("Delete Script", "Delete " .. Item.Name .. "?", "Delete")) then
			fs.delete(ScriptPath(Item.Name))
			Build()
		end
	end
	Page:Add(Ui.Label.new({ X = X, Y = Y + H - 3, W = W, Fg = "SubText", Text = function() return Describe(ScriptName) end }))
	Page:Add(Ui.Label.new({ X = X, Y = Y + H - 2, Text = "Args" }))
	ArgsField = Page:Add(Ui.Input.new({ X = X + 5, Y = Y + H - 2, W = W - 5, Placeholder = "e.g. 10" }))
	ArgsField.OnSubmit = function(_, Value)
		if (ScriptName) then RunScript(ScriptName, Value) end
	end
	local Bottom = Y + H - 1
	Page:Add(Ui.Button.new({ X = X, Y = Bottom, Text = " Run ", Style = "primary", OnClick = function()
		if (ScriptName) then RunScript(ScriptName, ArgsField.Value) end
	end }))
	Page:Add(Ui.Button.new({ X = X + 6, Y = Bottom, Text = " New ", OnClick = function()
		local Name = Ui.Prompt("New Script", "Script name:", "")
		if (not Name or #Name == 0) then return end
		if (not Name:match("%.lua$")) then Name = Name .. ".lua" end
		if (not fs.exists(ScriptPath(Name))) then Config.WriteText(ScriptPath(Name), NewScript) end
		ScriptName = Name
		BlockOS.Launch("editor", { ScriptPath(Name) })
		Build()
	end }))
	Page:Add(Ui.Button.new({ X = X + 12, Y = Bottom, Text = " Edit ", OnClick = function()
		if (ScriptName) then BlockOS.Launch("editor", { ScriptPath(ScriptName) }) end
	end }))
	if (X + 25 <= X + W) then
		Page:Add(Ui.Button.new({ X = X + 19, Y = Bottom, Text = " Stop ", Style = "danger", OnClick = function() Send("stop") end }))
	end
end

function Build()
	Page:Clear()
	local W, H = Page.W, Page.H
	local SideW = (W >= 40) and 14 or 0
	local Items = {}
	local Index = 0
	local IDs = {}
	for ID in pairs(Known) do
		if (ID ~= "local") then table.insert(IDs, ID) end
	end
	table.sort(IDs)
	if (Known["local"]) then table.insert(IDs, 1, "local") end
	for _, ID in ipairs(IDs) do
		local Entry = Known[ID]
		table.insert(Items, { Text = Entry.Label or tostring(ID), Icon = "\4", IconFg = colors.lime, ID = ID })
		if (ID == Selected) then Index = #Items end
	end
	local List = Page:Add(Ui.List.new({ X = 1, Y = 1, W = SideW, H = H - 2, Bg = "Panel", SingleClick = true, Focusable = false, Visible = SideW > 0 }))
	List:SetItems(Items)
	List.Selected = Index
	List.OnActivate = function(_, _, Item)
		Selected = Item.ID
		Message = ""
		Build()
		Send("status")
	end
	List.OnContext = function(_, _, Item, X, Y)
		if (not Item or Item.ID == "local") then return end
		local Choice = Ui.ContextMenu(X, Y, { "Forget" })
		if (Choice == 1) then
			Known[Item.ID] = nil
			if (Selected == Item.ID) then Selected = nil end
			SaveKnown()
			Build()
		end
	end
	Page:Add(Ui.Button.new({ X = 1, Y = H - 1, W = math.max(SideW, 1), Text = "Scan", Bg = "Panel", Visible = SideW > 0, OnClick = Scan }))
	local MainX = SideW + 2
	local MainW = W - SideW - 2
	if (SideW == 0) then
		Page:Add(Ui.Button.new({ X = 1, Y = 1, W = W, Text = "\31 " .. (Selected and Known[Selected] and Known[Selected].Label or "Choose a turtle"), Bg = "Panel", OnClick = function()
			local Names = { "Scan for turtles" }
			for _, Item in ipairs(Items) do table.insert(Names, Item.Text) end
			local Choice = Ui.Choose("Turtles", Names)
			if (Choice == 1) then
				Scan()
			elseif (Choice) then
				Selected = Items[Choice - 1].ID
				Build()
				Send("status")
			end
		end }))
	end
	local TopY = (SideW == 0) and 2 or 1
	if (Selected and Known[Selected]) then
		Page:Add(Ui.Tabs.new({
			X = MainX, Y = TopY, W = MainW, Items = { "Control", "Scripts" }, Selected = (View == "scripts") and 2 or 1,
			OnChange = function(_, Index)
				View = (Index == 2) and "scripts" or "control"
				Build()
			end
		}))
		if (View == "scripts") then
			BuildScripts(MainX, TopY + 1, MainW, H - TopY - 2)
		else
			BuildControls(MainX, TopY + 1, MainW, H - TopY - 2)
		end
	else
		Page:Add(Ui.Label.new({
			X = MainX, Y = TopY + 1, W = MainW, H = math.max(6, H - TopY - 2), Fg = "SubText",
			Text = "Select a turtle, or press Scan.\n\nOn each turtle, install BlockOS and choose \"Turtle Agent\". Turtles show a PIN for pairing.\n\nKeys: WASD move, R/F up/down, Q dig, E place, X attack. Scripts runs Lua files from /home/Turtles."
		}))
	end
	Page:Add(Ui.Label.new({ X = 1, Y = H, W = W, Bg = "Panel", Fg = "SubText", Text = function() return " " .. Message end }))
	Page:Invalidate()
end

function Page:OnLayout()
	Build()
end

function Page:OnEvent(Name, A, B, C)
	if (Name == "key" and Selected and View == "control" and KeyActions[A]) then
		Send("action", { Name = KeyActions[A] })
		return true
	elseif (Name == "rednet_message" and C == Protocol and type(B) == "table" and B.Event == "job_done") then
		if (Known[A]) then Known[A].Status = B.Status end
		Message = "Turtle #" .. A .. " finished its job"
		BlockOS.Notify("Turtles", Message, { AppID = "turtles" })
		return true
	end
	return false
end

if (turtle) then
	Known["local"] = { Label = "This turtle", Status = LocalStatus() }
	Selected = "local"
end
Page:Run()
]=]
Files["blockos/bin/bpm.lua"] = [[
-- bpm: the BlockOS package manager on the command line.

local Apps = BlockOS.Require("apps")
local Config = BlockOS.Require("config")
local Updater = BlockOS.Require("updater")

local Args = { ... }
local Command = Args[1]

local function Usage()
	print("Usage:")
	print("  bpm list                  installed apps")
	print("  bpm search [query]        search app catalogs")
	print("  bpm get <id>              install from a catalog")
	print("  bpm pastebin <code> [name] install from Pastebin")
	print("  bpm url <url> [name]      install from a URL")
	print("  bpm remove <id>           uninstall an app")
	print("  bpm update                update BlockOS")
end

local function Catalog()
	local Entries = {}
	for _, Url in ipairs(Config.Settings().Repositories) do
		local Body = Updater.Get(Url)
		local Data = Body and textutils.unserialise(Body)
		if (type(Data) == "table" and type(Data.Apps) == "table") then
			for _, Entry in ipairs(Data.Apps) do
				Entry.Base = Url
				table.insert(Entries, Entry)
			end
		else
			printError("Could not load " .. Url)
		end
	end
	return Entries
end

local function InstallSource(Meta, Source)
	local App = Apps.Install(Meta, Source)
	print("Installed " .. App.Name .. " (" .. App.ID .. ")")
end

if (Command == "list") then
	for _, App in ipairs(Apps.List(true)) do
		print((App.System and "  " or "* ") .. App.ID .. "  " .. App.Name .. (App.Version and (" " .. App.Version) or ""))
	end
	print("* = installed by you")
elseif (Command == "search") then
	local Query = (Args[2] or ""):lower()
	for _, Entry in ipairs(Catalog()) do
		if (Query == "" or Entry.Name:lower():find(Query, 1, true) or Entry.ID:find(Query, 1, true)) then
			print(Entry.ID .. " - " .. Entry.Name .. ": " .. (Entry.Description or ""))
		end
	end
elseif (Command == "get" and Args[2]) then
	for _, Entry in ipairs(Catalog()) do
		if (Entry.ID == Args[2]) then
			local Source, Err
			if (Entry.Source.Type == "pastebin") then
				Source, Err = Apps.FetchPastebin(Entry.Source.Code)
			elseif (Entry.Source.Type == "url") then
				local Url = Entry.Source.Url
				if (not Url:match("^https?://")) then Url = Entry.Base:gsub("[^/]*$", "") .. Url end
				Source, Err = Apps.Fetch(Url)
			elseif (Entry.Source.Type == "rom") then
				Source = "shell.run(" .. string.format("%q", Entry.Source.Program) .. ", ...)\n"
			end
			if (not Source) then
				printError(Err or "Download failed")
				return
			end
			InstallSource({
				ID = Entry.ID, Name = Entry.Name, Description = Entry.Description, Version = Entry.Version,
				StoreID = Entry.ID, Icon = Entry.Icon, Mode = Entry.Mode, Width = Entry.Width, Height = Entry.Height, Source = Entry.Source
			}, Source)
			return
		end
	end
	printError("No app with ID " .. Args[2])
elseif ((Command == "pastebin" or Command == "url") and Args[2]) then
	local Source, Err
	if (Command == "pastebin") then
		Source, Err = Apps.FetchPastebin(Args[2])
	else
		Source, Err = Apps.Fetch(Args[2])
	end
	if (not Source) then
		printError(Err or "Download failed")
		return
	end
	local Name = Args[3] or Args[2]:match("([%w_%-]+)%.?%w*$") or "App"
	InstallSource({ Name = Name, Description = "Installed with bpm", Source = { Type = Command, Code = Args[2], Url = Args[2] } }, Source)
elseif (Command == "remove" and Args[2]) then
	if (Apps.Uninstall(Args[2])) then
		print("Removed " .. Args[2])
	else
		printError("No installed app with ID " .. Args[2])
	end
elseif (Command == "update") then
	print("Checking " .. Updater.Base())
	local Manifest, Err = Updater.Check()
	if (not Manifest) then
		printError(Err)
		return
	end
	if (not Manifest.Newer) then
		print("BlockOS " .. Config.Version() .. " is up to date.")
		return
	end
	print("Updating to " .. Manifest.Version .. "...")
	local Ok, ApplyErr = Updater.Apply(Manifest, function(Done, Total)
		local _, Y = term.getCursorPos()
		term.setCursorPos(1, Y)
		term.clearLine()
		write(Done .. "/" .. Total)
	end)
	print()
	if (Ok) then
		print("Done. Restart to finish.")
	else
		printError(ApplyErr)
	end
else
	Usage()
end
]]
Files["blockos/bin/open.lua"] = [[
-- open: opens a file, folder or app the same way Finder does.

local Target = ...
if (not Target) then
	print("Usage: open <file | folder | app id>")
	return
end

local Path = shell.resolve(Target)
if (fs.exists(Path)) then
	BlockOS.Open("/" .. Path)
elseif (not BlockOS.Launch(Target)) then
	printError("Nothing called " .. Target)
end
]]
Files["blockos/boot.lua"] = [[
-- BlockOS boot: installs the global BlockOS API, runs first-time setup and starts the desktop.

local Shell = shell
local Loaded = {}
local Fresh = { ui = true }

_G.BlockOS = { Root = "/blockos" }

function BlockOS.Load(Path, ...)
	local Fn, Err = loadfile(Path, nil, _G)
	if (not Fn) then error(Err, 2) end
	return Fn(...)
end

-- Libraries are shared between apps, except those with per-app state (the UI toolkit).
function BlockOS.Require(Name)
	if (Loaded[Name]) then return Loaded[Name] end
	local Module = BlockOS.Load("/blockos/lib/" .. Name .. ".lua")
	if (not Fresh[Name]) then
		Loaded[Name] = Module
	end
	return Module
end

local function Panic(Err)
	term.redirect(term.native())
	if (term.nativePaletteColor) then
		for Index = 0, 15 do
			term.setPaletteColor(2 ^ Index, term.nativePaletteColor(2 ^ Index))
		end
	end
	term.setBackgroundColor(colors.blue)
	term.setTextColor(colors.white)
	term.clear()
	local W, H = term.getSize()
	term.setCursorPos(2, 2)
	print(" :(  BlockOS ran into a problem.")
	print()
	term.setTextColor(colors.lightBlue)
	print(" " .. tostring(Err))
	print()
	term.setTextColor(colors.white)
	print(" [R] Restart    [S] Recovery shell")
	print(" Details were saved to /blockos/data/log.txt")
	local Handle = fs.open("/blockos/data/log.txt", "a")
	if (Handle) then
		Handle.writeLine("PANIC " .. tostring(Err))
		Handle.close()
	end
	while (true) do
		local _, Key = os.pullEvent("key")
		if (Key == keys.r) then
			os.reboot()
		elseif (Key == keys.s) then
			term.setBackgroundColor(colors.black)
			term.clear()
			term.setCursorPos(1, 1)
			return
		end
	end
end

if (not term.isColor()) then
	print("BlockOS needs an Advanced Computer or Advanced Turtle.")
	return
end

-- Carries settings and files over from older releases.
local function Migrate(Config)
	if (fs.exists("/blockos/apps/btunes") and fs.exists("/blockos/apps/musicstream")) then
		fs.delete("/blockos/apps/musicstream")
	end
	-- Calculator moved from the App Store into BlockOS; drop the old store copy.
	if (fs.exists("/blockos/apps/calculator") and fs.exists("/blockos/userapps/calculator")) then
		fs.delete("/blockos/userapps/calculator")
	end
	local Settings = Config.Settings()
	local Changed = false
	for _, List in ipairs({ Settings.Dock or {}, Settings.StartupApps or {} }) do
		for Index, ID in ipairs(List) do
			if (ID == "musicstream") then
				List[Index] = "btunes"
				Changed = true
			end
		end
	end
	if (Changed) then
		local HasNotes = false
		for _, ID in ipairs(Settings.Dock or {}) do
			if (ID == "notes") then HasNotes = true end
		end
		for Index, ID in ipairs(Settings.Dock or {}) do
			if (ID == "btunes" and not HasNotes) then
				table.insert(Settings.Dock, Index, "notes")
				break
			end
		end
		Config.Save("settings")
	end
	-- Savannah ships with BlockOS 1.6.0: put it in the dock once, next to Launchpad.
	if (not Settings.SavannahDocked) then
		Settings.SavannahDocked = true
		local Docked, After = false, 0
		for Index, ID in ipairs(Settings.Dock) do
			if (ID == "savannah") then Docked = true end
			if (ID == "launchpad" or ID == "finder") then After = math.max(After, Index) end
		end
		if (not Docked) then table.insert(Settings.Dock, After + 1, "savannah") end
		Config.Save("settings")
	end
end

local Ok, Err = pcall(function()
	local Config = BlockOS.Require("config")
	BlockOS.Version = Config.Version()
	Migrate(Config)
	math.randomseed(os.epoch("utc") + os.getComputerID())

	local Users = BlockOS.Require("users")
	local Gfx = BlockOS.Require("gfx")
	if (Users.HasAny()) then
		BlockOS.Load("/blockos/sys/splash.lua").Run(term.current())
	else
		BlockOS.Load("/blockos/sys/setup.lua").Run({ Mode = "firstboot" })
	end
	if (not Config.Settings().Animations) then
		Gfx.SetFade(term.current(), 1)
	end

	if (not Shell.path():find("/blockos/bin", 1, true)) then
		Shell.setPath(Shell.path() .. ":/blockos/bin")
	end
	local Desktop = BlockOS.Load("/blockos/sys/desktop.lua")
	Desktop.Run(Shell)
end)

if (not Ok) then
	Panic(Err)
end
]]
Files["blockos/lib/apps.lua"] = [=[
-- Application registry: bundled apps in /blockos/apps, installed apps in /blockos/userapps.
-- Each app folder holds an app.cfg (serialised Lua table) and its entry script.

local Config = BlockOS.Require("config")

local Apps = {}

Apps.SystemDir = "/blockos/apps"
Apps.UserDir = "/blockos/userapps"

local IconColors = {
	"blue", "purple", "magenta", "red", "orange", "yellow", "lime", "green", "cyan", "lightBlue", "pink", "brown"
}

local function ColorOf(Value, Fallback)
	if (type(Value) == "number") then return Value end
	if (type(Value) == "string" and colors[Value]) then return colors[Value] end
	return Fallback
end

function Apps.DefaultIcon(Name)
	local Initials = Name:gsub("[^%w]", ""):sub(1, 2)
	if (#Initials == 0) then Initials = "?" end
	local Hash = 0
	for Index = 1, #Name do
		Hash = (Hash * 31 + Name:byte(Index)) % 997
	end
	return {
		Lines = { " " .. Initials:upper() .. string.rep(" ", 2 - #Initials), "   " },
		Fg = colors.white,
		Bg = colors[IconColors[Hash % #IconColors + 1]]
	}
end

local function Normalize(Meta, Dir, System)
	local App = {}
	for Key, Value in pairs(Meta) do
		App[Key] = Value
	end
	App.ID = fs.getName(Dir)
	App.Dir = "/" .. fs.combine(Dir, "")
	App.Path = "/" .. fs.combine(Dir, Meta.Main or "main.lua")
	App.System = System
	App.Name = Meta.Name or App.ID
	App.Mode = Meta.Mode or "window"
	local Icon = Meta.Icon
	if (type(Icon) == "table" and type(Icon.Lines) == "table") then
		App.Icon = {
			Lines = { tostring(Icon.Lines[1] or "   "), tostring(Icon.Lines[2] or "   ") },
			Fg = ColorOf(Icon.Fg, colors.white),
			Bg = ColorOf(Icon.Bg, colors.gray)
		}
	else
		App.Icon = Apps.DefaultIcon(App.Name)
	end
	return App
end

local function ReadDir(Root, System, Into)
	if (not fs.isDir(Root)) then return end
	for _, Name in ipairs(fs.list(Root)) do
		local Dir = fs.combine(Root, Name)
		local Meta = fs.isDir(Dir) and Config.Read(fs.combine(Dir, "app.cfg"))
		if (type(Meta) == "table") then
			Into[Name] = Normalize(Meta, Dir, System)
		end
	end
end

function Apps.All()
	local Result = {}
	ReadDir(Apps.SystemDir, true, Result)
	ReadDir(Apps.UserDir, false, Result)
	return Result
end

function Apps.List(IncludeHidden)
	local Result = {}
	for _, App in pairs(Apps.All()) do
		if (IncludeHidden or not App.Hidden) then
			table.insert(Result, App)
		end
	end
	table.sort(Result, function(A, B) return A.Name:lower() < B.Name:lower() end)
	return Result
end

function Apps.Get(ID)
	if (type(ID) ~= "string" or #ID == 0) then return nil end
	for _, Root in ipairs({ Apps.UserDir, Apps.SystemDir }) do
		local Dir = fs.combine(Root, ID)
		local Meta = Config.Read(fs.combine(Dir, "app.cfg"))
		if (type(Meta) == "table") then
			return Normalize(Meta, Dir, Root == Apps.SystemDir)
		end
	end
	return nil
end

function Apps.MakeID(Name)
	local ID = Name:lower():gsub("[^%w]+", "-"):gsub("^%-+", ""):gsub("%-+$", "")
	if (#ID == 0) then ID = "app" end
	return ID
end

-- Writes an app to /blockos/userapps. Meta uses the app.cfg fields.
function Apps.Install(Meta, Source)
	local ID = Meta.ID or Apps.MakeID(Meta.Name or "app")
	if (fs.exists(fs.combine(Apps.SystemDir, ID))) then
		ID = ID .. "-app"
	end
	local Dir = fs.combine(Apps.UserDir, ID)
	if (not fs.exists(Dir)) then fs.makeDir(Dir) end
	local Stored = {}
	for Key, Value in pairs(Meta) do
		if (Key ~= "ID") then Stored[Key] = Value end
	end
	Stored.Main = "main.lua"
	Stored.Installed = os.epoch and os.epoch("utc") or 0
	Config.WriteText(fs.combine(Dir, "main.lua"), Source)
	Config.Write(fs.combine(Dir, "app.cfg"), Stored)
	os.queueEvent("blockos_apps")
	return Apps.Get(ID)
end

function Apps.Uninstall(ID)
	local Dir = fs.combine(Apps.UserDir, ID)
	if (not fs.exists(Dir)) then return false end
	fs.delete(Dir)
	local Settings = Config.Settings()
	for Index = #Settings.Dock, 1, -1 do
		if (Settings.Dock[Index] == ID) then
			table.remove(Settings.Dock, Index)
		end
	end
	for Index = #Settings.Shortcuts, 1, -1 do
		if (Settings.Shortcuts[Index] == Apps.AppShortcut(ID)) then
			table.remove(Settings.Shortcuts, Index)
		end
	end
	Config.Save("settings")
	os.queueEvent("blockos_apps")
	return true
end

function Apps.Fetch(Url)
	if (not http) then return nil, "HTTP is disabled on this server" end
	local Ok, Err = http.checkURL(Url)
	if (not Ok) then return nil, Err or "URL not allowed" end
	local Response, Message = http.get(Url, nil, true)
	if (not Response) then return nil, Message or "Request failed" end
	local Body = Response.readAll()
	Response.close()
	return Body
end

function Apps.FetchPastebin(Code)
	Code = tostring(Code):gsub("^https?://pastebin%.com/", ""):gsub("^raw/", ""):gsub("[^%w]", "")
	if (#Code == 0) then return nil, "Invalid Pastebin code" end
	return Apps.Fetch("https://pastebin.com/raw/" .. Code .. "?cb=" .. ("%x"):format(math.random(0, 2 ^ 30)))
end

-- The app that edits a file: CCDream for .ccmd pages when it is installed, otherwise Editor.
function Apps.EditorFor(Path)
	if (tostring(Path):lower():match("%.ccmd$") and Apps.Get("ccdream")) then return "ccdream" end
	return "editor"
end

function Apps.IsPinned(ID)
	for _, Pinned in ipairs(Config.Settings().Dock) do
		if (Pinned == ID) then return true end
	end
	return false
end

function Apps.SetPinned(ID, Pinned)
	local Dock = Config.Settings().Dock
	for Index = #Dock, 1, -1 do
		if (Dock[Index] == ID) then
			table.remove(Dock, Index)
		end
	end
	if (Pinned) then
		table.insert(Dock, ID)
	end
	Config.Save("settings")
end

--
-- Desktop shortcuts: settings.Shortcuts holds "app:<id>" for apps and absolute paths for files.
--

function Apps.AppShortcut(ID)
	return "app:" .. ID
end

local function ShortcutTarget(Target)
	if (Target:sub(1, 4) == "app:") then return Target end
	return "/" .. fs.combine(Target, "")
end

function Apps.HasShortcut(Target)
	Target = ShortcutTarget(Target)
	for _, Entry in ipairs(Config.Settings().Shortcuts) do
		if (Entry == Target) then return true end
	end
	return false
end

function Apps.SetShortcut(Target, Enabled)
	Target = ShortcutTarget(Target)
	local Shortcuts = Config.Settings().Shortcuts
	for Index = #Shortcuts, 1, -1 do
		if (Shortcuts[Index] == Target) then
			table.remove(Shortcuts, Index)
		end
	end
	if (Enabled) then
		table.insert(Shortcuts, Target)
	end
	Config.Save("settings")
end

-- Follows a moved or renamed file or folder; a nil New drops the shortcuts instead.
function Apps.MoveShortcuts(Old, New)
	Old = ShortcutTarget(Old)
	New = New and ShortcutTarget(New)
	local Shortcuts = Config.Settings().Shortcuts
	local Changed = false
	for Index = #Shortcuts, 1, -1 do
		local Entry = Shortcuts[Index]
		if (Entry == Old or Entry:sub(1, #Old + 1) == Old .. "/") then
			Changed = true
			if (New) then
				Shortcuts[Index] = New .. Entry:sub(#Old + 1)
			else
				table.remove(Shortcuts, Index)
			end
		end
	end
	if (Changed) then Config.Save("settings") end
end

return Apps
]=]
Files["blockos/lib/ccinternet/ccmd.lua"] = [=[
-- .ccmd parser: turns page source into a document tree that any browser can lay out.
-- Pure Lua with no CC: Tweaked APIs, so it can also run outside the game.
-- Vendored from https://github.com/tamayaren/ccinternet (lib/ccmd.lua), shared by Savannah and CCDream.

local Ccmd = {}

Ccmd.Version = 1

-- Colour names map to blit characters ("0" white .. "f" black).
local ColourNames = {
	white = "0", orange = "1", magenta = "2", lightblue = "3", yellow = "4", lime = "5",
	pink = "6", gray = "7", grey = "7", lightgray = "8", lightgrey = "8", silver = "8",
	cyan = "9", purple = "a", blue = "b", brown = "c", green = "d", red = "e", black = "f"
}

Ccmd.Defaults = {
	Background = "f",
	TextColor = "0",
	LinkColor = "3",
	TopbarColor = "7",
	TopbarTextColor = "0",
	HeaderColor = "7",
	InputColor = "8",
	InputTextColor = "f",
	ButtonColor = "b",
	ButtonTextColor = "0",
	InputWidth = 20
}

-- Tags the parser understands. Anything else that looks like a tag stays as text.
local Containers = { topbar = true, p = true, table = true, button = true }
local Voids = { br = true, img = true, input = true }
local Known = { topbar = true, p = true, table = true, button = true, br = true, img = true, input = true, form = true }

local InputTypes = { text = true, password = true, file = true, hidden = true }

-- Returns the blit character for a colour name, or nil when it is not a colour.
function Ccmd.Colour(Name)
	if (type(Name) ~= "string") then return nil end
	local Key = Name:lower():gsub("[%s_%-]", "")
	if (ColourNames[Key]) then return ColourNames[Key] end
	if (Key:match("^[0-9a-f]$")) then return Key end
	return nil
end

-- Escapes text so it shows literally inside a page (used for server-generated pages).
function Ccmd.Escape(Text)
	Text = tostring(Text or "")
	Text = Text:gsub("[\\%[%]{}<]", "\\%0")
	Text = Text:gsub("\n#", "\n\\#")
	if (Text:sub(1, 1) == "#") then Text = "\\" .. Text end
	return Text
end

-- Makes a value safe to put inside a quoted attribute.
function Ccmd.Attribute(Text)
	return (tostring(Text or ""):gsub("[\"\n\r>]", ""))
end

local function Trim(Text)
	return (Text:gsub("^%s+", ""):gsub("%s+$", ""))
end

local function SplitLines(Source)
	local Lines = {}
	Source = Source:gsub("\r\n?", "\n")
	for Line in (Source .. "\n"):gmatch("(.-)\n") do
		Lines[#Lines + 1] = Line
	end
	return Lines
end

local function IsComment(Line)
	return Line:match("^%s*#") ~= nil
end

local function ParseAttributes(Text)
	local Attributes = {}
	local Pos = 1
	while (Pos <= #Text) do
		local A, B, Key, Value = Text:find("^%s*([%a_][%w_%-]*)%s*=%s*\"(.-)\"", Pos)
		if (not A) then A, B, Key, Value = Text:find("^%s*([%a_][%w_%-]*)%s*=%s*'(.-)'", Pos) end
		if (not A) then A, B, Key, Value = Text:find("^%s*([%a_][%w_%-]*)%s*=%s*([^%s\"']+)", Pos) end
		if (not A) then
			A, B, Key = Text:find("^%s*([%a_][%w_%-]*)", Pos)
			Value = "true"
		end
		if (not A) then break end
		Attributes[Key:lower()] = Value
		Pos = B + 1
	end
	return Attributes
end

-- Reads the front matter. Returns the metadata table, the index of the first body line and an error.
function Ccmd.ParseFrontMatter(Source)
	local Lines = type(Source) == "table" and Source or SplitLines(Source or "")
	local Index = 1
	while (Lines[Index] and (Trim(Lines[Index]) == "" or IsComment(Lines[Index]))) do
		Index = Index + 1
	end
	if (not Lines[Index] or not Trim(Lines[Index]):match("^%-%-%-?$")) then
		return nil, Index, "Missing front matter (the page must start with --)"
	end
	local Meta = {}
	Index = Index + 1
	while (Lines[Index]) do
		local Line = Trim(Lines[Index])
		if (Line:match("^%-%-%-?$")) then
			if (not Meta.title or Meta.title == "") then return Meta, Index + 1, "Front matter needs a title" end
			if (not Meta.location or Meta.location == "") then return Meta, Index + 1, "Front matter needs a location" end
			return Meta, Index + 1, nil
		end
		if (Line ~= "" and not IsComment(Line)) then
			local Key, Value = Line:match("^([%w_%-]+)%s*:%s*(.-)$")
			if (Key) then Meta[Key:lower()] = Value end
		end
		Index = Index + 1
	end
	return nil, Index, "Front matter is never closed (add a -- line)"
end

-- Parses inline markup: [text](url) links, {colour}...{/} and {colour on colour}...{/} spans, \ escapes.
-- Returns a list of spans { Text, Fg, Bg, Href } where Fg/Bg are blit characters or nil.
function Ccmd.ParseInline(Text)
	local Spans = {}
	local Stack = {}
	local Buffer = {}
	local Pos = 1

	local function Current()
		return Stack[#Stack] or {}
	end

	local function Flush()
		if (#Buffer == 0) then return end
		local Style = Current()
		local Value = table.concat(Buffer)
		Buffer = {}
		local Last = Spans[#Spans]
		if (Last and not Last.Href and Last.Fg == Style.Fg and Last.Bg == Style.Bg) then
			Last.Text = Last.Text .. Value
		else
			Spans[#Spans + 1] = { Text = Value, Fg = Style.Fg, Bg = Style.Bg }
		end
	end

	while (Pos <= #Text) do
		local Char = Text:sub(Pos, Pos)
		if (Char == "\\" and Pos < #Text) then
			Buffer[#Buffer + 1] = Text:sub(Pos + 1, Pos + 1)
			Pos = Pos + 2
		elseif (Char == "[") then
			local A, B, Label, Href = Text:find("^%[([^%]]*)%]%(([^%)]*)%)", Pos)
			if (A) then
				Flush()
				local Style = Current()
				Spans[#Spans + 1] = { Text = Label:gsub("\\(.)", "%1"), Href = Trim(Href), Fg = Style.Fg, Bg = Style.Bg, Link = true }
				Pos = B + 1
			else
				Buffer[#Buffer + 1] = Char
				Pos = Pos + 1
			end
		elseif (Char == "{") then
			local A, B, Inner = Text:find("^{([^{}]*)}", Pos)
			local Handled = false
			if (A) then
				Inner = Trim(Inner)
				if (Inner == "/") then
					Flush()
					Stack[#Stack] = nil
					Handled = true
				else
					local FgName, BgName = Inner:match("^(.-)%s+on%s+(.-)$")
					local Fg, Bg
					if (FgName) then
						Fg, Bg = Ccmd.Colour(FgName), Ccmd.Colour(BgName)
						if (FgName == "" or BgName == "") then Fg = nil end
					else
						Fg = Ccmd.Colour(Inner)
						Bg = Current().Bg
					end
					if (Fg and (Bg or not FgName)) then
						Flush()
						Stack[#Stack + 1] = { Fg = Fg, Bg = Bg }
						Handled = true
					end
				end
			end
			if (Handled) then
				Pos = B + 1
			else
				Buffer[#Buffer + 1] = Char
				Pos = Pos + 1
			end
		else
			Buffer[#Buffer + 1] = Char
			Pos = Pos + 1
		end
	end
	Flush()
	return Spans
end

-- Removes the indentation shared by every non-blank line.
local function Dedent(Lines)
	local Common
	for _, Line in ipairs(Lines) do
		if (Trim(Line) ~= "") then
			local Indent = #Line:match("^[ \t]*")
			if (not Common or Indent < Common) then Common = Indent end
		end
	end
	if (Common and Common > 0) then
		for Index, Line in ipairs(Lines) do
			Lines[Index] = Line:sub(Common + 1)
		end
	end
	return Lines
end

local function Alignment(Attributes)
	local Value = (Attributes.alignment or Attributes.align or "left"):lower()
	if (Value == "centre") then Value = "center" end
	if (Value ~= "center" and Value ~= "right") then Value = "left" end
	return Value
end

local function SplitCells(Line)
	Line = Trim(Line)
	local Cells = {}
	local Buffer = {}
	local Pos = 1
	if (Line:sub(1, 1) == "|") then Pos = 2 end
	while (Pos <= #Line) do
		local Char = Line:sub(Pos, Pos)
		if (Char == "\\" and Line:sub(Pos + 1, Pos + 1) == "|") then
			Buffer[#Buffer + 1] = "|"
			Pos = Pos + 2
		elseif (Char == "|") then
			Cells[#Cells + 1] = Trim(table.concat(Buffer))
			Buffer = {}
			Pos = Pos + 1
		else
			Buffer[#Buffer + 1] = Char
			Pos = Pos + 1
		end
	end
	local Rest = Trim(table.concat(Buffer))
	if (Rest ~= "") then Cells[#Cells + 1] = Rest end
	return Cells
end

local function ParseTable(Inner, Attributes)
	local Rows = {}
	for _, Line in ipairs(SplitLines(Inner)) do
		if (Trim(Line):sub(1, 1) == "|") then
			Rows[#Rows + 1] = SplitCells(Line)
		end
	end
	local Block = {
		Type = "table",
		HeaderColor = Ccmd.Colour(Attributes["header-color"]) or Ccmd.Defaults.HeaderColor,
		HeaderTextColor = Ccmd.Colour(Attributes["header-text-color"]),
		TextColor = Ccmd.Colour(Attributes["text-color"]),
		Color = Ccmd.Colour(Attributes.color),
		Align = {},
		Header = nil,
		Rows = {}
	}
	local Start = 1
	local Separator = Rows[2]
	local IsSeparator = Separator ~= nil and #Separator > 0
	if (Separator) then
		for _, Cell in ipairs(Separator) do
			if (not Cell:match("^:?%-+:?$")) then IsSeparator = false end
		end
	end
	if (IsSeparator) then
		for Column, Cell in ipairs(Separator) do
			local Left, Right = Cell:sub(1, 1) == ":", Cell:sub(-1) == ":"
			Block.Align[Column] = (Left and Right) and "center" or (Right and "right") or "left"
		end
		Block.Header = {}
		for Column, Cell in ipairs(Rows[1]) do
			Block.Header[Column] = Ccmd.ParseInline(Cell)
		end
		Start = 3
	end
	for Index = Start, #Rows do
		local Row = {}
		for Column, Cell in ipairs(Rows[Index]) do
			Row[Column] = Ccmd.ParseInline(Cell)
		end
		Block.Rows[#Block.Rows + 1] = Row
	end
	local Columns = Block.Header and #Block.Header or 0
	for _, Row in ipairs(Block.Rows) do
		if (#Row > Columns) then Columns = #Row end
	end
	Block.Columns = Columns
	return Block
end

local function TextLines(Inner, KeepBlank)
	local Lines = SplitLines(Inner)
	if (KeepBlank) then
		while (Lines[1] and Trim(Lines[1]) == "") do table.remove(Lines, 1) end
		while (Lines[#Lines] and Trim(Lines[#Lines]) == "") do table.remove(Lines) end
		Dedent(Lines)
	end
	local Result = {}
	for _, Line in ipairs(Lines) do
		Line = Line:gsub("%s+$", "")
		if (not KeepBlank) then Line = Line:gsub("^%s+", "") end
		if (KeepBlank or Line ~= "") then
			Result[#Result + 1] = Ccmd.ParseInline((Line:gsub("\t", "    ")))
		end
	end
	return Result
end

-- Parses a whole page. Always returns a document; problems are listed in Doc.Errors.
function Ccmd.Parse(Source)
	local Lines = SplitLines(Source or "")
	local Doc = {
		Meta = {},
		Title = "Untitled",
		Location = "/",
		Blocks = {},
		Inputs = {},
		Forms = {},
		Errors = {}
	}

	local Meta, BodyStart, Problem = Ccmd.ParseFrontMatter(Lines)
	if (Problem) then Doc.Errors[#Doc.Errors + 1] = Problem end
	if (not Meta) then
		Meta = {}
		BodyStart = 1
	end
	Doc.Meta = Meta
	Doc.Title = Meta.title and Meta.title ~= "" and Meta.title or Doc.Title
	Doc.Location = Meta.location and Meta.location ~= "" and Meta.location or Doc.Location
	Doc.Background = Ccmd.Colour(Meta.background) or Ccmd.Defaults.Background
	Doc.TextColor = Ccmd.Colour(Meta["text-color"]) or Ccmd.Defaults.TextColor
	Doc.LinkColor = Ccmd.Colour(Meta["link-color"]) or Ccmd.Defaults.LinkColor

	-- Drop comment lines and turn \# at the start of a line into #.
	local Body = {}
	for Index = BodyStart, #Lines do
		local Line = Lines[Index]
		if (not IsComment(Line)) then
			Body[#Body + 1] = (Line:gsub("^(%s*)\\#", "%1#"))
		end
	end
	local Text = table.concat(Body, "\n")
	local Lower = Text:lower()

	local Target = Doc.Blocks
	local CurrentForm = nil

	local function AddText(Chunk)
		local Result = TextLines(Chunk, false)
		if (#Result > 0) then
			Target[#Target + 1] = { Type = "text", Align = "left", Lines = Result }
		end
	end

	local Pos = 1
	local TextStart = 1
	while (Pos <= #Text) do
		local Start = Text:find("<", Pos, true)
		if (not Start) then break end
		local A, B, Slash, Name, AttrStart, AttrEnd, SelfClose = Lower:find("^<(/?)([%a][%w%-]*)()[^<>]-()(/?)>", Start)
		if (A and Known[Name]) then
			AddText(Text:sub(TextStart, Start - 1))
			local Attributes = ParseAttributes(Text:sub(AttrStart, AttrEnd - 1))
			local Closing = Slash == "/"
			local Next = B + 1
			if (Closing) then
				if (Name == "form" and CurrentForm) then
					Target = Doc.Blocks
					CurrentForm = nil
				else
					Doc.Errors[#Doc.Errors + 1] = "Unexpected </" .. Name .. ">"
				end
			elseif (Name == "form") then
				if (CurrentForm) then
					Doc.Errors[#Doc.Errors + 1] = "Forms cannot be nested"
				else
					local Method = (Attributes.method or "POST"):upper()
					if (Method ~= "GET") then Method = "POST" end
					CurrentForm = { Type = "form", Action = Attributes.action, Method = Method, Blocks = {}, Index = #Doc.Forms + 1 }
					Doc.Forms[#Doc.Forms + 1] = CurrentForm
					Doc.Blocks[#Doc.Blocks + 1] = CurrentForm
					Target = CurrentForm.Blocks
				end
			elseif (Containers[Name] and SelfClose ~= "/") then
				local CloseA, CloseB = Lower:find("</%s*" .. Name .. "%s*>", B + 1)
				local Inner
				if (CloseA) then
					Inner = Text:sub(B + 1, CloseA - 1)
					Next = CloseB + 1
				else
					Doc.Errors[#Doc.Errors + 1] = "<" .. Name .. "> is never closed"
					Inner = Text:sub(B + 1)
					Next = #Text + 1
				end
				if (Name == "topbar") then
					local Layout = (Attributes.layout or "horizontal"):lower()
					Doc.Topbar = {
						Color = Ccmd.Colour(Attributes.color) or Ccmd.Defaults.TopbarColor,
						TextColor = Ccmd.Colour(Attributes["text-color"]) or Ccmd.Defaults.TopbarTextColor,
						Layout = Layout == "vertical" and "vertical" or "horizontal",
						Items = TextLines(Inner, false)
					}
				elseif (Name == "p") then
					Inner = Inner:gsub("<[bB][rR]%s*/?>", "\n")
					Target[#Target + 1] = {
						Type = "text",
						Align = Alignment(Attributes),
						TextColor = Ccmd.Colour(Attributes["text-color"]),
						Color = Ccmd.Colour(Attributes.color),
						Lines = TextLines(Inner, true)
					}
				elseif (Name == "table") then
					Target[#Target + 1] = ParseTable(Inner, Attributes)
				elseif (Name == "button") then
					Attributes.text = Attributes.text or Trim(Inner)
					Name = "button"
				end
			end
			if (Name == "button" and not Closing) then
				local Block = {
					Type = "button",
					Text = Attributes.text or "Submit",
					Name = Attributes.name,
					Value = Attributes.value,
					Href = Attributes.href,
					Align = Alignment(Attributes),
					Color = Ccmd.Colour(Attributes.color) or Ccmd.Defaults.ButtonColor,
					TextColor = Ccmd.Colour(Attributes["text-color"]) or Ccmd.Defaults.ButtonTextColor,
					Form = CurrentForm and CurrentForm.Index or nil
				}
				Target[#Target + 1] = Block
			elseif (not Closing and Voids[Name]) then
				if (Name == "br") then
					Target[#Target + 1] = { Type = "break" }
				elseif (Name == "img") then
					if (Attributes.src and Attributes.src ~= "") then
						Target[#Target + 1] = { Type = "image", Src = Attributes.src, Alt = Attributes.alt, Align = Alignment(Attributes) }
					else
						Doc.Errors[#Doc.Errors + 1] = "<img> needs a src"
					end
				elseif (Name == "input") then
					local Kind = (Attributes.type or "text"):lower()
					if (not InputTypes[Kind]) then Kind = "text" end
					local Input = {
						Type = "input",
						Kind = Kind,
						Name = Attributes.name or ("input" .. (#Doc.Inputs + 1)),
						Label = Attributes.label,
						Value = Attributes.value,
						Placeholder = Attributes.placeholder,
						Width = math.max(1, math.min(tonumber(Attributes.width) or Ccmd.Defaults.InputWidth, 200)),
						Color = Ccmd.Colour(Attributes.color) or Ccmd.Defaults.InputColor,
						TextColor = Ccmd.Colour(Attributes["text-color"]) or Ccmd.Defaults.InputTextColor,
						Form = CurrentForm and CurrentForm.Index or nil,
						Id = #Doc.Inputs + 1
					}
					Doc.Inputs[#Doc.Inputs + 1] = Input
					Target[#Target + 1] = Input
				end
			end
			Pos = Next
			TextStart = Next
		else
			Pos = Start + 1
		end
	end
	AddText(Text:sub(TextStart))
	if (CurrentForm) then Doc.Errors[#Doc.Errors + 1] = "<form> is never closed" end
	return Doc
end

-- Collects the fields a form would submit. State maps input Id -> value typed by the user.
-- Button is the button block that was pressed (its name/value is included when set).
function Ccmd.FormFields(Doc, FormIndex, State, Button)
	local Fields = {}
	for _, Input in ipairs(Doc.Inputs) do
		if (Input.Form == FormIndex) then
			local Value = State and State[Input.Id]
			if (Value == nil) then Value = Input.Value or "" end
			Fields[Input.Name] = Value
		end
	end
	if (Button and Button.Name) then Fields[Button.Name] = Button.Value or Button.Text end
	return Fields
end

return Ccmd
]=]
Files["blockos/lib/ccinternet/image.lua"] = [[
-- Text-mode images used by .ccmd pages: .nft (cc.image.nft), .bimg (BlockOS / blit image) and .nfp (paintutils).
-- Every format becomes { W, H, Rows = { { Text, Fg, Bg } } }. A space in Bg means transparent.
-- Vendored from https://github.com/tamayaren/ccinternet (lib/image.lua), shared by Savannah and CCDream.

local Image = {}

Image.Extensions = { nft = true, bimg = true, nfp = true }

local function Pad(Text, Width, Filler)
	if (#Text >= Width) then return Text:sub(1, Width) end
	return Text .. string.rep(Filler, Width - #Text)
end

local function Hex(Text, Fallback)
	return (Text:lower():gsub("[^0-9a-f ]", Fallback))
end

function Image.Kind(Path)
	local Extension = (tostring(Path or ""):match("%.(%w+)$") or ""):lower()
	if (Image.Extensions[Extension]) then return Extension end
	return nil
end

local function Finish(Rows)
	local W = 0
	for _, Row in ipairs(Rows) do
		if (#Row[1] > W) then W = #Row[1] end
	end
	if (W == 0 or #Rows == 0) then return nil end
	for _, Row in ipairs(Rows) do
		Row[1] = Pad(Row[1], W, " ")
		Row[2] = Pad(Row[2], W, "0")
		Row[3] = Pad(Row[3], W, " ")
	end
	return { W = W, H = #Rows, Rows = Rows }
end

function Image.ParseNft(Data)
	local Rows = {}
	for Line in ((Data or ""):gsub("\r", "") .. "\n"):gmatch("(.-)\n") do
		local Text, Fg, Bg = {}, {}, {}
		local Foreground, Background = "0", "f"
		local Pos = 1
		while (Pos <= #Line) do
			local Char = Line:sub(Pos, Pos)
			if (Char == "\30") then
				Background = Hex(Line:sub(Pos + 1, Pos + 1), "f")
				Pos = Pos + 2
			elseif (Char == "\31") then
				Foreground = Hex(Line:sub(Pos + 1, Pos + 1), "0")
				Pos = Pos + 2
			else
				Text[#Text + 1] = Char
				Fg[#Fg + 1] = Foreground
				Bg[#Bg + 1] = Background
				Pos = Pos + 1
			end
		end
		Rows[#Rows + 1] = { table.concat(Text), table.concat(Fg), table.concat(Bg) }
	end
	while (#Rows > 0 and #Rows[#Rows][1] == 0) do Rows[#Rows] = nil end
	return Finish(Rows)
end

function Image.ParseNfp(Data)
	local Rows = {}
	for Line in ((Data or ""):gsub("\r", "") .. "\n"):gmatch("(.-)\n") do
		local Bg = Hex(Line, " ")
		Rows[#Rows + 1] = { string.rep(" ", #Bg), string.rep("0", #Bg), Bg }
	end
	while (#Rows > 0 and #Rows[#Rows][1] == 0) do Rows[#Rows] = nil end
	return Finish(Rows)
end

function Image.ParseBimg(Data, Unserialise)
	Unserialise = Unserialise or (textutils and textutils.unserialise)
	if (not Unserialise) then return nil end
	local Ok, Value = pcall(Unserialise, Data or "")
	if (not Ok or type(Value) ~= "table" or type(Value[1]) ~= "table") then return nil end
	local Rows = {}
	for _, Line in ipairs(Value[1]) do
		if (type(Line) ~= "table") then return nil end
		local Text = tostring(Line[1] or "")
		Rows[#Rows + 1] = {
			Text,
			Hex(Pad(tostring(Line[2] or ""), #Text, "0"), "0"),
			Hex(Pad(tostring(Line[3] or ""), #Text, "f"), "f")
		}
	end
	return Finish(Rows)
end

-- Parses image data. Kind is "nft", "bimg" or "nfp" (or a path to take the extension from).
function Image.Parse(Data, Kind)
	Kind = Image.Extensions[Kind] and Kind or Image.Kind(Kind)
	if (Kind == "nft") then return Image.ParseNft(Data) end
	if (Kind == "nfp") then return Image.ParseNfp(Data) end
	if (Kind == "bimg") then return Image.ParseBimg(Data) end
	return nil
end

-- Draws an image on a terminal-like target. Transparent pixels use Background (default black).
function Image.Draw(Picture, Target, X, Y, Background)
	Background = Background or "f"
	for Index, Row in ipairs(Picture.Rows) do
		Target.setCursorPos(X, Y + Index - 1)
		Target.blit(Row[1], Row[2], (Row[3]:gsub(" ", Background)))
	end
end

return Image
]]
Files["blockos/lib/ccinternet/layout.lua"] = [[
-- Lays out a parsed .ccmd document for a given screen size.
-- The result is a list of blit rows plus clickable regions, so drawing is just term.blit per row.
-- Vendored from https://github.com/tamayaren/ccinternet (lib/layout.lua), shared by Savannah and CCDream.

local Ccmd = BlockOS.Require("ccinternet/ccmd")

local Layout = {}

local function Clamp(Value, Low, High)
	if (Value < Low) then return Low end
	if (Value > High) then return High end
	return Value
end

-- Converts spans into cells { Ch, Fg, Bg, Link }.
local function SpanCells(Spans, Fg, Bg, LinkFg)
	local Cells = {}
	for _, Span in ipairs(Spans) do
		local Link = Span.Link and { Kind = "link", Href = Span.Href } or nil
		local SpanFg = Span.Fg or (Link and LinkFg) or Fg
		local SpanBg = Span.Bg or Bg
		local Text = Span.Text:gsub("\t", "    ")
		for Index = 1, #Text do
			Cells[#Cells + 1] = { Ch = Text:sub(Index, Index), Fg = SpanFg, Bg = SpanBg, Link = Link }
		end
	end
	return Cells
end

local function TextCells(Text, Fg, Bg)
	local Cells = {}
	for Index = 1, #Text do
		Cells[#Cells + 1] = { Ch = Text:sub(Index, Index), Fg = Fg, Bg = Bg }
	end
	return Cells
end

local function Slice(Cells, First, Last)
	local Result = {}
	for Index = First, Last do Result[#Result + 1] = Cells[Index] end
	return Result
end

local function TrimEnd(Cells)
	while (#Cells > 0 and Cells[#Cells].Ch == " " and not Cells[#Cells].Link) do Cells[#Cells] = nil end
	return Cells
end

-- Word-wraps cells into rows no wider than Width.
local function Wrap(Cells, Width)
	local Rows = {}
	local Count = #Cells
	if (Count == 0) then return { {} } end
	local Start = 1
	while (Start <= Count) do
		if (Count - Start + 1 <= Width) then
			Rows[#Rows + 1] = Slice(Cells, Start, Count)
			break
		end
		local Break
		for Index = Start + Width, Start + 1, -1 do
			if (Cells[Index].Ch == " ") then
				Break = Index
				break
			end
		end
		if (Break) then
			Rows[#Rows + 1] = TrimEnd(Slice(Cells, Start, Break - 1))
			Start = Break + 1
			while (Cells[Start] and Cells[Start].Ch == " ") do Start = Start + 1 end
		else
			Rows[#Rows + 1] = Slice(Cells, Start, Start + Width - 1)
			Start = Start + Width
		end
	end
	return Rows
end

local function NewCanvas(Width, Fg, Bg)
	return { Width = Width, Text = {}, Fg = {}, Bg = {}, DefaultFg = Fg, DefaultBg = Bg }
end

local function Put(Canvas, X, Cell)
	if (X < 1 or X > Canvas.Width) then return end
	Canvas.Text[X] = Cell.Ch
	Canvas.Fg[X] = Cell.Fg
	Canvas.Bg[X] = Cell.Bg
end

local function Finish(Canvas)
	local Text, Fg, Bg = {}, {}, {}
	for X = 1, Canvas.Width do
		Text[X] = Canvas.Text[X] or " "
		Fg[X] = Canvas.Fg[X] or Canvas.DefaultFg
		Bg[X] = Canvas.Bg[X] or Canvas.DefaultBg
	end
	return { table.concat(Text), table.concat(Fg), table.concat(Bg) }
end

local function AlignOffset(Align, Used, Width)
	if (Align == "center") then return math.floor((Width - Used) / 2) end
	if (Align == "right") then return Width - Used end
	return 0
end

-- Places cells on a canvas starting at X and records link regions on row Y.
local function PlaceCells(Canvas, Regions, Cells, X, Y)
	local Open
	for Index, Cell in ipairs(Cells) do
		local CX = X + Index - 1
		Put(Canvas, CX, Cell)
		if (Cell.Link and CX >= 1 and CX <= Canvas.Width) then
			if (Open and Open.Source == Cell.Link and Open.X2 == CX - 1) then
				Open.X2 = CX
			else
				Open = { Kind = Cell.Link.Kind, Href = Cell.Link.Href, Source = Cell.Link, Y = Y, X1 = CX, X2 = CX }
				Regions[#Regions + 1] = Open
			end
		end
	end
end

local Builder = {}
Builder.__index = Builder

function Builder:Row(Bg)
	return NewCanvas(self.Width, self.Fg, Bg or self.Bg)
end

function Builder:Push(Canvas)
	self.Rows[#self.Rows + 1] = Finish(Canvas)
	return #self.Rows
end

function Builder:Blank(Bg)
	self:Push(self:Row(Bg))
end

function Builder:Text(Block)
	local Fg = Block.TextColor or self.Fg
	local Bg = Block.Color or self.Bg
	for _, Spans in ipairs(Block.Lines) do
		local Cells = SpanCells(Spans, Fg, Bg, self.LinkFg)
		for _, Line in ipairs(Wrap(Cells, self.Width)) do
			local Canvas = self:Row(Bg)
			local Offset = AlignOffset(Block.Align, #Line, self.Width)
			PlaceCells(Canvas, self.Regions, Line, Offset + 1, #self.Rows + 1)
			self:Push(Canvas)
		end
	end
end

local function CellsWidth(Spans)
	local Width = 0
	for _, Span in ipairs(Spans or {}) do Width = Width + #Span.Text end
	return Width
end

function Builder:Table(Block)
	local Columns = Block.Columns
	if (Columns == 0) then return end
	local Widths = {}
	local function Measure(Row)
		for Column = 1, Columns do
			local Width = CellsWidth(Row[Column])
			if (Width > (Widths[Column] or 0)) then Widths[Column] = Width end
		end
	end
	for Column = 1, Columns do Widths[Column] = 1 end
	if (Block.Header) then Measure(Block.Header) end
	for _, Row in ipairs(Block.Rows) do Measure(Row) end

	-- One space before every column and one after the last.
	local Available = math.max(Columns, self.Width - Columns - 1)
	local Total = 0
	for Column = 1, Columns do Total = Total + Widths[Column] end
	while (Total > Available) do
		local Widest = 1
		for Column = 2, Columns do
			if (Widths[Column] > Widths[Widest]) then Widest = Column end
		end
		if (Widths[Widest] <= 1) then break end
		Widths[Widest] = Widths[Widest] - 1
		Total = Total - 1
	end
	local TableWidth = math.min(self.Width, Total + Columns + 1)

	local TextFg = Block.TextColor or self.Fg
	local BodyBg = Block.Color or self.Bg

	local function Emit(Row, Fg, Bg, IsHeader)
		local Wrapped = {}
		local Height = 1
		for Column = 1, Columns do
			local Cells = SpanCells(Row[Column] or {}, Fg, Bg, IsHeader and Fg or self.LinkFg)
			Wrapped[Column] = Wrap(Cells, Widths[Column])
			if (#Wrapped[Column] > Height) then Height = #Wrapped[Column] end
		end
		for Line = 1, Height do
			local Canvas = self:Row(self.Bg)
			for X = 1, TableWidth do Put(Canvas, X, { Ch = " ", Fg = Fg, Bg = Bg }) end
			local X = 2
			for Column = 1, Columns do
				local Cells = Wrapped[Column][Line] or {}
				local Offset = AlignOffset(Block.Align[Column], #Cells, Widths[Column])
				PlaceCells(Canvas, self.Regions, Cells, X + Offset, #self.Rows + 1)
				X = X + Widths[Column] + 1
			end
			self:Push(Canvas)
		end
	end

	if (Block.Header) then
		Emit(Block.Header, Block.HeaderTextColor or TextFg, Block.HeaderColor, true)
	end
	for _, Row in ipairs(Block.Rows) do
		Emit(Row, TextFg, BodyBg, false)
	end
end

function Builder:Image(Block)
	local Picture = self.Images and self.Images(Block.Src)
	if (type(Picture) ~= "table") then
		local Label = Picture == false and ("[image failed: " .. (Block.Alt or Block.Src) .. "]") or ("[" .. (Block.Alt or Block.Src) .. "]")
		local Cells = TextCells(Label:sub(1, self.Width), "7", self.Bg)
		local Canvas = self:Row()
		PlaceCells(Canvas, self.Regions, Cells, AlignOffset(Block.Align, #Cells, self.Width) + 1, #self.Rows + 1)
		self:Push(Canvas)
		return
	end
	local Width = math.min(Picture.W, self.Width)
	local Offset = AlignOffset(Block.Align, Width, self.Width)
	for _, Row in ipairs(Picture.Rows) do
		local Canvas = self:Row()
		for X = 1, Width do
			local Bg = Row[3]:sub(X, X)
			if (Bg == " ") then Bg = self.Bg end
			Put(Canvas, Offset + X, { Ch = Row[1]:sub(X, X), Fg = Row[2]:sub(X, X), Bg = Bg })
		end
		self:Push(Canvas)
	end
end

-- Text shown inside an input field.
function Layout.InputText(Input, Value)
	if (Input.Kind == "file") then
		if (type(Value) == "table") then
			local Count = 0
			for _ in pairs(Value) do Count = Count + 1 end
			return Count .. (Count == 1 and " file" or " files"), false
		end
		return Input.Placeholder or "Choose...", true
	end
	Value = tostring(Value or "")
	if (Value == "") then return Input.Placeholder or "", true end
	if (Input.Kind == "password") then return string.rep("*", #Value), false end
	return Value, false
end

function Builder:Input(Block)
	if (Block.Kind == "hidden") then return end
	local Value = self.State[Block.Id]
	if (Value == nil) then Value = Block.Value end
	local Label = Block.Label and (Block.Label .. " ") or ""
	local FieldWidth = math.min(Block.Width, self.Width)
	if (#Label + FieldWidth > self.Width) then
		if (#Label + 4 <= self.Width) then
			FieldWidth = self.Width - #Label
		else
			local Canvas = self:Row()
			PlaceCells(Canvas, self.Regions, TextCells(Block.Label:sub(1, self.Width), self.Fg, self.Bg), 1, #self.Rows + 1)
			self:Push(Canvas)
			Label = ""
		end
	end
	local Focused = self.Focus == Block.Id
	local Shown, IsPlaceholder = Layout.InputText(Block, Value)
	if (#Shown > FieldWidth) then
		Shown = Focused and Shown:sub(-FieldWidth) or Shown:sub(1, FieldWidth)
	end
	local FieldBg = Focused and "0" or Block.Color
	local FieldFg = IsPlaceholder and "7" or Block.TextColor
	local Canvas = self:Row()
	local Y = #self.Rows + 1
	PlaceCells(Canvas, self.Regions, TextCells(Label, self.Fg, self.Bg), 1, Y)
	local Field = TextCells(Shown .. string.rep(" ", FieldWidth - #Shown), FieldFg, FieldBg)
	PlaceCells(Canvas, self.Regions, Field, #Label + 1, Y)
	self.Regions[#self.Regions + 1] = { Kind = "input", Input = Block, Y = Y, X1 = #Label + 1, X2 = #Label + FieldWidth }
	self:Push(Canvas)
end

function Builder:Button(Block)
	local Text = " " .. Block.Text .. " "
	Text = Text:sub(1, self.Width)
	local Canvas = self:Row()
	local X = AlignOffset(Block.Align, #Text, self.Width) + 1
	local Y = #self.Rows + 1
	PlaceCells(Canvas, self.Regions, TextCells(Text, Block.TextColor, Block.Color), X, Y)
	self.Regions[#self.Regions + 1] = { Kind = "button", Button = Block, Href = Block.Href, Y = Y, X1 = X, X2 = X + #Text - 1 }
	self:Push(Canvas)
end

function Builder:Blocks(Blocks)
	for _, Block in ipairs(Blocks) do
		if (Block.Type == "text") then self:Text(Block)
		elseif (Block.Type == "break") then self:Blank()
		elseif (Block.Type == "table") then self:Table(Block)
		elseif (Block.Type == "image") then self:Image(Block)
		elseif (Block.Type == "input") then self:Input(Block)
		elseif (Block.Type == "button") then self:Button(Block)
		elseif (Block.Type == "form") then self:Blocks(Block.Blocks)
		end
	end
end

local function BuildTopbar(Bar, Width, Height)
	local Rows, Regions = {}, {}
	local Canvas = NewCanvas(Width, Bar.TextColor, Bar.Color)
	local X = 2
	local Used = false
	local MaxRows = math.max(1, math.floor(Height / 2))
	for _, Spans in ipairs(Bar.Items) do
		local Cells = SpanCells(Spans, Bar.TextColor, Bar.Color, Bar.TextColor)
		if (Used and X + #Cells - 1 > Width) then
			if (#Rows + 1 >= MaxRows) then break end
			Rows[#Rows + 1] = Finish(Canvas)
			Canvas = NewCanvas(Width, Bar.TextColor, Bar.Color)
			X = 2
		end
		PlaceCells(Canvas, Regions, Cells, X, #Rows + 1)
		X = X + #Cells + 2
		Used = true
	end
	Rows[#Rows + 1] = Finish(Canvas)
	return { Side = "top", Size = #Rows, Rows = Rows, Regions = Regions }
end

local function BuildSidebar(Bar, Width, Height)
	local Items = {}
	local Widest = 1
	for _, Spans in ipairs(Bar.Items) do
		local Cells = SpanCells(Spans, Bar.TextColor, Bar.Color, Bar.TextColor)
		Items[#Items + 1] = Cells
		if (#Cells > Widest) then Widest = #Cells end
	end
	local Size = Clamp(Widest + 2, 3, math.max(3, math.floor(Width / 3)))
	local Rows, Regions = {}, {}
	for Y = 1, Height do
		local Canvas = NewCanvas(Size, Bar.TextColor, Bar.Color)
		local Cells = Items[Y - 1]
		if (Cells) then PlaceCells(Canvas, Regions, Slice(Cells, 1, math.min(#Cells, Size - 2)), 2, Y) end
		Rows[Y] = Finish(Canvas)
	end
	return { Side = "left", Size = Size, Rows = Rows, Regions = Regions }
end

-- Builds a page for an area Width x Height.
-- Options: Images = function(Src) -> image | false (failed) | nil (not loaded), State = { [InputId] = value }, Focus = InputId.
function Layout.Build(Doc, Width, Height, Options)
	Options = Options or {}
	local Page = { Doc = Doc, Width = Width, Height = Height, ViewX = 1, ViewY = 1, ViewW = Width, ViewH = Height }
	if (Doc.Topbar) then
		if (Doc.Topbar.Layout == "vertical") then
			Page.Bar = BuildSidebar(Doc.Topbar, Width, Height)
			Page.ViewX = Page.Bar.Size + 1
			Page.ViewW = Width - Page.Bar.Size
		else
			Page.Bar = BuildTopbar(Doc.Topbar, Width, Height)
			Page.ViewY = Page.Bar.Size + 1
			Page.ViewH = Height - Page.Bar.Size
		end
	end
	local Build = setmetatable({
		Width = math.max(1, Page.ViewW),
		Fg = Doc.TextColor or Ccmd.Defaults.TextColor,
		Bg = Doc.Background or Ccmd.Defaults.Background,
		LinkFg = Doc.LinkColor or Ccmd.Defaults.LinkColor,
		Images = Options.Images,
		State = Options.State or {},
		Focus = Options.Focus,
		Rows = {},
		Regions = {}
	}, Builder)
	Build:Blocks(Doc.Blocks)
	Page.Rows = Build.Rows
	Page.Regions = Build.Regions
	Page.Background = Build.Bg
	Page.MaxScroll = math.max(0, #Build.Rows - Page.ViewH)
	return Page
end

-- Draws the page on a terminal-like target (usually a window the size of the page area).
function Layout.Draw(Page, Target, Scroll)
	Scroll = Clamp(Scroll or 0, 0, Page.MaxScroll)
	local Blank = { string.rep(" ", Page.ViewW), string.rep("0", Page.ViewW), string.rep(Page.Background, Page.ViewW) }
	for Y = 1, Page.ViewH do
		local Row = Page.Rows[Scroll + Y] or Blank
		Target.setCursorPos(Page.ViewX, Page.ViewY + Y - 1)
		Target.blit(Row[1], Row[2], Row[3])
	end
	if (Page.Bar) then
		for Index, Row in ipairs(Page.Bar.Rows) do
			Target.setCursorPos(1, Index)
			Target.blit(Row[1], Row[2], Row[3])
		end
	end
end

-- Returns the region under page-area coordinates X, Y.
function Layout.Hit(Page, X, Y, Scroll)
	if (Page.Bar) then
		for _, Region in ipairs(Page.Bar.Regions) do
			if (Region.Y == Y and X >= Region.X1 and X <= Region.X2) then return Region end
		end
	end
	if (X < Page.ViewX or Y < Page.ViewY or Y >= Page.ViewY + Page.ViewH) then return nil end
	local CX = X - Page.ViewX + 1
	local CY = Y - Page.ViewY + 1 + (Scroll or 0)
	for _, Region in ipairs(Page.Regions) do
		if (Region.Y == CY and CX >= Region.X1 and CX <= Region.X2) then return Region end
	end
	return nil
end

-- Returns page-area coordinates of a region, or nil when it is scrolled out of view.
function Layout.RegionPosition(Page, Region, Scroll)
	local Y = Region.Y - (Scroll or 0) + Page.ViewY - 1
	if (Y < Page.ViewY or Y >= Page.ViewY + Page.ViewH) then return nil end
	return Region.X1 + Page.ViewX - 1, Y
end

-- Scroll needed so a content row is visible.
function Layout.ScrollTo(Page, Row, Scroll)
	if (Row <= Scroll) then return Clamp(Row - 1, 0, Page.MaxScroll) end
	if (Row > Scroll + Page.ViewH) then return Clamp(Row - Page.ViewH, 0, Page.MaxScroll) end
	return Scroll
end

-- Finds the region of an input by its Id.
function Layout.InputRegion(Page, Id)
	for _, Region in ipairs(Page.Regions) do
		if (Region.Kind == "input" and Region.Input.Id == Id) then return Region end
	end
	return nil
end

return Layout
]]
Files["blockos/lib/ccinternet/protocol.lua"] = [[
-- ccinternet wire protocol: URLs, a safe data encoding, chunked rednet messages and a client helper.
-- Vendored from https://github.com/tamayaren/ccinternet (lib/protocol.lua), shared by Savannah and CCDream.

local Protocol = {}

Protocol.Name = "ccinternet"        -- rednet protocol
Protocol.DefaultHost = "ccinternet" -- hostname browsers look up by default
Protocol.Version = 1
Protocol.ChunkSize = 16384
Protocol.MaxParts = 64              -- 1 MB per message
Protocol.MaxPending = 32
Protocol.PendingTimeout = 30

Protocol.StatusText = {
	[200] = "OK", [301] = "Moved Permanently", [302] = "Found", [303] = "See Other",
	[400] = "Bad Request", [403] = "Forbidden", [404] = "Not Found", [405] = "Method Not Allowed",
	[409] = "Conflict", [413] = "Too Large", [429] = "Too Many Requests",
	[500] = "Server Error", [503] = "Unavailable", [507] = "Out of Space"
}

Protocol.ContentTypes = {
	ccmd = "text/ccmd", txt = "text/plain", lua = "text/plain", md = "text/plain",
	nft = "image/nft", bimg = "image/bimg", nfp = "image/nfp"
}

function Protocol.ContentType(Path)
	local Extension = (tostring(Path):match("%.(%w+)$") or ""):lower()
	return Protocol.ContentTypes[Extension] or "application/octet-stream"
end

------------------------------------------------------------------------
-- URLs
------------------------------------------------------------------------

function Protocol.Escape(Text)
	return (tostring(Text):gsub("[^%w%-%._~/]", function(Char)
		return string.format("%%%02X", Char:byte())
	end))
end

function Protocol.Unescape(Text)
	return (tostring(Text):gsub("+", " "):gsub("%%(%x%x)", function(Hex)
		return string.char(tonumber(Hex, 16))
	end))
end

function Protocol.EncodeQuery(Params)
	local Keys = {}
	for Key in pairs(Params) do Keys[#Keys + 1] = tostring(Key) end
	table.sort(Keys)
	local Parts = {}
	for _, Key in ipairs(Keys) do
		local Value = Params[Key]
		if (type(Value) ~= "table") then
			Parts[#Parts + 1] = Protocol.Escape(Key):gsub("/", "%%2F") .. "=" .. Protocol.Escape(tostring(Value)):gsub("/", "%%2F")
		end
	end
	return table.concat(Parts, "&")
end

function Protocol.DecodeQuery(Query)
	local Params = {}
	for Pair in tostring(Query or ""):gmatch("[^&]+") do
		local Key, Value = Pair:match("^([^=]*)=?(.*)$")
		if (Key and Key ~= "") then Params[Protocol.Unescape(Key)] = Protocol.Unescape(Value) end
	end
	return Params
end

-- Collapses "." and ".." segments. Returns nil when the path escapes the root.
function Protocol.NormalizePath(Path)
	local Parts = {}
	for Segment in tostring(Path or ""):gmatch("[^/\\]+") do
		if (Segment == "..") then
			if (#Parts == 0) then return nil end
			Parts[#Parts] = nil
		elseif (Segment ~= ".") then
			Parts[#Parts + 1] = Segment
		end
	end
	return "/" .. table.concat(Parts, "/")
end

-- Parses an absolute URL, or a relative one against Base (a parsed URL).
-- Without a scheme or base, "example.com/page" is read as ccmd://example.com/page.
function Protocol.ParseUrl(Url, Base)
	Url = tostring(Url or ""):gsub("^%s+", ""):gsub("%s+$", "")
	Url = Url:gsub("#.*$", "")
	local Scheme, Rest = Url:match("^(%a[%w+%.%-]*)://(.*)$")
	local Host, Path, Query
	if (Scheme) then
		Host, Rest = Rest:match("^([^/%?]*)(.*)$")
	elseif (Base and Base.Scheme) then
		Scheme, Host = Base.Scheme, Base.Host
		if (Url:sub(1, 1) == "/") then
			Rest = Url
		elseif (Url:sub(1, 1) == "?" or Url == "") then
			Rest = Base.Path .. Url
		else
			Rest = Base.Path:gsub("[^/]*$", "") .. Url
		end
	else
		Scheme = "ccmd"
		Host, Rest = Url:match("^([^/%?]*)(.*)$")
	end
	Path, Query = Rest:match("^([^%?]*)%??(.*)$")
	Path = Protocol.NormalizePath(Protocol.Unescape((Path or ""):gsub("+", "%%2B")))
	if (not Path) then return nil, "Bad path" end
	return {
		Scheme = Scheme:lower(),
		Host = (Host or ""):lower(),
		Path = Path,
		Query = Query or "",
		Params = Protocol.DecodeQuery(Query)
	}
end

function Protocol.FormatUrl(Parsed)
	local Path = Parsed.Path or "/"
	if (Path == "/") then Path = "" end
	local Text = Parsed.Scheme .. "://" .. (Parsed.Host or "") .. Protocol.Escape(Path)
	if (Parsed.Query and Parsed.Query ~= "") then Text = Text .. "?" .. Parsed.Query end
	return Text
end

-- Builds a URL from parts, e.g. Protocol.Url("domain", "manage", "/", { domain = "x" }).
function Protocol.Url(Scheme, Host, Path, Params)
	return Protocol.FormatUrl({ Scheme = Scheme, Host = Host, Path = Path or "/", Query = Params and Protocol.EncodeQuery(Params) or "" })
end

------------------------------------------------------------------------
-- Data encoding: a small length-prefixed format for nested tables of strings, numbers and booleans.
-- Unlike textutils.unserialise it never runs code, so it is safe on input from other computers.
------------------------------------------------------------------------

local function EncodeValue(Value, Out, Depth)
	local Kind = type(Value)
	if (Kind == "string") then
		Out[#Out + 1] = "s" .. #Value .. ":" .. Value
	elseif (Kind == "number") then
		Out[#Out + 1] = "n" .. string.format("%.17g", Value) .. ";"
	elseif (Kind == "boolean") then
		Out[#Out + 1] = Value and "T" or "F"
	elseif (Kind == "table") then
		if (Depth > 16) then error("Table nested too deeply", 0) end
		Out[#Out + 1] = "{"
		for Key, Item in pairs(Value) do
			local KeyKind = type(Key)
			if ((KeyKind == "string" or KeyKind == "number") and type(Item) ~= "function") then
				EncodeValue(Key, Out, Depth + 1)
				EncodeValue(Item, Out, Depth + 1)
			end
		end
		Out[#Out + 1] = "}"
	else
		Out[#Out + 1] = "N"
	end
end

function Protocol.Encode(Value)
	local Out = {}
	EncodeValue(Value, Out, 0)
	return table.concat(Out)
end

function Protocol.Decode(Text)
	if (type(Text) ~= "string") then return nil, "Not a string" end
	local Pos = 1
	local Length = #Text

	local function Read(Depth)
		if (Depth > 17) then error("Too deep", 0) end
		local Tag = Text:sub(Pos, Pos)
		Pos = Pos + 1
		if (Tag == "s") then
			local Size, Next = Text:match("^(%d+):()", Pos)
			if (not Size) then error("Bad string", 0) end
			Size = tonumber(Size)
			if (Next + Size - 1 > Length) then error("Truncated string", 0) end
			Pos = Next + Size
			return Text:sub(Next, Next + Size - 1)
		elseif (Tag == "n") then
			local Number, Next = Text:match("^([^;]+);()", Pos)
			Number = tonumber(Number)
			if (not Number) then error("Bad number", 0) end
			Pos = Next
			return Number
		elseif (Tag == "T") then
			return true
		elseif (Tag == "F") then
			return false
		elseif (Tag == "N") then
			return nil
		elseif (Tag == "{") then
			local Result = {}
			while (true) do
				if (Pos > Length) then error("Unclosed table", 0) end
				if (Text:sub(Pos, Pos) == "}") then
					Pos = Pos + 1
					return Result
				end
				local Key = Read(Depth + 1)
				local Value = Read(Depth + 1)
				if (Key ~= nil) then Result[Key] = Value end
			end
		end
		error("Bad tag", 0)
	end

	local Ok, Value = pcall(Read, 0)
	if (not Ok) then return nil, Value end
	if (Pos <= Length) then return nil, "Trailing data" end
	return Value
end

------------------------------------------------------------------------
-- Messages
------------------------------------------------------------------------

-- Splits a request or response into rednet messages.
-- Head is a small table ({ Method, Url, Headers } or { Status, Headers }); Body is a string, a table or nil.
function Protocol.Pack(Type, Id, Head, Body)
	local Kind, Data = "nil", ""
	if (type(Body) == "string") then
		Kind, Data = "string", Body
	elseif (type(Body) == "table") then
		Kind, Data = "table", Protocol.Encode(Body)
	end
	local Parts = math.max(1, math.ceil(#Data / Protocol.ChunkSize))
	local Messages = {}
	for Part = 1, Parts do
		Messages[Part] = {
			CCI = Protocol.Version,
			Type = Type,
			Id = Id,
			Part = Part,
			Parts = Parts,
			Kind = Part == 1 and Kind or nil,
			Head = Part == 1 and Head or nil,
			Data = Data:sub((Part - 1) * Protocol.ChunkSize + 1, Part * Protocol.ChunkSize)
		}
	end
	return Messages
end

function Protocol.Send(Recipient, Type, Id, Head, Body)
	for _, Message in ipairs(Protocol.Pack(Type, Id, Head, Body)) do
		rednet.send(Recipient, Message, Protocol.Name)
	end
end

local Assembler = {}
Assembler.__index = Assembler

-- Collects message parts. Feed returns the finished message { Sender, Type, Id, Head, Body } once all parts arrived.
function Protocol.Assembler(Clock)
	return setmetatable({ Pending = {}, Count = 0, Clock = Clock or os.clock }, Assembler)
end

local function Valid(Message)
	return type(Message) == "table" and Message.CCI == Protocol.Version
		and (Message.Type == "request" or Message.Type == "response")
		and type(Message.Id) == "number" and type(Message.Part) == "number" and type(Message.Parts) == "number"
		and type(Message.Data) == "string" and Message.Parts >= 1 and Message.Parts <= Protocol.MaxParts
		and Message.Part >= 1 and Message.Part <= Message.Parts and Message.Part % 1 == 0
end

local function Finish(Sender, First, Data)
	local Body
	if (First.Kind == "string") then
		Body = Data
	elseif (First.Kind == "table") then
		Body = Protocol.Decode(Data)
	end
	return { Sender = Sender, Type = First.Type, Id = First.Id, Head = type(First.Head) == "table" and First.Head or {}, Body = Body }
end

function Assembler:Feed(Sender, Message)
	if (not Valid(Message)) then return nil end
	if (Message.Parts == 1) then return Finish(Sender, Message, Message.Data) end
	local Key = tostring(Sender) .. ":" .. Message.Type .. ":" .. Message.Id
	local Entry = self.Pending[Key]
	if (not Entry) then
		self:Prune()
		if (self.Count >= Protocol.MaxPending) then return nil end
		Entry = { Parts = {}, Received = 0, Total = Message.Parts }
		self.Pending[Key] = Entry
		self.Count = self.Count + 1
	end
	Entry.Time = self.Clock()
	if (Message.Parts ~= Entry.Total) then return nil end
	if (not Entry.Parts[Message.Part]) then
		Entry.Parts[Message.Part] = Message.Data
		Entry.Received = Entry.Received + 1
	end
	if (Message.Part == 1) then Entry.First = Message end
	if (Entry.Received < Entry.Total or not Entry.First) then return nil end
	self.Pending[Key] = nil
	self.Count = self.Count - 1
	return Finish(Sender, Entry.First, table.concat(Entry.Parts))
end

-- Progress of a pending message: received parts, total parts.
function Assembler:Progress(Sender, Type, Id)
	local Entry = self.Pending[tostring(Sender) .. ":" .. Type .. ":" .. Id]
	if (not Entry) then return 0, 0 end
	return Entry.Received, Entry.Total
end

function Assembler:Prune()
	local Now = self.Clock()
	for Key, Entry in pairs(self.Pending) do
		if (Now - Entry.Time > Protocol.PendingTimeout) then
			self.Pending[Key] = nil
			self.Count = self.Count - 1
		end
	end
end

------------------------------------------------------------------------
-- Client side
------------------------------------------------------------------------

-- Opens every attached modem for rednet. Returns how many were opened.
function Protocol.OpenModems()
	local Count = 0
	for _, Name in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Name) == "modem") then
			if (not rednet.isOpen(Name)) then pcall(rednet.open, Name) end
			if (rednet.isOpen(Name)) then Count = Count + 1 end
		end
	end
	return Count
end

local NextId = 0

-- Sends a request to a server computer and waits for the whole response.
-- Returns { Status, Headers, Body } or nil and an error message.
-- Options: Timeout (seconds without data, default 10), OnProgress(Received, Total).
function Protocol.Request(Server, Method, Url, Headers, Body, Options)
	Options = Options or {}
	NextId = NextId + 1
	local Id = (os.getComputerID() * 1000003 + NextId * 7919 + math.random(0, 999)) % 2147483647
	Protocol.Send(Server, "request", Id, { Method = Method, Url = Url, Headers = Headers or {} }, Body)
	local Collector = Protocol.Assembler()
	local Timeout = Options.Timeout or 10
	local Timer = os.startTimer(Timeout)
	while (true) do
		local Event, A, B, C = os.pullEvent()
		if (Event == "rednet_message" and A == Server and C == Protocol.Name and type(B) == "table" and B.Id == Id and B.Type == "response") then
			os.cancelTimer(Timer)
			Timer = os.startTimer(Timeout)
			local Full = Collector:Feed(A, B)
			if (Full) then
				os.cancelTimer(Timer)
				local Head = Full.Head
				return { Status = tonumber(Head.Status) or 500, Headers = type(Head.Headers) == "table" and Head.Headers or {}, Body = Full.Body }
			elseif (Options.OnProgress) then
				Options.OnProgress(Collector:Progress(A, "response", Id))
			end
		elseif (Event == "timer" and A == Timer) then
			return nil, "The server did not answer"
		end
	end
end

-- A transport sends a request and returns a response table (or nil, error).
-- This one talks to a core over rednet, looking it up by hostname the first time.
function Protocol.NetworkTransport(Hostname)
	local Transport = { Hostname = Hostname or Protocol.DefaultHost }
	function Transport.Find(Force)
		if (Transport.Server and not Force) then return Transport.Server end
		if (Protocol.OpenModems() == 0) then return nil, "No modem attached" end
		Transport.Server = rednet.lookup(Protocol.Name, Transport.Hostname)
		if (not Transport.Server) then return nil, "Could not find the server \"" .. Transport.Hostname .. "\"" end
		return Transport.Server
	end
	function Transport.Send(Method, Url, Headers, Body, Options)
		local Server, Problem = Transport.Find()
		if (not Server) then return nil, Problem end
		local Response, Error = Protocol.Request(Server, Method, Url, Headers, Body, Options)
		if (not Response) then
			-- The core may have moved or been renamed; look it up once more.
			Server = Transport.Find(true)
			if (Server) then Response, Error = Protocol.Request(Server, Method, Url, Headers, Body, Options) end
		end
		return Response, Error
	end
	return Transport
end

return Protocol
]]
Files["blockos/lib/ccinternet/site.lua"] = [[
-- Serves a folder of .ccmd pages the way a ccinternet core serves a domain, so sites can be
-- browsed and previewed before they are uploaded. Used by Savannah (local:// addresses) and CCDream.

local Ccmd = BlockOS.Require("ccinternet/ccmd")
local Protocol = BlockOS.Require("ccinternet/protocol")

local Site = {}
Site.__index = Site

Site.MaxFiles = 256
Site.MaxDepth = 8

local function ReadFile(Path)
	if (not fs.exists(Path) or fs.isDir(Path)) then return nil end
	local Handle = fs.open(Path, "rb")
	if (not Handle) then return nil end
	local Data = Handle.readAll() or ""
	Handle.close()
	return Data
end

Site.ReadFile = ReadFile

-- Builds a small .ccmd page: a coloured title, a message and optional links { { Text, Url } }.
function Site.Message(Title, Message, Colour, Links)
	local Lines = {
		"--", "title: " .. tostring(Title):gsub("\n", " "), "location: /", "--",
		"<br/>",
		"<p alignment=\"center\">",
		"{" .. (Colour or "red") .. "}" .. Ccmd.Escape(Title) .. "{/}",
		"</p>",
		"<br/>",
		"<p alignment=\"center\">",
		Ccmd.Escape(Message or ""),
		"</p>"
	}
	if (Links and #Links > 0) then
		Lines[#Lines + 1] = "<br/>"
		Lines[#Lines + 1] = "<p alignment=\"center\">"
		local Parts = {}
		for _, Link in ipairs(Links) do
			Parts[#Parts + 1] = "[" .. Ccmd.Escape(Link[1]) .. "](" .. tostring(Link[2]):gsub("[%(%)%s]", "") .. ")"
		end
		Lines[#Lines + 1] = table.concat(Parts, "   ")
		Lines[#Lines + 1] = "</p>"
	end
	return table.concat(Lines, "\n")
end

-- The folder a page belongs to: the nearest folder (the page's own, or one above it) holding a
-- page with "location: /". Falls back to the page's own folder.
function Site.FindRoot(Path)
	Path = "/" .. fs.combine(Path, "")
	local Dir = fs.isDir(Path) and Path or "/" .. fs.getDir(Path)
	local Start = Dir
	for _ = 1, Site.MaxDepth do
		if (fs.isDir(Dir)) then
			for _, Name in ipairs(fs.list(Dir)) do
				local Full = fs.combine(Dir, Name)
				if (Name:lower():match("%.ccmd$") and not fs.isDir(Full)) then
					local Meta = Ccmd.ParseFrontMatter(ReadFile(Full) or "")
					if (Meta and Meta.location and Protocol.NormalizePath(Meta.location) == "/") then
						return "/" .. fs.combine(Dir, "")
					end
				end
			end
		end
		if (Dir == "/" or Dir == "/home" or Dir == "") then break end
		Dir = "/" .. fs.getDir(Dir)
	end
	return Start
end

function Site.New(Root)
	return setmetatable({ Root = "/" .. fs.combine(Root, "") }, Site)
end

-- Every file of the site as { Path = "/sub/file.ccmd", Full = "/real/path", Size }.
function Site:Files()
	local Files = {}
	local function Walk(Dir, Prefix, Depth)
		if (Depth > Site.MaxDepth or #Files >= Site.MaxFiles) then return end
		local Names = fs.list(Dir)
		table.sort(Names, function(A, B) return A:lower() < B:lower() end)
		for _, Name in ipairs(Names) do
			local Full = fs.combine(Dir, Name)
			if (fs.isDir(Full)) then
				if (Name:sub(1, 1) ~= ".") then Walk(Full, Prefix .. Name .. "/", Depth + 1) end
			elseif (#Files < Site.MaxFiles) then
				Files[#Files + 1] = { Path = Prefix .. Name, Full = "/" .. Full, Size = fs.getSize(Full) }
			end
		end
	end
	if (fs.isDir(self.Root)) then Walk(self.Root, "/", 1) end
	return Files
end

-- Maps page locations to files by reading every page's front matter. Cached until Refresh.
-- Returns Routes ({ [location] = path }), Pages ({ Path, Location, Title, Error }) and Conflicts.
function Site:Routes()
	if (self.Cache) then return self.Cache.Routes, self.Cache.Pages, self.Cache.Conflicts end
	local Routes, Pages, Conflicts = {}, {}, {}
	for _, File in ipairs(self:Files()) do
		if (File.Path:lower():match("%.ccmd$")) then
			local Meta, _, Problem = Ccmd.ParseFrontMatter(ReadFile(File.Full) or "")
			local Info = { Path = File.Path, Full = File.Full, Title = Meta and Meta.title, Error = Problem }
			local Location = Meta and Meta.location and Protocol.NormalizePath(Meta.location)
			if (Location) then
				Info.Location = Location
				if (Routes[Location]) then
					Conflicts[#Conflicts + 1] = Location
				else
					Routes[Location] = File.Path
				end
			end
			Pages[#Pages + 1] = Info
		end
	end
	self.Cache = { Routes = Routes, Pages = Pages, Conflicts = Conflicts }
	return Routes, Pages, Conflicts
end

function Site:Refresh()
	self.Cache = nil
end

-- Real path of a site path, or nil when it would leave the site.
function Site:RealPath(Path)
	local Clean = Protocol.NormalizePath(Path)
	if (not Clean) then return nil end
	return "/" .. fs.combine(self.Root, Clean)
end

-- Site path ("/sub/page.ccmd") of a real path inside the site, or nil.
function Site:SitePath(Full)
	Full = "/" .. fs.combine(Full, "")
	local Root = self.Root == "/" and "/" or self.Root .. "/"
	if (Full == self.Root) then return "/" end
	if (Full:sub(1, #Root) ~= Root) then return nil end
	return "/" .. Full:sub(#Root + 1)
end

-- The address of a file in the site: its location for pages, else its path.
function Site:Address(Full)
	local Path = self:SitePath(Full)
	if (not Path) then return nil end
	local Meta = Ccmd.ParseFrontMatter(ReadFile(Full) or "")
	local Location = Meta and Meta.location and Protocol.NormalizePath(Meta.location)
	return Location or Path
end

-- Finds the file for a request path: a page location first, then a file path, then a folder's index.ccmd.
function Site:Resolve(Path)
	local Routes = self:Routes()
	local Clean = Protocol.NormalizePath(Path)
	if (not Clean) then return nil end
	if (Routes[Clean]) then return Routes[Clean] end
	local Real = self:RealPath(Clean)
	if (Real and fs.exists(Real)) then
		if (not fs.isDir(Real)) then return Clean end
		local Index = (Clean == "/" and "" or Clean) .. "/index.ccmd"
		if (fs.exists(self:RealPath(Index))) then return Index end
	end
	return nil
end

function Site:Read(Path)
	local Real = self:RealPath(Path)
	return Real and ReadFile(Real)
end

local function Page(Status, Source)
	return { Status = Status, Headers = { ["Content-Type"] = "text/ccmd" }, Body = Source }
end

-- Answers a request like a core would. Url is a parsed URL; Base is the address prefix
-- ("local://mysite") used in generated links.
function Site:Request(Method, Url, Body, Base)
	Base = Base or ""
	if (Method == "POST") then
		return Page(200, Site.Message("Sent!", "This is a local preview, so the form was not sent anywhere. Upload the site to a ccinternet core to receive form submissions.", "lime", { { "Back to the site", Base .. "/" } }))
	end
	local File = self:Resolve(Url.Path)
	local Data = File and self:Read(File)
	if (not Data) then
		local Missing = self:Resolve("/404")
		local Custom = Missing and self:Read(Missing)
		if (Custom) then return Page(404, Custom) end
		return Page(404, Site.Message("Page not found", Url.Path .. " is not a page or file of this site.\n\nPages get their address from the location line of their front matter.", "red", { { "Home page", Base .. "/" } }))
	end
	return { Status = 200, Headers = { ["Content-Type"] = Protocol.ContentType(File), ["Content-Length"] = #Data }, Body = Data }
end

return Site
]]
Files["blockos/lib/chat.lua"] = [[
-- Messages backend: rooms over rednet with optional shared-key encryption.
-- Encrypted rooms use a SHA-256 keystream with an HMAC tag; wrong keys are dropped silently.

local Config = BlockOS.Require("config")
local Sha256 = BlockOS.Require("sha256")

local Chat = {}

Chat.Protocol = "blockos_chat"
Chat.HistoryLimit = 150
Chat.Loaded = false
Chat.Nick = nil
Chat.Rooms = {}
Chat.Order = {}
Chat.Seen = {}

local DataPath = "/blockos/data/chat.dat"

local function ToHex(Text)
	return (Text:gsub(".", function(Char) return string.format("%02x", Char:byte()) end))
end

local function FromHex(Text)
	return (Text:gsub("%x%x", function(Pair) return string.char(tonumber(Pair, 16)) end))
end

local function RandomHex(Length)
	local Parts = {}
	for Index = 1, Length do
		Parts[Index] = string.format("%x", math.random(0, 15))
	end
	return table.concat(Parts)
end

local function Keystream(Key, Nonce, Length)
	local Blocks = {}
	local Counter = 0
	local Total = 0
	while (Total < Length) do
		local Block = Sha256.Digest(Key .. Nonce .. Counter)
		table.insert(Blocks, Block)
		Total = Total + #Block
		Counter = Counter + 1
	end
	return table.concat(Blocks):sub(1, Length)
end

local function Xor(Text, Stream)
	local Out = {}
	for Index = 1, #Text do
		Out[Index] = string.char(bit32.bxor(Text:byte(Index), Stream:byte(Index)))
	end
	return table.concat(Out)
end

function Chat.RoomID(Name)
	return Sha256.Hex("blockos-room:" .. Name:lower()):sub(1, 16)
end

local function RoomKey(Room)
	if (not Room.Key or Room.Key == "") then return nil end
	if (not Room.KeyBytes) then
		Room.KeyBytes = Sha256.Digest(Room.Key .. ":" .. Room.Name:lower())
	end
	return Room.KeyBytes
end

local function Seal(Room, Payload)
	local Text = textutils.serialise(Payload)
	local Key = RoomKey(Room)
	if (not Key) then
		return { Plain = Text }
	end
	local Nonce = RandomHex(16)
	local Cipher = Xor(Text, Keystream(Key, Nonce, #Text))
	return {
		Nonce = Nonce,
		Body = ToHex(Cipher),
		Tag = ToHex(Sha256.Hmac(Key, Nonce .. Cipher):sub(1, 8))
	}
end

local function Open(Room, Packet)
	local Key = RoomKey(Room)
	local Text
	if (Key) then
		if (type(Packet.Body) ~= "string" or type(Packet.Nonce) ~= "string" or type(Packet.Tag) ~= "string") then return nil end
		local Cipher = FromHex(Packet.Body)
		if (ToHex(Sha256.Hmac(Key, Packet.Nonce .. Cipher):sub(1, 8)) ~= Packet.Tag) then return nil end
		Text = Xor(Cipher, Keystream(Key, Packet.Nonce, #Cipher))
	else
		if (type(Packet.Plain) ~= "string") then return nil end
		Text = Packet.Plain
	end
	local Payload = textutils.unserialise(Text)
	if (type(Payload) ~= "table") then return nil end
	return Payload
end

function Chat.Load()
	if (Chat.Loaded) then return end
	Chat.Loaded = true
	local Data = Config.Read(DataPath) or {}
	Chat.Nick = Data.Nick
	Chat.Rooms = {}
	Chat.Order = {}
	for _, Saved in ipairs(Data.Rooms or {}) do
		local Room = Chat.Join(Saved.Name, Saved.Key, Saved.Target, true)
		Room.Messages = Saved.Messages or {}
	end
	if (#Chat.Order == 0) then
		Chat.Join("general", nil, nil, true)
	end
end

function Chat.Save()
	local Data = { Nick = Chat.Nick, Rooms = {} }
	for _, ID in ipairs(Chat.Order) do
		local Room = Chat.Rooms[ID]
		local Messages = {}
		for Index = math.max(1, #Room.Messages - Chat.HistoryLimit + 1), #Room.Messages do
			table.insert(Messages, Room.Messages[Index])
		end
		table.insert(Data.Rooms, { Name = Room.Name, Key = Room.Key, Target = Room.Target, Messages = Messages })
	end
	Config.Write(DataPath, Data)
end

function Chat.GetNick()
	Chat.Load()
	if (Chat.Nick) then return Chat.Nick end
	local Users = BlockOS.Require("users")
	local User = Users.Primary()
	return (User and User.Name) or os.getComputerLabel() or ("user" .. os.getComputerID())
end

function Chat.SetNick(Nick)
	Chat.Nick = Nick
	Chat.Save()
end

function Chat.Join(Name, Key, Target, Silent)
	local ID = Target and ("dm:" .. math.min(Target, os.getComputerID()) .. ":" .. math.max(Target, os.getComputerID())) or Chat.RoomID(Name)
	if (Chat.Rooms[ID]) then return Chat.Rooms[ID] end
	local Room = {
		ID = ID,
		Name = Name,
		Key = (Key ~= "" and Key) or nil,
		Target = Target,
		Messages = {},
		Users = {},
		Unread = 0
	}
	Chat.Rooms[ID] = Room
	table.insert(Chat.Order, ID)
	if (not Silent) then
		Chat.Save()
		Chat.Presence(Room)
	end
	return Room
end

function Chat.Leave(ID)
	local Room = Chat.Rooms[ID]
	if (not Room) then return end
	Chat.Transmit(Room, "leave", {})
	Chat.Rooms[ID] = nil
	for Index, Other in ipairs(Chat.Order) do
		if (Other == ID) then
			table.remove(Chat.Order, Index)
			break
		end
	end
	Chat.Save()
end

function Chat.OpenModems()
	if (not rednet) then return false end
	local Any = false
	for _, Side in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Side) == "modem") then
			if (not rednet.isOpen(Side)) then
				pcall(rednet.open, Side)
			end
			Any = true
		end
	end
	return Any
end

function Chat.Transmit(Room, Kind, Payload)
	if (not Chat.OpenModems()) then return false, "No modem attached" end
	Payload.Nick = Chat.GetNick()
	local Packet = Seal(Room, Payload)
	Packet.App = "BlockOS"
	Packet.V = 1
	Packet.Type = Kind
	Packet.Room = Room.ID
	Packet.MsgID = RandomHex(12)
	Chat.Seen[Packet.MsgID] = true
	if (Room.Target) then
		Packet.DMFrom = os.getComputerID()
		rednet.send(Room.Target, Packet, Chat.Protocol)
	else
		rednet.broadcast(Packet, Chat.Protocol)
	end
	return true
end

local function Append(Room, Message)
	table.insert(Room.Messages, Message)
	if (#Room.Messages > Chat.HistoryLimit * 2) then
		table.remove(Room.Messages, 1)
	end
end

function Chat.Send(ID, Text, Kind)
	local Room = Chat.Rooms[ID]
	if (not Room) then return false, "Unknown room" end
	Kind = Kind or "msg"
	local Ok, Err = Chat.Transmit(Room, Kind, { Text = Text })
	local Message = {
		Nick = Chat.GetNick(),
		Text = Text,
		Kind = Kind,
		Time = os.epoch("utc"),
		Self = true,
		Failed = not Ok
	}
	Append(Room, Message)
	Chat.Save()
	return Ok, Err
end

function Chat.Presence(Room)
	if (Room) then
		if (not Room.Target) then Chat.Transmit(Room, "presence", {}) end
		return
	end
	for _, ID in ipairs(Chat.Order) do
		local Other = Chat.Rooms[ID]
		if (not Other.Target) then Chat.Transmit(Other, "presence", {}) end
	end
end

function Chat.OnlineUsers(Room)
	local Now = os.epoch("utc")
	local List = {}
	for Sender, Info in pairs(Room.Users) do
		if (Now - Info.Seen < 90000) then
			table.insert(List, { ID = Sender, Nick = Info.Nick })
		end
	end
	table.sort(List, function(A, B) return A.Nick:lower() < B.Nick:lower() end)
	return List
end

-- Processes a rednet packet. Returns the room and message when something should be shown.
function Chat.Receive(Sender, Packet)
	Chat.Load()
	if (type(Packet) ~= "table" or Packet.App ~= "BlockOS" or type(Packet.Room) ~= "string") then return nil end
	if (Packet.MsgID and Chat.Seen[Packet.MsgID]) then return nil end
	if (Packet.MsgID) then Chat.Seen[Packet.MsgID] = true end
	local Room = Chat.Rooms[Packet.Room]
	if (not Room and Packet.DMFrom == Sender) then
		local ID = "dm:" .. math.min(Sender, os.getComputerID()) .. ":" .. math.max(Sender, os.getComputerID())
		if (ID == Packet.Room) then
			Room = Chat.Join("@" .. Sender, nil, Sender, true)
		end
	end
	if (not Room) then return nil end
	local Payload = Open(Room, Packet)
	if (not Payload) then return nil end
	local Nick = tostring(Payload.Nick or ("#" .. Sender)):sub(1, 20)
	if (Packet.Type == "leave") then
		Room.Users[Sender] = nil
		return nil
	end
	local Known = Room.Users[Sender] ~= nil
	Room.Users[Sender] = { Nick = Nick, Seen = os.epoch("utc") }
	if (Packet.Type == "presence") then
		if (not Known) then
			Chat.Transmit(Room, "presence", {})
		end
		return nil
	end
	if (Packet.Type ~= "msg" and Packet.Type ~= "me") then return nil end
	local Message = {
		Nick = Nick,
		Text = tostring(Payload.Text or ""):sub(1, 500),
		Kind = Packet.Type,
		Time = os.epoch("utc"),
		Sender = Sender
	}
	Append(Room, Message)
	Room.Unread = Room.Unread + 1
	Chat.Save()
	return Room, Message
end

function Chat.UnreadTotal()
	local Total = 0
	for _, Room in pairs(Chat.Rooms) do
		Total = Total + Room.Unread
	end
	return Total
end

return Chat
]]
Files["blockos/lib/config.lua"] = [[
-- Persistent configuration stored as serialised Lua tables under /blockos/data.

local Config = {}

Config.DataDir = "/blockos/data"
Config.Repo = "https://raw.githubusercontent.com/tamayaren/BlockOS/main/"

Config.Defaults = {
	settings = {
		Theme = "light",
		Accent = colors.blue,
		Wallpaper = "overworld",
		WallpaperColor = colors.cyan,
		Dock = { "finder", "launchpad", "savannah", "terminal", "editor", "appstore", "messages", "notes", "btunes", "settings" },
		DockSize = "small",
		DockStyle = "solid",
		TopbarStyle = "solid",
		Animations = true,
		NetworkVisible = true,
		LockColors = "accent",
		Clock24 = true,
		ClockSource = "real",
		ShowSeconds = false,
		AutoUpdate = true,
		AutoInstall = false,
		UpdateURL = Config.Repo,
		Notifications = true,
		NotificationSound = true,
		AutoLogin = false,
		IdleLock = 0,
		StartupApps = {},
		Shortcuts = {},
		Repositories = { Config.Repo .. "store/catalog.cfg" }
	}
}

local Cache = {}

local function DeepCopy(Value)
	if (type(Value) ~= "table") then return Value end
	local Copy = {}
	for Key, Item in pairs(Value) do
		Copy[Key] = DeepCopy(Item)
	end
	return Copy
end

Config.DeepCopy = DeepCopy

function Config.Read(Path)
	if (not fs.exists(Path) or fs.isDir(Path)) then return nil end
	local Handle = fs.open(Path, "r")
	if (not Handle) then return nil end
	local Data = Handle.readAll()
	Handle.close()
	return textutils.unserialise(Data or "")
end

function Config.Write(Path, Value)
	local Dir = fs.getDir(Path)
	if (Dir ~= "" and not fs.exists(Dir)) then
		fs.makeDir(Dir)
	end
	local Handle = fs.open(Path, "w")
	if (not Handle) then return false end
	Handle.write(textutils.serialise(Value))
	Handle.close()
	return true
end

function Config.ReadText(Path)
	if (not fs.exists(Path) or fs.isDir(Path)) then return nil end
	local Handle = fs.open(Path, "r")
	if (not Handle) then return nil end
	local Data = Handle.readAll()
	Handle.close()
	return Data
end

function Config.WriteText(Path, Text)
	local Dir = fs.getDir(Path)
	if (Dir ~= "" and not fs.exists(Dir)) then
		fs.makeDir(Dir)
	end
	local Handle = fs.open(Path, "w")
	if (not Handle) then return false end
	Handle.write(Text)
	Handle.close()
	return true
end

-- Returns a cached table for Name, filling in any missing default keys.
function Config.Load(Name)
	if (Cache[Name]) then return Cache[Name] end
	local Data = Config.Read(fs.combine(Config.DataDir, Name .. ".dat")) or {}
	local Defaults = Config.Defaults[Name]
	if (Defaults) then
		for Key, Value in pairs(Defaults) do
			if (Data[Key] == nil) then
				Data[Key] = DeepCopy(Value)
			end
		end
	end
	Cache[Name] = Data
	return Data
end

function Config.Save(Name)
	local Data = Cache[Name]
	if (not Data) then return false end
	local Ok = Config.Write(fs.combine(Config.DataDir, Name .. ".dat"), Data)
	if (Name == "settings") then
		os.queueEvent("blockos_settings")
	end
	return Ok
end

function Config.Settings()
	return Config.Load("settings")
end

function Config.Reload(Name)
	Cache[Name] = nil
	return Config.Load(Name)
end

function Config.Version()
	local Version = Config.ReadText("/blockos/version.txt")
	if (not Version) then return "0.0.0" end
	return (Version:gsub("%s+", ""))
end

return Config
]]
Files["blockos/lib/gfx.lua"] = [[
-- Low-level drawing helpers shared by the window manager and apps.

local Gfx = {}

Gfx.Hex = {}
for Index = 0, 15 do
	Gfx.Hex[2 ^ Index] = string.format("%x", Index)
end

function Gfx.ToBlit(Color)
	return Gfx.Hex[Color] or "0"
end

-- Colours light enough to need black text on top of them.
Gfx.Light = {
	[colors.white] = true, [colors.lightGray] = true, [colors.yellow] = true, [colors.lime] = true,
	[colors.lightBlue] = true, [colors.pink] = true, [colors.cyan] = true, [colors.orange] = true
}

-- Black or white, whichever reads better on Bg.
function Gfx.Contrast(Bg)
	return Gfx.Light[Bg] and colors.black or colors.white
end

-- Gfx.Contrast for a single blit character.
function Gfx.ContrastBlit(Char)
	local Index = tonumber(Char, 16)
	return Gfx.ToBlit(Gfx.Contrast(Index and 2 ^ Index or colors.black))
end

function Gfx.Write(T, X, Y, Text, Fg, Bg)
	Text = tostring(Text)
	if (Fg) then T.setTextColor(Fg) end
	if (Bg) then T.setBackgroundColor(Bg) end
	T.setCursorPos(X, Y)
	T.write(Text)
end

function Gfx.Fill(T, X, Y, W, H, Bg, Fg, Char)
	if (W <= 0 or H <= 0) then return end
	Char = Char or " "
	local Row = string.rep(Char, W)
	local FgRow = string.rep(Gfx.ToBlit(Fg or colors.white), W)
	local BgRow = string.rep(Gfx.ToBlit(Bg), W)
	for Line = Y, Y + H - 1 do
		T.setCursorPos(X, Line)
		T.blit(Row, FgRow, BgRow)
	end
end

function Gfx.Truncate(Text, W)
	Text = tostring(Text)
	if (W <= 0) then return "" end
	if (#Text <= W) then return Text end
	if (W <= 2) then return Text:sub(1, W) end
	return Text:sub(1, W - 2) .. ".."
end

function Gfx.Pad(Text, W, Align)
	Text = Gfx.Truncate(Text, W)
	local Space = W - #Text
	if (Align == "center") then
		local Left = math.floor(Space / 2)
		return string.rep(" ", Left) .. Text .. string.rep(" ", Space - Left)
	elseif (Align == "right") then
		return string.rep(" ", Space) .. Text
	end
	return Text .. string.rep(" ", Space)
end

function Gfx.Center(T, Y, Text, Fg, Bg, X, W)
	if (not X) then
		X = 1
		W = T.getSize()
	end
	Text = Gfx.Truncate(Text, W)
	Gfx.Write(T, X + math.floor((W - #Text) / 2), Y, Text, Fg, Bg)
end

-- Splits text into lines no wider than W, keeping explicit newlines.
function Gfx.Wrap(Text, W)
	local Lines = {}
	W = math.max(W, 1)
	for Paragraph in (tostring(Text) .. "\n"):gmatch("(.-)\n") do
		local Line = ""
		for Word in Paragraph:gmatch("%S+") do
			while (#Word > W) do
				if (#Line > 0) then
					table.insert(Lines, Line)
					Line = ""
				end
				table.insert(Lines, Word:sub(1, W))
				Word = Word:sub(W + 1)
			end
			if (#Line == 0) then
				Line = Word
			elseif (#Line + 1 + #Word <= W) then
				Line = Line .. " " .. Word
			else
				table.insert(Lines, Line)
				Line = Word
			end
		end
		table.insert(Lines, Line)
	end
	return Lines
end

-- Draws a drop shadow to the right and below a rectangle.
function Gfx.Shadow(T, X, Y, W, H, Color)
	Color = Color or colors.gray
	Gfx.Fill(T, X + W, Y + 1, 1, H, Color)
	Gfx.Fill(T, X + 1, Y + H, W, 1, Color)
end

function Gfx.FormatSize(Bytes)
	if (Bytes >= 1048576) then
		return string.format("%.1f MB", Bytes / 1048576)
	elseif (Bytes >= 1024) then
		return string.format("%.1f KB", Bytes / 1024)
	end
	return string.format("%d B", Bytes)
end

-- 3x5 digits for large clocks.
Gfx.Font = {
	["0"] = { "###", "# #", "# #", "# #", "###" },
	["1"] = { " # ", "## ", " # ", " # ", "###" },
	["2"] = { "###", "  #", "###", "#  ", "###" },
	["3"] = { "###", "  #", " ##", "  #", "###" },
	["4"] = { "# #", "# #", "###", "  #", "  #" },
	["5"] = { "###", "#  ", "###", "  #", "###" },
	["6"] = { "###", "#  ", "###", "# #", "###" },
	["7"] = { "###", "  #", "  #", " # ", " # " },
	["8"] = { "###", "# #", "###", "# #", "###" },
	["9"] = { "###", "# #", "###", "  #", "###" },
	[":"] = { " ", "#", " ", "#", " " },
	["."] = { " ", " ", " ", " ", "#" }
}

function Gfx.BigWidth(Text)
	local Width = 0
	for Index = 1, #Text do
		local Glyph = Gfx.Font[Text:sub(Index, Index)]
		Width = Width + (Glyph and #Glyph[1] or 1) + 1
	end
	return Width - 1
end

-- Calls Plot(X, Y) for every filled cell of Text drawn in the large font.
function Gfx.EachBigCell(X, Y, Text, Plot)
	for Index = 1, #Text do
		local Glyph = Gfx.Font[Text:sub(Index, Index)]
		if (Glyph) then
			for Row = 1, 5 do
				local Line = Glyph[Row]
				for Column = 1, #Line do
					if (Line:sub(Column, Column) == "#") then
						Plot(X + Column - 1, Y + Row - 1)
					end
				end
			end
			X = X + #Glyph[1] + 1
		else
			X = X + 2
		end
	end
end

-- Scales the whole palette towards black; Level 1 restores the normal colours.
function Gfx.SetFade(T, Level)
	if (not T.setPaletteColor or not term.nativePaletteColor) then return false end
	for Index = 0, 15 do
		local Color = 2 ^ Index
		local R, G, B = term.nativePaletteColor(Color)
		T.setPaletteColor(Color, R * Level, G * Level, B * Level)
	end
	return true
end

return Gfx
]]
Files["blockos/lib/image.lua"] = [[
-- Text-mode images: .bimg (blit image, characters with text and background colours)
-- and .nfp (paintutils, background colours only). Images are { W, H, Rows = { { Text, Fg, Bg } } }.

local Image = {}

Image.Extensions = { bimg = true, nfp = true }

local function Extension(Path)
	return (tostring(Path):match("%.(%w+)$") or ""):lower()
end

function Image.IsImage(Path)
	return Image.Extensions[Extension(Path)] == true
end

local function Fit(Text, W, Filler)
	if (#Text >= W) then return Text:sub(1, W) end
	return Text .. string.rep(Filler, W - #Text)
end

function Image.new(W, H, Bg)
	local Rows = {}
	for Y = 1, H do
		Rows[Y] = { string.rep(" ", W), string.rep("f", W), string.rep(Bg or "0", W) }
	end
	return { W = W, H = H, Rows = Rows }
end

local function ParseBimg(Data)
	local Value = textutils.unserialise(Data or "")
	if (type(Value) ~= "table" or type(Value[1]) ~= "table") then return nil end
	local Frame = Value[1]
	local W = tonumber(Value.width) or 0
	local H = 0
	for _, Line in ipairs(Frame) do
		if (type(Line) ~= "table") then return nil end
		H = H + 1
		W = math.max(W, #tostring(Line[1] or ""))
	end
	if (W == 0 or H == 0) then return nil end
	local Rows = {}
	for Y, Line in ipairs(Frame) do
		Rows[Y] = {
			Fit(tostring(Line[1] or ""), W, " "),
			Fit(tostring(Line[2] or ""):lower():gsub("[^0-9a-f]", "f"), W, "f"),
			Fit(tostring(Line[3] or ""):lower():gsub("[^0-9a-f]", "0"), W, "0")
		}
	end
	return { W = W, H = H, Rows = Rows }
end

-- Transparent nfp pixels (spaces) become white.
local function ParseNfp(Data)
	local Lines = {}
	local W = 0
	for Line in ((Data or ""):gsub("\r", "") .. "\n"):gmatch("(.-)\n") do
		table.insert(Lines, Line)
		W = math.max(W, #Line)
	end
	while (#Lines > 0 and #Lines[#Lines] == 0) do
		table.remove(Lines)
	end
	if (W == 0 or #Lines == 0) then return nil end
	local Rows = {}
	for Y, Line in ipairs(Lines) do
		local Bg = Fit(Line:lower():gsub("[^0-9a-f]", "0"), W, "0")
		Rows[Y] = { string.rep(" ", W), string.rep("f", W), Bg }
	end
	return { W = W, H = #Lines, Rows = Rows }
end

function Image.Load(Path)
	if (not Path or not fs.exists(Path) or fs.isDir(Path)) then return nil, "File not found" end
	local Handle = fs.open(Path, "r")
	if (not Handle) then return nil, "Could not open file" end
	local Data = Handle.readAll()
	Handle.close()
	local Result
	if (Extension(Path) == "nfp") then
		Result = ParseNfp(Data)
	else
		Result = ParseBimg(Data)
	end
	if (not Result) then return nil, "Not a valid image" end
	return Result
end

-- .nfp keeps only background colours; everything else is written as .bimg.
function Image.Save(Path, Img, Title)
	local Text
	if (Extension(Path) == "nfp") then
		local Lines = {}
		for Y = 1, Img.H do
			Lines[Y] = Img.Rows[Y][3]
		end
		Text = table.concat(Lines, "\n")
	else
		local Frame = {}
		for Y = 1, Img.H do
			Frame[Y] = { Img.Rows[Y][1], Img.Rows[Y][2], Img.Rows[Y][3] }
		end
		Text = textutils.serialise({
			Frame,
			version = "1.0.0",
			animation = false,
			width = Img.W,
			height = Img.H,
			title = Title,
			creator = "Brocreate"
		})
	end
	local Dir = fs.getDir(Path)
	if (Dir ~= "" and not fs.exists(Dir)) then fs.makeDir(Dir) end
	local Handle = fs.open(Path, "w")
	if (not Handle) then return false end
	Handle.write(Text)
	Handle.close()
	return true
end

-- Nearest-neighbour resample to W x H blit rows.
function Image.Scale(Img, W, H)
	if (Img.W == W and Img.H == H) then return Img.Rows end
	local Rows = {}
	for Y = 1, H do
		local Source = Img.Rows[math.min(Img.H, math.floor((Y - 1) * Img.H / H) + 1)]
		local Text, Fg, Bg = {}, {}, {}
		for X = 1, W do
			local SourceX = math.min(Img.W, math.floor((X - 1) * Img.W / W) + 1)
			Text[X] = Source[1]:sub(SourceX, SourceX)
			Fg[X] = Source[2]:sub(SourceX, SourceX)
			Bg[X] = Source[3]:sub(SourceX, SourceX)
		end
		Rows[Y] = { table.concat(Text), table.concat(Fg), table.concat(Bg) }
	end
	return Rows
end

return Image
]]
Files["blockos/lib/logo.lua"] = [=[
-- The BlockOS logo: an ASCII grass block with a bite taken out of its side.

local Logo = {}

-- Each letter maps to { Char, Fg, Bg }; spaces are transparent.
local Legend = {
	G = { " ", colors.lime, colors.green },
	g = { "\"", colors.lime, colors.green },
	v = { "'", colors.lime, colors.green },
	D = { " ", colors.orange, colors.brown },
	d = { ".", colors.orange, colors.brown },
	o = { ":", colors.lightGray, colors.brown },
	x = { "'", colors.orange, colors.brown }
}

Logo.Legend = Legend

Logo.Big = {
	"GgGGGvGGGGgGGGvG",
	"GGDGGGGDGGGvG   ",
	"DdDDGDDDDdDD    ",
	"DDDoDDDxDDDD    ",
	"DdDDDDoDDDDdD   ",
	"DDDdDDDDDoDDDDdD",
	"DoDDDxDDDDDDdDDD"
}

Logo.Small = {
	"GvGGgG  ",
	"DDdDD   ",
	"DoDDxD  ",
	"DDDdDDo "
}

Logo.Text = {
	" ____  _            _     ___  ____  ",
	"| __ )| | ___   ___| | __/ _ \\/ ___| ",
	"|  _ \\| |/ _ \\ / __| |/ / | | \\___ \\ ",
	"| |_) | | (_) | (__|   <| |_| |___) |",
	"|____/|_|\\___/ \\___|_|\\_\\\\___/|____/ "
}

local Hex = {}
for Index = 0, 15 do
	Hex[2 ^ Index] = string.format("%x", Index)
end

function Logo.Size(Art)
	Art = Art or Logo.Big
	return #Art[1], #Art
end

function Logo.Draw(T, X, Y, Art)
	Art = Art or Logo.Big
	for Row, Line in ipairs(Art) do
		for Column = 1, #Line do
			local Entry = Legend[Line:sub(Column, Column)]
			if (Entry) then
				T.setCursorPos(X + Column - 1, Y + Row - 1)
				T.blit(Entry[1], Hex[Entry[2]], Hex[Entry[3]])
			end
		end
	end
end

-- Draws the logo with rows revealed up to Progress (0..1), used for intro animations.
function Logo.DrawPartial(T, X, Y, Progress, Art)
	Art = Art or Logo.Big
	local Visible = math.floor(#Art * Progress + .5)
	local Partial = {}
	for Row = #Art - Visible + 1, #Art do
		Partial[#Partial + 1] = Art[Row]
	end
	Logo.Draw(T, X, Y + #Art - Visible, Partial)
end

function Logo.DrawText(T, X, Y, Fg)
	if (Fg) then T.setTextColor(Fg) end
	for Row, Line in ipairs(Logo.Text) do
		T.setCursorPos(X, Y + Row - 1)
		T.write(Line)
	end
end

return Logo
]=]
Files["blockos/lib/presence.lua"] = [[
-- Lets BlockOS computers find each other over rednet, with GPS positions when a cluster is in range.

local Config = BlockOS.Require("config")
local Users = BlockOS.Require("users")

local Presence = {}

Presence.Protocol = "blockos_presence"
Presence.Position = nil
Presence.LocatedAt = nil

function Presence.Visible()
	return Config.Settings().NetworkVisible ~= false
end

-- Opens every modem for rednet; returns whether any modem is attached.
function Presence.OpenModems()
	if (not rednet) then return false end
	local Any = false
	for _, Side in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Side) == "modem") then
			if (not rednet.isOpen(Side)) then pcall(rednet.open, Side) end
			Any = true
		end
	end
	return Any
end

-- Asks the GPS cluster for this computer's position. Blocks for up to Timeout seconds.
function Presence.Locate(Timeout)
	if (not gps) then return nil end
	local Ok, X, Y, Z = pcall(gps.locate, Timeout or 2)
	if (Ok and X) then
		Presence.Position = { X = math.floor(X + .5), Y = math.floor(Y + .5), Z = math.floor(Z + .5) }
	else
		Presence.Position = nil
	end
	Presence.LocatedAt = os.clock()
	return Presence.Position
end

function Presence.Info()
	local User = Users.Primary()
	return {
		Type = "here",
		ID = os.getComputerID(),
		Label = os.getComputerLabel(),
		User = User and User.Name or nil,
		Version = Config.Version(),
		Turtle = turtle ~= nil,
		Position = Presence.Position
	}
end

-- Replies to a scan from another computer, unless this one is hidden.
function Presence.Answer(Sender, Message)
	if (type(Message) ~= "table" or Message.Type ~= "scan") then return false end
	if (Sender == os.getComputerID() or not Presence.Visible()) then return false end
	rednet.send(Sender, Presence.Info(), Presence.Protocol)
	return true
end

function Presence.Scan()
	if (not Presence.OpenModems()) then return false, "No modem attached" end
	rednet.broadcast({ Type = "scan" }, Presence.Protocol)
	return true
end

-- Turns a reply into a tidy record, or nil if it is not one.
function Presence.Parse(Sender, Message)
	if (type(Message) ~= "table" or Message.Type ~= "here") then return nil end
	local Position = type(Message.Position) == "table" and Message.Position or nil
	if (Position and not (tonumber(Position.X) and tonumber(Position.Y) and tonumber(Position.Z))) then
		Position = nil
	end
	return {
		ID = Sender,
		Label = type(Message.Label) == "string" and Message.Label or nil,
		User = type(Message.User) == "string" and Message.User or nil,
		Version = type(Message.Version) == "string" and Message.Version or nil,
		Turtle = Message.Turtle == true,
		Position = Position
	}
end

function Presence.Name(Entry)
	return Entry.Label or ("Computer #" .. Entry.ID)
end

local Directions = { "N", "NE", "E", "SE", "S", "SW", "W", "NW" }

-- Distance in blocks and a compass direction from one position to another (north is -Z).
function Presence.Bearing(From, To)
	local DX, DY, DZ = To.X - From.X, To.Y - From.Y, To.Z - From.Z
	local Distance = math.sqrt(DX * DX + DY * DY + DZ * DZ)
	if (DX == 0 and DZ == 0) then return Distance, "" end
	local Angle = math.deg((math.atan2 or math.atan)(DX, -DZ)) % 360
	return Distance, Directions[math.floor((Angle + 22.5) / 45) % 8 + 1]
end

return Presence
]]
Files["blockos/lib/schedule.lua"] = [[
-- Shared store for reminders and clock alarms; the desktop service fires their notifications.

local Config = BlockOS.Require("config")

local Schedule = {}

local DataPath = "/blockos/data/schedule.dat"

Schedule.Data = nil

function Schedule.Load()
	if (Schedule.Data) then return Schedule.Data end
	local Data = Config.Read(DataPath) or {}
	Data.Lists = Data.Lists or { "Personal", "Work" }
	Data.Reminders = Data.Reminders or {}
	Data.Alarms = Data.Alarms or {}
	Data.NextID = Data.NextID or 1
	Schedule.Data = Data
	return Data
end

function Schedule.Save()
	Config.Write(DataPath, Schedule.Load())
	os.queueEvent("blockos_schedule")
end

function Schedule.Now()
	return math.floor(os.epoch("local") / 1000)
end

function Schedule.AddReminder(Reminder)
	local Data = Schedule.Load()
	Reminder.ID = Data.NextID
	Data.NextID = Data.NextID + 1
	Reminder.Created = Schedule.Now()
	Reminder.Done = false
	table.insert(Data.Reminders, Reminder)
	Schedule.Save()
	return Reminder
end

function Schedule.RemoveReminder(ID)
	local Data = Schedule.Load()
	for Index, Reminder in ipairs(Data.Reminders) do
		if (Reminder.ID == ID) then
			table.remove(Data.Reminders, Index)
			break
		end
	end
	Schedule.Save()
end

function Schedule.AddAlarm(Alarm)
	local Data = Schedule.Load()
	Alarm.ID = Data.NextID
	Data.NextID = Data.NextID + 1
	Alarm.Enabled = true
	table.insert(Data.Alarms, Alarm)
	Schedule.Save()
	return Alarm
end

function Schedule.RemoveAlarm(ID)
	local Data = Schedule.Load()
	for Index, Alarm in ipairs(Data.Alarms) do
		if (Alarm.ID == ID) then
			table.remove(Data.Alarms, Index)
			break
		end
	end
	Schedule.Save()
end

-- Parses "in 10m", "in 2h", "14:30", "tomorrow 9:00", "2026-11-02 08:15" into a local timestamp.
function Schedule.ParseDue(Text)
	Text = tostring(Text or ""):lower():gsub("^%s+", ""):gsub("%s+$", "")
	if (Text == "") then return nil end
	local Now = Schedule.Now()
	local Amount, Unit = Text:match("^in%s+(%d+)%s*(%a+)$")
	if (Amount) then
		local Scale = ({ s = 1, sec = 1, m = 60, min = 60, mins = 60, h = 3600, hr = 3600, hour = 3600, hours = 3600, d = 86400, day = 86400, days = 86400 })[Unit]
		if (not Scale) then return nil end
		return Now + tonumber(Amount) * Scale
	end
	local Today = os.date("!*t", Now)
	local function At(Day, Hour, Minute)
		local Base = Now - (Today.hour * 3600 + Today.min * 60 + Today.sec)
		return Base + Day * 86400 + Hour * 3600 + Minute * 60
	end
	local Year, Month, Day, Hour, Minute = Text:match("^(%d%d%d%d)%-(%d%d?)%-(%d%d?)%s+(%d%d?):(%d%d)$")
	if (Year) then
		local Target = { year = tonumber(Year), month = tonumber(Month), day = tonumber(Day), hour = 0, min = 0, sec = 0 }
		local Midnight = os.time(Target) - os.time({ year = 1970, month = 1, day = 1, hour = 0, min = 0, sec = 0 })
		return Midnight + tonumber(Hour) * 3600 + tonumber(Minute) * 60
	end
	local Tomorrow, TimeText = Text:match("^(tomorrow)%s*(.*)$")
	if (Tomorrow) then
		local H, M = TimeText:match("^(%d%d?):(%d%d)$")
		return At(1, tonumber(H or 9), tonumber(M or 0))
	end
	local H, M, Suffix = Text:match("^(%d%d?):(%d%d)%s*([ap]?m?)$")
	if (H) then
		H = tonumber(H)
		if (Suffix == "pm" and H < 12) then H = H + 12 end
		if (Suffix == "am" and H == 12) then H = 0 end
		local Target = At(0, H, tonumber(M))
		if (Target <= Now) then Target = Target + 86400 end
		return Target
	end
	return nil
end

function Schedule.FormatDue(Stamp)
	if (not Stamp) then return "" end
	local Now = Schedule.Now()
	local Delta = Stamp - Now
	local Clock = os.date("!%H:%M", Stamp)
	if (os.date("!%Y%m%d", Stamp) == os.date("!%Y%m%d", Now)) then
		return "Today " .. Clock
	elseif (os.date("!%Y%m%d", Stamp) == os.date("!%Y%m%d", Now + 86400)) then
		return "Tomorrow " .. Clock
	elseif (Delta < 0 and Delta > -86400) then
		return "Yesterday " .. Clock
	end
	return os.date("!%b %d %H:%M", Stamp)
end

-- Returns reminders and alarms that just became due, marking them as fired.
function Schedule.CollectDue()
	local Data = Schedule.Load()
	local Now = Schedule.Now()
	local Fired = {}
	local Changed = false
	for _, Reminder in ipairs(Data.Reminders) do
		if (not Reminder.Done and Reminder.Due and not Reminder.Notified and Reminder.Due <= Now) then
			Reminder.Notified = true
			Changed = true
			table.insert(Fired, { Kind = "reminder", Item = Reminder })
		end
	end
	local GameTime = os.time()
	local Day = os.day()
	for _, Alarm in ipairs(Data.Alarms) do
		if (Alarm.Enabled) then
			if (Alarm.Source == "game") then
				local Key = Day
				if (Alarm.LastDay ~= Key and GameTime >= Alarm.Time and GameTime < Alarm.Time + .25) then
					Alarm.LastDay = Key
					Changed = true
					table.insert(Fired, { Kind = "alarm", Item = Alarm })
				end
			else
				local Key = os.date("!%Y%m%d", Now)
				local Minutes = tonumber(os.date("!%H", Now)) * 60 + tonumber(os.date("!%M", Now))
				if (Alarm.LastDay ~= Key and Minutes == Alarm.Time) then
					Alarm.LastDay = Key
					Changed = true
					table.insert(Fired, { Kind = "alarm", Item = Alarm })
				end
			end
		end
	end
	if (Changed) then Schedule.Save() end
	return Fired
end

return Schedule
]]
Files["blockos/lib/screensaver.lua"] = [=[
-- Animated ASCII plasma used behind the lock screen, with selectable colour palettes.

local Config = BlockOS.Require("config")

local Screensaver = {}

local Density = { " ", ".", ":", "-", "=", "+", "*", "#", "%", "@" }

-- Shades run from the background colour up to the brightest highlight.
Screensaver.Palettes = {
	{ ID = "accent", Name = "Accent Colour" },
	{ ID = "aurora", Name = "Aurora", Shades = { colors.black, colors.gray, colors.blue, colors.purple, colors.magenta, colors.cyan, colors.lightBlue, colors.white }, High = colors.blue },
	{ ID = "sunset", Name = "Sunset", Shades = { colors.black, colors.purple, colors.red, colors.orange, colors.yellow, colors.white }, High = colors.red },
	{ ID = "forest", Name = "Forest", Shades = { colors.black, colors.gray, colors.green, colors.lime, colors.yellow, colors.white }, High = colors.green },
	{ ID = "ocean", Name = "Ocean", Shades = { colors.black, colors.blue, colors.cyan, colors.lightBlue, colors.white }, High = colors.blue },
	{ ID = "ember", Name = "Ember", Shades = { colors.black, colors.brown, colors.red, colors.orange, colors.yellow }, High = colors.brown },
	{ ID = "mono", Name = "Monochrome", Shades = { colors.black, colors.gray, colors.lightGray, colors.white }, High = colors.gray }
}

local AccentShades = {
	[colors.blue] = { colors.black, colors.gray, colors.blue, colors.cyan, colors.lightBlue, colors.white },
	[colors.purple] = { colors.black, colors.gray, colors.purple, colors.magenta, colors.pink, colors.white },
	[colors.magenta] = { colors.black, colors.purple, colors.magenta, colors.pink, colors.white },
	[colors.red] = { colors.black, colors.brown, colors.red, colors.orange, colors.pink, colors.white },
	[colors.orange] = { colors.black, colors.brown, colors.orange, colors.yellow, colors.white },
	[colors.yellow] = { colors.black, colors.brown, colors.orange, colors.yellow, colors.white },
	[colors.green] = { colors.black, colors.gray, colors.green, colors.lime, colors.yellow, colors.white },
	[colors.cyan] = { colors.black, colors.gray, colors.cyan, colors.lightBlue, colors.white }
}

local Hex = {}
for Index = 0, 15 do
	Hex[2 ^ Index] = string.format("%x", Index)
end

-- Seconds of animation time per frame; the plasma drifts very slowly.
Screensaver.Speed = .012

function Screensaver.Get(ID)
	for _, Entry in ipairs(Screensaver.Palettes) do
		if (Entry.ID == ID) then return Entry end
	end
	return Screensaver.Palettes[1]
end

-- Returns the shade list and highlight background for a palette ID.
function Screensaver.Colours(ID)
	local Entry = Screensaver.Get(ID or Config.Settings().LockColors)
	if (Entry.Shades) then
		return Entry.Shades, Entry.High
	end
	local Accent = Config.Settings().Accent or colors.blue
	local Shades = AccentShades[Accent] or AccentShades[colors.blue]
	local High = Accent
	if (Accent == colors.yellow) then High = colors.orange end
	return Shades, High
end

-- Renders one frame into Canvas.Chars/Fg/Bg (rows of per-cell blit characters).
function Screensaver.Render(Canvas, Time, ID)
	local W, H = Canvas.W, Canvas.H
	local Shades, High = Screensaver.Colours(ID)
	local HighHex, BaseHex = Hex[High], Hex[Shades[1]]
	local Columns, Rows, Diagonal = {}, {}, {}
	for X = 1, W do
		Columns[X] = math.sin(X / 5 + Time)
	end
	for Y = 1, H do
		Rows[Y] = math.sin(Y / 2.5 - Time * .7)
	end
	for Index = 1, W + H do
		Diagonal[Index] = math.sin(Index / 7 + Time * 1.3)
	end
	for Y = 1, H do
		local Chars, Fg, Bg = Canvas.Chars[Y], Canvas.Fg[Y], Canvas.Bg[Y]
		for X = 1, W do
			local Value = (Columns[X] + Rows[Y] + Diagonal[X + Y] + 3) / 6
			local CharIndex = math.max(1, math.min(#Density, math.floor(Value * #Density) + 1))
			local ShadeIndex = math.max(1, math.min(#Shades, math.floor(Value * #Shades) + 1))
			Chars[X] = Density[CharIndex]
			Fg[X] = Hex[Shades[ShadeIndex]]
			Bg[X] = (Value > .78) and HighHex or BaseHex
		end
	end
end

function Screensaver.NewCanvas(W, H)
	local Canvas = { W = W, H = H, Chars = {}, Fg = {}, Bg = {} }
	for Y = 1, H do
		Canvas.Chars[Y], Canvas.Fg[Y], Canvas.Bg[Y] = {}, {}, {}
	end
	return Canvas
end

function Screensaver.Blit(T, Canvas, X, Y)
	X, Y = X or 1, Y or 1
	for Row = 1, Canvas.H do
		T.setCursorPos(X, Y + Row - 1)
		T.blit(table.concat(Canvas.Chars[Row]), table.concat(Canvas.Fg[Row]), table.concat(Canvas.Bg[Row]))
	end
end

return Screensaver
]=]
Files["blockos/lib/sha256.lua"] = [[
-- Pure Lua SHA-256 using the bit32 library available in CC: Tweaked.

local Band, Bor, Bxor, Bnot = bit32.band, bit32.bor, bit32.bxor, bit32.bnot
local Rrotate, Rshift = bit32.rrotate, bit32.rshift

local Sha256 = {}

local K = {
	0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
	0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
	0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
	0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
	0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
	0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
	0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
	0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
}

local function Preprocess(Message)
	local Length = #Message
	local Extra = 64 - ((Length + 9) % 64)
	if (Extra == 64) then Extra = 0 end
	local Bits = Length * 8
	local Suffix = {}
	for Index = 7, 0, -1 do
		Suffix[#Suffix + 1] = string.char(math.floor(Bits / 2 ^ (Index * 8)) % 256)
	end
	return Message .. "\128" .. string.rep("\0", Extra) .. table.concat(Suffix)
end

local function DigestBlock(Message, Start, Hash)
	local W = {}
	for Index = 0, 15 do
		local A, B, C, D = Message:byte(Start + Index * 4, Start + Index * 4 + 3)
		W[Index] = ((A * 256 + B) * 256 + C) * 256 + D
	end
	for Index = 16, 63 do
		local V0 = W[Index - 15]
		local S0 = Bxor(Rrotate(V0, 7), Rrotate(V0, 18), Rshift(V0, 3))
		local V1 = W[Index - 2]
		local S1 = Bxor(Rrotate(V1, 17), Rrotate(V1, 19), Rshift(V1, 10))
		W[Index] = Band(W[Index - 16] + S0 + W[Index - 7] + S1, 0xffffffff)
	end
	local A, B, C, D, E, F, G, H = Hash[1], Hash[2], Hash[3], Hash[4], Hash[5], Hash[6], Hash[7], Hash[8]
	for Index = 0, 63 do
		local S1 = Bxor(Rrotate(E, 6), Rrotate(E, 11), Rrotate(E, 25))
		local Ch = Bxor(Band(E, F), Band(Bnot(E), G))
		local Temp1 = H + S1 + Ch + K[Index + 1] + W[Index]
		local S0 = Bxor(Rrotate(A, 2), Rrotate(A, 13), Rrotate(A, 22))
		local Maj = Bxor(Band(A, B), Band(A, C), Band(B, C))
		local Temp2 = S0 + Maj
		H = G
		G = F
		F = E
		E = Band(D + Temp1, 0xffffffff)
		D = C
		C = B
		B = A
		A = Band(Temp1 + Temp2, 0xffffffff)
	end
	Hash[1] = Band(Hash[1] + A, 0xffffffff)
	Hash[2] = Band(Hash[2] + B, 0xffffffff)
	Hash[3] = Band(Hash[3] + C, 0xffffffff)
	Hash[4] = Band(Hash[4] + D, 0xffffffff)
	Hash[5] = Band(Hash[5] + E, 0xffffffff)
	Hash[6] = Band(Hash[6] + F, 0xffffffff)
	Hash[7] = Band(Hash[7] + G, 0xffffffff)
	Hash[8] = Band(Hash[8] + H, 0xffffffff)
end

-- Returns the raw 32-byte digest.
function Sha256.Digest(Message)
	Message = Preprocess(tostring(Message))
	local Hash = {
		0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
		0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
	}
	for Start = 1, #Message, 64 do
		DigestBlock(Message, Start, Hash)
	end
	local Bytes = {}
	for Index = 1, 8 do
		local Value = Hash[Index]
		Bytes[#Bytes + 1] = string.char(
			math.floor(Value / 16777216) % 256,
			math.floor(Value / 65536) % 256,
			math.floor(Value / 256) % 256,
			Value % 256
		)
	end
	return table.concat(Bytes)
end

function Sha256.Hex(Message)
	return (Sha256.Digest(Message):gsub(".", function(Char)
		return string.format("%02x", Char:byte())
	end))
end

function Sha256.Hmac(Key, Message)
	if (#Key > 64) then Key = Sha256.Digest(Key) end
	Key = Key .. string.rep("\0", 64 - #Key)
	local Inner = Key:gsub(".", function(Char) return string.char(Bxor(Char:byte(), 0x36)) end)
	local Outer = Key:gsub(".", function(Char) return string.char(Bxor(Char:byte(), 0x5c)) end)
	return Sha256.Digest(Outer .. Sha256.Digest(Inner .. Message))
end

return Sha256
]]
Files["blockos/lib/tasks.lua"] = [[
-- Background tasks for GUI apps. A task is a coroutine that may block on the network; the app
-- forwards every event here (before its page handles it) so the window keeps responding while
-- requests run. Each app needs its own instance: BlockOS.Load("/blockos/lib/tasks.lua").

local Tasks = { List = {} }

local function Remove(Task)
	for Index, Other in ipairs(Tasks.List) do
		if (Other == Task) then
			table.remove(Tasks.List, Index)
			return
		end
	end
end

local function Finish(Task, Ok, ...)
	Remove(Task)
	Task.Done = true
	if (Task.OnDone) then Task.OnDone(Ok, ...) end
end

local function Resume(Task, ...)
	local Result = table.pack(coroutine.resume(Task.Co, ...))
	if (Task.Done) then return end
	if (not Result[1]) then
		Finish(Task, false, Result[2])
	elseif (coroutine.status(Task.Co) == "dead") then
		Finish(Task, true, table.unpack(Result, 2, Result.n))
	else
		Task.Filter = Result[2]
	end
end

-- Starts Fn in the background. OnDone(Ok, ...) receives its results (or false and the error).
function Tasks.Spawn(Fn, OnDone)
	local Task = { Co = coroutine.create(Fn), OnDone = OnDone }
	table.insert(Tasks.List, Task)
	Resume(Task)
	return Task
end

-- Stops a task without calling its OnDone.
function Tasks.Cancel(Task)
	if (not Task or Task.Done) then return end
	Task.Done = true
	Remove(Task)
end

-- Feeds an event to waiting tasks. Returns true when any task was resumed.
function Tasks.Dispatch(Name, ...)
	if (#Tasks.List == 0 or Name == "terminate") then return false end
	local Any = false
	for _, Task in ipairs({ table.unpack(Tasks.List) }) do
		if (not Task.Done and (Task.Filter == nil or Task.Filter == Name)) then
			Resume(Task, Name, ...)
			Any = true
		end
	end
	return Any
end

function Tasks.Busy()
	return #Tasks.List > 0
end

return Tasks
]]
Files["blockos/lib/theme.lua"] = [[
-- Colour roles for light and dark appearance, resolved from settings on each call.

local Config = BlockOS.Require("config")

local Theme = {}

local Palettes = {
	light = {
		TopbarBg = colors.white,
		TopbarFg = colors.black,
		TopbarDim = colors.gray,
		DockBg = colors.lightGray,
		DockFg = colors.gray,
		WindowBg = colors.white,
		Panel = colors.lightGray,
		PanelFg = colors.black,
		Text = colors.black,
		SubText = colors.gray,
		Border = colors.lightGray,
		TitleBg = colors.lightGray,
		TitleFg = colors.black,
		TitleIdleBg = colors.lightGray,
		TitleIdleFg = colors.gray,
		InputBg = colors.lightGray,
		InputFg = colors.black,
		ButtonBg = colors.lightGray,
		ButtonFg = colors.black,
		MenuBg = colors.white,
		MenuFg = colors.black,
		MenuDim = colors.lightGray,
		Shadow = colors.gray,
		Dark = false
	},
	dark = {
		TopbarBg = colors.gray,
		TopbarFg = colors.white,
		TopbarDim = colors.lightGray,
		DockBg = colors.gray,
		DockFg = colors.lightGray,
		WindowBg = colors.black,
		Panel = colors.gray,
		PanelFg = colors.white,
		Text = colors.white,
		SubText = colors.lightGray,
		Border = colors.gray,
		TitleBg = colors.gray,
		TitleFg = colors.white,
		TitleIdleBg = colors.gray,
		TitleIdleFg = colors.lightGray,
		InputBg = colors.gray,
		InputFg = colors.white,
		ButtonBg = colors.gray,
		ButtonFg = colors.white,
		MenuBg = colors.gray,
		MenuFg = colors.white,
		MenuDim = colors.lightGray,
		Shadow = colors.black,
		Dark = true
	}
}

Theme.Accents = {
	colors.blue, colors.purple, colors.magenta, colors.red,
	colors.orange, colors.yellow, colors.green, colors.cyan
}

function Theme.Get()
	local Settings = Config.Settings()
	local Base = Palettes[Settings.Theme] or Palettes.light
	local Result = {}
	for Key, Value in pairs(Base) do
		Result[Key] = Value
	end
	Result.Accent = Settings.Accent or colors.blue
	Result.AccentFg = colors.white
	if (Result.Accent == colors.yellow or Result.Accent == colors.cyan) then
		Result.AccentFg = colors.black
	end
	Result.Close = colors.red
	Result.Minimize = colors.yellow
	Result.Zoom = colors.lime
	return Result
end

return Theme
]]
Files["blockos/lib/ui.lua"] = [=[
-- Retained-mode widget toolkit used by BlockOS apps.
-- A Page owns a buffered window; widgets are positioned in page-local coordinates.

local Gfx = BlockOS.Require("gfx")
local Theme = BlockOS.Require("theme")

local Ui = {}

Ui.Current = nil

local InputEvents = {
	mouse_click = true, mouse_drag = true, mouse_up = true, mouse_scroll = true,
	key = true, key_up = true, char = true, paste = true
}

local MouseEvents = { mouse_click = true, mouse_drag = true, mouse_up = true, mouse_scroll = true }

Ui.InputEvents = InputEvents

-- Modifier state shared by pages and dialogs, so a key released inside a dialog is not missed.
Ui.Modifiers = {}

local ModifierKeys = {
	[keys.leftCtrl] = "Ctrl", [keys.rightCtrl] = "Ctrl",
	[keys.leftShift] = "Shift", [keys.rightShift] = "Shift",
	[keys.leftAlt] = "Alt", [keys.rightAlt] = "Alt"
}

local function TrackModifiers(Name, Key)
	if ((Name == "key" or Name == "key_up") and ModifierKeys[Key]) then
		Ui.Modifiers[ModifierKeys[Key]] = Name == "key"
	end
end

local function Resolve(Value, Th, Fallback)
	if (type(Value) == "string") then
		return Th[Value] or Fallback
	end
	if (Value == nil) then return Fallback end
	return Value
end

Ui.Resolve = Resolve

local function Inside(Item, X, Y)
	return X >= Item.X and X < Item.X + Item.W and Y >= Item.Y and Y < Item.Y + Item.H
end

Ui.Inside = Inside

local function TextOf(Value)
	if (type(Value) == "function") then
		return tostring(Value())
	end
	return tostring(Value or "")
end

local function Class(Defaults)
	local NewClass = { Defaults = Defaults }
	NewClass.__index = NewClass
	function NewClass.new(Props)
		local Object = setmetatable(Props or {}, NewClass)
		for Key, Value in pairs(Defaults) do
			if (Object[Key] == nil) then
				Object[Key] = Value
			end
		end
		Object.Visible = Object.Visible ~= false
		if (Object.Init) then
			Object:Init()
		end
		return Object
	end
	return NewClass
end

--
-- Page
--

Ui.Page = {}
Ui.Page.__index = Ui.Page

function Ui.Page.new(Props)
	local Self = setmetatable(Props or {}, Ui.Page)
	Self.Parent = Self.Parent or term.current()
	Self.Widgets = {}
	Self.Intervals = {}
	Self.Dirty = true
	if (Self.X) then
		Self.Fixed = true
	else
		Self.X = 1
		Self.Y = 1
		Self.W, Self.H = Self.Parent.getSize()
	end
	Self.Buffer = window.create(Self.Parent, Self.X, Self.Y, Self.W, Self.H, false)
	return Self
end

function Ui.Page:Add(Item)
	table.insert(self.Widgets, Item)
	Item.Page = self
	self.Dirty = true
	return Item
end

function Ui.Page:Remove(Item)
	for Index, Other in ipairs(self.Widgets) do
		if (Other == Item) then
			table.remove(self.Widgets, Index)
			break
		end
	end
	if (self.Focus == Item) then self.Focus = nil end
	self.Dirty = true
end

function Ui.Page:Clear()
	self.Widgets = {}
	self.Focus = nil
	self.Captured = nil
	self.Dirty = true
end

function Ui.Page:SetFocus(Item)
	if (self.Focus == Item) then return end
	if (self.Focus and self.Focus.OnBlur) then self.Focus:OnBlur() end
	self.Focus = Item
	if (Item and Item.OnFocus) then Item:OnFocus() end
	self.Dirty = true
end

function Ui.Page:GetBg(Th)
	return Resolve(self.Bg, Th, Th.WindowBg)
end

function Ui.Page:Invalidate()
	self.Dirty = true
end

function Ui.Page:Resize()
	if (not self.Fixed) then
		self.W, self.H = self.Parent.getSize()
	end
	self.Buffer.reposition(self.X, self.Y, self.W, self.H)
	if (self.OnLayout) then
		self:OnLayout(self.W, self.H)
	end
	self.Dirty = true
end

function Ui.Page:Draw()
	local T = self.Buffer
	local Th = Theme.Get()
	T.setVisible(false)
	T.setCursorBlink(false)
	T.setBackgroundColor(self:GetBg(Th))
	T.clear()
	if (self.OnDraw) then
		self:OnDraw(T, Th)
	end
	for _, Item in ipairs(self.Widgets) do
		if (Item.Visible) then
			Item:Draw(T, Th, self)
		end
	end
	if (self.OnDrawOver) then
		self:OnDrawOver(T, Th)
	end
	local CursorX, CursorY, CursorColor
	if (self.Focus and self.Focus.Visible and self.Focus.CursorPos) then
		CursorX, CursorY, CursorColor = self.Focus:CursorPos(Th)
	end
	if (self.CursorOverride) then
		CursorX, CursorY, CursorColor = self:CursorOverride(Th)
	end
	T.setVisible(true)
	if (CursorX) then
		T.setCursorPos(CursorX, CursorY)
		T.setTextColor(CursorColor or Th.Text)
		T.setCursorBlink(true)
	end
	self.Dirty = false
end

function Ui.Page:WidgetAt(X, Y)
	for Index = #self.Widgets, 1, -1 do
		local Item = self.Widgets[Index]
		if (Item.Visible and Item.Event and Inside(Item, X, Y)) then
			return Item
		end
	end
	return nil
end

-- Routes an input event to widgets. Returns true when a widget consumed it.
function Ui.Page:Dispatch(Name, A, B, C)
	if (MouseEvents[Name]) then
		local X, Y = B - self.X + 1, C - self.Y + 1
		if (Name == "mouse_click") then
			local Item = self:WidgetAt(X, Y)
			self.Captured = Item
			if (Item and Item.Focusable) then
				self:SetFocus(Item)
			elseif (not Item or not Item.KeepFocus) then
				self:SetFocus(nil)
			end
			if (Item) then
				return Item:Event(self, Name, A, X, Y) ~= false
			end
			return false
		elseif (Name == "mouse_scroll") then
			local Item = self:WidgetAt(X, Y)
			if (Item) then
				return Item:Event(self, Name, A, X, Y) == true
			end
			return false
		end
		local Item = self.Captured
		if (Name == "mouse_up") then
			self.Captured = nil
		end
		if (Item) then
			return Item:Event(self, Name, A, X, Y) == true
		end
		return false
	end
	if (self.Focus and self.Focus.Visible and self.Focus.Event) then
		if (self.Focus:Event(self, Name, A, B, C)) then
			return true
		end
	end
	if (Name == "key" and A == keys.tab) then
		self:FocusNext()
		return true
	end
	return false
end

function Ui.Page:FocusNext()
	local Focusable = {}
	local Current = 0
	for _, Item in ipairs(self.Widgets) do
		if (Item.Visible and Item.Focusable) then
			table.insert(Focusable, Item)
			if (Item == self.Focus) then
				Current = #Focusable
			end
		end
	end
	if (#Focusable == 0) then return end
	self:SetFocus(Focusable[Current % #Focusable + 1])
end

function Ui.Page:SetInterval(Seconds, Callback)
	local Interval = { Seconds = Seconds, Callback = Callback }
	Interval.Timer = os.startTimer(Seconds)
	self.Intervals[Interval.Timer] = Interval
	return Interval
end

function Ui.Page:ClearInterval(Interval)
	if (not Interval) then return end
	self.Intervals[Interval.Timer] = nil
	os.cancelTimer(Interval.Timer)
end

-- Handles events that are not routed to widgets (timers, settings, custom events).
function Ui.Page:Background(Name, ...)
	if (Name == "timer") then
		local Id = ...
		local Interval = self.Intervals[Id]
		if (Interval) then
			self.Intervals[Id] = nil
			Interval.Timer = os.startTimer(Interval.Seconds)
			self.Intervals[Interval.Timer] = Interval
			if (Interval.Callback() ~= false) then
				self.Dirty = true
			end
			return
		end
	elseif (Name == "blockos_settings") then
		self.Dirty = true
	elseif (Name == "term_resize") then
		self:Resize()
	end
	if (self.OnEvent and self:OnEvent(Name, ...)) then
		self.Dirty = true
	end
end

function Ui.Page:Handle(Name, ...)
	TrackModifiers(Name, ...)
	if (Name == "terminate") then
		if (self.OnTerminate) then
			self:OnTerminate()
		else
			self.Running = false
		end
		return
	end
	if (InputEvents[Name]) then
		if (self:Dispatch(Name, ...)) then
			self.Dirty = true
		elseif (self.OnEvent and self:OnEvent(Name, ...)) then
			self.Dirty = true
		end
		return
	end
	self:Background(Name, ...)
end

function Ui.Page:Run()
	self.Running = true
	local Previous = Ui.Current
	Ui.Current = self
	self:Resize()
	self:Draw()
	while (self.Running) do
		local Event = table.pack(os.pullEventRaw())
		self:Handle(table.unpack(Event, 1, Event.n))
		if (self.Running and self.Dirty) then
			self:Draw()
		end
	end
	Ui.Current = Previous
end

function Ui.Page:Stop()
	self.Running = false
end

--
-- Widgets
--

Ui.Panel = Class({ X = 1, Y = 1, W = 1, H = 1, Bg = "Panel" })

function Ui.Panel:Draw(T, Th)
	Gfx.Fill(T, self.X, self.Y, self.W, self.H, Resolve(self.Bg, Th, Th.Panel))
end

Ui.Label = Class({ X = 1, Y = 1, H = 1, Text = "", Align = "left" })

function Ui.Label:Draw(T, Th, Page)
	local Text = TextOf(self.Text)
	local W = self.W or #Text
	local Bg = Resolve(self.Bg, Th, Page:GetBg(Th))
	local Fg = Resolve(self.Fg, Th, Th.Text)
	if (self.H > 1) then
		local Lines = Gfx.Wrap(Text, W)
		for Row = 1, self.H do
			Gfx.Write(T, self.X, self.Y + Row - 1, Gfx.Pad(Lines[Row] or "", W, self.Align), Fg, Bg)
		end
		return
	end
	Gfx.Write(T, self.X, self.Y, Gfx.Pad(Text, W, self.Align), Fg, Bg)
end

Ui.Button = Class({ X = 1, Y = 1, H = 1, Text = "Button", Style = "default", Enabled = true })

function Ui.Button:Init()
	self.W = self.W or #TextOf(self.Text) + 2
end

function Ui.Button:Colors(Th, Page)
	if (not self.Enabled) then
		return Th.ButtonBg, Th.SubText
	end
	if (self.Style == "primary") then
		return Resolve(self.Bg, Th, Th.Accent), Resolve(self.Fg, Th, Th.AccentFg)
	elseif (self.Style == "danger") then
		return colors.red, colors.white
	elseif (self.Style == "plain") then
		return Resolve(self.Bg, Th, Page:GetBg(Th)), Resolve(self.Fg, Th, Th.Accent)
	end
	return Resolve(self.Bg, Th, Th.ButtonBg), Resolve(self.Fg, Th, Th.ButtonFg)
end

function Ui.Button:Draw(T, Th, Page)
	local Bg, Fg = self:Colors(Th, Page)
	Gfx.Fill(T, self.X, self.Y, self.W, self.H, Bg)
	Gfx.Write(T, self.X, self.Y + math.floor((self.H - 1) / 2), Gfx.Pad(TextOf(self.Text), self.W, "center"), Fg, Bg)
end

function Ui.Button:Event(Page, Name, Button)
	if (Name == "mouse_click" and self.Enabled and self.OnClick) then
		self:OnClick(Button)
		return true
	end
	return Name == "mouse_click"
end

Ui.Input = Class({ X = 1, Y = 1, W = 10, H = 1, Value = "", Placeholder = "", Cursor = 1, Scroll = 0, Focusable = true })

function Ui.Input:Init()
	self.Value = tostring(self.Value)
	self.Cursor = #self.Value + 1
end

function Ui.Input:SetValue(Value)
	self.Value = tostring(Value or "")
	self.Cursor = #self.Value + 1
	self.Scroll = 0
	self.AllSelected = false
end

-- Highlights the whole value so the next typed text replaces it.
function Ui.Input:SelectAll()
	self.AllSelected = #self.Value > 0
end

function Ui.Input:ReplaceSelection()
	if (not self.AllSelected) then return end
	self.AllSelected = false
	self.Value = ""
	self.Cursor = 1
	self.Scroll = 0
end

function Ui.Input:Clamp()
	if (self.Cursor < 1) then self.Cursor = 1 end
	if (self.Cursor > #self.Value + 1) then self.Cursor = #self.Value + 1 end
	if (self.Cursor - 1 - self.Scroll >= self.W) then
		self.Scroll = self.Cursor - self.W
	end
	if (self.Cursor - 1 < self.Scroll) then
		self.Scroll = self.Cursor - 1
	end
end

function Ui.Input:Draw(T, Th, Page)
	self:Clamp()
	local Bg = Resolve(self.Bg, Th, Th.InputBg)
	local Fg = Resolve(self.Fg, Th, Th.InputFg)
	local Display = self.Value
	if (self.Mask) then
		Display = string.rep(self.Mask, #self.Value)
	end
	if (#Display == 0 and Page.Focus ~= self) then
		Gfx.Write(T, self.X, self.Y, Gfx.Pad(self.Placeholder, self.W), Th.SubText, Bg)
		return
	end
	local Visible = Display:sub(self.Scroll + 1, self.Scroll + self.W)
	Gfx.Write(T, self.X, self.Y, Gfx.Pad(Visible, self.W), Fg, Bg)
	if (self.AllSelected and Page.Focus == self) then
		Gfx.Write(T, self.X, self.Y, Visible, Th.AccentFg, Th.Accent)
	end
end

function Ui.Input:CursorPos(Th)
	self:Clamp()
	return self.X + self.Cursor - 1 - self.Scroll, self.Y, Resolve(self.Fg, Th, Th.InputFg)
end

function Ui.Input:Insert(Text)
	if (self.MaxLength and #self.Value + #Text > self.MaxLength) then
		Text = Text:sub(1, math.max(self.MaxLength - #self.Value, 0))
	end
	if (#Text == 0) then return end
	self.Value = self.Value:sub(1, self.Cursor - 1) .. Text .. self.Value:sub(self.Cursor)
	self.Cursor = self.Cursor + #Text
	if (self.OnChange) then self:OnChange(self.Value) end
end

function Ui.Input:Event(Page, Name, A, X)
	if (Name == "mouse_click") then
		self.AllSelected = false
		self.Cursor = X - self.X + self.Scroll + 1
		self:Clamp()
		return true
	elseif (Name == "char") then
		self:ReplaceSelection()
		self:Insert(A)
		return true
	elseif (Name == "paste") then
		self:ReplaceSelection()
		self:Insert((A:gsub("[\r\n]", "")))
		return true
	elseif (Name == "key") then
		-- Shift, Ctrl and Alt alone keep the selection, so a capital letter still replaces it.
		if (ModifierKeys[A]) then return false end
		if (self.AllSelected and (A == keys.backspace or A == keys.delete)) then
			self:ReplaceSelection()
			if (self.OnChange) then self:OnChange(self.Value) end
			return true
		elseif (A ~= keys.enter and A ~= keys.numPadEnter and A ~= keys.tab) then
			self.AllSelected = false
		end
		if (A == keys.backspace) then
			if (self.Cursor > 1) then
				self.Value = self.Value:sub(1, self.Cursor - 2) .. self.Value:sub(self.Cursor)
				self.Cursor = self.Cursor - 1
				if (self.OnChange) then self:OnChange(self.Value) end
			end
		elseif (A == keys.delete) then
			self.Value = self.Value:sub(1, self.Cursor - 1) .. self.Value:sub(self.Cursor + 1)
			if (self.OnChange) then self:OnChange(self.Value) end
		elseif (A == keys.left) then
			self.Cursor = self.Cursor - 1
		elseif (A == keys.right) then
			self.Cursor = self.Cursor + 1
		elseif (A == keys.home) then
			self.Cursor = 1
		elseif (A == keys["end"]) then
			self.Cursor = #self.Value + 1
		elseif (A == keys.enter or A == keys.numPadEnter) then
			if (self.OnSubmit) then self:OnSubmit(self.Value) end
		else
			return false
		end
		self:Clamp()
		return true
	end
	return false
end

Ui.List = Class({ X = 1, Y = 1, W = 10, H = 5, Selected = 0, Scroll = 0, Focusable = true })

function Ui.List:Init()
	self.Items = self.Items or {}
end

function Ui.List:SetItems(Items, KeepSelection)
	self.Items = Items
	if (not KeepSelection) then
		self.Selected = 0
		self.Scroll = 0
	end
	if (self.Selected > #Items) then self.Selected = #Items end
	self:EnsureVisible()
end

function Ui.List:EnsureVisible()
	local MaxScroll = math.max(#self.Items - self.H, 0)
	if (self.Selected > 0) then
		if (self.Selected <= self.Scroll) then
			self.Scroll = self.Selected - 1
		elseif (self.Selected > self.Scroll + self.H) then
			self.Scroll = self.Selected - self.H
		end
	end
	self.Scroll = math.max(0, math.min(self.Scroll, MaxScroll))
end

function Ui.List:Draw(T, Th, Page)
	local Bg = Resolve(self.Bg, Th, Page:GetBg(Th))
	local Fg = Resolve(self.Fg, Th, Th.Text)
	local Overflow = #self.Items > self.H
	local TextW = Overflow and self.W - 1 or self.W
	for Row = 1, self.H do
		local Index = Row + self.Scroll
		local Item = self.Items[Index]
		local Y = self.Y + Row - 1
		local RowBg, RowFg, SubFg = Bg, Fg, Th.SubText
		if (Item and Index == self.Selected) then
			RowBg = Th.Accent
			RowFg = Th.AccentFg
			SubFg = Th.AccentFg
		end
		Gfx.Fill(T, self.X, Y, TextW, 1, RowBg)
		if (Item) then
			if (self.RenderItem) then
				self:RenderItem(T, Th, Item, self.X, Y, TextW, Index == self.Selected, RowBg, RowFg)
			else
				local X = self.X
				if (Item.Icon) then
					Gfx.Write(T, X, Y, Item.Icon, (Index == self.Selected) and RowFg or Resolve(Item.IconFg, Th, RowFg), RowBg)
					X = X + #Item.Icon + 1
				end
				local Right = Item.Right and tostring(Item.Right) or ""
				local Space = self.X + TextW - X - (#Right > 0 and #Right + 1 or 0)
				Gfx.Write(T, X, Y, Gfx.Truncate(Item.Text or "", Space), (Index == self.Selected) and RowFg or Resolve(Item.Fg, Th, RowFg), RowBg)
				if (#Right > 0) then
					Gfx.Write(T, self.X + TextW - #Right, Y, Right, SubFg, RowBg)
				end
			end
		end
	end
	if (Overflow) then
		local Track = self.H
		local Thumb = math.max(1, math.floor(Track * self.H / #self.Items))
		local MaxScroll = #self.Items - self.H
		local ThumbY = math.floor((Track - Thumb) * self.Scroll / MaxScroll + .5)
		Gfx.Fill(T, self.X + self.W - 1, self.Y, 1, Track, Th.Border)
		Gfx.Fill(T, self.X + self.W - 1, self.Y + ThumbY, 1, Thumb, Th.SubText)
	end
end

function Ui.List:Select(Index)
	if (Index < 1 or Index > #self.Items) then return end
	self.Selected = Index
	self:EnsureVisible()
	if (self.OnSelect) then self:OnSelect(Index, self.Items[Index]) end
end

function Ui.List:Event(Page, Name, A, X, Y)
	if (Name == "mouse_click") then
		local Index = Y - self.Y + 1 + self.Scroll
		local Item = self.Items[Index]
		if (not Item) then
			if (A == 2 and self.OnContext) then self:OnContext(nil, nil, X, Y) end
			return true
		end
		local Now = os.clock()
		local Double = (self.LastClick == Index and Now - (self.LastTime or 0) < .5)
		self.LastClick = Index
		self.LastTime = Now
		if (Index ~= self.Selected) then
			self:Select(Index)
		end
		if (A == 2) then
			if (self.OnContext) then self:OnContext(Index, Item, X, Y) end
		elseif (Double or self.SingleClick) then
			self.LastClick = nil
			if (self.OnActivate) then self:OnActivate(Index, Item) end
		end
		return true
	elseif (Name == "mouse_scroll") then
		self.Scroll = math.max(0, math.min(self.Scroll + A, math.max(#self.Items - self.H, 0)))
		return true
	elseif (Name == "key") then
		if (A == keys.up) then
			self:Select(math.max(1, self.Selected - 1))
		elseif (A == keys.down) then
			self:Select(math.min(#self.Items, self.Selected + 1))
		elseif (A == keys.pageUp) then
			self:Select(math.max(1, self.Selected - self.H))
		elseif (A == keys.pageDown) then
			self:Select(math.min(#self.Items, self.Selected + self.H))
		elseif (A == keys.home) then
			self:Select(1)
		elseif (A == keys["end"]) then
			self:Select(#self.Items)
		elseif ((A == keys.enter or A == keys.numPadEnter) and self.Items[self.Selected]) then
			if (self.OnActivate) then self:OnActivate(self.Selected, self.Items[self.Selected]) end
		else
			return false
		end
		return true
	end
	return false
end

Ui.Toggle = Class({ X = 1, Y = 1, W = 4, H = 1, Value = false })

function Ui.Toggle:Draw(T, Th)
	if (self.Value) then
		Gfx.Fill(T, self.X, self.Y, 3, 1, Th.Accent)
		Gfx.Fill(T, self.X + 3, self.Y, 1, 1, colors.white)
	else
		Gfx.Fill(T, self.X, self.Y, 1, 1, colors.white)
		Gfx.Fill(T, self.X + 1, self.Y, 3, 1, Th.Dark and colors.black or colors.gray)
	end
end

function Ui.Toggle:Event(Page, Name)
	if (Name == "mouse_click") then
		self.Value = not self.Value
		if (self.OnChange) then self:OnChange(self.Value) end
		return true
	end
	return false
end

Ui.Checkbox = Class({ X = 1, Y = 1, H = 1, Value = false, Text = "" })

function Ui.Checkbox:Init()
	self.W = self.W or #self.Text + 4
end

function Ui.Checkbox:Draw(T, Th, Page)
	local Bg = Resolve(self.Bg, Th, Page:GetBg(Th))
	Gfx.Write(T, self.X, self.Y, self.Value and "[x]" or "[ ]", self.Value and Th.Accent or Th.SubText, Bg)
	Gfx.Write(T, self.X + 4, self.Y, Gfx.Truncate(self.Text, self.W - 4), Resolve(self.Fg, Th, Th.Text), Bg)
end

Ui.Checkbox.Event = Ui.Toggle.Event

Ui.Tabs = Class({ X = 1, Y = 1, W = 20, H = 1, Selected = 1 })

function Ui.Tabs:Init()
	self.Items = self.Items or {}
end

function Ui.Tabs:Draw(T, Th)
	local Count = #self.Items
	if (Count == 0) then return end
	local X = self.X
	for Index, Text in ipairs(self.Items) do
		local Width = math.floor(self.W * Index / Count) - math.floor(self.W * (Index - 1) / Count)
		local Bg = (Index == self.Selected) and Th.Accent or Th.ButtonBg
		local Fg = (Index == self.Selected) and Th.AccentFg or Th.ButtonFg
		Gfx.Write(T, X, self.Y, Gfx.Pad(Text, Width, "center"), Fg, Bg)
		X = X + Width
	end
end

function Ui.Tabs:Event(Page, Name, A, X)
	if (Name ~= "mouse_click") then return false end
	local Count = #self.Items
	local Offset = X - self.X
	for Index = 1, Count do
		if (Offset < math.floor(self.W * Index / Count)) then
			if (Index ~= self.Selected) then
				self.Selected = Index
				if (self.OnChange) then self:OnChange(Index, self.Items[Index]) end
			end
			return true
		end
	end
	return true
end

Ui.Progress = Class({ X = 1, Y = 1, W = 10, H = 1, Value = 0 })

function Ui.Progress:Draw(T, Th)
	local Value = math.max(0, math.min(1, TextOf(self.Value) + 0))
	local Filled = math.floor(self.W * Value + .5)
	Gfx.Fill(T, self.X, self.Y, self.W, self.H, Th.Border)
	Gfx.Fill(T, self.X, self.Y, Filled, self.H, Resolve(self.Color, Th, Th.Accent))
end

Ui.Canvas = Class({ X = 1, Y = 1, W = 1, H = 1 })

function Ui.Canvas:Draw(T, Th, Page)
	if (self.OnDraw) then self:OnDraw(T, Th, Page) end
end

function Ui.Canvas:Event(Page, Name, A, B, C)
	if (self.OnEvent) then
		return self:OnEvent(Name, A, B, C)
	end
	return false
end

function Ui.Canvas:CursorPos(Th)
	if (self.OnCursor) then return self:OnCursor(Th) end
	return nil
end

--
-- Modal dialogs. These block the calling coroutine but keep the
-- current page's timers and background events flowing.
--

local function AnimationsEnabled()
	local Ok, Config = pcall(BlockOS.Require, "config")
	return not (Ok and Config.Settings().Animations == false)
end

-- Grows a menu downwards over a few frames, keeping any events that arrive meanwhile.
local function Unroll(Modal, Pending)
	local FullH = Modal.H
	local Frames = 3
	for Frame = 1, Frames do
		local H = math.max(1, math.ceil(FullH * (1 - (1 - Frame / (Frames + 1)) ^ 2)))
		Modal.Buffer.reposition(Modal.X, Modal.Y, Modal.W, H)
		Modal:Draw()
		local Timer = os.startTimer(.05)
		while (true) do
			local Event = table.pack(os.pullEventRaw())
			if (Event[1] == "timer" and Event[2] == Timer) then break end
			table.insert(Pending, Event)
		end
	end
	Modal.Buffer.reposition(Modal.X, Modal.Y, Modal.W, FullH)
end

local function RunModal(Modal)
	local Previous = Ui.Current
	Ui.Current = Modal
	Modal.Running = true
	if (Modal.OnLayout) then Modal:OnLayout(Modal.W, Modal.H) end
	local Pending = {}
	if (Modal.Unroll and Modal.H > 1 and AnimationsEnabled()) then
		Unroll(Modal, Pending)
	end
	Modal:Draw()
	while (Modal.Running) do
		local Event = table.remove(Pending, 1) or table.pack(os.pullEventRaw())
		local Name = Event[1]
		TrackModifiers(Name, Event[2])
		if (Name == "terminate") then
			Modal.Running = false
		elseif (InputEvents[Name]) then
			local Outside = MouseEvents[Name] and Name == "mouse_click" and not Inside(Modal, Event[3], Event[4])
			if (Outside) then
				if (Modal.OnOutside) then Modal:OnOutside() end
			elseif (not Modal:Dispatch(table.unpack(Event, 1, Event.n)) and Modal.OnEvent) then
				Modal:OnEvent(table.unpack(Event, 1, Event.n))
			end
		elseif (Previous) then
			Previous:Background(table.unpack(Event, 1, Event.n))
			if (Previous.Dirty) then
				Previous:Draw()
			end
		end
		if (Modal.Running) then
			Modal:Draw()
		end
	end
	Modal.Buffer.setVisible(false)
	Ui.Current = Previous
	if (Previous) then
		Previous:Draw()
	end
	return Modal.Result
end

local function CreateModal(W, H, Parent)
	Parent = Parent or (Ui.Current and Ui.Current.Parent) or term.current()
	local ScreenW, ScreenH = Parent.getSize()
	W = math.min(W, ScreenW)
	H = math.min(H, ScreenH)
	local X = math.floor((ScreenW - W) / 2) + 1
	local Y = math.floor((ScreenH - H) / 2) + 1
	return Ui.Page.new({ Parent = Parent, X = X, Y = Y, W = W, H = H, Bg = "MenuBg" })
end

local function DrawModalTitle(Modal, Title)
	function Modal:OnDraw(T, Th)
		Gfx.Fill(T, 1, 1, self.W, 1, Th.TitleBg)
		Gfx.Center(T, 1, Title, Th.TitleFg, Th.TitleBg)
	end
end

-- Shows a message with buttons; returns the index of the pressed button.
function Ui.Alert(Title, Message, Buttons)
	Buttons = Buttons or { "OK" }
	local Parent = (Ui.Current and Ui.Current.Parent) or term.current()
	local ScreenW = Parent.getSize()
	local ButtonsW = 1
	for _, Text in ipairs(Buttons) do
		ButtonsW = ButtonsW + #Text + 3
	end
	local W = math.min(ScreenW - 2, math.max(26, #Title + 4, ButtonsW))
	local Lines = Gfx.Wrap(Message or "", W - 4)
	local Modal = CreateModal(W, #Lines + 5, Parent)
	DrawModalTitle(Modal, Title)
	for Index, Line in ipairs(Lines) do
		Modal:Add(Ui.Label.new({ X = 3, Y = Index + 2, W = W - 4, Text = Line, Fg = "MenuFg" }))
	end
	local X = Modal.W
	for Index = #Buttons, 1, -1 do
		local Text = Buttons[Index]
		X = X - #Text - 3
		Modal:Add(Ui.Button.new({
			X = X + 1, Y = Modal.H - 1, Text = Text,
			Style = (Index == #Buttons) and "primary" or "default",
			OnClick = function()
				Modal.Result = Index
				Modal.Running = false
			end
		}))
	end
	function Modal:OnEvent(Name, Key)
		if (Name == "key" and (Key == keys.enter or Key == keys.numPadEnter)) then
			self.Result = #Buttons
			self.Running = false
		end
	end
	return RunModal(Modal)
end

function Ui.Confirm(Title, Message, YesText, NoText)
	return Ui.Alert(Title, Message, { NoText or "Cancel", YesText or "OK" }) == 2
end

-- Asks for a line of text; returns nil when cancelled.
function Ui.Prompt(Title, Message, Default, Mask)
	local Parent = (Ui.Current and Ui.Current.Parent) or term.current()
	local ScreenW = Parent.getSize()
	local W = math.min(ScreenW - 2, 32)
	local Lines = Gfx.Wrap(Message or "", W - 4)
	local Modal = CreateModal(W, #Lines + 7, Parent)
	DrawModalTitle(Modal, Title)
	for Index, Line in ipairs(Lines) do
		Modal:Add(Ui.Label.new({ X = 3, Y = Index + 2, W = W - 4, Text = Line, Fg = "MenuFg" }))
	end
	local Field = Modal:Add(Ui.Input.new({ X = 3, Y = #Lines + 4, W = W - 4, Value = Default or "", Mask = Mask }))
	Field:SelectAll()
	Field.OnSubmit = function()
		Modal.Result = Field.Value
		Modal.Running = false
	end
	Modal:Add(Ui.Button.new({
		X = W - 14, Y = Modal.H - 1, W = 8, Text = "Cancel",
		OnClick = function()
			Modal.Result = nil
			Modal.Running = false
		end
	}))
	Modal:Add(Ui.Button.new({
		X = W - 5, Y = Modal.H - 1, W = 4, Text = "OK", Style = "primary",
		OnClick = function()
			Modal.Result = Field.Value
			Modal.Running = false
		end
	}))
	Modal:SetFocus(Field)
	return RunModal(Modal)
end

-- Picks one entry from a list; returns index and item or nil.
function Ui.Choose(Title, Items, Selected)
	local Parent = (Ui.Current and Ui.Current.Parent) or term.current()
	local ScreenW, ScreenH = Parent.getSize()
	local W = math.min(ScreenW - 2, 30)
	local H = math.min(ScreenH - 2, #Items + 5)
	local Modal = CreateModal(W, H, Parent)
	DrawModalTitle(Modal, Title)
	local Entries = {}
	for _, Item in ipairs(Items) do
		if (type(Item) == "table") then
			table.insert(Entries, Item)
		else
			table.insert(Entries, { Text = tostring(Item) })
		end
	end
	local Picker = Modal:Add(Ui.List.new({ X = 2, Y = 3, W = W - 2, H = H - 5, Items = Entries, Bg = "MenuBg" }))
	Picker.Selected = Selected or 1
	Picker:EnsureVisible()
	Picker.OnActivate = function(_, Index)
		Modal.Result = Index
		Modal.Running = false
	end
	Modal:Add(Ui.Button.new({
		X = W - 14, Y = H - 1, W = 8, Text = "Cancel",
		OnClick = function()
			Modal.Running = false
		end
	}))
	Modal:Add(Ui.Button.new({
		X = W - 5, Y = H - 1, W = 4, Text = "OK", Style = "primary",
		OnClick = function()
			if (Picker.Selected > 0) then Modal.Result = Picker.Selected end
			Modal.Running = false
		end
	}))
	Modal:SetFocus(Picker)
	local Index = RunModal(Modal)
	return Index, Index and Items[Index]
end

-- Character map of all 256 font characters. Type a key, click or use the arrows; returns the byte or nil.
function Ui.PickChar(Title, Selected)
	local Parent = (Ui.Current and Ui.Current.Parent) or term.current()
	local Modal = CreateModal(34, 13, Parent)
	DrawModalTitle(Modal, Title or "Characters")
	local Current = Selected or 65
	local LastClick = 0
	local function Finish()
		Modal.Result = Current
		Modal.Running = false
	end
	Modal:Add(Ui.Canvas.new({
		X = 2, Y = 3, W = 32, H = 8,
		OnDraw = function(Self, T, Th)
			for Row = 0, 7 do
				local Chars = {}
				for Column = 0, 31 do
					Chars[Column + 1] = string.char(Row * 32 + Column)
				end
				Gfx.Write(T, Self.X, Self.Y + Row, table.concat(Chars), Th.InputFg, Th.InputBg)
			end
			Gfx.Write(T, Self.X + Current % 32, Self.Y + math.floor(Current / 32), string.char(Current), Th.AccentFg, Th.Accent)
		end,
		OnEvent = function(Self, Name, _, X, Y)
			if (Name ~= "mouse_click" and Name ~= "mouse_drag") then return false end
			local Code = (Y - Self.Y) * 32 + (X - Self.X)
			if (Name == "mouse_click" and Code == Current and os.clock() - LastClick < .5) then
				Finish()
			end
			Current = math.max(0, math.min(255, Code))
			LastClick = os.clock()
			return true
		end
	}))
	Modal:Add(Ui.Label.new({
		X = 2, Y = 11, W = 32, Fg = "SubText",
		Text = function()
			return "Character " .. Current .. "  " .. string.char(Current)
		end
	}))
	Modal:Add(Ui.Button.new({
		X = 34 - 17, Y = 12, W = 8, Text = "Cancel",
		OnClick = function()
			Modal.Running = false
		end
	}))
	Modal:Add(Ui.Button.new({ X = 34 - 8, Y = 12, W = 8, Text = "Choose", Style = "primary", OnClick = Finish }))
	function Modal:OnEvent(Name, A)
		if (Name == "char") then
			Current = A:byte()
		elseif (Name == "key") then
			local Steps = { [keys.left] = -1, [keys.right] = 1, [keys.up] = -32, [keys.down] = 32 }
			if (Steps[A]) then
				Current = math.max(0, math.min(255, Current + Steps[A]))
			elseif (A == keys.enter or A == keys.numPadEnter) then
				Finish()
			end
		end
	end
	return RunModal(Modal)
end

-- Pops up a menu at X, Y (in parent coordinates). Items may be strings, "-" separators,
-- or { Text = ..., Disabled = true }. Returns the chosen index or nil.
function Ui.ContextMenu(X, Y, Items)
	local Parent = (Ui.Current and Ui.Current.Parent) or term.current()
	local ScreenW, ScreenH = Parent.getSize()
	local W = 4
	for _, Item in ipairs(Items) do
		local Text = type(Item) == "table" and Item.Text or Item
		W = math.max(W, #Text + 2)
	end
	local H = #Items
	X = math.max(1, math.min(X, ScreenW - W + 1))
	Y = math.max(1, math.min(Y, ScreenH - H + 1))
	local Modal = Ui.Page.new({ Parent = Parent, X = X, Y = Y, W = W, H = H, Bg = "MenuBg", Unroll = true })
	Modal.Hover = 0
	function Modal:OnDraw(T, Th)
		for Index, Item in ipairs(Items) do
			local Text = type(Item) == "table" and Item.Text or Item
			local Disabled = type(Item) == "table" and Item.Disabled
			if (Text == "-") then
				Gfx.Write(T, 1, Index, string.rep("\140", W), Th.MenuDim, Th.MenuBg)
			elseif (Index == self.Hover) then
				Gfx.Write(T, 1, Index, Gfx.Pad(" " .. Text, W), Th.AccentFg, Th.Accent)
			else
				Gfx.Write(T, 1, Index, Gfx.Pad(" " .. Text, W), Disabled and Th.MenuDim or Th.MenuFg, Th.MenuBg)
			end
		end
	end
	local function Selectable(Index)
		local Item = Items[Index]
		if (not Item) then return false end
		local Text = type(Item) == "table" and Item.Text or Item
		return Text ~= "-" and not (type(Item) == "table" and Item.Disabled)
	end
	function Modal:OnOutside()
		self.Running = false
	end
	function Modal:OnEvent(Name, A, MouseX, MouseY)
		if (Name == "mouse_click" or (Name == "mouse_up" and self.Dragged)) then
			local Index = MouseY - self.Y + 1
			if (Selectable(Index)) then
				self.Result = Index
				self.Running = false
			end
		elseif (Name == "mouse_drag") then
			local Index = MouseY - self.Y + 1
			self.Dragged = true
			if (Selectable(Index)) then self.Hover = Index end
		elseif (Name == "key") then
			if (A == keys.down or A == keys.up) then
				local Step = (A == keys.down) and 1 or -1
				for _ = 1, #Items do
					self.Hover = (self.Hover - 1 + Step) % #Items + 1
					if (Selectable(self.Hover)) then break end
				end
			elseif ((A == keys.enter or A == keys.numPadEnter) and Selectable(self.Hover)) then
				self.Result = self.Hover
				self.Running = false
			elseif (A == keys.backspace) then
				self.Running = false
			end
		end
	end
	return RunModal(Modal)
end

-- File chooser. Opts: Title, Dir, Save (ask for a file name), Extension, Folders (pick folder).
function Ui.PickFile(Opts)
	Opts = Opts or {}
	local Parent = (Ui.Current and Ui.Current.Parent) or term.current()
	local ScreenW, ScreenH = Parent.getSize()
	local W = math.min(ScreenW - 2, 40)
	local H = math.min(ScreenH - 2, 16)
	local Modal = CreateModal(W, H, Parent)
	local Dir = fs.combine(Opts.Dir or "home", "")
	if (not fs.isDir(Dir)) then Dir = "" end
	DrawModalTitle(Modal, Opts.Title or (Opts.Save and "Save As" or "Open"))
	local PathLabel = Modal:Add(Ui.Label.new({ X = 2, Y = 2, W = W - 2, Fg = "SubText" }))
	local Files = Modal:Add(Ui.List.new({ X = 2, Y = 3, W = W - 2, H = H - (Opts.Save and 6 or 5), Bg = "MenuBg" }))
	local NameField
	if (Opts.Save) then
		NameField = Modal:Add(Ui.Input.new({ X = 2, Y = H - 2, W = W - 2, Value = Opts.Name or "", Placeholder = "File name" }))
		NameField:SelectAll()
	end
	local function Refresh()
		PathLabel.Text = "/" .. Dir
		local Items = {}
		if (Dir ~= "") then
			table.insert(Items, { Text = "..", Icon = "\24", IconFg = "SubText", Up = true })
		end
		local Names = fs.list(Dir)
		table.sort(Names, function(A, B) return A:lower() < B:lower() end)
		for _, Name in ipairs(Names) do
			local Path = fs.combine(Dir, Name)
			if (fs.isDir(Path)) then
				table.insert(Items, { Text = Name, Icon = "\16", IconFg = colors.lightBlue, Path = Path, Dir = true })
			end
		end
		if (not Opts.Folders) then
			for _, Name in ipairs(Names) do
				local Path = fs.combine(Dir, Name)
				if (not fs.isDir(Path) and (not Opts.Extension or Name:sub(-#Opts.Extension) == Opts.Extension)) then
					table.insert(Items, { Text = Name, Icon = "\7", IconFg = "SubText", Path = Path })
				end
			end
		end
		Files:SetItems(Items)
	end
	local function Finish()
		if (Opts.Save) then
			if (#NameField.Value == 0) then return end
			Modal.Result = "/" .. fs.combine(Dir, NameField.Value)
		elseif (Opts.Folders) then
			Modal.Result = "/" .. Dir
		else
			local Item = Files.Items[Files.Selected]
			if (not Item or Item.Dir or Item.Up) then return end
			Modal.Result = "/" .. Item.Path
		end
		Modal.Running = false
	end
	Files.OnActivate = function(_, _, Item)
		if (Item.Up) then
			Dir = fs.getDir(Dir)
			Refresh()
		elseif (Item.Dir) then
			Dir = Item.Path
			Refresh()
		else
			Finish()
		end
	end
	Files.OnSelect = function(_, _, Item)
		if (NameField and Item and not Item.Dir and not Item.Up) then
			NameField:SetValue(fs.getName(Item.Path))
		end
	end
	if (NameField) then
		NameField.OnSubmit = Finish
	end
	Modal:Add(Ui.Button.new({
		X = W - 18, Y = H - 1, W = 8, Text = "Cancel",
		OnClick = function()
			Modal.Running = false
		end
	}))
	Modal:Add(Ui.Button.new({
		X = W - 9, Y = H - 1, W = 8, Text = Opts.Save and "Save" or (Opts.Folders and "Choose" or "Open"), Style = "primary",
		OnClick = Finish
	}))
	Refresh()
	Modal:SetFocus(NameField or Files)
	return RunModal(Modal)
end

return Ui
]=]
Files["blockos/lib/updater.lua"] = [[
-- Checks the update channel for a newer manifest and installs it in place.

local Config = BlockOS.Require("config")

local Updater = {}

Updater.State = { Status = "idle" }

local Protected = { ["blockos/data"] = true, ["blockos/userapps"] = true }

function Updater.Base()
	local Base = Config.Settings().UpdateURL or Config.Repo
	if (Base:sub(-1) ~= "/") then Base = Base .. "/" end
	return Base
end

local function ParseVersion(Version)
	local Parts = {}
	for Number in tostring(Version):gmatch("%d+") do
		table.insert(Parts, tonumber(Number))
	end
	return Parts
end

function Updater.Compare(A, B)
	local Left, Right = ParseVersion(A), ParseVersion(B)
	for Index = 1, math.max(#Left, #Right) do
		local L, R = Left[Index] or 0, Right[Index] or 0
		if (L ~= R) then
			return L < R and -1 or 1
		end
	end
	return 0
end

local function Get(Url)
	if (not http) then return nil, "HTTP is disabled" end
	local Separator = Url:find("?", 1, true) and "&" or "?"
	local Response, Err = http.get(Url .. Separator .. "t=" .. tostring(os.epoch and os.epoch("utc") or os.clock()), nil, true)
	if (not Response) then return nil, Err or "Request failed" end
	local Body = Response.readAll()
	Response.close()
	return Body
end

Updater.Get = Get

function Updater.Check()
	Updater.State.Status = "checking"
	local Body, Err = Get(Updater.Base() .. "manifest.cfg")
	if (not Body) then
		Updater.State.Status = "error"
		Updater.State.Error = Err
		return nil, Err
	end
	local Manifest = textutils.unserialise(Body)
	if (type(Manifest) ~= "table" or type(Manifest.Files) ~= "table") then
		Updater.State.Status = "error"
		Updater.State.Error = "Invalid manifest"
		return nil, "Invalid manifest"
	end
	Manifest.Newer = Updater.Compare(Config.Version(), Manifest.Version) < 0
	Updater.State.Latest = Manifest
	Updater.State.Status = Manifest.Newer and "available" or "uptodate"
	Updater.State.Checked = os.epoch and os.epoch("utc") or 0
	return Manifest
end

-- Downloads every file in the manifest to a staging folder, then swaps them in.
function Updater.Apply(Manifest, OnProgress)
	local Staging = "/blockos/.update"
	if (fs.exists(Staging)) then fs.delete(Staging) end
	Updater.State.Status = "downloading"
	local Base = Updater.Base()
	for Index, Path in ipairs(Manifest.Files) do
		local Top = Path:match("^(blockos/[^/]+)")
		if (not Protected[Top or ""]) then
			if (OnProgress) then OnProgress(Index - 1, #Manifest.Files, Path) end
			local Body, Err = Get(Base .. Path)
			if (not Body) then
				Updater.State.Status = "error"
				Updater.State.Error = Path .. ": " .. tostring(Err)
				fs.delete(Staging)
				return false, Updater.State.Error
			end
			Config.WriteText(fs.combine(Staging, Path), Body)
		end
	end
	for _, Path in ipairs(Manifest.Files) do
		local Source = fs.combine(Staging, Path)
		if (fs.exists(Source)) then
			if (fs.exists(Path)) then fs.delete(Path) end
			local Dir = fs.getDir(Path)
			if (Dir ~= "" and not fs.exists(Dir)) then fs.makeDir(Dir) end
			fs.move(Source, Path)
		end
	end
	fs.delete(Staging)
	Config.WriteText("/blockos/version.txt", Manifest.Version)
	if (OnProgress) then OnProgress(#Manifest.Files, #Manifest.Files, "") end
	Updater.State.Status = "ready"
	return true
end

return Updater
]]
Files["blockos/lib/users.lua"] = [[
-- User accounts with salted SHA-256 password hashes.

local Config = BlockOS.Require("config")
local Sha256 = BlockOS.Require("sha256")

local Users = {}

Users.Path = "/blockos/data/users.dat"
Users.Home = "/home"

local function RandomSalt()
	local Bytes = {}
	for Index = 1, 16 do
		Bytes[Index] = string.format("%02x", math.random(0, 255))
	end
	return table.concat(Bytes)
end

local function Hash(Salt, Password)
	return Sha256.Hex(Salt .. ":" .. Password)
end

function Users.Load()
	local Data = Config.Read(Users.Path)
	if (type(Data) ~= "table") then return {} end
	return Data
end

function Users.Save(List)
	return Config.Write(Users.Path, List)
end

function Users.HasAny()
	return #Users.Load() > 0
end

function Users.Primary()
	return Users.Load()[1]
end

function Users.Find(Name)
	for _, User in ipairs(Users.Load()) do
		if (User.Name == Name) then return User end
	end
	return nil
end

function Users.Create(Name, Password, Extra)
	local List = Users.Load()
	local Salt = RandomSalt()
	local User = {
		Name = Name,
		Salt = Salt,
		Hash = Hash(Salt, Password or ""),
		HasPassword = (Password or "") ~= "",
		Color = colors.blue
	}
	for Key, Value in pairs(Extra or {}) do
		User[Key] = Value
	end
	table.insert(List, User)
	Users.Save(List)
	Users.EnsureHome()
	return User
end

function Users.Update(Name, Changes)
	local List = Users.Load()
	for _, User in ipairs(List) do
		if (User.Name == Name) then
			for Key, Value in pairs(Changes) do
				User[Key] = Value
			end
			Users.Save(List)
			return User
		end
	end
	return nil
end

function Users.SetPassword(Name, Password)
	local Salt = RandomSalt()
	return Users.Update(Name, { Salt = Salt, Hash = Hash(Salt, Password), HasPassword = Password ~= "" })
end

function Users.Verify(Name, Password)
	local User = Users.Find(Name)
	if (not User) then return false end
	return Hash(User.Salt, Password or "") == User.Hash
end

function Users.EnsureHome()
	for _, Folder in ipairs({ "", "Documents", "Desktop", "Music", "Recordings", "Pictures", "Downloads" }) do
		local Path = fs.combine(Users.Home, Folder)
		if (not fs.exists(Path)) then
			fs.makeDir(Path)
		end
	end
end

return Users
]]
Files["blockos/lib/wallpaper.lua"] = [[
-- Procedural ASCII wallpapers rendered to blit rows, or a picture saved from Brocreate.

local Image = BlockOS.Require("image")

local Wallpaper = {}

Wallpaper.List = {
	{ ID = "overworld", Name = "Overworld" },
	{ ID = "night", Name = "Starry Night" },
	{ ID = "nether", Name = "Nether" },
	{ ID = "ocean", Name = "Ocean" },
	{ ID = "dusk", Name = "Dusk" },
	{ ID = "deepslate", Name = "Deepslate" },
	{ ID = "cave", Name = "Cave" },
	{ ID = "theend", Name = "The End" },
	{ ID = "grid", Name = "Grid" },
	{ ID = "solid", Name = "Solid Colour" }
}

-- Wallpapers that use the chosen colour.
Wallpaper.Coloured = { grid = true, solid = true }

-- Extra Settings entry, offered once Settings.WallpaperImage is set.
Wallpaper.Picture = { ID = "picture", Name = "Picture" }

-- Bumped when a picture file changes so cached renders are redrawn.
Wallpaper.Revision = 0

local Hex = {}
for Index = 0, 15 do
	Hex[2 ^ Index] = string.format("%x", Index)
end

local function Random(Seed)
	local State = Seed
	return function(Max)
		State = (State * 1103515245 + 12345) % 2147483648
		return State % Max
	end
end

local function NewCanvas(W, H, Bg)
	local Canvas = { W = W, H = H, Chars = {}, Fg = {}, Bg = {} }
	for Y = 1, H do
		Canvas.Chars[Y] = {}
		Canvas.Fg[Y] = {}
		Canvas.Bg[Y] = {}
		for X = 1, W do
			Canvas.Chars[Y][X] = " "
			Canvas.Fg[Y][X] = Hex[colors.white]
			Canvas.Bg[Y][X] = Hex[Bg]
		end
	end
	return Canvas
end

local function Set(Canvas, X, Y, Char, Fg, Bg)
	if (X < 1 or Y < 1 or X > Canvas.W or Y > Canvas.H) then return end
	if (Char) then Canvas.Chars[Y][X] = Char end
	if (Fg) then Canvas.Fg[Y][X] = Hex[Fg] end
	if (Bg) then Canvas.Bg[Y][X] = Hex[Bg] end
end

local function Finish(Canvas)
	local Rows = {}
	for Y = 1, Canvas.H do
		Rows[Y] = {
			table.concat(Canvas.Chars[Y]),
			table.concat(Canvas.Fg[Y]),
			table.concat(Canvas.Bg[Y])
		}
	end
	return Rows
end

local function Terrain(Canvas, Rand, Base, Amplitude, Grass, Dirt, Stone, Speck)
	local W, H = Canvas.W, Canvas.H
	local Phase = Rand(100) / 10
	for X = 1, W do
		local Height = math.floor(Base + math.sin(X / 7 + Phase) * Amplitude + math.sin(X / 3.1 + Phase * 2) * Amplitude * .4 + .5)
		for Y = Height, H do
			if (Y == Height) then
				Set(Canvas, X, Y, (Rand(4) == 0) and "\"" or " ", Speck, Grass)
			elseif (Y < Height + 3) then
				Set(Canvas, X, Y, (Rand(5) == 0) and "." or " ", colors.orange, Dirt)
			else
				Set(Canvas, X, Y, (Rand(6) == 0) and ":" or " ", colors.lightGray, Stone)
			end
		end
	end
end

local Renderers = {}

function Renderers.overworld(W, H)
	local Canvas = NewCanvas(W, H, colors.lightBlue)
	local Rand = Random(42)
	for _ = 1, math.max(2, math.floor(W / 14)) do
		local CloudX, CloudY = Rand(W) + 1, Rand(math.max(1, math.floor(H / 3))) + 2
		local Length = Rand(6) + 5
		for X = CloudX, CloudX + Length do
			Set(Canvas, X, CloudY, " ", nil, colors.white)
		end
		for X = CloudX + 2, CloudX + Length - 2 do
			Set(Canvas, X, CloudY - 1, " ", nil, colors.white)
		end
	end
	for Y = 3, 4 do
		for X = W - 8, W - 5 do
			Set(Canvas, X, Y, " ", nil, colors.yellow)
		end
	end
	Terrain(Canvas, Rand, H * .62, 2.2, colors.lime, colors.brown, colors.gray, colors.green)
	return Finish(Canvas)
end

function Renderers.night(W, H)
	local Canvas = NewCanvas(W, H, colors.black)
	local Rand = Random(7)
	for _ = 1, math.floor(W * H / 18) do
		local Star = ({ ".", ".", "+", "*", "\7" })[Rand(5) + 1]
		Set(Canvas, Rand(W) + 1, Rand(math.floor(H * .7)) + 1, Star, (Rand(3) == 0) and colors.yellow or colors.white)
	end
	for Y = 3, 4 do
		for X = 6, 9 do
			Set(Canvas, X, Y, " ", nil, colors.lightGray)
		end
	end
	Set(Canvas, 7, 3, " ", nil, colors.white)
	Terrain(Canvas, Rand, H * .7, 1.8, colors.green, colors.gray, colors.black, colors.lime)
	return Finish(Canvas)
end

function Renderers.nether(W, H)
	local Canvas = NewCanvas(W, H, colors.red)
	local Rand = Random(13)
	for Y = 1, H do
		for X = 1, W do
			local Wave = math.sin(X / 4 + Y / 3) + math.sin(X / 9 - Y / 2)
			if (Wave > 1.1) then
				Set(Canvas, X, Y, (Rand(3) == 0) and "~" or " ", colors.yellow, colors.orange)
			elseif (Wave < -1.2) then
				Set(Canvas, X, Y, (Rand(4) == 0) and "#" or " ", colors.red, colors.brown)
			elseif (Rand(14) == 0) then
				Set(Canvas, X, Y, "'", colors.orange)
			end
		end
	end
	return Finish(Canvas)
end

function Renderers.ocean(W, H)
	local Canvas = NewCanvas(W, H, colors.blue)
	local Rand = Random(99)
	for Y = 1, H do
		local Band = (Y < H * .35) and colors.lightBlue or ((Y < H * .7) and colors.cyan or colors.blue)
		for X = 1, W do
			local Char = (math.sin(X / 3 + Y * 1.7) > .6) and "~" or " "
			Set(Canvas, X, Y, Char, (Band == colors.blue) and colors.cyan or colors.white, Band)
		end
	end
	for _ = 1, math.floor(W / 8) do
		Set(Canvas, Rand(W) + 1, H - Rand(3), "\"", colors.lime)
	end
	return Finish(Canvas)
end

function Renderers.dusk(W, H)
	local Canvas = NewCanvas(W, H, colors.black)
	local Rand = Random(21)
	local Bands = { colors.black, colors.black, colors.blue, colors.purple, colors.magenta }
	for Y = 1, H do
		local Band = Bands[math.min(#Bands, math.floor(Y / H * #Bands * .9) + 1)]
		for X = 1, W do
			Set(Canvas, X, Y, " ", nil, Band)
		end
	end
	for _ = 1, math.floor(W * H / 40) do
		Set(Canvas, Rand(W) + 1, Rand(math.max(1, math.floor(H * .35))) + 1, (Rand(3) == 0) and "+" or ".", colors.lightGray)
	end
	for X = W - 9, W - 7 do
		Set(Canvas, X, 3, " ", nil, colors.white)
	end
	Set(Canvas, W - 8, 4, " ", nil, colors.lightGray)
	local Phase = Rand(100) / 10
	for X = 1, W do
		local Height = math.floor(H * .78 + math.sin(X / 6 + Phase) * 2 + math.sin(X / 2.3) * .6 + .5)
		for Y = Height, H do
			Set(Canvas, X, Y, (Y == Height and Rand(3) == 0) and "\"" or " ", colors.gray, colors.black)
		end
	end
	return Finish(Canvas)
end

function Renderers.deepslate(W, H)
	local Canvas = NewCanvas(W, H, colors.gray)
	local Rand = Random(64)
	for Y = 1, H do
		for X = 1, W do
			local Offset = (math.floor((Y - 1) / 2) % 2) * 4
			if ((X + Offset) % 8 == 0 or Y % 2 == 0 and Rand(3) == 0) then
				Set(Canvas, X, Y, (Rand(2) == 0) and "_" or " ", colors.black, colors.gray)
			end
			if (Rand(9) == 0) then
				Set(Canvas, X, Y, ({ ".", ":", "'" })[Rand(3) + 1], colors.black)
			end
		end
	end
	for _ = 1, math.max(2, math.floor(W * H / 180)) do
		local OreX, OreY = Rand(W - 2) + 1, Rand(H - 1) + 1
		local Ore = ({ colors.cyan, colors.red, colors.lightBlue, colors.lime })[Rand(4) + 1]
		Set(Canvas, OreX, OreY, "\7", Ore)
		Set(Canvas, OreX + 1, OreY, ".", Ore)
	end
	return Finish(Canvas)
end

function Renderers.cave(W, H)
	local Canvas = NewCanvas(W, H, colors.black)
	local Rand = Random(31)
	for X = 1, W do
		local Ceiling = math.floor(2 + math.sin(X / 4) * 1.5 + math.sin(X / 1.7) * .7 + .5)
		local Floor = math.floor(H * .72 + math.sin(X / 5 + 1) * 1.6 + .5)
		for Y = 1, H do
			if (Y <= Ceiling or Y >= Floor) then
				Set(Canvas, X, Y, (Rand(5) == 0) and ":" or " ", colors.lightGray, colors.gray)
			end
		end
		if (Rand(9) == 0) then
			Set(Canvas, X, Ceiling + 1, "'", colors.gray)
		end
	end
	local PoolX = math.floor(W * .55)
	for X = PoolX, math.min(W, PoolX + math.floor(W / 5)) do
		Set(Canvas, X, H - 1, (Rand(3) == 0) and "~" or " ", colors.yellow, colors.orange)
		Set(Canvas, X, H, " ", nil, colors.red)
	end
	for _ = 1, math.max(3, math.floor(W / 8)) do
		Set(Canvas, Rand(W) + 1, H - Rand(3), "\7", ({ colors.cyan, colors.red, colors.yellow })[Rand(3) + 1])
	end
	Set(Canvas, 4, math.floor(H * .6), "i", colors.yellow)
	return Finish(Canvas)
end

function Renderers.theend(W, H)
	local Canvas = NewCanvas(W, H, colors.black)
	local Rand = Random(77)
	for _ = 1, math.floor(W * H / 25) do
		Set(Canvas, Rand(W) + 1, Rand(H) + 1, ".", (Rand(3) == 0) and colors.purple or colors.gray)
	end
	local Center = math.floor(W / 2)
	local Top = math.floor(H * .7)
	for Y = Top, H do
		local Half = math.floor((W * .45) * (1 - (Y - Top) / (H - Top + 2)))
		for X = Center - Half, Center + Half do
			Set(Canvas, X, Y, (Rand(4) == 0) and "." or " ", colors.brown, (Y == Top) and colors.yellow or colors.white)
		end
	end
	for _ = 1, 3 do
		local PlantX = Center + Rand(math.floor(W * .6)) - math.floor(W * .3)
		local Height = Rand(4) + 3
		for Y = Top - Height, Top - 1 do
			Set(Canvas, PlantX, Y, " ", nil, colors.purple)
		end
		Set(Canvas, PlantX, Top - Height - 1, " ", nil, colors.magenta)
	end
	for _, Pillar in ipairs({ math.floor(W * .2), math.floor(W * .8) }) do
		for Y = Top - 5, Top - 1 do
			Set(Canvas, Pillar, Y, " ", nil, colors.gray)
		end
		Set(Canvas, Pillar, Top - 6, "\7", colors.pink, colors.black)
	end
	return Finish(Canvas)
end

function Renderers.grid(W, H, Color)
	local Canvas = NewCanvas(W, H, Color)
	local Dot = colors.lightGray
	if (Color == colors.white or Color == colors.lightGray) then
		Dot = colors.gray
	elseif (Color == colors.black) then
		Dot = colors.gray
	end
	for Y = 1, H, 2 do
		for X = 1, W, 4 do
			Set(Canvas, X, Y, "+", Dot)
		end
	end
	return Finish(Canvas)
end

function Renderers.solid(W, H, Color)
	return Finish(NewCanvas(W, H, Color))
end

-- Stretches the picture to fill the screen; falls back to the solid colour if it cannot be read.
function Renderers.picture(W, H, Color, ImagePath)
	local Img = Image.Load(ImagePath)
	if (not Img) then return Renderers.solid(W, H, Color) end
	return Image.Scale(Img, W, H)
end

function Wallpaper.Invalidate()
	Wallpaper.Revision = Wallpaper.Revision + 1
end

local CacheKey, CacheRows

function Wallpaper.Render(Name, W, H, Color, ImagePath)
	local Key = table.concat({ tostring(Name), W, H, tostring(Color), tostring(ImagePath), Wallpaper.Revision }, ":")
	if (Key == CacheKey) then return CacheRows end
	local Renderer = Renderers[Name] or Renderers.overworld
	CacheRows = Renderer(W, H, Color or colors.cyan, ImagePath)
	CacheKey = Key
	return CacheRows
end

function Wallpaper.Draw(T, X, Y, W, H, Name, Color, ImagePath)
	local Rows = Renderers[Name] and Renderers[Name](W, H, Color or colors.cyan, ImagePath) or Renderers.overworld(W, H)
	for Row = 1, H do
		T.setCursorPos(X, Y + Row - 1)
		T.blit(Rows[Row][1], Rows[Row][2], Rows[Row][3])
	end
end

return Wallpaper
]]
Files["blockos/sys/desktop.lua"] = [[
-- BlockOS desktop: a compositing window manager with a macOS-style topbar, dock,
-- launchpad, notifications and lock screen. Every window runs a program in its own
-- coroutine; the focused window draws straight through while the rest are composited.

local Gfx = BlockOS.Require("gfx")
local Theme = BlockOS.Require("theme")
local Config = BlockOS.Require("config")
local Apps = BlockOS.Require("apps")
local Wallpaper = BlockOS.Require("wallpaper")
local Users = BlockOS.Require("users")
local Login = BlockOS.Load("/blockos/sys/login.lua")

local Desktop = {}

local MinW, MinH = 14, 4
local FrameTime = .05
local LogPath = "/blockos/data/log.txt"

local Native, Screen, Hidden
local ScreenW, ScreenH = 51, 19
local RootShell

local Processes = {}
local Services = {}
local Focused = nil
local CurrentProc = nil
local NextID = 1
local Running = true
local SessionStarted = false

local Menu = nil
local Dialog = nil
local Launchpad = { Open = false, Query = "", Page = 1, Regions = {} }
local Toasts = {}
local History = {}
local Drag = nil
local MouseTarget = nil
local RevealUntil = nil
local Locked = false
local LockScreen = nil
local Modifiers = {}
local RedrawTimer = nil
local ClockTimer = nil
local LastInput = os.clock()
local AppCache = {}
local Topbar = { Regions = {} }
local DockRegions = {}
local LastTitleClick = { Time = 0 }
local Recording = false
local AnimationQueue = {}
local Deferred = {}
local Ghost = nil
local PendingLock = false
local PendingUnlock = false
local FadeLevel = 1
local FullscreenHinted = false
local DesktopHidden = nil

local Redraw, ScheduleRedraw, Focus, Launch, Notify, Lock, CloseProc, Kill, OpenMenu, Multishell

local ModifierKeys = {
	[keys.leftCtrl] = "Ctrl", [keys.rightCtrl] = "Ctrl",
	[keys.leftShift] = "Shift", [keys.rightShift] = "Shift",
	[keys.leftAlt] = "Alt", [keys.rightAlt] = "Alt"
}

local InputEvents = {
	mouse_click = true, mouse_drag = true, mouse_up = true, mouse_scroll = true,
	key = true, key_up = true, char = true, paste = true
}

local function Log(Text)
	local Handle = fs.open(LogPath, fs.exists(LogPath) and fs.getSize(LogPath) < 16384 and "a" or "w")
	if (not Handle) then return end
	Handle.writeLine(os.date("%Y-%m-%d %H:%M:%S ") .. tostring(Text))
	Handle.close()
end

local function Copy(List)
	local Result = {}
	for Index, Item in ipairs(List) do
		Result[Index] = Item
	end
	return Result
end

local function RefreshApps()
	AppCache = Apps.All()
end

-- The small dock shows one row of icons with the running indicator below it.
local function DockHeight()
	return (Config.Settings().DockSize == "large") and 3 or 2
end

local function DockTop()
	return ScreenH - DockHeight() + 1
end

-- Usable window area between the topbar and dock: X, Y, W, H.
local function WorkArea()
	return 1, 2, ScreenW, ScreenH - DockHeight() - 1
end

local function AnimationsEnabled()
	return Config.Settings().Animations ~= false
end

-- Dims the whole screen; 1 is normal colours, 0 is black.
local function SetFadeLevel(Level)
	if (not Gfx.SetFade(Screen, Level)) then return false end
	FadeLevel = Level
	return true
end

-- Animations run from the desktop's main loop, never inside an app's coroutine.
local function QueueAnimation(Animation)
	if (not AnimationsEnabled()) then return false end
	table.insert(AnimationQueue, Animation)
	return true
end

local function HintFullscreen()
	if (FullscreenHinted) then return end
	FullscreenHinted = true
	Notify("Full Screen", "Right-click the top row to show window buttons.", { Sound = false, Duration = 7 })
end

local function WindowRect(Proc)
	if (Proc.Fullscreen) then
		return { 1, 1, ScreenW, ScreenH }
	end
	return { Proc.X, Proc.Y, Proc.W, Proc.H }
end

local function FocusedFullscreen()
	return Focused ~= nil and Focused.Fullscreen and not Focused.Minimized
end

local function RevealActive()
	return RevealUntil ~= nil and os.clock() < RevealUntil
end

local function ContentRect(Proc)
	if (Proc.Fullscreen) then
		return 1, 1, ScreenW, ScreenH
	end
	return Proc.X, Proc.Y + 1, Proc.W, Proc.H - 1
end

local function ClampWindow(Proc)
	local _, AreaY, AreaW, AreaH = WorkArea()
	Proc.W = math.max(MinW, math.min(Proc.W, AreaW))
	Proc.H = math.max(MinH, math.min(Proc.H, AreaH))
	Proc.X = math.max(1, math.min(Proc.X, AreaW - Proc.W + 1))
	Proc.Y = math.max(AreaY, math.min(Proc.Y, AreaY + AreaH - Proc.H))
end

local function ApplyGeometry(Proc)
	local X, Y, W, H = ContentRect(Proc)
	local OldW, OldH = Proc.Window.getSize()
	Proc.Window.reposition(X, Y, W, H)
	if (OldW ~= W or OldH ~= H) then
		Proc.PendingResize = true
	end
end

local function Show(Proc)
	if (Proc.Shown) then
		Proc.Window.redraw()
	else
		Proc.Window.setVisible(true)
		Proc.Shown = true
	end
end

local function Hide(Proc)
	Proc.Live = false
	if (Proc.Shown) then
		Proc.Window.setVisible(false)
		Proc.Shown = false
	end
end

local function Post(Proc, ...)
	Proc.Inbox = Proc.Inbox or {}
	table.insert(Proc.Inbox, table.pack(...))
end

local function TopVisible()
	for Index = #Processes, 1, -1 do
		if (not Processes[Index].Minimized) then
			return Processes[Index]
		end
	end
	return nil
end

local function FindProc(ID)
	for _, Proc in ipairs(Processes) do
		if (Proc.ID == ID) then return Proc end
	end
	return nil
end

local function ProcsOf(AppID)
	local Result = {}
	for _, Proc in ipairs(Processes) do
		if (Proc.AppID == AppID) then
			table.insert(Result, Proc)
		end
	end
	return Result
end

--
-- Process management
--

local Mutators = { write = true, blit = true, clear = true, clearLine = true, scroll = true }

-- Wraps a window so that drawing from a background window schedules a composite.
local function MakeProxy(Proc)
	local Proxy = {}
	for Name, Fn in pairs(Proc.Window) do
		if (Mutators[Name]) then
			Proxy[Name] = function(...)
				if (not Proc.Live and not Proc.Minimized) then
					ScheduleRedraw()
				end
				return Fn(...)
			end
		else
			Proxy[Name] = Fn
		end
	end
	Proxy.setVisible = function(Visible)
		Proc.AppHidden = not Visible
		if (Proc.Live) then
			Proc.Window.setVisible(Visible)
			Proc.Shown = Visible
		elseif (Visible) then
			ScheduleRedraw()
		end
	end
	Proxy.reposition = function() end
	return Proxy
end

local function Crash(Proc, Err)
	Proc.Dead = true
	Proc.Title = Proc.Title .. " (crashed)"
	Log((Proc.AppID or Proc.Title) .. ": " .. tostring(Err))
	local T = Proc.Window
	local W, H = T.getSize()
	T.setBackgroundColor(colors.black)
	T.clear()
	T.setTextColor(colors.red)
	local Lines = Gfx.Wrap("This app quit unexpectedly:\n" .. tostring(Err), W - 2)
	for Row = 1, math.min(#Lines, H - 2) do
		T.setCursorPos(2, Row + 1)
		T.write(Lines[Row])
	end
	T.setTextColor(colors.lightGray)
	T.setCursorPos(2, H)
	T.write(Gfx.Truncate("Click or press a key to close", W - 2))
	T.setCursorBlink(false)
	ScheduleRedraw()
end

local function Resume(Proc, Name, ...)
	if (Proc.Dead or Proc.PendingStart and Name) then return end
	if (Name and Proc.Filter and Proc.Filter ~= Name and Name ~= "terminate") then return end
	local Previous = term.redirect(Proc.Redirect)
	local PreviousProc = CurrentProc
	CurrentProc = Proc
	local Ok, Result
	if (Name) then
		Ok, Result = coroutine.resume(Proc.Co, Name, ...)
	else
		Ok, Result = coroutine.resume(Proc.Co)
	end
	CurrentProc = PreviousProc
	Proc.Redirect = term.current()
	term.redirect(Previous)
	if (Proc.Service) then
		if (not Ok or coroutine.status(Proc.Co) == "dead") then
			if (not Ok) then Log(Proc.Name .. ": " .. tostring(Result)) end
			Proc.Dead = true
			for Index, Other in ipairs(Services) do
				if (Other == Proc) then
					table.remove(Services, Index)
					break
				end
			end
		else
			Proc.Filter = Result
		end
		return
	end
	if (not Ok) then
		Crash(Proc, Result)
	elseif (Proc.Closing or coroutine.status(Proc.Co) == "dead") then
		Kill(Proc)
	else
		Proc.Filter = Result
	end
end

function Kill(Proc)
	for Index, Other in ipairs(Processes) do
		if (Other == Proc) then
			table.remove(Processes, Index)
			break
		end
	end
	Proc.Dead = true
	Hide(Proc)
	if (MouseTarget == Proc) then MouseTarget = nil end
	if (Drag and Drag.Proc == Proc) then Drag = nil end
	if (Focused == Proc) then Focused = TopVisible() end
	Redraw()
end

function CloseProc(Proc)
	if (not Proc) then return end
	if (Proc.CloseHandler and not Proc.Dead) then
		Post(Proc, "blockos_close")
		return
	end
	Kill(Proc)
end

local function Spawn(Opts)
	local _, AreaY, AreaW, AreaH = WorkArea()
	local Proc = {
		ID = NextID,
		Title = Opts.Title or "Untitled",
		AppID = Opts.AppID,
		Icon = Opts.Icon,
		AllowTitle = Opts.AllowTitle,
		PendingStart = true,
		Live = false
	}
	NextID = NextID + 1
	Proc.W = Opts.Width or math.min(40, AreaW - 4)
	Proc.H = Opts.Height or math.min(14, AreaH)
	local Count = #Processes
	Proc.X = math.floor((AreaW - Proc.W) / 2) + 1 + (Count % 4) * 2 - 3
	Proc.Y = AreaY + (Count % 3)
	ClampWindow(Proc)
	Proc.Fullscreen = Opts.Mode == "fullscreen"
	if (Proc.Fullscreen) then HintFullscreen() end
	local X, Y, W, H = ContentRect(Proc)
	Proc.Window = window.create(Screen, X, Y, W, H, false)
	-- Windows copy their parent's palette, so one made mid-fade would keep the dimmed colours.
	if (FadeLevel < 1) then Gfx.SetFade(Proc.Window, 1) end
	Proc.Term = MakeProxy(Proc)
	Proc.Redirect = Proc.Term
	Proc.Co = coroutine.create(Opts.Fn)
	table.insert(Processes, Proc)
	if (QueueAnimation({ Kind = "open", Proc = Proc, From = Opts.From })) then
		Proc.Opening = true
	end
	Focus(Proc)
	return Proc
end

local function Quote(Arg)
	Arg = tostring(Arg)
	if (Arg == "" or Arg:find("[%s\"]")) then
		return "\"" .. Arg:gsub("\"", "") .. "\""
	end
	return Arg
end

-- Runs a program inside a fresh CraftOS shell so it gets its own shell API and require.
local function ProgramFn(Path, Args, Hold)
	return function()
		local Env = { shell = RootShell, multishell = Multishell }
		local List = { "/blockos/sys/run.lua", Hold and "hold" or "nohold", Quote(Path) }
		for _, Arg in ipairs(Args or {}) do
			table.insert(List, Quote(Arg))
		end
		os.run(Env, "/rom/programs/shell.lua", table.unpack(List))
	end
end

local function LaunchpadSeed()
	local W, H = math.max(3, math.floor(ScreenW / 6)), math.max(2, math.floor(ScreenH / 6))
	return { math.floor((ScreenW - W) / 2) + 1, math.floor((ScreenH - H) / 2) + 1, W, H }
end

local function CloseLaunchpad()
	if (not Launchpad.Open) then return end
	if (not QueueAnimation({ Kind = "launchpad" })) then
		Launchpad.Open = false
		Redraw()
	end
end

local function ToggleLaunchpad()
	Menu = nil
	if (Launchpad.Open) then
		CloseLaunchpad()
		return
	end
	Launchpad.Open = true
	Launchpad.Query = ""
	Launchpad.Page = 1
	if (QueueAnimation({ Kind = "launchpad", Opening = true })) then
		Launchpad.Rect = LaunchpadSeed()
	end
	Redraw()
end

function Launch(Target, Args, Opts)
	Opts = Opts or {}
	local App = AppCache[Target] or Apps.Get(Target)
	if (App) then
		if (App.Builtin == "launchpad") then
			ToggleLaunchpad()
			return nil
		end
		if (App.Single) then
			local Existing = ProcsOf(App.ID)
			if (#Existing > 0) then
				Focus(Existing[#Existing])
				if (Args and #Args > 0) then
					Post(Existing[#Existing], "blockos_open", table.unpack(Args))
				end
				return Existing[#Existing].ID
			end
		end
		local Proc = Spawn({
			Title = App.Name,
			AppID = App.ID,
			Icon = App.Icon,
			Mode = Opts.Mode or App.Mode,
			Width = App.Width,
			Height = App.Height,
			AllowTitle = App.AllowTitle,
			From = Opts.From,
			Fn = ProgramFn(App.Path, Args, false)
		})
		return Proc.ID
	end
	local Path = Target
	if (type(Path) == "string" and not fs.exists(Path)) then
		Path = RootShell.resolveProgram(Path)
	end
	if (type(Path) == "string" and fs.exists(Path) and not fs.isDir(Path)) then
		local Proc = Spawn({
			Title = fs.getName(Path),
			AllowTitle = true,
			Mode = Opts.Mode,
			Fn = ProgramFn(Path, Args, Opts.Hold ~= false)
		})
		return Proc.ID
	end
	return nil, "Not found: " .. tostring(Target)
end

local function OpenFile(Path)
	if (not fs.exists(Path)) then return false end
	if (fs.isDir(Path)) then
		Launch("finder", { Path })
		return true
	end
	local Extension = Path:match("%.([%w]+)$")
	Extension = Extension and Extension:lower()
	if (Extension == "dfpwm") then
		Launch("btunes", { Path })
	elseif (Extension == "rec") then
		Launch("recorder", { Path })
	elseif (Extension == "txt" and AppCache.notes) then
		Launch("notes", { Path })
	elseif ((Extension == "bimg" or Extension == "nfp") and AppCache.brocreate) then
		Launch("brocreate", { Path })
	elseif (Extension == "ccmd" and AppCache.savannah) then
		Launch("savannah", { Path })
	elseif (Extension == "lua" or not Extension) then
		Launch(Path, {}, { Hold = true })
	else
		Launch("editor", { Path })
	end
	return true
end

local function StartService(Name, Fn)
	local Service = {
		Name = Name,
		Service = true,
		Redirect = Hidden,
		Co = coroutine.create(function()
			local Ok, Err = pcall(Fn)
			if (not Ok) then Log(Name .. ": " .. tostring(Err)) end
		end)
	}
	table.insert(Services, Service)
	Resume(Service)
end

local function Broadcast(Event)
	for _, Proc in ipairs(Copy(Processes)) do
		if (not Proc.Dead and not Proc.PendingStart) then
			Resume(Proc, table.unpack(Event, 1, Event.n))
		end
	end
	for _, Service in ipairs(Copy(Services)) do
		Resume(Service, table.unpack(Event, 1, Event.n))
	end
end

local function SendMouse(Proc, Name, Button, X, Y)
	local CX, CY = ContentRect(Proc)
	Resume(Proc, Name, Button, X - CX + 1, Y - CY + 1)
end

local function FlushPending()
	for _ = 1, 8 do
		local Any = false
		for _, Proc in ipairs(Copy(Processes)) do
			if (not Proc.Dead and Proc.PendingStart) then
				Proc.PendingStart = nil
				Any = true
				Resume(Proc)
			end
			if (not Proc.Dead and Proc.PendingResize) then
				Proc.PendingResize = nil
				Any = true
				Resume(Proc, "term_resize")
			end
			while (not Proc.Dead and Proc.Inbox and #Proc.Inbox > 0) do
				local Event = table.remove(Proc.Inbox, 1)
				Any = true
				Resume(Proc, table.unpack(Event, 1, Event.n))
			end
		end
		if (not Any) then break end
	end
end

--
-- Window state
--

-- A window losing focus never sees the release of keys still held, so send it now.
local function ReleaseModifiers(Proc)
	if (not Proc or Proc.Dead) then return end
	if (Modifiers.Ctrl) then Post(Proc, "key_up", keys.leftCtrl) end
	if (Modifiers.Shift) then Post(Proc, "key_up", keys.leftShift) end
	if (Modifiers.Alt) then Post(Proc, "key_up", keys.leftAlt) end
end

function Focus(Proc)
	if (Focused and Focused ~= Proc) then
		ReleaseModifiers(Focused)
	end
	if (Proc) then
		if (Proc.Minimized and QueueAnimation({ Kind = "open", Proc = Proc })) then
			Proc.Opening = true
		end
		Proc.Minimized = false
		for Index, Other in ipairs(Processes) do
			if (Other == Proc) then
				table.remove(Processes, Index)
				break
			end
		end
		table.insert(Processes, Proc)
	end
	if (Focused ~= Proc) then
		RevealUntil = nil
	end
	Focused = Proc
	Redraw()
end

local function Minimize(Proc)
	if (not Proc or Proc.Minimized) then return end
	QueueAnimation({ Kind = "minimize", Proc = Proc, From = WindowRect(Proc) })
	Proc.Minimized = true
	Hide(Proc)
	if (Focused == Proc) then
		ReleaseModifiers(Proc)
		Focused = TopVisible()
	end
	Redraw()
end

local function ToggleFullscreen(Proc)
	if (not Proc) then return end
	Proc.Fullscreen = not Proc.Fullscreen
	if (Proc.Fullscreen) then HintFullscreen() end
	RevealUntil = nil
	if (not Proc.Fullscreen) then
		ClampWindow(Proc)
	end
	ApplyGeometry(Proc)
	Focus(Proc)
end

local function Zoom(Proc)
	if (not Proc or Proc.Fullscreen) then return end
	if (Proc.Saved) then
		Proc.X, Proc.Y, Proc.W, Proc.H = table.unpack(Proc.Saved)
		Proc.Saved = nil
	else
		Proc.Saved = { Proc.X, Proc.Y, Proc.W, Proc.H }
		local AreaX, AreaY, AreaW, AreaH = WorkArea()
		Proc.X, Proc.Y, Proc.W, Proc.H = AreaX, AreaY, AreaW, AreaH
	end
	ClampWindow(Proc)
	ApplyGeometry(Proc)
	Redraw()
end

local function RevealTopbar()
	RevealUntil = os.clock() + 3
	Redraw()
end

-- Hides every window to show the desktop; pressed again before opening anything, brings them back.
local function ShowDesktop()
	Menu = nil
	local Visible = {}
	for _, Proc in ipairs(Processes) do
		if (not Proc.Minimized) then table.insert(Visible, Proc) end
	end
	if (#Visible > 0) then
		ReleaseModifiers(Focused)
		for _, Proc in ipairs(Visible) do
			Proc.Minimized = true
			Hide(Proc)
		end
		DesktopHidden = Visible
		Focused = nil
		RevealUntil = nil
		Redraw()
		return
	end
	local Restore = DesktopHidden
	DesktopHidden = nil
	if (not Restore) then return end
	local Top
	-- Restore bottom to top so the windows keep their stacking order.
	for _, Proc in ipairs(Restore) do
		if (not Proc.Dead and Proc.Minimized) then
			for Index, Other in ipairs(Processes) do
				if (Other == Proc) then
					table.remove(Processes, Index)
					break
				end
			end
			table.insert(Processes, Proc)
			Proc.Minimized = false
			Top = Proc
		end
	end
	if (Top) then
		Focus(Top)
	else
		Redraw()
	end
end

--
-- Drawing
--

-- Helpers are grouped into tables: CC's Lua counts every local of the enclosing chunk
-- against each function's 200-local limit, so this file keeps its top-level locals few.
local Draw = {}

local function WallpaperRows()
	local Settings = Config.Settings()
	return Wallpaper.Render(Settings.Wallpaper, ScreenW, ScreenH, Settings.WallpaperColor, Settings.WallpaperImage)
end

function Draw.Wallpaper()
	local Rows = WallpaperRows()
	for Y = 1, ScreenH do
		Screen.setCursorPos(1, Y)
		Screen.blit(Rows[Y][1], Rows[Y][2], Rows[Y][3])
	end
end

function Draw.Frame(Proc, Th, Active, Row)
	local Y = Row or Proc.Y
	local X, W = Proc.X, Proc.W
	if (Proc.Fullscreen) then
		X, W = 1, ScreenW
	end
	local Bg = Active and Th.TitleBg or Th.TitleIdleBg
	local Fg = Active and Th.TitleFg or Th.TitleIdleFg
	Gfx.Fill(Screen, X, Y, W, 1, Bg)
	local Title = Gfx.Truncate(Proc.Title, W - 9)
	local TitleX = math.max(X + 8, X + math.floor((W - #Title) / 2))
	Gfx.Write(Screen, TitleX, Y, Title, Fg, Bg)
	local Lights = Active and { Th.Close, Th.Minimize, Th.Zoom } or { Th.TitleIdleFg, Th.TitleIdleFg, Th.TitleIdleFg }
	for Index, Color in ipairs(Lights) do
		Gfx.Write(Screen, X + Index * 2 - 1, Y, "\7", Color, Bg)
	end
end

function Topbar.Clock()
	local Settings = Config.Settings()
	if (Settings.ClockSource == "game") then
		return "Day " .. os.day() .. " " .. textutils.formatTime(os.time(), Settings.Clock24)
	end
	local Format = Settings.Clock24 and "%H:%M" or "%I:%M %p"
	if (Settings.ShowSeconds) then
		Format = Settings.Clock24 and "%H:%M:%S" or "%I:%M:%S %p"
	end
	return os.date("%a " .. Format)
end

function Topbar.UpdateStatus()
	local Ok, Updater = pcall(BlockOS.Require, "updater")
	if (not Ok) then return nil end
	return Updater.State.Status
end

local function UnreadMessages()
	local Ok, Chat = pcall(BlockOS.Require, "chat")
	if (not Ok or not Chat.Loaded) then return 0 end
	return Chat.UnreadTotal()
end

local function AppName()
	if (Focused) then
		local App = Focused.AppID and AppCache[Focused.AppID]
		return App and App.Name or Focused.Title
	end
	return "BlockOS"
end

-- Smears the top of the wallpaper into blocks of its most common background colour.
function Topbar.Blur(Rows)
	if (Topbar.BlurSource == Rows) then return Topbar.BlurRow end
	local Radius = 3
	local Depth = math.min(3, #Rows)
	local Out = {}
	for X = 1, ScreenW do
		local Counts, Best, BestCount = {}, Rows[1][3]:sub(X, X), 0
		for Y = 1, Depth do
			local Line = Rows[Y][3]
			for Column = math.max(1, X - Radius), math.min(#Line, X + Radius) do
				local Color = Line:sub(Column, Column)
				local Count = (Counts[Color] or 0) + 1
				Counts[Color] = Count
				if (Count > BestCount) then
					Best, BestCount = Color, Count
				end
			end
		end
		Out[X] = Best
	end
	Topbar.BlurSource, Topbar.BlurRow = Rows, table.concat(Out)
	return Topbar.BlurRow
end

-- The menu bar row before any text: solid theme colour, the wallpaper itself, or a blurred copy of it.
function Topbar.Background(Th, Style)
	if (Style == "clear") then
		local Row = WallpaperRows()[1]
		return Row[1], Row[2], Row[3]
	elseif (Style == "blur") then
		return string.rep(" ", ScreenW), string.rep(Gfx.ToBlit(Th.TopbarFg), ScreenW), Topbar.Blur(WallpaperRows())
	end
	return string.rep(" ", ScreenW), string.rep(Gfx.ToBlit(Th.TopbarFg), ScreenW), string.rep(Gfx.ToBlit(Th.TopbarBg), ScreenW)
end

function Draw.Topbar(Th)
	Topbar.Regions = {}
	local Style = Config.Settings().TopbarStyle or "solid"
	-- The wallpaper is hidden behind a full-screen app, so its revealed menu bar stays solid.
	if (FocusedFullscreen()) then Style = "solid" end
	local Chars, Fgs, Bgs = Topbar.Background(Th, Style)
	Screen.setCursorPos(1, 1)
	Screen.blit(Chars, Fgs, Bgs)
	-- Text without a colour picks black or white to stand out from the cell behind it.
	local function Put(X, Text, Fg)
		if (X < 1 or X + #Text - 1 > ScreenW) then return end
		local Bg = Bgs:sub(X, X + #Text - 1)
		local FgRow
		if (Fg) then
			FgRow = string.rep(Gfx.ToBlit(Fg), #Text)
		elseif (Style == "solid") then
			FgRow = string.rep(Gfx.ToBlit(Th.TopbarFg), #Text)
		else
			FgRow = Bg:gsub(".", Gfx.ContrastBlit)
		end
		Screen.setCursorPos(X, 1)
		Screen.blit(Text, FgRow, Bg)
	end
	Screen.setCursorPos(2, 1)
	Screen.blit("\131", Gfx.ToBlit(colors.lime), Gfx.ToBlit(colors.brown))
	table.insert(Topbar.Regions, { X = 1, W = 3, Menu = "logo" })
	local X = 4
	local Name = Gfx.Truncate(AppName(), 14)
	Put(X, Name)
	table.insert(Topbar.Regions, { X = X - 1, W = #Name + 2, Menu = "app" })
	X = X + #Name + 2
	for _, Title in ipairs({ "Go", "Window" }) do
		if (X + #Title < ScreenW - 14) then
			Put(X, Title)
			table.insert(Topbar.Regions, { X = X - 1, W = #Title + 2, Menu = Title:lower() })
			X = X + #Title + 2
		end
	end
	-- Show Desktop sits in the very corner, like the sliver at the end of a taskbar.
	local Right = ScreenW
	Put(Right, "\149")
	table.insert(Topbar.Regions, { X = Right - 1, W = 2, Action = "desktop" })
	local Clock = Topbar.Clock()
	Right = Right - #Clock - 1
	Put(Right, Clock)
	table.insert(Topbar.Regions, { X = Right, W = #Clock, Action = "clock" })
	local Status = Topbar.UpdateStatus()
	if (Status == "available" or Status == "ready") then
		Right = Right - 3
		Put(Right, "\24", (Style == "solid") and Th.Accent or nil)
		table.insert(Topbar.Regions, { X = Right - 1, W = 3, Action = "update" })
	end
	if (Recording) then
		Right = Right - 7
		Put(Right, "\7 REC", colors.red)
		table.insert(Topbar.Regions, { X = Right - 1, W = 7, Action = "recording" })
	end
end

local function DockItems()
	local Items = {}
	local Seen = {}
	for _, ID in ipairs(Config.Settings().Dock) do
		local App = AppCache[ID]
		if (App and not Seen[ID]) then
			Seen[ID] = true
			table.insert(Items, { App = App, Pinned = true })
		end
	end
	for _, Proc in ipairs(Processes) do
		if (Proc.AppID and AppCache[Proc.AppID]) then
			if (not Seen[Proc.AppID]) then
				Seen[Proc.AppID] = true
				table.insert(Items, { App = AppCache[Proc.AppID] })
			end
		elseif (not Proc.AppID) then
			table.insert(Items, { Proc = Proc, Icon = { Lines = { ">_ ", "   " }, Fg = colors.lime, Bg = colors.black } })
		end
	end
	local Max = math.floor((ScreenW - 1) / 4)
	while (#Items > Max) do
		table.remove(Items)
	end
	return Items
end

local function ItemRunning(Item)
	if (Item.Proc) then return true, Focused == Item.Proc end
	local Windows = ProcsOf(Item.App.ID)
	return #Windows > 0, Focused ~= nil and Focused.AppID == Item.App.ID
end

-- Writes text over whatever is already on screen, keeping its background colours.
local function WriteOver(X, Y, Text, Fg)
	if (Y < 1 or Y > ScreenH or X < 1 or X + #Text - 1 > ScreenW) then return end
	local _, _, Bg = Screen.getLine(Y)
	Screen.setCursorPos(X, Y)
	Screen.blit(Text, string.rep(Gfx.ToBlit(Fg), #Text), Bg:sub(X, X + #Text - 1))
end

function Draw.Dock(Th)
	local Settings = Config.Settings()
	local Clear = Settings.DockStyle == "transparent"
	local Height = DockHeight()
	local IconRows = Height - 1
	local Items = DockItems()
	local W = #Items * 4 + 1
	local X0 = math.floor((ScreenW - W) / 2) + 1
	local Top = DockTop()
	if (not Clear) then
		Gfx.Fill(Screen, X0, Top, W, Height, Th.DockBg)
	end
	DockRegions = {}
	local Unread = UnreadMessages()
	for Index, Item in ipairs(Items) do
		local X = X0 + 1 + (Index - 1) * 4
		local Icon = Item.App and Item.App.Icon or Item.Icon
		for Row = 1, IconRows do
			Screen.setCursorPos(X, Top + Row - 1)
			Screen.blit(Gfx.Pad(Icon.Lines[Row] or "", 3), string.rep(Gfx.ToBlit(Icon.Fg), 3), string.rep(Gfx.ToBlit(Icon.Bg), 3))
		end
		if (Item.App and Item.App.ID == "messages" and Unread > 0) then
			Gfx.Write(Screen, X + 2, Top, Unread > 9 and "+" or tostring(Unread), colors.white, colors.red)
		end
		local IsRunning, IsFocused = ItemRunning(Item)
		if (IsRunning) then
			local Color = IsFocused and Th.Accent or Th.DockFg
			if (Clear) then
				WriteOver(X + 1, Top + IconRows, "\7", IsFocused and Th.Accent or colors.white)
			else
				Gfx.Write(Screen, X + 1, Top + IconRows, "\7", Color, Th.DockBg)
			end
		end
		Item.X = X
		table.insert(DockRegions, Item)
	end
end

-- The dock icon a window minimizes into or opens from: X, Y, W, H.
local function DockSlot(Proc)
	local Rows = DockHeight() - 1
	for _, Item in ipairs(DockRegions) do
		if (Item.Proc == Proc or (Item.App and Proc.AppID and Item.App.ID == Proc.AppID)) then
			return { Item.X, DockTop(), 3, Rows }
		end
	end
	return { math.floor(ScreenW / 2), DockTop(), 3, Rows }
end

--
-- Desktop shortcuts
--

local Shortcuts = { Regions = {}, Selected = nil, LastClick = { Time = 0 }, W = 9, H = 4 }

-- Glyph, foreground and background of a file's shortcut icon by extension.
Shortcuts.Icons = {
	lua = { "\4", colors.black, colors.yellow },
	txt = { "\7", colors.gray, colors.white },
	md = { "\7", colors.gray, colors.white },
	dfpwm = { "\14", colors.white, colors.red },
	rec = { "\7", colors.white, colors.red },
	nfp = { "\127", colors.white, colors.pink },
	bimg = { "\127", colors.white, colors.magenta },
	ccmd = { "@", colors.white, colors.orange },
	json = { "\7", colors.white, colors.orange },
	cfg = { "\7", colors.white, colors.orange },
	[""] = { "\7", colors.white, colors.gray }
}

-- Name and icon of a shortcut, or nil while its app or file is missing (an uninstalled app, an ejected disk).
function Shortcuts.Info(Entry)
	local ID = Entry:match("^app:(.+)$")
	if (ID) then
		local App = AppCache[ID]
		return App and { Name = App.Name, Icon = App.Icon, App = App }
	end
	if (not fs.exists(Entry)) then return nil end
	local Name = fs.getName(Entry)
	if (fs.isDir(Entry)) then
		return { Name = Name, Path = Entry, IsDir = true, Icon = { Lines = { " \16 ", "   " }, Fg = colors.white, Bg = colors.lightBlue } }
	end
	local Extension = (Name:match("%.(%w+)$") or ""):lower()
	local Kind = Shortcuts.Icons[Extension] or Shortcuts.Icons[""]
	return { Name = Name, Path = Entry, Icon = { Lines = { " " .. Kind[1] .. " ", Gfx.Pad(Extension:sub(1, 3), 3, "center") }, Fg = Kind[2], Bg = Kind[3] } }
end

-- Shortcuts fill columns down the left of the desktop, between the menu bar and the dock.
function Shortcuts.Draw(Th)
	Shortcuts.Regions = {}
	local List = Config.Settings().Shortcuts or {}
	if (#List == 0) then return end
	local Rows = math.floor((DockTop() - 6) / Shortcuts.H) + 1
	local Cols = math.floor((ScreenW - 1) / Shortcuts.W)
	if (Rows < 1) then return end
	local Wall = WallpaperRows()
	local Slot = 0
	for _, Entry in ipairs(List) do
		local Info = Shortcuts.Info(Entry)
		if (Info) then
			local Col, Row = math.floor(Slot / Rows), Slot % Rows
			if (Col >= Cols) then break end
			Slot = Slot + 1
			local X, Y = 2 + Col * Shortcuts.W, 3 + Row * Shortcuts.H
			local Icon = Info.Icon
			for Line = 1, 2 do
				Screen.setCursorPos(X + 3, Y + Line - 1)
				Screen.blit(Gfx.Pad(Icon.Lines[Line] or "", 3), string.rep(Gfx.ToBlit(Icon.Fg), 3), string.rep(Gfx.ToBlit(Icon.Bg), 3))
			end
			local Label = Gfx.Pad(Info.Name, Shortcuts.W - 1, "center")
			local Fg, Bg
			if (Entry == Shortcuts.Selected) then
				Fg, Bg = string.rep(Gfx.ToBlit(Th.AccentFg), #Label), string.rep(Gfx.ToBlit(Th.Accent), #Label)
			else
				-- Labels sit straight on the wallpaper, in black or white to stand out from it.
				Bg = Wall[Y + 2][3]:sub(X, X + #Label - 1)
				Fg = Bg:gsub(".", Gfx.ContrastBlit)
			end
			Screen.setCursorPos(X, Y + 2)
			Screen.blit(Label, Fg, Bg)
			Info.Entry, Info.X, Info.Y = Entry, X, Y
			table.insert(Shortcuts.Regions, Info)
		end
	end
end

function Shortcuts.At(X, Y)
	for _, Info in ipairs(Shortcuts.Regions) do
		if (X >= Info.X and X < Info.X + Shortcuts.W - 1 and Y >= Info.Y and Y < Info.Y + 3) then
			return Info
		end
	end
	return nil
end

local function LaunchpadApps()
	local List = {}
	local Query = Launchpad.Query:lower()
	for _, App in pairs(AppCache) do
		if (not App.Hidden and App.Builtin ~= "launchpad") then
			if (Query == "" or App.Name:lower():find(Query, 1, true)) then
				table.insert(List, App)
			end
		end
	end
	table.sort(List, function(A, B) return A.Name:lower() < B.Name:lower() end)
	return List
end

function Draw.Launchpad(Th)
	Launchpad.Regions = {}
	if (Launchpad.Rect) then
		local Rect = Launchpad.Rect
		Gfx.Fill(Screen, Rect[1], Rect[2], Rect[3], Rect[4], colors.gray, colors.lightGray, "\127")
		return
	end
	Gfx.Fill(Screen, 1, 1, ScreenW, ScreenH, colors.gray, colors.lightGray, "\127")
	local SearchW = math.min(24, ScreenW - 4)
	local SearchX = math.floor((ScreenW - SearchW) / 2) + 1
	local Query = Launchpad.Query
	local Text = (#Query > 0) and Query or "Search"
	Gfx.Write(Screen, SearchX, 2, Gfx.Pad(" \16 " .. Text, SearchW), (#Query > 0) and colors.white or colors.lightGray, colors.black)
	local List = LaunchpadApps()
	local CellW, CellH = 10, 4
	local Cols = math.max(1, math.floor((ScreenW - 2) / CellW))
	local Rows = math.max(1, math.floor((ScreenH - 5) / CellH))
	local PerPage = Cols * Rows
	local Pages = math.max(1, math.ceil(#List / PerPage))
	Launchpad.Pages = Pages
	Launchpad.Page = math.max(1, math.min(Launchpad.Page, Pages))
	local StartX = math.floor((ScreenW - Cols * CellW) / 2) + 1
	local StartY = 4
	local First = (Launchpad.Page - 1) * PerPage
	for Slot = 1, PerPage do
		local App = List[First + Slot]
		if (not App) then break end
		local Col = (Slot - 1) % Cols
		local Row = math.floor((Slot - 1) / Cols)
		local X = StartX + Col * CellW
		local Y = StartY + Row * CellH
		for Line = 1, 2 do
			Screen.setCursorPos(X + 3, Y + Line - 1)
			Screen.blit(Gfx.Pad(App.Icon.Lines[Line] or "", 3), string.rep(Gfx.ToBlit(App.Icon.Fg), 3), string.rep(Gfx.ToBlit(App.Icon.Bg), 3))
		end
		Gfx.Write(Screen, X, Y + 2, Gfx.Pad(App.Name, CellW - 1, "center"), colors.white, colors.gray)
		table.insert(Launchpad.Regions, { X = X, Y = Y, W = CellW - 1, H = 3, App = App })
	end
	if (#List == 0) then
		Gfx.Center(Screen, 6, "No apps found", colors.white, colors.gray)
	end
	if (Pages > 1) then
		local Dots = ""
		for Page = 1, Pages do
			Dots = Dots .. "\7 "
		end
		local DotX = math.floor((ScreenW - #Dots) / 2) + 1
		for Page = 1, Pages do
			Gfx.Write(Screen, DotX + (Page - 1) * 2, ScreenH, "\7", (Page == Launchpad.Page) and colors.white or colors.lightGray, colors.gray)
		end
	end
end

local function ToastWidth()
	return math.min(28, ScreenW - 2)
end

function Draw.Toasts(Th)
	local Y = (FocusedFullscreen() and not RevealActive()) and 1 or 2
	local W = ToastWidth()
	for _, Toast in ipairs(Toasts) do
		local X = ScreenW - W + (Toast.Slide or 0)
		local Lines = Gfx.Wrap(Toast.Text or "", W - 2)
		local H = math.min(#Lines, 2) + 2
		Gfx.Fill(Screen, X, Y, W, H, Th.MenuBg)
		Gfx.Write(Screen, X + 1, Y, Gfx.Truncate(Toast.Title, W - 2), Th.Accent, Th.MenuBg)
		for Row = 1, H - 2 do
			Gfx.Write(Screen, X + 1, Y + Row, Gfx.Truncate(Lines[Row], W - 2), Th.MenuFg, Th.MenuBg)
		end
		Gfx.Write(Screen, X + W - 2, Y, "x", Th.MenuDim, Th.MenuBg)
		Toast.X, Toast.Y, Toast.W, Toast.H = X, Y, W, H
		Y = Y + H + 1
		if (Y > ScreenH - 3) then break end
	end
end

function Draw.Menu(Th)
	local Current = Menu
	local Height = #Current.Items
	local Shown = Current.Reveal or Height
	-- Dock menus sit above the dock, so they unroll upwards.
	local First = Current.Up and (Height - Shown + 1) or 1
	local Last = Current.Up and Height or Shown
	Gfx.Fill(Screen, Current.X, Current.Y + First - 1, Current.W, Last - First + 1, Th.MenuBg)
	for Index = First, Last do
		local Item = Current.Items[Index]
		local Y = Current.Y + Index - 1
		if (Item == "-") then
			Gfx.Write(Screen, Current.X, Y, string.rep("\140", Current.W), Th.MenuDim, Th.MenuBg)
		else
			local Bg, Fg = Th.MenuBg, Item.Disabled and Th.MenuDim or Th.MenuFg
			if (Index == Current.Hover and not Item.Disabled) then
				Bg, Fg = Th.Accent, Th.AccentFg
			end
			local Prefix = Item.Checked and "\4" or " "
			local Hint = Item.Hint or ""
			Gfx.Write(Screen, Current.X, Y, Gfx.Pad(Prefix .. Item.Text, Current.W - #Hint - 1) .. Hint .. " ", Fg, Bg)
		end
	end
	if (not Current.Reveal) then
		Gfx.Shadow(Screen, Current.X, Current.Y, Current.W, Height, Th.Shadow)
	end
end

function Draw.Dialog(Th)
	local Current = Dialog
	local W = math.min(34, ScreenW - 4)
	local Lines = Gfx.Wrap(Current.Text or "", W - 4)
	local H = #Lines + 5
	local X = math.floor((ScreenW - W) / 2) + 1
	local Y = math.floor((ScreenH - H) / 2) + 1
	Gfx.Fill(Screen, X, Y, W, H, Th.MenuBg)
	Gfx.Fill(Screen, X, Y, W, 1, Th.TitleBg)
	Gfx.Center(Screen, Y, Current.Title, Th.TitleFg, Th.TitleBg, X, W)
	for Row, Line in ipairs(Lines) do
		Gfx.Write(Screen, X + 2, Y + Row + 1, Line, Th.MenuFg, Th.MenuBg)
	end
	local ButtonX = X + W - 1
	for Index = #Current.Buttons, 1, -1 do
		local Button = Current.Buttons[Index]
		local Text = " " .. Button.Text .. " "
		ButtonX = ButtonX - #Text
		local Bg = Button.Primary and Th.Accent or Th.ButtonBg
		local Fg = Button.Primary and Th.AccentFg or Th.ButtonFg
		Gfx.Write(Screen, ButtonX, Y + H - 2, Text, Fg, Bg)
		Button.X, Button.Y, Button.W = ButtonX, Y + H - 2, #Text
		ButtonX = ButtonX - 1
	end
	Gfx.Shadow(Screen, X, Y, W, H, Th.Shadow)
end

-- An empty window outline used while a window opens or minimizes.
function Draw.Ghost(Th)
	local X, Y, W, H = Ghost[1], Ghost[2], Ghost[3], Ghost[4]
	Gfx.Fill(Screen, X, Y, W, H, Th.WindowBg)
	Gfx.Fill(Screen, X, Y, W, 1, Th.TitleBg)
	if (W >= 6 and H >= 2) then
		Gfx.Write(Screen, X + 1, Y, "\7 \7 \7", Th.TitleIdleFg, Th.TitleBg)
	end
	if (W >= 4 and H >= 3) then
		Gfx.Shadow(Screen, X, Y, W, H, Th.Shadow)
	end
end

local function RestoreCursor()
	if (Focused and Focused.Live and not Focused.AppHidden) then
		if (Focused.Window.restoreCursor) then
			Focused.Window.restoreCursor()
		else
			Focused.Window.setCursorPos(Focused.Window.getCursorPos())
		end
	else
		Screen.setCursorBlink(false)
	end
end

function Redraw()
	if (RedrawTimer) then
		os.cancelTimer(RedrawTimer)
		RedrawTimer = nil
	end
	if (Locked) then
		if (LockScreen and LockScreen.Timer) then LockScreen:Draw() end
		return
	end
	local Th = Theme.Get()
	Screen.setVisible(false)
	Draw.Wallpaper()
	local FullFocus = FocusedFullscreen()
	if (FullFocus) then
		Shortcuts.Regions = {}
	else
		Shortcuts.Draw(Th)
	end
	local Revealed = FullFocus and RevealActive()
	local Overlay = Menu or Dialog or Launchpad.Open or #Toasts > 0 or Revealed or Ghost
	for _, Proc in ipairs(Processes) do
		Proc.Live = false
		if (Proc.Minimized or Proc.Opening) then
			Hide(Proc)
		else
			if (not Proc.Fullscreen) then
				Draw.Frame(Proc, Th, Proc == Focused)
			end
			Show(Proc)
			if (Proc == Focused and not Overlay and not Proc.Dead) then
				Proc.Live = true
				if (Proc.AppHidden) then
					Proc.Window.setVisible(false)
					Proc.Shown = false
				end
			else
				Hide(Proc)
			end
		end
	end
	if (not FullFocus) then
		Draw.Topbar(Th)
		Draw.Dock(Th)
	elseif (Revealed) then
		Draw.Topbar(Th)
		Draw.Frame(Focused, Th, true, 2)
	end
	if (Launchpad.Open) then Draw.Launchpad(Th) end
	Draw.Toasts(Th)
	if (Menu) then Draw.Menu(Th) end
	if (Dialog) then Draw.Dialog(Th) end
	if (Ghost) then Draw.Ghost(Th) end
	Screen.setVisible(true)
	RestoreCursor()
end

function ScheduleRedraw()
	if (Locked or RedrawTimer) then return end
	RedrawTimer = os.startTimer(.1)
end

--
-- Notifications and dialogs
--

local function PlaySound(Count)
	local Speaker = peripheral.find("speaker")
	if (not Speaker) then return end
	for _ = 1, Count or 1 do
		pcall(Speaker.playNote, "bell", 1, 18)
	end
end

function Notify(Title, Text, Opts)
	Opts = Opts or {}
	local Entry = { Title = tostring(Title), Text = tostring(Text or ""), AppID = Opts.AppID, Args = Opts.Args, Expires = os.clock() + (Opts.Duration or 5) }
	table.insert(History, 1, Entry)
	while (#History > 30) do table.remove(History) end
	local Settings = Config.Settings()
	if (not Settings.Notifications) then return end
	table.insert(Toasts, 1, Entry)
	while (#Toasts > 3) do table.remove(Toasts) end
	if (QueueAnimation({ Kind = "toast", Toast = Entry })) then
		Entry.Slide = ToastWidth() + 1
	end
	if (Settings.NotificationSound and Opts.Sound ~= false) then
		PlaySound(Opts.Repeat)
	end
	Redraw()
end

local function ShowDialog(Title, Text, Buttons)
	Menu = nil
	Dialog = { Title = Title, Text = Text, Buttons = Buttons }
	Redraw()
end

local function Confirm(Title, Text, YesText, OnYes)
	ShowDialog(Title, Text, {
		{ Text = "Cancel" },
		{ Text = YesText, Primary = true, Action = OnYes }
	})
end

--
-- Session: lock, login, services
--

local Daemons = {}

function Daemons.Scheduler()
	local Schedule = BlockOS.Require("schedule")
	while (true) do
		for _, Entry in ipairs(Schedule.CollectDue()) do
			if (Entry.Kind == "reminder") then
				Notify("Reminder", Entry.Item.Title, { AppID = "reminders" })
			else
				Notify("Alarm", Entry.Item.Label or "Alarm", { AppID = "clock", Repeat = 3, Duration = 10 })
			end
		end
		sleep(1)
	end
end

function Daemons.Chat()
	local Chat = BlockOS.Require("chat")
	Chat.Load()
	Chat.OpenModems()
	Chat.Presence()
	local Timer = os.startTimer(30)
	while (true) do
		local Event, A, B, C = os.pullEvent()
		if (Event == "rednet_message" and C == Chat.Protocol) then
			local Room, Message = Chat.Receive(A, B)
			if (Room) then
				os.queueEvent("blockos_chat", Room.ID)
				if (not (Focused and Focused.AppID == "messages")) then
					local Title = Room.Target and Message.Nick or ("#" .. Room.Name)
					local Body = Message.Text
					if (Message.Kind == "me") then
						Body = "* " .. Message.Nick .. " " .. Body
					elseif (not Room.Target) then
						Body = Message.Nick .. ": " .. Body
					end
					Notify(Title, Body, { AppID = "messages" })
				else
					ScheduleRedraw()
				end
			end
		elseif (Event == "timer" and A == Timer) then
			Chat.Presence()
			Timer = os.startTimer(30)
		elseif (Event == "peripheral") then
			Chat.OpenModems()
		end
	end
end

function Daemons.Update()
	local Updater = BlockOS.Require("updater")
	sleep(10)
	while (true) do
		local Settings = Config.Settings()
		if (Settings.AutoUpdate and http) then
			local Manifest = Updater.Check()
			if (Manifest and Manifest.Newer) then
				if (Settings.AutoInstall) then
					if (Updater.Apply(Manifest)) then
						Notify("Software Update", "BlockOS " .. Manifest.Version .. " was installed. Restart to finish.", { AppID = "settings", Args = { "update" } })
					end
				else
					Notify("Software Update", "BlockOS " .. Manifest.Version .. " is available.", { AppID = "settings", Args = { "update" } })
				end
			end
			ScheduleRedraw()
		end
		sleep(7200)
	end
end

function Daemons.Presence()
	local Presence = BlockOS.Require("presence")
	Presence.OpenModems()
	Presence.Locate()
	local Timer = os.startTimer(60)
	while (true) do
		local Event, A, B, C = os.pullEvent()
		if (Event == "rednet_message" and C == Presence.Protocol) then
			Presence.Answer(A, B)
		elseif (Event == "timer" and A == Timer) then
			Presence.Locate()
			Timer = os.startTimer(Presence.Position and 60 or 300)
		elseif (Event == "peripheral") then
			Presence.OpenModems()
		end
	end
end

local function StartSession()
	if (SessionStarted) then return end
	SessionStarted = true
	Users.EnsureHome()
	RefreshApps()
	StartService("scheduler", Daemons.Scheduler)
	StartService("chat", Daemons.Chat)
	StartService("presence", Daemons.Presence)
	StartService("updater", Daemons.Update)
	for _, ID in ipairs(Config.Settings().StartupApps or {}) do
		Launch(ID)
	end
end

local function Power(Action)
	local Run = (Action == "restart") and os.reboot or os.shutdown
	if (not QueueAnimation({ Kind = "power", Run = Run })) then
		Run()
	end
end

local function EnterLock()
	Menu = nil
	Dialog = nil
	Launchpad.Open = false
	Drag = nil
	MouseTarget = nil
	for _, Proc in ipairs(Processes) do
		Hide(Proc)
	end
	Locked = true
	LockScreen = Login.new(Screen, { OnPower = Power })
	LockScreen:Start()
end

-- Locking fades the desktop out and the lock screen in.
function Lock()
	if (Locked or PendingLock) then return end
	if (SessionStarted and QueueAnimation({ Kind = "lock" })) then
		PendingLock = true
		return
	end
	EnterLock()
end

local function Unlock()
	if (LockScreen) then LockScreen:Stop() end
	LockScreen = nil
	Locked = false
	Modifiers = {}
	LastInput = os.clock()
	StartSession()
	Redraw()
end

local function LogOut()
	for _, Proc in ipairs(Copy(Processes)) do
		Kill(Proc)
	end
	Lock()
end

--
-- Menus
--

local function MenuWidth(Items)
	local W = 8
	for _, Item in ipairs(Items) do
		if (Item ~= "-") then
			W = math.max(W, #Item.Text + #(Item.Hint or "") + 4)
		end
	end
	return math.min(W, ScreenW - 2)
end

function OpenMenu(Name, X, Y, Items)
	if (not Items) then
		Items = {}
		local User = Users.Primary()
		if (Name == "logo") then
			Items = {
				{ Text = "About BlockOS", Action = function() Launch("about") end },
				"-",
				{ Text = "System Settings...", Action = function() Launch("settings") end },
				{ Text = "App Store...", Action = function() Launch("appstore") end },
				"-",
				{ Text = "Force Quit...", Action = function() OpenMenu("forcequit", 2, 2) end, Disabled = #Processes == 0 },
				"-",
				{ Text = "Lock Screen", Hint = "^\24L", Action = Lock },
				{ Text = "Log Out " .. (User and User.Name or ""), Action = LogOut },
				"-",
				{ Text = "Restart...", Action = function() Confirm("Restart", "Restart the computer now?", "Restart", function() Power("restart") end) end },
				{ Text = "Shut Down...", Action = function() Confirm("Shut Down", "Shut down the computer now?", "Shut Down", function() Power("shutdown") end) end }
			}
		elseif (Name == "forcequit") then
			for _, Proc in ipairs(Processes) do
				local Target = Proc
				table.insert(Items, { Text = Gfx.Truncate(Proc.Title, 24), Action = function() Kill(Target) end })
			end
		elseif (Name == "app") then
			local Current = Focused
			local Title = AppName()
			Items = {
				{ Text = "About " .. Title, Disabled = not Current, Action = function()
					local App = Current and Current.AppID and AppCache[Current.AppID]
					ShowDialog(Title, App and ((App.Description or "") .. "\n\nVersion " .. (App.Version or Config.Version())) or "A program running on BlockOS.", { { Text = "OK", Primary = true } })
				end },
				"-",
				{ Text = "Hide " .. Title, Hint = "^\24M", Disabled = not Current, Action = function() Minimize(Current) end },
				{ Text = "Quit " .. Title, Hint = "^\24W", Disabled = not Current, Action = function()
					if (Current and Current.AppID) then
						for _, Proc in ipairs(ProcsOf(Current.AppID)) do CloseProc(Proc) end
					else
						CloseProc(Current)
					end
				end }
			}
		elseif (Name == "go") then
			local Places = {
				{ "Home", "/home" }, { "Documents", "/home/Documents" }, { "Downloads", "/home/Downloads" },
				{ "Music", "/home/Music" }, { "Applications", "apps:" }, { "Computer", "/" }
			}
			for _, Place in ipairs(Places) do
				local Target = Place[2]
				table.insert(Items, { Text = Place[1], Action = function() Launch("finder", { Target }) end })
			end
			table.insert(Items, "-")
			table.insert(Items, { Text = "Terminal", Hint = "^\24T", Action = function() Launch("terminal") end })
			table.insert(Items, { Text = "Launchpad", Hint = "^\24Spc", Action = ToggleLaunchpad })
		elseif (Name == "window") then
			local Current = Focused
			Items = {
				{ Text = "Minimize", Hint = "^\24M", Disabled = not Current, Action = function() Minimize(Current) end },
				{ Text = "Zoom", Disabled = not Current or (Current and Current.Fullscreen), Action = function() Zoom(Current) end },
				{ Text = (Current and Current.Fullscreen) and "Exit Full Screen" or "Enter Full Screen", Hint = "^\24F", Disabled = not Current, Action = function() ToggleFullscreen(Current) end },
				{ Text = "Show Desktop", Hint = "^\24D", Action = ShowDesktop },
				"-",
				{ Text = "Close Window", Hint = "^\24W", Disabled = not Current, Action = function() CloseProc(Current) end }
			}
			if (#Processes > 0) then
				table.insert(Items, "-")
				for Index = #Processes, 1, -1 do
					local Proc = Processes[Index]
					table.insert(Items, { Text = Gfx.Truncate(Proc.Title, 22), Checked = Proc == Focused, Action = function() Focus(Proc) end })
				end
			end
		end
	end
	if (#Items == 0) then return end
	local W = MenuWidth(Items)
	Y = Y or 2
	while (Y + #Items - 1 > ScreenH) do
		Y = Y - 1
	end
	Menu = {
		Name = Name,
		Items = Items,
		X = math.max(1, math.min(X or 1, ScreenW - W)),
		Y = math.max(1, Y),
		W = W,
		Hover = 0,
		Up = Name == "dock"
	}
	if (#Items > 1 and QueueAnimation({ Kind = "menu", Menu = Menu })) then
		Menu.Reveal = 1
	end
	Redraw()
end

local function RunMenuItem(Index)
	local Item = Menu and Menu.Items[Index]
	if (not Item or Item == "-" or Item.Disabled) then return false end
	Menu = nil
	Redraw()
	if (Item.Action) then Item.Action() end
	return true
end

local function OpenDockMenu(Item)
	local Items = {}
	if (Item.Proc) then
		Items = {
			{ Text = "Show", Action = function() Focus(Item.Proc) end },
			{ Text = "Quit", Action = function() CloseProc(Item.Proc) end }
		}
	else
		local App = Item.App
		local Windows = ProcsOf(App.ID)
		for Index = #Windows, 1, -1 do
			local Proc = Windows[Index]
			table.insert(Items, { Text = Gfx.Truncate(Proc.Title, 20), Checked = Proc == Focused, Action = function() Focus(Proc) end })
		end
		if (#Windows > 0) then table.insert(Items, "-") end
		if (App.Builtin ~= "launchpad") then
			table.insert(Items, { Text = (#Windows > 0) and "New Window" or "Open", Action = function() Launch(App.ID) end })
		end
		local Pinned = Apps.IsPinned(App.ID)
		table.insert(Items, { Text = Pinned and "Remove from Dock" or "Keep in Dock", Action = function() Apps.SetPinned(App.ID, not Pinned) end })
		local Shortcut = Apps.AppShortcut(App.ID)
		local OnDesktop = Apps.HasShortcut(Shortcut)
		table.insert(Items, { Text = OnDesktop and "Remove from Desktop" or "Add to Desktop", Action = function() Apps.SetShortcut(Shortcut, not OnDesktop) end })
		if (#Windows > 0) then
			table.insert(Items, "-")
			table.insert(Items, { Text = "Quit", Action = function()
				for _, Proc in ipairs(Windows) do CloseProc(Proc) end
			end })
		end
	end
	OpenMenu("dock", Item.X, DockTop() - #Items, Items)
end

local function OpenLaunchpadMenu(Region)
	local App = Region.App
	local From = { Region.X + 3, Region.Y, 3, 2 }
	local Pinned = Apps.IsPinned(App.ID)
	local Shortcut = Apps.AppShortcut(App.ID)
	local OnDesktop = Apps.HasShortcut(Shortcut)
	local function Open(Mode)
		Launchpad.Open = false
		Launch(App.ID, nil, { From = From, Mode = Mode })
		Redraw()
	end
	OpenMenu("launchpad", Region.X + 3, Region.Y + 2, {
		{ Text = "Open", Action = function() Open() end },
		{ Text = "Open Full Screen", Action = function() Open("fullscreen") end },
		"-",
		{ Text = Pinned and "Remove from Dock" or "Keep in Dock", Action = function() Apps.SetPinned(App.ID, not Pinned) end },
		{ Text = OnDesktop and "Remove from Desktop" or "Add to Desktop", Action = function() Apps.SetShortcut(Shortcut, not OnDesktop) end }
	})
end

function Shortcuts.Open(Info)
	if (Info.App) then
		Launch(Info.App.ID, nil, { From = { Info.X + 3, Info.Y, 3, 2 } })
	else
		OpenFile(Info.Path)
	end
end

function Shortcuts.OpenMenu(Info, X, Y)
	local Items = { { Text = "Open", Action = function() Shortcuts.Open(Info) end } }
	if (Info.Path) then
		if (not Info.IsDir) then
			table.insert(Items, { Text = "Edit", Action = function() Launch(Apps.EditorFor(Info.Path), { Info.Path }) end })
		end
		table.insert(Items, { Text = "Show in Finder", Action = function() Launch("finder", { "/" .. fs.getDir(Info.Path) }) end })
	end
	table.insert(Items, "-")
	table.insert(Items, { Text = "Remove Shortcut", Action = function() Apps.SetShortcut(Info.Entry, false) end })
	if (Info.Path) then
		local Kind = Info.IsDir and "Folder" or "File"
		table.insert(Items, { Text = "Delete " .. Kind .. "...", Disabled = fs.isReadOnly(Info.Path), Action = function()
			Confirm("Delete " .. Kind, "Delete \"" .. Info.Name .. "\"? This cannot be undone.", "Delete", function()
				local Ok, Err = pcall(fs.delete, Info.Path)
				if (Ok) then
					Apps.MoveShortcuts(Info.Path, nil)
				else
					Notify("Delete failed", Err, { Sound = false })
				end
			end)
		end })
	elseif (not Info.App.System) then
		table.insert(Items, { Text = "Uninstall...", Action = function()
			Confirm("Uninstall", "Remove " .. Info.Name .. " from this computer?", "Uninstall", function()
				Apps.Uninstall(Info.App.ID)
			end)
		end })
	end
	OpenMenu("shortcut", X, Y, Items)
end

-- One click selects a shortcut and a second one soon after opens it.
function Shortcuts.Click(Info)
	local Now = os.clock()
	if (Shortcuts.LastClick.Entry == Info.Entry and Now - Shortcuts.LastClick.Time < .4) then
		Shortcuts.LastClick = { Time = 0 }
		Shortcuts.Open(Info)
		return
	end
	Shortcuts.LastClick = { Entry = Info.Entry, Time = Now }
	Shortcuts.Selected = Info.Entry
	Redraw()
end

local function OpenDesktopMenu(X, Y)
	OpenMenu("desktop", X, Y, {
		{ Text = "New Terminal", Action = function() Launch("terminal") end },
		{ Text = "Open Finder", Action = function() Launch("finder") end },
		{ Text = "Launchpad", Action = ToggleLaunchpad },
		"-",
		{ Text = "Change Wallpaper...", Action = function() Launch("settings", { "appearance" }) end },
		{ Text = "About BlockOS", Action = function() Launch("about") end }
	})
end

--
-- Input
--

local function ActivateDockItem(Item)
	if (Item.Proc) then
		Focus(Item.Proc)
		return
	end
	local App = Item.App
	if (App.Builtin == "launchpad") then
		ToggleLaunchpad()
		return
	end
	local Windows = ProcsOf(App.ID)
	if (#Windows == 0) then
		Launch(App.ID)
	elseif (Focused and Focused.AppID == App.ID and #Windows > 1) then
		Focus(Windows[1])
	else
		Focus(Windows[#Windows])
	end
end

local function TopbarClick(Button, X)
	for _, Region in ipairs(Topbar.Regions) do
		if (X >= Region.X and X < Region.X + Region.W) then
			if (Region.Menu) then
				OpenMenu(Region.Menu, Region.X, 2)
			elseif (Region.Action == "clock") then
				Launch("clock")
			elseif (Region.Action == "desktop") then
				ShowDesktop()
			elseif (Region.Action == "update") then
				Launch("settings", { "update" })
			elseif (Region.Action == "recording") then
				os.queueEvent("blockos_recorder_stop")
			end
			if (RevealUntil) then RevealUntil = os.clock() + 3 end
			return
		end
	end
end

local function TitlebarClick(Proc, Relative, X, Y)
	if (Relative == 1) then
		CloseProc(Proc)
	elseif (Relative == 3) then
		Minimize(Proc)
	elseif (Relative == 5) then
		ToggleFullscreen(Proc)
	elseif (not Proc.Fullscreen) then
		local Now = os.clock()
		if (LastTitleClick.Proc == Proc and Now - LastTitleClick.Time < .4) then
			LastTitleClick = { Time = 0 }
			Zoom(Proc)
			return
		end
		LastTitleClick = { Proc = Proc, Time = Now }
		Drag = { Proc = Proc, Mode = "move", OffX = X - Proc.X, OffY = Y - Proc.Y }
	end
end

local function LaunchpadClick(Button, X, Y)
	for _, Region in ipairs(Launchpad.Regions) do
		if (X >= Region.X and X < Region.X + Region.W and Y >= Region.Y and Y < Region.Y + Region.H) then
			if (Button == 2) then
				OpenLaunchpadMenu(Region)
				return
			end
			Launchpad.Open = false
			Launch(Region.App.ID, nil, { From = { Region.X + 3, Region.Y, 3, 2 } })
			Redraw()
			return
		end
	end
	if (Y == 2 or Y == ScreenH) then return end
	CloseLaunchpad()
end

local Input = {}

function Input.Click(Button, X, Y)
	if (Dialog) then
		for _, Item in ipairs(Dialog.Buttons) do
			if (Item.X and Y == Item.Y and X >= Item.X and X < Item.X + Item.W) then
				Dialog = nil
				Redraw()
				if (Item.Action) then Item.Action() end
				return
			end
		end
		return
	end
	if (Menu) then
		local Current = Menu
		if (X >= Current.X and X < Current.X + Current.W and Y >= Current.Y and Y < Current.Y + #Current.Items) then
			RunMenuItem(Y - Current.Y + 1)
			return
		end
		Menu = nil
		Redraw()
		if (Y ~= 1) then return end
		for _, Region in ipairs(Topbar.Regions) do
			if (Region.Menu == Current.Name and X >= Region.X and X < Region.X + Region.W) then
				return
			end
		end
	end
	if (Launchpad.Open) then
		LaunchpadClick(Button, X, Y)
		return
	end
	for Index, Toast in ipairs(Toasts) do
		if (Toast.X and X >= Toast.X and X < Toast.X + Toast.W and Y >= Toast.Y and Y < Toast.Y + Toast.H) then
			table.remove(Toasts, Index)
			if (Toast.AppID and X < Toast.X + Toast.W - 2) then
				Launch(Toast.AppID, Toast.Args)
			end
			Redraw()
			return
		end
	end
	local FullFocus = FocusedFullscreen()
	local Revealed = FullFocus and RevealActive()
	if (FullFocus and not Revealed and Y == 1 and (X <= 2 or Button == 2)) then
		RevealTopbar()
		return
	end
	if (Y == 1 and (not FullFocus or Revealed)) then
		TopbarClick(Button, X)
		return
	end
	if (Revealed and Y == 2) then
		TitlebarClick(Focused, X - 1, X, Y)
		return
	end
	if (not FullFocus and Y >= DockTop()) then
		for _, Item in ipairs(DockRegions) do
			if (X >= Item.X and X < Item.X + 3) then
				if (Button == 2) then
					OpenDockMenu(Item)
				else
					ActivateDockItem(Item)
				end
				return
			end
		end
		if (Config.Settings().DockStyle ~= "transparent") then return end
	end
	for Index = #Processes, 1, -1 do
		local Proc = Processes[Index]
		local Inside
		if (Proc.Fullscreen) then
			Inside = true
		else
			Inside = X >= Proc.X and X < Proc.X + Proc.W and Y >= Proc.Y and Y < Proc.Y + Proc.H
		end
		if (not Proc.Minimized and not Proc.Opening and Inside) then
			if (Proc ~= Focused) then Focus(Proc) end
			if (not Proc.Fullscreen and Y == Proc.Y) then
				TitlebarClick(Proc, X - Proc.X, X, Y)
				return
			end
			if (Proc.Dead) then
				Kill(Proc)
				return
			end
			if (not Proc.Fullscreen and X == Proc.X + Proc.W - 1 and Y == Proc.Y + Proc.H - 1) then
				Drag = { Proc = Proc, Mode = "resize" }
				return
			end
			MouseTarget = Proc
			SendMouse(Proc, "mouse_click", Button, X, Y)
			return
		end
	end
	if (Focused) then
		Focused = nil
		Redraw()
	end
	local Info = Shortcuts.At(X, Y)
	if (Info) then
		if (Button == 2) then
			Shortcuts.Selected = Info.Entry
			Shortcuts.OpenMenu(Info, X, Y)
		else
			Shortcuts.Click(Info)
		end
		return
	end
	if (Shortcuts.Selected) then
		Shortcuts.Selected = nil
		Redraw()
	end
	if (Button == 2) then
		OpenDesktopMenu(X, Y)
	end
end

function Input.Drag(Button, X, Y)
	if (Menu) then
		local Index = Y - Menu.Y + 1
		if (X >= Menu.X and X < Menu.X + Menu.W and Menu.Items[Index]) then
			Menu.Hover = Index
			Redraw()
		end
		return
	end
	if (Drag) then
		local Proc = Drag.Proc
		local _, AreaY, AreaW, AreaH = WorkArea()
		if (Drag.Mode == "move") then
			Proc.X = X - Drag.OffX
			Proc.Y = Y - Drag.OffY
		else
			Proc.W = math.min(X - Proc.X + 1, AreaW - Proc.X + 1)
			Proc.H = math.min(Y - Proc.Y + 1, AreaY + AreaH - Proc.Y)
		end
		Proc.Saved = nil
		ClampWindow(Proc)
		ApplyGeometry(Proc)
		Redraw()
		return
	end
	if (MouseTarget and not MouseTarget.Dead) then
		SendMouse(MouseTarget, "mouse_drag", Button, X, Y)
	end
end

function Input.Up(Button, X, Y)
	if (Menu and Menu.Hover > 0 and Y ~= 1) then
		local Index = Y - Menu.Y + 1
		if (X >= Menu.X and X < Menu.X + Menu.W and Index == Menu.Hover) then
			RunMenuItem(Index)
			return
		end
	end
	if (Drag) then
		Drag = nil
		return
	end
	if (MouseTarget and not MouseTarget.Dead) then
		SendMouse(MouseTarget, "mouse_up", Button, X, Y)
	end
	MouseTarget = nil
end

function Input.Scroll(Direction, X, Y)
	if (Launchpad.Open) then
		Launchpad.Page = math.max(1, math.min((Launchpad.Pages or 1), Launchpad.Page + Direction))
		Redraw()
		return
	end
	if (Menu or Dialog) then return end
	local FullFocus = FocusedFullscreen()
	if (FullFocus and Y == 1 and Direction < 0) then
		RevealTopbar()
		return
	end
	for Index = #Processes, 1, -1 do
		local Proc = Processes[Index]
		if (not Proc.Minimized and not Proc.Opening) then
			local CX, CY, CW, CH = ContentRect(Proc)
			if (X >= CX and X < CX + CW and Y >= CY and Y < CY + CH) then
				if (not Proc.Dead) then
					SendMouse(Proc, "mouse_scroll", Direction, X, Y)
				end
				return
			end
		end
	end
end

local function CycleWindows()
	if (#Processes < 2) then
		if (Processes[1]) then Focus(Processes[1]) end
		return
	end
	Focus(Processes[1])
end

local function Shortcut(Key)
	if (Key == keys.f) then
		ToggleFullscreen(Focused)
	elseif (Key == keys.w or Key == keys.q) then
		CloseProc(Focused)
	elseif (Key == keys.m) then
		Minimize(Focused)
	elseif (Key == keys.tab) then
		CycleWindows()
	elseif (Key == keys.space) then
		ToggleLaunchpad()
	elseif (Key == keys.l) then
		Lock()
	elseif (Key == keys.t) then
		Launch("terminal")
	elseif (Key == keys.d) then
		ShowDesktop()
	elseif (Key == keys.up and FocusedFullscreen()) then
		RevealTopbar()
	else
		return false
	end
	return true
end

function Input.Key(Name, Key, Held)
	local Modifier = ModifierKeys[Key]
	if (Modifier) then
		Modifiers[Modifier] = (Name == "key")
	end
	if (Name == "key" and not Modifier and Modifiers.Ctrl and Modifiers.Shift and Shortcut(Key)) then
		return
	end
	if (Dialog) then
		if (Name == "key" and (Key == keys.enter or Key == keys.numPadEnter)) then
			local Primary = Dialog.Buttons[#Dialog.Buttons]
			Dialog = nil
			Redraw()
			if (Primary.Action) then Primary.Action() end
		end
		return
	end
	if (Menu) then
		if (Name ~= "key") then return end
		if (Key == keys.down or Key == keys.up) then
			local Step = (Key == keys.down) and 1 or -1
			for _ = 1, #Menu.Items do
				Menu.Hover = (Menu.Hover - 1 + Step) % #Menu.Items + 1
				local Item = Menu.Items[Menu.Hover]
				if (Item ~= "-" and not Item.Disabled) then break end
			end
			Redraw()
		elseif (Key == keys.enter or Key == keys.numPadEnter) then
			RunMenuItem(Menu.Hover)
		elseif (not Modifier) then
			Menu = nil
			Redraw()
		end
		return
	end
	if (Launchpad.Open) then
		if (Name ~= "key") then return end
		if (Key == keys.backspace) then
			if (#Launchpad.Query == 0) then
				CloseLaunchpad()
			else
				Launchpad.Query = Launchpad.Query:sub(1, -2)
			end
			Redraw()
		elseif (Key == keys.enter or Key == keys.numPadEnter) then
			local First = LaunchpadApps()[1]
			Launchpad.Open = false
			if (First) then Launch(First.ID) end
			Redraw()
		end
		return
	end
	if (Focused) then
		if (Focused.Dead) then
			if (Name == "key" and not Modifier) then Kill(Focused) end
			return
		end
		Resume(Focused, Name, Key, Held)
	end
end

function Input.Text(Event)
	if (Dialog or Menu) then return end
	if (Launchpad.Open) then
		Launchpad.Query = (Launchpad.Query .. Event[2]):sub(1, 20)
		Launchpad.Page = 1
		Redraw()
		return
	end
	if (Focused and not Focused.Dead) then
		Resume(Focused, table.unpack(Event, 1, Event.n))
	end
end

function Input.Resize()
	ScreenW, ScreenH = Native.getSize()
	Screen.reposition(1, 1, ScreenW, ScreenH)
	for _, Proc in ipairs(Processes) do
		ClampWindow(Proc)
		ApplyGeometry(Proc)
	end
	Redraw()
end

local function ClockTick()
	local Changed = false
	local Now = os.clock()
	for Index = #Toasts, 1, -1 do
		local Toast = Toasts[Index]
		if (Toast.Expires <= Now and not Toast.Leaving) then
			if (QueueAnimation({ Kind = "toastout", Toast = Toast })) then
				Toast.Leaving = true
			else
				table.remove(Toasts, Index)
				Changed = true
			end
		end
	end
	if (RevealUntil and Now >= RevealUntil) then
		RevealUntil = nil
		Changed = true
	end
	local IdleLock = Config.Settings().IdleLock or 0
	if (not Locked and IdleLock > 0 and Now - LastInput > IdleLock * 60) then
		Lock()
		return
	end
	if (Locked) then return end
	if (Changed) then
		Redraw()
	elseif (not FocusedFullscreen() and not Launchpad.Open) then
		Draw.Topbar(Theme.Get())
		if (Menu) then Draw.Menu(Theme.Get()) end
		RestoreCursor()
	end
end

local function HandleEvent(Event)
	local Name = Event[1]
	if (Name == "timer") then
		local ID = Event[2]
		if (ID == RedrawTimer) then
			RedrawTimer = nil
			Redraw()
			return
		elseif (ID == ClockTimer) then
			ClockTimer = os.startTimer(1)
			ClockTick()
			return
		elseif (Locked and LockScreen and ID == LockScreen.Timer) then
			LockScreen:Event("timer", ID)
			return
		end
		Broadcast(Event)
		return
	end
	if (Name == "term_resize") then
		Input.Resize()
		return
	end
	if (Locked) then
		if (InputEvents[Name]) then
			LastInput = os.clock()
			if (not PendingUnlock and LockScreen:Event(table.unpack(Event, 1, Event.n))) then
				if (QueueAnimation({ Kind = "unlock" })) then
					PendingUnlock = true
				else
					Unlock()
				end
			end
		elseif (Name ~= "terminate") then
			Broadcast(Event)
		end
		return
	end
	if (InputEvents[Name]) then
		LastInput = os.clock()
	end
	if (Name == "mouse_click") then
		Input.Click(Event[2], Event[3], Event[4])
	elseif (Name == "mouse_drag") then
		Input.Drag(Event[2], Event[3], Event[4])
	elseif (Name == "mouse_up") then
		Input.Up(Event[2], Event[3], Event[4])
	elseif (Name == "mouse_scroll") then
		Input.Scroll(Event[2], Event[3], Event[4])
	elseif (Name == "key" or Name == "key_up") then
		Input.Key(Name, Event[2], Event[3])
	elseif (Name == "char" or Name == "paste") then
		Input.Text(Event)
	elseif (Name == "terminate") then
		if (Focused and not Focused.Dead) then
			Resume(Focused, "terminate")
		end
	elseif (Name == "blockos_settings" or Name == "blockos_apps") then
		RefreshApps()
		for _, Proc in ipairs(Processes) do
			ClampWindow(Proc)
			ApplyGeometry(Proc)
		end
		Redraw()
		Broadcast(Event)
	elseif (Name == "disk") then
		local Side = Event[2]
		local Label = disk.getLabel(Side) or (disk.hasAudio(Side) and disk.getAudioTitle(Side)) or "Untitled disk"
		Notify("Disk inserted", Label .. " (" .. Side .. ")", { AppID = "finder", Args = { disk.getMountPath(Side) or "/" } })
		Broadcast(Event)
	else
		Broadcast(Event)
	end
end

--
-- Animations
--

-- Waits without losing events: anything that arrives is handled after the animation.
local Anim = {}

function Anim.Wait(Seconds)
	local Timer = os.startTimer(Seconds)
	while (true) do
		local Event = table.pack(os.pullEventRaw())
		if (Event[1] == "timer" and Event[2] == Timer) then return end
		table.insert(Deferred, Event)
	end
end

function Anim.EaseOut(T)
	return 1 - (1 - T) ^ 2
end

function Anim.EaseIn(T)
	return T * T
end

function Anim.Lerp(A, B, T)
	return math.floor(A + (B - A) * T + .5)
end

function Anim.PlayRect(From, To, Frames, Ease)
	for Frame = 1, Frames do
		local T = Ease(Frame / Frames)
		Ghost = {
			Anim.Lerp(From[1], To[1], T), Anim.Lerp(From[2], To[2], T),
			math.max(1, Anim.Lerp(From[3], To[3], T)), math.max(1, Anim.Lerp(From[4], To[4], T))
		}
		Redraw()
		Anim.Wait(FrameTime)
	end
	Ghost = nil
end

function Anim.Fade(From, To, Steps)
	for Step = 1, Steps do
		if (not SetFadeLevel(From + (To - From) * Step / Steps)) then return end
		Anim.Wait(FrameTime)
	end
end

local Players = {}

function Players.open(Animation)
	local Proc = Animation.Proc
	if (Proc.Dead or not Proc.Opening) then
		Proc.Opening = nil
		return
	end
	Anim.PlayRect(Animation.From or DockSlot(Proc), WindowRect(Proc), 5, Anim.EaseOut)
	Proc.Opening = nil
	Redraw()
end

function Players.minimize(Animation)
	if (not Animation.Proc.Minimized) then return end
	Anim.PlayRect(Animation.From, DockSlot(Animation.Proc), 5, Anim.EaseIn)
	Redraw()
end

function Anim.HasToast(Toast)
	for _, Other in ipairs(Toasts) do
		if (Other == Toast) then return true end
	end
	return false
end

function Players.toast(Animation)
	local Toast = Animation.Toast
	while (Anim.HasToast(Toast) and (Toast.Slide or 0) > 0) do
		Toast.Slide = math.floor(Toast.Slide * .45)
		Redraw()
		Anim.Wait(FrameTime)
	end
end

function Players.toastout(Animation)
	local Toast = Animation.Toast
	local W = ToastWidth()
	while (Anim.HasToast(Toast) and (Toast.Slide or 0) < W) do
		Toast.Slide = math.min(W, (Toast.Slide or 0) + math.ceil(W / 3))
		Redraw()
		Anim.Wait(FrameTime)
	end
	for Index, Other in ipairs(Toasts) do
		if (Other == Toast) then table.remove(Toasts, Index) break end
	end
	Redraw()
end

function Anim.CaptureScreen()
	local Rows = {}
	for Y = 1, ScreenH do
		Rows[Y] = { Screen.getLine(Y) }
	end
	return Rows
end

function Anim.PaintRows(Rows)
	for Y = 1, ScreenH do
		Screen.setCursorPos(1, Y)
		Screen.blit(Rows[Y][1], Rows[Y][2], Rows[Y][3])
	end
end

-- Bleeds one screen into another cell by cell, spreading out from the middle.
function Anim.Dissolve(From, To, Frames)
	local MidX, MidY = (ScreenW + 1) / 2, (ScreenH + 1) / 2
	local Reach = math.sqrt(MidX ^ 2 + (MidY * 1.5) ^ 2)
	local Ranks = {}
	for Y = 1, ScreenH do
		Ranks[Y] = {}
		for X = 1, ScreenW do
			local Distance = math.sqrt((X - MidX) ^ 2 + ((Y - MidY) * 1.5) ^ 2) / Reach
			Ranks[Y][X] = Distance * .5 + math.random() * .45
		end
	end
	for Frame = 1, Frames do
		local Cut = Anim.EaseIn(Frame / Frames)
		for Y = 1, ScreenH do
			local Old, New, Rank = From[Y], To[Y], Ranks[Y]
			local Text, Fg, Bg = {}, {}, {}
			for X = 1, ScreenW do
				local Source = (Rank[X] < Cut) and New or Old
				Text[X] = Source[1]:sub(X, X)
				Fg[X] = Source[2]:sub(X, X)
				Bg[X] = Source[3]:sub(X, X)
			end
			Screen.setCursorPos(1, Y)
			Screen.blit(table.concat(Text), table.concat(Fg), table.concat(Bg))
		end
		Anim.Wait(FrameTime)
	end
end

function Players.lock()
	local From = Anim.CaptureScreen()
	EnterLock()
	local To = Anim.CaptureScreen()
	-- Nothing reaches the monitor until we yield, so the lock screen never flashes up early.
	Anim.PaintRows(From)
	Anim.Dissolve(From, To, 16)
	PendingLock = false
	if (LockScreen) then LockScreen:Draw() end
end

function Players.unlock()
	local From = Anim.CaptureScreen()
	PendingUnlock = false
	Unlock()
	local To = Anim.CaptureScreen()
	Anim.PaintRows(From)
	Anim.Dissolve(From, To, 12)
	Redraw()
end

function Players.menu(Animation)
	local Current = Animation.Menu
	local Count = #Current.Items
	local Frames = 5
	for Frame = 1, Frames - 1 do
		if (Menu ~= Current) then return end
		Current.Reveal = math.max(1, math.ceil(Count * Frame / Frames))
		Redraw()
		Anim.Wait(FrameTime)
	end
	Current.Reveal = nil
	if (Menu == Current) then Redraw() end
end

function Players.launchpad(Animation)
	local Full = { 1, 1, ScreenW, ScreenH }
	local Seed = LaunchpadSeed()
	local From, To = Seed, Full
	if (not Animation.Opening) then From, To = Full, Seed end
	for Frame = 1, 4 do
		if (not Launchpad.Open) then break end
		local T = Animation.Opening and Anim.EaseOut(Frame / 4) or Anim.EaseIn(Frame / 4)
		Launchpad.Rect = {
			Anim.Lerp(From[1], To[1], T), Anim.Lerp(From[2], To[2], T),
			math.max(1, Anim.Lerp(From[3], To[3], T)), math.max(1, Anim.Lerp(From[4], To[4], T))
		}
		Redraw()
		Anim.Wait(FrameTime)
	end
	Launchpad.Rect = nil
	if (not Animation.Opening) then Launchpad.Open = false end
	Redraw()
end

function Players.fadein()
	Anim.Fade(0, 1, 5)
end

function Players.power(Animation)
	Anim.Fade(1, 0, 6)
	Animation.Run()
end

local function RunAnimations()
	while (#AnimationQueue > 0) do
		local Animation = table.remove(AnimationQueue, 1)
		local Ok, Err = pcall(Players[Animation.Kind], Animation)
		if (not Ok) then
			Ghost = nil
			Launchpad.Rect = nil
			if (Menu) then Menu.Reveal = nil end
			PendingLock, PendingUnlock = false, false
			if (Animation.Proc) then Animation.Proc.Opening = nil end
			SetFadeLevel(1)
			Log("animation: " .. tostring(Err))
			Redraw()
		end
	end
end

--
-- Public API for apps
--

local function InstallAPI()
	BlockOS.Desktop = true
	BlockOS.Shell = RootShell
	BlockOS.Launch = function(Target, Args, Opts)
		return Launch(Target, Args, Opts)
	end
	BlockOS.Open = OpenFile
	BlockOS.Notify = function(Title, Text, Opts)
		Notify(Title, Text, Opts)
	end
	BlockOS.SetTitle = function(Title)
		if (CurrentProc and not CurrentProc.Service) then
			CurrentProc.Title = tostring(Title)
			ScheduleRedraw()
		end
	end
	BlockOS.Current = function()
		local Proc = CurrentProc
		if (not Proc or Proc.Service) then return nil end
		return { ID = Proc.ID, AppID = Proc.AppID, Title = Proc.Title, Fullscreen = Proc.Fullscreen, Focused = Proc == Focused }
	end
	BlockOS.IsFocused = function()
		return CurrentProc ~= nil and CurrentProc == Focused
	end
	BlockOS.SetFullscreen = function(Value)
		local Proc = CurrentProc
		if (Proc and not Proc.Service and Proc.Fullscreen ~= (Value and true or false)) then
			ToggleFullscreen(Proc)
		end
	end
	BlockOS.Minimize = function()
		if (CurrentProc and not CurrentProc.Service) then Minimize(CurrentProc) end
	end
	BlockOS.Quit = function()
		if (CurrentProc and not CurrentProc.Service) then CurrentProc.Closing = true end
	end
	BlockOS.SetCloseHandler = function(Value)
		if (CurrentProc) then CurrentProc.CloseHandler = Value and true or nil end
	end
	BlockOS.Focus = function(ID)
		local Proc = FindProc(ID)
		if (Proc) then Focus(Proc) end
	end
	BlockOS.Kill = function(ID)
		local Proc = FindProc(ID)
		if (Proc and Proc ~= CurrentProc) then Kill(Proc) end
	end
	BlockOS.Processes = function()
		local List = {}
		for _, Proc in ipairs(Processes) do
			table.insert(List, { ID = Proc.ID, AppID = Proc.AppID, Title = Proc.Title, Minimized = Proc.Minimized })
		end
		return List
	end
	BlockOS.Capture = function()
		local Lines = {}
		for Y = 1, ScreenH do
			Lines[Y] = { Screen.getLine(Y) }
		end
		return { W = ScreenW, H = ScreenH, Lines = Lines }
	end
	BlockOS.SetRecording = function(Value)
		Recording = Value and true or false
		ScheduleRedraw()
	end
	BlockOS.Notifications = function()
		return History
	end
	BlockOS.Lock = function() Lock() end
	BlockOS.Restart = function() Power("restart") end
	BlockOS.Shutdown = function() Power("shutdown") end
	BlockOS.User = function() return Users.Primary() end
	BlockOS.ScreenSize = function() return ScreenW, ScreenH end

	Multishell = {
		getCurrent = function() return CurrentProc and CurrentProc.ID or 0 end,
		getCount = function() return #Processes end,
		getFocus = function() return Focused and Focused.ID or 0 end,
		setFocus = function(ID)
			local Proc = FindProc(ID)
			if (not Proc) then return false end
			Focus(Proc)
			return true
		end,
		getTitle = function(ID)
			local Proc = FindProc(ID)
			return Proc and Proc.Title
		end,
		setTitle = function(ID, Title)
			local Proc = FindProc(ID)
			if (Proc and Proc.AllowTitle) then
				Proc.Title = tostring(Title)
				ScheduleRedraw()
			end
		end,
		launch = function(Env, Path, ...)
			local Args = table.pack(...)
			local Proc = Spawn({
				Title = fs.getName(Path),
				AllowTitle = true,
				Fn = function()
					os.run(Env, Path, table.unpack(Args, 1, Args.n))
				end
			})
			return Proc.ID
		end
	}
	BlockOS.Multishell = Multishell
end

function Desktop.Run(Shell)
	RootShell = Shell
	Native = term.current()
	ScreenW, ScreenH = Native.getSize()
	-- The boot screen ends faded to black; restore the palette before any window copies it.
	Gfx.SetFade(Native, 1)
	Screen = window.create(Native, 1, 1, ScreenW, ScreenH, true)
	Hidden = window.create(Screen, 1, 1, 1, 1, false)
	term.redirect(Screen)
	InstallAPI()
	RefreshApps()
	ClockTimer = os.startTimer(1)
	-- Fade the first screen in from black.
	if (not (AnimationsEnabled() and SetFadeLevel(0) and QueueAnimation({ Kind = "fadein" }))) then
		SetFadeLevel(1)
	end
	if (Config.Settings().AutoLogin) then
		StartSession()
		Redraw()
	else
		EnterLock()
	end
	while (Running) do
		local Event = table.remove(Deferred, 1)
		if (not Event) then
			RunAnimations()
			Event = table.remove(Deferred, 1) or table.pack(os.pullEventRaw())
		end
		local Ok, Err = pcall(HandleEvent, Event)
		if (not Ok) then
			Log("desktop: " .. tostring(Err))
		end
		Ok, Err = pcall(FlushPending)
		if (not Ok) then
			Log("desktop: " .. tostring(Err))
		end
	end
end

return Desktop
]]
Files["blockos/sys/login.lua"] = [[
-- Login / lock screen drawn straight over a slow ASCII plasma, without a panel.
-- Used by the desktop for logging in and locking.

local Gfx = BlockOS.Require("gfx")
local Users = BlockOS.Require("users")
local Config = BlockOS.Require("config")
local Logo = BlockOS.Require("logo")
local Screensaver = BlockOS.Require("screensaver")

local Login = {}
Login.__index = Login

local Hex = {}
for Index = 0, 15 do
	Hex[2 ^ Index] = string.format("%x", Index)
end

local PowerItems = { { Text = "Restart", Action = "restart" }, { Text = "Shut Down", Action = "shutdown" } }

function Login.new(T, Opts)
	local Self = setmetatable({}, Login)
	Self.T = T
	Self.Opts = Opts or {}
	Self.User = Users.Primary()
	Self.Password = ""
	Self.Message = nil
	Self.Frame = math.random(0, 2000)
	Self.Shake = 0
	Self.Buttons = {}
	Self.PowerOpen = false
	return Self
end

function Login:Start()
	self.Timer = os.startTimer(.1)
	self:Draw()
end

-- Writes text onto the canvas, keeping the plasma's background colour unless Bg is given.
local function Put(Canvas, X, Y, Text, Fg, Bg)
	if (Y < 1 or Y > Canvas.H) then return end
	for Index = 1, #Text do
		local Column = X + Index - 1
		if (Column >= 1 and Column <= Canvas.W) then
			Canvas.Chars[Y][Column] = Text:sub(Index, Index)
			Canvas.Fg[Y][Column] = Hex[Fg]
			if (Bg) then Canvas.Bg[Y][Column] = Hex[Bg] end
		end
	end
end

-- Clears the plasma characters behind a block of text so it stays readable.
local function Clear(Canvas, X, Y, W)
	Put(Canvas, X, Y, string.rep(" ", W), colors.white)
end

local function PutCentered(Canvas, Y, Text, Fg, Bg)
	local X = math.floor((Canvas.W - #Text) / 2) + 1
	Clear(Canvas, X - 1, Y, #Text + 2)
	Put(Canvas, X, Y, Text, Fg, Bg)
	return X
end

local function PutLogo(Canvas, X, Y, Art)
	for Row, Line in ipairs(Art) do
		for Column = 1, #Line do
			local Entry = Logo.Legend[Line:sub(Column, Column)]
			if (Entry) then
				Put(Canvas, X + Column - 1, Y + Row - 1, Entry[1], Entry[2], Entry[3])
			end
		end
	end
end

local function ClockText()
	local Settings = Config.Settings()
	if (Settings.Clock24) then
		return os.date("%H:%M"), nil
	end
	return (os.date("%I:%M"):gsub("^0", "")), os.date("%p")
end

function Login:Draw()
	local T = self.T
	local W, H = T.getSize()
	if (not self.Canvas or self.Canvas.W ~= W or self.Canvas.H ~= H) then
		self.Canvas = Screensaver.NewCanvas(W, H)
	end
	local Canvas = self.Canvas
	Screensaver.Render(Canvas, self.Frame * Screensaver.Speed)

	local Time, Suffix = ClockText()
	local Y = 2
	PutCentered(Canvas, Y, os.date("%A, %B %d"), colors.white)
	if (H >= 17 and W >= 24) then
		local BigW = Gfx.BigWidth(Time)
		local BigX = math.floor((W - BigW) / 2) + 1
		Gfx.EachBigCell(BigX, Y + 2, Time, function(X, CellY)
			Put(Canvas, X, CellY, " ", colors.white, colors.white)
		end)
		if (Suffix) then
			Put(Canvas, BigX + BigW + 1, Y + 6, Suffix, colors.white)
		end
		Y = Y + 8
	else
		PutCentered(Canvas, Y + 1, Time .. (Suffix and (" " .. Suffix) or ""), colors.white)
		Y = Y + 3
	end

	local Offset = 0
	if (self.Shake > 0) then
		Offset = (self.Shake % 2 == 0) and 1 or -1
	end
	local LogoW, LogoH = Logo.Size(Logo.Small)
	local BottomSpace = 5
	local LogoY = math.max(Y, H - BottomSpace - LogoH - 1)
	if (LogoY + LogoH + 4 <= H) then
		PutLogo(Canvas, math.floor((W - LogoW) / 2) + 1, LogoY, Logo.Small)
		Y = LogoY + LogoH
	end

	local Name = self.User and self.User.Name or "Guest"
	PutCentered(Canvas, Y, Name, colors.white)
	Y = Y + 2

	self.Buttons = {}
	local NeedsPassword = self.User and self.User.HasPassword
	local FieldW = math.min(20, W - 6)
	local FieldX = math.floor((W - FieldW - 3) / 2) + 1 + Offset
	if (NeedsPassword) then
		local Masked = string.rep("\7", #self.Password)
		if (#Masked > FieldW - 2) then Masked = Masked:sub(-(FieldW - 2)) end
		local Text = (#self.Password == 0) and " Enter Password" or (" " .. Masked)
		Put(Canvas, FieldX, Y, Gfx.Pad(Text, FieldW), (#self.Password == 0) and colors.lightGray or colors.white, colors.gray)
	else
		Put(Canvas, FieldX, Y, Gfx.Pad("Click to log in", FieldW, "center"), colors.white, colors.gray)
	end
	Put(Canvas, FieldX + FieldW, Y, " \26 ", colors.white, colors.gray)
	table.insert(self.Buttons, { X = FieldX, Y = Y, W = FieldW + 3, Action = "submit" })
	self.FieldX, self.FieldY, self.FieldW = FieldX, Y, FieldW

	if (self.Message) then
		PutCentered(Canvas, Y + 1, self.Message, colors.red)
	end

	-- Power button: a small circle in the bottom-right corner that opens a menu.
	local PowerX, PowerY = W - 2, H - 1
	Clear(Canvas, PowerX - 1, PowerY, 3)
	Put(Canvas, PowerX, PowerY, "\7", self.PowerOpen and colors.lightGray or colors.white)
	table.insert(self.Buttons, { X = PowerX - 1, Y = PowerY, W = 3, Action = "power" })
	if (self.PowerOpen) then
		local MenuW = 11
		local MenuX = W - MenuW
		local MenuY = PowerY - #PowerItems - 1
		for Index, Item in ipairs(PowerItems) do
			Put(Canvas, MenuX, MenuY + Index - 1, Gfx.Pad(" " .. Item.Text, MenuW), colors.black, colors.white)
			table.insert(self.Buttons, { X = MenuX, Y = MenuY + Index - 1, W = MenuW, Action = Item.Action })
		end
	end

	Screensaver.Blit(T, Canvas)
	if (NeedsPassword and not self.PowerOpen) then
		T.setCursorPos(FieldX + math.min(#self.Password, FieldW - 2) + 1, Y)
		T.setTextColor(colors.white)
		T.setCursorBlink(true)
	else
		T.setCursorBlink(false)
	end
end

function Login:Submit()
	if (not self.User) then return true end
	if (not self.User.HasPassword or Users.Verify(self.User.Name, self.Password)) then
		self.T.setCursorBlink(false)
		return true
	end
	self.Password = ""
	self.Message = "Incorrect password"
	self.Shake = 6
	return false
end

function Login:Power(Action)
	self.PowerOpen = false
	if (self.Opts.OnPower) then
		self.Opts.OnPower(Action)
	elseif (Action == "restart") then
		os.reboot()
	else
		os.shutdown()
	end
end

-- Feeds one event. Returns true once the user is authenticated.
function Login:Event(Name, A, B, C)
	if (Name == "timer" and A == self.Timer) then
		self.Frame = self.Frame + 1
		if (self.Shake > 0) then self.Shake = self.Shake - 1 end
		self.Timer = os.startTimer(.1)
		self:Draw()
		return false
	elseif (Name == "char") then
		if (#self.Password < 64) then
			self.Password = self.Password .. A
		end
		self.Message = nil
	elseif (Name == "paste") then
		self.Password = (self.Password .. A):sub(1, 64)
	elseif (Name == "key") then
		if (A == keys.backspace) then
			self.Password = self.Password:sub(1, -2)
		elseif (A == keys.enter or A == keys.numPadEnter) then
			if (self:Submit()) then return true end
		end
	elseif (Name == "mouse_click") then
		local Hit = nil
		for _, Button in ipairs(self.Buttons) do
			if (B >= Button.X and B < Button.X + Button.W and C == Button.Y) then
				Hit = Button
			end
		end
		if (not Hit) then
			self.PowerOpen = false
		elseif (Hit.Action == "power") then
			self.PowerOpen = not self.PowerOpen
		elseif (Hit.Action == "submit") then
			self.PowerOpen = false
			if (self:Submit()) then return true end
		else
			self:Power(Hit.Action)
		end
	else
		return false
	end
	self:Draw()
	return false
end

function Login:Stop()
	if (self.Timer) then
		os.cancelTimer(self.Timer)
		self.Timer = nil
	end
end

-- Blocks until login succeeds.
function Login.Run(T)
	local Screen = Login.new(T)
	if (Config.Settings().AutoLogin) then
		return true
	end
	Screen:Start()
	while (true) do
		local Event = table.pack(os.pullEventRaw())
		if (Event[1] ~= "terminate" and Screen:Event(table.unpack(Event, 1, Event.n))) then
			Screen:Stop()
			return true
		end
	end
end

return Login
]]
Files["blockos/sys/run.lua"] = [[
-- Runs a program inside a desktop window and optionally waits before the window closes.

local Args = { ... }
local Hold = table.remove(Args, 1) == "hold"
local Path = table.remove(Args, 1)

local Ok
if (shell.execute) then
	Ok = shell.execute(Path, table.unpack(Args))
else
	Ok = shell.run(Path, table.unpack(Args))
end

if (Hold or not Ok) then
	term.setTextColor(colors.lightGray)
	print()
	print(Ok and "Process finished." or "Process exited with an error.")
	write("Press any key to close this window.")
	os.pullEvent("key")
end
]]
Files["blockos/sys/setup.lua"] = [[
-- Setup Assistant: the onboarding flow shown by the installer and on first boot.

local Ui = BlockOS.Require("ui")
local Gfx = BlockOS.Require("gfx")
local Theme = BlockOS.Require("theme")
local Config = BlockOS.Require("config")
local Logo = BlockOS.Require("logo")
local Users = BlockOS.Require("users")
local Wallpaper = BlockOS.Require("wallpaper")

local Setup = {}

function Setup.Run(Opts)
	Opts = Opts or {}
	local Settings = Config.Settings()
	local State = {
		Label = os.getComputerLabel() or ("BlockOS-" .. os.getComputerID()),
		Name = "",
		Password = "",
		Confirm = "",
		AutoLogin = false
	}
	local Steps = { "welcome", "computer", "account", "appearance", "updates" }
	if (Opts.Install) then
		table.insert(Steps, "install")
	end
	table.insert(Steps, "done")

	local Page = Ui.Page.new({ Bg = "WindowBg" })
	local StepIndex = 1
	local Error = nil
	local Frame = 0
	local Stars = {}
	local Build

	local function Go(Delta)
		StepIndex = math.max(1, math.min(#Steps, StepIndex + Delta))
		Error = nil
		Frame = 0
		Build()
	end

	local function Footer(CanBack, NextText, OnNext)
		local W, H = Page.W, Page.H
		if (CanBack) then
			Page:Add(Ui.Button.new({ X = 2, Y = H - 1, Text = " Back ", OnClick = function() Go(-1) end }))
		end
		Page:Add(Ui.Button.new({
			X = W - #NextText - 3, Y = H - 1, Text = " " .. NextText .. " ", Style = "primary",
			OnClick = OnNext or function() Go(1) end
		}))
	end

	local function Heading(Title, Subtitle)
		Page:Add(Ui.Label.new({ X = 3, Y = 2, W = Page.W - 4, Text = Title, Fg = "Accent" }))
		if (Subtitle) then
			Page:Add(Ui.Label.new({ X = 3, Y = 3, W = Page.W - 4, H = 2, Text = Subtitle, Fg = "SubText" }))
		end
	end

	local function Finish()
		Settings.AutoLogin = State.AutoLogin
		Config.Save("settings")
		if (#State.Label > 0) then
			os.setComputerLabel(State.Label)
		end
		if (not Users.Find(State.Name)) then
			Users.Create(State.Name, State.Password, { Color = Settings.Accent })
		end
	end

	local function BuildWelcome()
		Page.Bg = colors.black
		local W, H = Page.W, Page.H
		Stars = {}
		for _ = 1, math.floor(W * H / 14) do
			table.insert(Stars, { X = math.random(1, W), Y = math.random(1, H), Phase = math.random(0, 10) })
		end
		function Page:OnDraw(T)
			for _, Star in ipairs(Stars) do
				local Bright = (Frame + Star.Phase) % 12
				local Char = (Bright < 2) and "+" or ((Bright < 6) and "." or " ")
				Gfx.Write(T, Star.X, Star.Y, Char, (Bright < 2) and colors.white or colors.gray, colors.black)
			end
			local LogoW, LogoH = Logo.Size()
			local LogoY = math.max(2, math.floor(H / 2) - LogoH)
			Logo.DrawPartial(T, math.floor((W - LogoW) / 2) + 1, LogoY, math.min(1, Frame / 10))
			if (Frame >= 10) then
				Gfx.Center(T, LogoY + LogoH + 1, "Welcome to BlockOS", colors.white, colors.black)
				Gfx.Center(T, LogoY + LogoH + 2, "A desktop for CC: Tweaked", colors.lightGray, colors.black)
			end
		end
		Page:Add(Ui.Button.new({
			X = math.floor((W - 15) / 2) + 1, Y = H - 2, W = 15, Text = "Get Started \26", Style = "primary",
			OnClick = function() Go(1) end
		}))
	end

	local function BuildComputer()
		Heading("Name this computer", "Other computers see this name in Messages and on the network.")
		local Field = Page:Add(Ui.Input.new({ X = 3, Y = 7, W = math.min(30, Page.W - 6), Value = State.Label, MaxLength = 32 }))
		Field.OnChange = function(_, Value) State.Label = Value end
		Field.OnSubmit = function() Go(1) end
		Page:Add(Ui.Label.new({ X = 3, Y = 9, W = Page.W - 4, Text = "Computer ID: " .. os.getComputerID(), Fg = "SubText" }))
		Page:SetFocus(Field)
		Footer(true, "Continue")
	end

	local function BuildAccount()
		Heading("Create your account", "Choose a name and a password for the login screen.")
		local FieldW = math.min(26, Page.W - 18)
		Page:Add(Ui.Label.new({ X = 3, Y = 6, Text = "Name", Fg = "Text" }))
		local Name = Page:Add(Ui.Input.new({ X = 14, Y = 6, W = FieldW, Value = State.Name, MaxLength = 20, Placeholder = "Steve" }))
		Page:Add(Ui.Label.new({ X = 3, Y = 8, Text = "Password", Fg = "Text" }))
		local Password = Page:Add(Ui.Input.new({ X = 14, Y = 8, W = FieldW, Value = State.Password, Mask = "\7" }))
		Page:Add(Ui.Label.new({ X = 3, Y = 10, Text = "Confirm", Fg = "Text" }))
		local Confirm = Page:Add(Ui.Input.new({ X = 14, Y = 10, W = FieldW, Value = State.Confirm, Mask = "\7" }))
		local Auto = Page:Add(Ui.Checkbox.new({ X = 3, Y = 12, Text = "Log in automatically", Value = State.AutoLogin }))
		Auto.OnChange = function(_, Value) State.AutoLogin = Value end
		Page:Add(Ui.Label.new({ X = 3, Y = 14, W = Page.W - 4, Fg = colors.red, Text = function() return Error or "" end }))
		Name.OnChange = function(_, Value) State.Name = Value end
		Password.OnChange = function(_, Value) State.Password = Value end
		Confirm.OnChange = function(_, Value) State.Confirm = Value end
		local function Validate()
			if (#State.Name:gsub("%s", "") == 0) then
				Error = "Please enter a name."
			elseif (State.Password ~= State.Confirm) then
				Error = "Passwords do not match."
			else
				Go(1)
				return
			end
			Page:Invalidate()
		end
		Name.OnSubmit = function() Page:SetFocus(Password) end
		Password.OnSubmit = function() Page:SetFocus(Confirm) end
		Confirm.OnSubmit = Validate
		Page:SetFocus(Name)
		Footer(true, "Continue", Validate)
	end

	local function BuildAppearance()
		Heading("Choose your look")
		local W = Page.W
		Page:Add(Ui.Label.new({ X = 3, Y = 4, Text = "Appearance" }))
		local Mode = Page:Add(Ui.Tabs.new({ X = 16, Y = 4, W = 16, Items = { "Light", "Dark" }, Selected = Settings.Theme == "dark" and 2 or 1 }))
		Mode.OnChange = function(_, Index)
			Settings.Theme = (Index == 2) and "dark" or "light"
		end
		Page:Add(Ui.Label.new({ X = 3, Y = 6, Text = "Accent" }))
		Page:Add(Ui.Canvas.new({
			X = 16, Y = 6, W = #Theme.Accents * 3, H = 1,
			OnDraw = function(Self, T, Th)
				for Index, Color in ipairs(Theme.Accents) do
					local Char = (Color == Settings.Accent) and " \7 " or "   "
					Gfx.Write(T, Self.X + (Index - 1) * 3, Self.Y, Char, colors.white, Color)
				end
			end,
			OnEvent = function(Self, Name, Button, X)
				if (Name ~= "mouse_click") then return false end
				local Index = math.floor((X - Self.X) / 3) + 1
				if (Theme.Accents[Index]) then
					Settings.Accent = Theme.Accents[Index]
				end
				return true
			end
		}))
		Page:Add(Ui.Label.new({ X = 3, Y = 8, Text = "Wallpaper" }))
		local Items = {}
		local Selected = 1
		for Index, Entry in ipairs(Wallpaper.List) do
			table.insert(Items, { Text = Entry.Name, ID = Entry.ID })
			if (Entry.ID == Settings.Wallpaper) then Selected = Index end
		end
		local List = Page:Add(Ui.List.new({ X = 3, Y = 9, W = 16, H = math.min(#Items, Page.H - 11), Items = Items, Bg = "Panel" }))
		List.Selected = Selected
		List.OnSelect = function(_, _, Item)
			Settings.Wallpaper = Item.ID
		end
		local PreviewW = math.min(24, W - 24)
		if (PreviewW >= 8) then
			Page:Add(Ui.Canvas.new({
				X = 21, Y = 9, W = PreviewW, H = math.min(7, Page.H - 11),
				OnDraw = function(Self, T)
					Wallpaper.Draw(T, Self.X, Self.Y, Self.W, Self.H, Settings.Wallpaper, Settings.WallpaperColor)
					Gfx.Fill(T, Self.X, Self.Y, Self.W, 1, colors.white)
					Gfx.Write(T, Self.X + 1, Self.Y, "\131", colors.lime, colors.brown)
					Gfx.Fill(T, Self.X + 4, Self.Y + 2, math.max(Self.W - 8, 4), 3, colors.white)
					Gfx.Fill(T, Self.X + 4, Self.Y + 2, math.max(Self.W - 8, 4), 1, colors.lightGray)
					Gfx.Write(T, Self.X + 5, Self.Y + 2, "\7\7\7", Settings.Accent, colors.lightGray)
				end
			}))
		end
		Footer(true, "Continue")
	end

	local function BuildUpdates()
		Heading("Software updates", "BlockOS can keep itself up to date from github.com/tamayaren/BlockOS.")
		local Check = Page:Add(Ui.Toggle.new({ X = 3, Y = 7, Value = Settings.AutoUpdate }))
		Check.OnChange = function(_, Value) Settings.AutoUpdate = Value end
		Page:Add(Ui.Label.new({ X = 9, Y = 7, Text = "Check for updates automatically" }))
		local Install = Page:Add(Ui.Toggle.new({ X = 3, Y = 9, Value = Settings.AutoInstall }))
		Install.OnChange = function(_, Value) Settings.AutoInstall = Value end
		Page:Add(Ui.Label.new({ X = 9, Y = 9, Text = "Install updates in the background" }))
		Page:Add(Ui.Label.new({ X = 3, Y = 11, W = Page.W - 4, H = 3, Fg = "SubText", Text = "You can change this later in Settings > Software Update." }))
		Footer(true, Opts.Install and "Install" or "Continue")
	end

	local function BuildInstall()
		Heading("Installing BlockOS " .. (Opts.Version or ""), "Copying system files. This only takes a moment.")
		local Bar = Page:Add(Ui.Progress.new({ X = 3, Y = 8, W = Page.W - 4, Value = 0 }))
		local Status = Page:Add(Ui.Label.new({ X = 3, Y = 10, W = Page.W - 4, Text = "Preparing...", Fg = "SubText" }))
		Page:Draw()
		local Ok, Err = pcall(Opts.Install, function(Done, Total, Path)
			Bar.Value = Total > 0 and Done / Total or 1
			Status.Text = Path or ""
			Page:Draw()
		end)
		if (not Ok) then
			Status.Text = "Install failed: " .. tostring(Err)
			Status.Fg = colors.red
			Page:Draw()
			Footer(false, "Quit", function() Page:Stop() end)
			return
		end
		Finish()
		State.Finished = true
		Go(1)
	end

	local function BuildDone()
		if (not Opts.Install and not State.Finished) then
			Finish()
			State.Finished = true
		end
		local W, H = Page.W, Page.H
		local LogoW, LogoH = Logo.Size(Logo.Small)
		function Page:OnDraw(T, Th)
			Logo.Draw(T, math.floor((W - LogoW) / 2) + 1, 3, Logo.Small)
			Gfx.Center(T, 4 + LogoH, "You're all set, " .. State.Name .. "!", Th.Accent, Th.WindowBg)
			Gfx.Center(T, 6 + LogoH, "Tip: right-click the dock or desktop for options.", Th.SubText, Th.WindowBg)
			Gfx.Center(T, 7 + LogoH, "Ctrl+Shift+Space opens Launchpad.", Th.SubText, Th.WindowBg)
		end
		local Text = Opts.Install and "Restart" or "Start BlockOS"
		Page:Add(Ui.Button.new({
			X = math.floor((W - #Text - 4) / 2) + 1, Y = H - 2, W = #Text + 4, Text = Text, Style = "primary",
			OnClick = function() Page:Stop() end
		}))
	end

	local Builders = {
		welcome = BuildWelcome,
		computer = BuildComputer,
		account = BuildAccount,
		appearance = BuildAppearance,
		updates = BuildUpdates,
		install = BuildInstall,
		done = BuildDone
	}

	function Build()
		Page:Clear()
		Page.OnDraw = nil
		Page.Bg = "WindowBg"
		local Name = Steps[StepIndex]
		function Page:OnDrawOver(T, Th)
			if (Name == "welcome") then return end
			local Dots = #Steps * 2 - 1
			local X = math.floor((self.W - Dots) / 2) + 1
			for Index = 1, #Steps do
				Gfx.Write(T, X + (Index - 1) * 2, self.H, "\7", (Index == StepIndex) and Th.Accent or Th.Border, self:GetBg(Th))
			end
		end
		Builders[Name]()
		Page:Invalidate()
	end

	function Page:OnLayout()
		Build()
	end

	function Page:OnTerminate()
		if (Opts.Install) then self:Stop() end
	end

	Page:SetInterval(.1, function()
		Frame = Frame + 1
		return Steps[StepIndex] == "welcome"
	end)

	Page:Run()
	term.setBackgroundColor(colors.black)
	term.clear()
	term.setCursorPos(1, 1)
	return State
end

return Setup
]]
Files["blockos/sys/splash.lua"] = [[
-- Boot screen: the logo on black with a progress bar that fills over one to two seconds.

local Gfx = BlockOS.Require("gfx")
local Logo = BlockOS.Require("logo")

local Splash = {}

function Splash.Run(T)
	T = T or term.current()
	Gfx.SetFade(T, 1)
	local W, H = T.getSize()
	local Art = (W >= 20 and H >= 12) and Logo.Big or Logo.Small
	local LogoW, LogoH = Logo.Size(Art)
	local BarW = math.min(20, W - 6)
	local BarX = math.floor((W - BarW) / 2) + 1
	local LogoY = math.max(1, math.floor((H - LogoH - 3) / 2))
	local BarY = math.min(H, LogoY + LogoH + 2)
	T.setBackgroundColor(colors.black)
	T.clear()
	T.setCursorBlink(false)
	Logo.Draw(T, math.floor((W - LogoW) / 2) + 1, LogoY, Art)

	local Duration = 1 + math.random()
	local Started = os.clock()
	-- A few uneven pauses make the bar feel like it is really loading.
	local Stalls = { math.random() * .6 + .1, math.random() * .5 + .4 }
	while (true) do
		local Progress = math.min(1, (os.clock() - Started) / Duration)
		local Shown = Progress
		for _, Stall in ipairs(Stalls) do
			if (Progress > Stall and Progress < Stall + .08) then Shown = Stall end
		end
		local Filled = math.floor(BarW * Shown + .5)
		Gfx.Write(T, BarX, BarY, string.rep(" ", Filled), colors.white, colors.white)
		Gfx.Write(T, BarX + Filled, BarY, string.rep(" ", BarW - Filled), colors.gray, colors.gray)
		if (Progress >= 1) then break end
		sleep(.05)
	end
	sleep(.2)
	for Step = 4, 0, -1 do
		Gfx.SetFade(T, Step / 5)
		sleep(.05)
	end
	T.setBackgroundColor(colors.black)
	T.clear()
end

return Splash
]]
Files["blockos/turtle/agent.lua"] = [[
-- BlockOS Turtle Agent: lets paired BlockOS computers drive this turtle over rednet.
-- Standalone so it also runs on basic turtles that only have the agent installed.

local Protocol = "blockos_turtle"
local ConfigPath = "/blockos/data/agent.dat"
-- Scripts sent from the Turtles app are saved here before they run.
local ScriptDir = "/blockos/data/scripts"

local function ReadConfig()
	if (not fs.exists(ConfigPath)) then return {} end
	local Handle = fs.open(ConfigPath, "r")
	local Data = textutils.unserialise(Handle.readAll() or "") or {}
	Handle.close()
	return Data
end

local function WriteConfig(Data)
	local Handle = fs.open(ConfigPath, "w")
	Handle.write(textutils.serialise(Data))
	Handle.close()
end

local Config = ReadConfig()
Config.Trusted = Config.Trusted or {}
if (not Config.Pin) then
	Config.Pin = tostring(math.random(1000, 9999))
	WriteConfig(Config)
end

local Color = term.isColor()
local Job = nil
local LastAction = "Waiting for commands"
local Controller = nil
local Position = nil

local Actions = {
	forward = turtle.forward, back = turtle.back, up = turtle.up, down = turtle.down,
	turnLeft = turtle.turnLeft, turnRight = turtle.turnRight,
	dig = turtle.dig, digUp = turtle.digUp, digDown = turtle.digDown,
	place = turtle.place, placeUp = turtle.placeUp, placeDown = turtle.placeDown,
	attack = turtle.attack, attackUp = turtle.attackUp, attackDown = turtle.attackDown,
	suck = turtle.suck, suckUp = turtle.suckUp, suckDown = turtle.suckDown,
	drop = turtle.drop, dropUp = turtle.dropUp, dropDown = turtle.dropDown,
	detect = turtle.detect, detectUp = turtle.detectUp, detectDown = turtle.detectDown,
	inspect = turtle.inspect, inspectUp = turtle.inspectUp, inspectDown = turtle.inspectDown
}

local function OpenModems()
	local Any = false
	for _, Side in ipairs(peripheral.getNames()) do
		if (peripheral.getType(Side) == "modem") then
			if (not rednet.isOpen(Side)) then rednet.open(Side) end
			Any = true
		end
	end
	return Any
end

local function SetColor(Fg, Bg)
	if (not Color) then return end
	if (Fg) then term.setTextColor(Fg) end
	if (Bg) then term.setBackgroundColor(Bg) end
end

local function Draw()
	if (Job) then return end
	local W, H = term.getSize()
	SetColor(colors.white, colors.black)
	term.clear()
	SetColor(colors.black, colors.lime)
	term.setCursorPos(1, 1)
	term.clearLine()
	term.write(" BlockOS Turtle Agent")
	SetColor(colors.white, colors.black)
	local Fuel = turtle.getFuelLevel()
	local Lines = {
		"Label:  " .. (os.getComputerLabel() or "(none)"),
		"ID:     " .. os.getComputerID(),
		"Fuel:   " .. tostring(Fuel) .. (Fuel ~= "unlimited" and (" / " .. tostring(turtle.getFuelLimit())) or ""),
		"Slot:   " .. turtle.getSelectedSlot(),
		"Pair PIN: " .. Config.Pin,
		"",
		"Last:   " .. LastAction
	}
	for Index, Line in ipairs(Lines) do
		term.setCursorPos(2, Index + 2)
		term.write(Line:sub(1, W - 2))
	end
	SetColor(colors.gray)
	term.setCursorPos(2, H)
	term.write((OpenModems() and "Listening on rednet" or "No modem attached!"):sub(1, W - 2))
end

local function Inventory()
	local Items = {}
	for Slot = 1, 16 do
		local Detail = turtle.getItemDetail(Slot)
		if (Detail) then
			Items[Slot] = { Name = Detail.name, Count = Detail.count }
		end
	end
	return Items
end

local function Status()
	return {
		Label = os.getComputerLabel() or ("turtle-" .. os.getComputerID()),
		ID = os.getComputerID(),
		Fuel = turtle.getFuelLevel(),
		FuelLimit = turtle.getFuelLimit(),
		Slot = turtle.getSelectedSlot(),
		Inventory = Inventory(),
		Position = Position,
		Busy = Job and Job.Name or nil,
		Last = LastAction
	}
end

local function StartJob(Command, Name)
	Job = {
		Name = Name or Command,
		Co = coroutine.create(function()
			SetColor(colors.white, colors.black)
			term.clear()
			term.setCursorPos(1, 1)
			print("Running: " .. Command)
			shell.run(Command)
		end)
	}
	LastAction = "Job: " .. Job.Name
	local Ok, Filter = coroutine.resume(Job.Co)
	if (not Ok or coroutine.status(Job.Co) == "dead") then
		Job = nil
	else
		Job.Filter = Filter
	end
end

local function Handle(Sender, Message)
	if (type(Message) ~= "table" or type(Message.Cmd) ~= "string") then return end
	local Args = type(Message.Args) == "table" and Message.Args or {}
	local Reply = { Re = Message.Seq }
	if (Message.Cmd == "pair") then
		if (tostring(Args.Pin) == Config.Pin) then
			Config.Trusted[Sender] = true
			WriteConfig(Config)
			Reply.Ok = true
			LastAction = "Paired with #" .. Sender
		else
			Reply.Error = "Wrong PIN"
		end
	elseif (not Config.Trusted[Sender]) then
		Reply.Error = "pin"
	elseif (Job and Message.Cmd ~= "status" and Message.Cmd ~= "stop") then
		Reply.Error = "Busy running " .. Job.Name
	elseif (Message.Cmd == "status") then
		Reply.Ok = true
	elseif (Message.Cmd == "action") then
		local Fn = Actions[Args.Name]
		if (Job) then
			Reply.Error = "Busy running " .. Job.Name
		elseif (not Fn) then
			Reply.Error = "Unknown action"
		else
			local Ok, Result, Detail = pcall(Fn)
			Reply.Ok = Ok and Result ~= false
			Reply.Result = Detail or Result
			if (not Ok or Result == false) then
				Reply.Error = tostring(Detail or Result or "failed")
			end
			LastAction = Args.Name .. (Reply.Ok and "" or (" (" .. tostring(Reply.Error) .. ")"))
		end
	elseif (Message.Cmd == "select") then
		Reply.Ok = turtle.select(math.max(1, math.min(16, tonumber(Args.Slot) or 1)))
	elseif (Message.Cmd == "refuel") then
		local Total = 0
		for Slot = 1, 16 do
			if (turtle.getItemCount(Slot) > 0) then
				turtle.select(Slot)
				if (turtle.refuel(Args.Count)) then Total = Total + 1 end
			end
		end
		Reply.Ok = Total > 0
		Reply.Error = (Total == 0) and "Nothing to burn" or nil
		LastAction = "Refuel"
	elseif (Message.Cmd == "run") then
		if (Job) then
			Reply.Error = "Busy running " .. Job.Name
		else
			StartJob(tostring(Args.Command or ""))
			Reply.Ok = true
		end
	elseif (Message.Cmd == "script") then
		local Name = fs.getName(tostring(Args.Name or "script.lua")):gsub("[^%w%._%-]", "")
		if (#Name == 0) then Name = "script.lua" end
		local Path = fs.combine(ScriptDir, Name)
		if (not fs.exists(ScriptDir)) then fs.makeDir(ScriptDir) end
		local Handle = type(Args.Source) == "string" and fs.open(Path, "w")
		if (not Handle) then
			Reply.Error = "Cannot save script"
		else
			Handle.write(Args.Source)
			Handle.close()
			local Extra = tostring(Args.Args or ""):gsub("^%s+", ""):gsub("%s+$", "")
			StartJob("/" .. Path .. ((#Extra > 0) and (" " .. Extra) or ""), Name .. ((#Extra > 0) and (" " .. Extra) or ""))
			Reply.Ok = true
		end
	elseif (Message.Cmd == "stop") then
		if (Job) then
			LastAction = "Stopped " .. Job.Name
			Job = nil
		end
		Reply.Ok = true
	elseif (Message.Cmd == "locate") then
		local X, Y, Z = gps.locate(1)
		Position = X and { X = X, Y = Y, Z = Z } or nil
		Reply.Ok = Position ~= nil
		Reply.Error = Position and nil or "No GPS signal"
	else
		Reply.Error = "Unknown command"
	end
	Controller = Sender
	Reply.Status = Status()
	rednet.send(Sender, Reply, Protocol)
end

OpenModems()
pcall(rednet.host, Protocol, os.getComputerLabel() or ("turtle-" .. os.getComputerID()))
Draw()

while (true) do
	local Event = table.pack(os.pullEventRaw())
	local Name = Event[1]
	if (Name == "terminate" and not Job) then
		SetColor(colors.white, colors.black)
		term.clear()
		term.setCursorPos(1, 1)
		print("BlockOS Turtle Agent stopped.")
		break
	end
	if (Name == "rednet_message" and Event[4] == Protocol) then
		Handle(Event[2], Event[3])
	elseif (Job and (Job.Filter == nil or Job.Filter == Name or Name == "terminate")) then
		local Ok, Filter = coroutine.resume(Job.Co, table.unpack(Event, 1, Event.n))
		if (not Ok or coroutine.status(Job.Co) == "dead") then
			LastAction = Ok and ("Finished " .. Job.Name) or ("Job failed: " .. tostring(Filter))
			Job = nil
			if (Controller) then
				rednet.send(Controller, { Event = "job_done", Status = Status() }, Protocol)
			end
		else
			Job.Filter = Filter
		end
	elseif (Name == "peripheral" or Name == "peripheral_detach") then
		OpenModems()
	end
	Draw()
end
]]
Files["blockos/version.txt"] = [[
1.6.0
]]

local Loaded = {}
local Fresh = { ui = true }

local function Key(Path)
	return (Path:gsub("^/+", ""))
end

local function WriteFile(Path, Content)
	local Dir = fs.getDir(Path)
	if (Dir ~= "" and not fs.exists(Dir)) then
		fs.makeDir(Dir)
	end
	local Handle = fs.open(Path, "w")
	if (not Handle) then error("Cannot write " .. Path, 0) end
	Handle.write(Content)
	Handle.close()
end

local function SortedPaths()
	local List = {}
	for Path in pairs(Files) do
		table.insert(List, Path)
	end
	table.sort(List)
	return List
end

local function BackupStartup()
	if (fs.exists("startup.lua") and not fs.exists("blockos")) then
		if (fs.exists("startup.lua.bak")) then fs.delete("startup.lua.bak") end
		fs.move("startup.lua", "startup.lua.bak")
	end
end

local function InstallFiles(Progress)
	BackupStartup()
	local List = SortedPaths()
	for Index, Path in ipairs(List) do
		if (Progress) then Progress(Index - 1, #List, Path) end
		WriteFile(Path, Files[Path])
		if (Index % 6 == 0) then sleep(0) end
	end
	if (Progress) then Progress(#List, #List, "Done") end
end

local function InstallAgent()
	print("Installing the BlockOS Turtle Agent...")
	WriteFile("blockos/turtle/agent.lua", Files["blockos/turtle/agent.lua"])
	if (fs.exists("startup.lua")) then
		if (fs.exists("startup.lua.bak")) then fs.delete("startup.lua.bak") end
		fs.move("startup.lua", "startup.lua.bak")
	end
	WriteFile("startup.lua", "shell.run(\"/blockos/turtle/agent.lua\")\n")
	if (not os.getComputerLabel()) then
		os.setComputerLabel("turtle-" .. os.getComputerID())
	end
	print("Done. The agent starts on boot and shows a pairing PIN.")
	print("Rebooting in 3 seconds...")
	sleep(3)
	os.reboot()
end

local function Ask(Question, Choices)
	while (true) do
		write(Question .. " ")
		local Answer = (read() or ""):lower():sub(1, 1)
		for _, Choice in ipairs(Choices) do
			if (Answer == Choice) then return Choice end
		end
	end
end

_G.BlockOS = { Root = "/blockos", Installer = true, Version = Version }

function BlockOS.Load(Path, ...)
	local Source = Files[Key(Path)]
	local Fn, Err
	if (Source) then
		Fn, Err = load(Source, "@/" .. Key(Path), "t", _G)
	else
		Fn, Err = loadfile(Path, nil, _G)
	end
	if (not Fn) then error(Err, 2) end
	return Fn(...)
end

function BlockOS.Require(Name)
	if (Loaded[Name]) then return Loaded[Name] end
	local Module = BlockOS.Load("/blockos/lib/" .. Name .. ".lua")
	if (not Fresh[Name]) then Loaded[Name] = Module end
	return Module
end

math.randomseed(os.epoch("utc") + os.getComputerID())

term.setBackgroundColor(colors.black)
term.clear()
term.setCursorPos(1, 1)
if (term.isColor()) then term.setTextColor(colors.lime) end
print("BlockOS " .. Version .. " installer")
if (term.isColor()) then term.setTextColor(colors.white) end

if (turtle) then
	if (not term.isColor()) then
		InstallAgent()
		return
	end
	print("This is an advanced turtle.")
	print("[F] Full BlockOS desktop  [A] Turtle Agent only")
	if (Ask("Choice (f/a):", { "f", "a" }) == "a") then
		InstallAgent()
		return
	end
elseif (not term.isColor()) then
	print("BlockOS needs an Advanced Computer (gold).")
	print("Basic turtles can install the Turtle Agent instead.")
	return
end

if (fs.exists("/blockos/data/users.dat")) then
	local Installed = "unknown"
	if (fs.exists("/blockos/version.txt")) then
		local Handle = fs.open("/blockos/version.txt", "r")
		Installed = (Handle.readAll() or ""):gsub("%s+", "")
		Handle.close()
	end
	print("BlockOS " .. Installed .. " is already installed.")
	if (Ask("Update it to " .. Version .. "? Your data is kept. (y/n):", { "y", "n" }) ~= "y") then return end
	InstallFiles(function(Done, Total, Path)
		term.setCursorPos(1, select(2, term.getCursorPos()))
		term.clearLine()
		write(string.format("[%3d%%] %s", math.floor(Done / math.max(Total, 1) * 100), Path:sub(1, 40)))
	end)
	print()
	print("Updated. Rebooting...")
	sleep(1)
	os.reboot()
	return
end

local Setup = BlockOS.Load("/blockos/sys/setup.lua")
local State = Setup.Run({ Mode = "install", Version = Version, Install = InstallFiles })
if (State and State.Finished) then
	os.reboot()
end