<#
.SYNOPSIS
Downloads and installs the latest DSH Plugin Installer release.

.DESCRIPTION
Installs the latest stable release into a DSH Profile through DSH's own plugin
command. The `web` Profile is started after a successful installation; the
`desktop` Profile is installed through the DeepSeek Harness Desktop application's
own bundled CLI, because DSH refuses to manage that reserved Profile from an
npm-installed CLI.

.EXAMPLE
.\Install-DshPluginInstaller.ps1

.EXAMPLE
.\Install-DshPluginInstaller.ps1 -Profile work -NoStart

.EXAMPLE
.\Install-DshPluginInstaller.ps1 -Profile desktop
#>
[CmdletBinding()]
param(
  [ValidatePattern('^[A-Za-z0-9_-]+$')]
  [string] $Profile = 'web',

  [switch] $NoStart,

  # Explicit dsh launcher to use instead of auto-detection.
  [string] $DshCommand
)

Set-StrictMode -Version Latest
$ErrorActionPreference = 'Stop'

$repository = 'Toukaiteio/dsh-plugin-installer'
$headers = @{
  Accept = 'application/vnd.github+json'
  'User-Agent' = 'dsh-plugin-installer-bootstrap'
}
# Optional, only to lift the anonymous GitHub API rate limit.
if ($null -ne $env:GITHUB_TOKEN -and $env:GITHUB_TOKEN.Trim().Length -gt 0) {
  $headers.Authorization = "Bearer $($env:GITHUB_TOKEN.Trim())"
}

<#
The launcher DeepSeek Harness Desktop ships in its own installation. The
desktop application reserves the `desktop` Profile and its CLI is the only one
allowed to manage that Profile, so the installer must find it rather than rely
on whatever `dsh` happens to be first on PATH.
#>
function Find-DesktopDsh {
  $candidates = [System.Collections.Generic.List[string]]::new()

  $uninstallRoots = @(
    'HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall',
    'HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall',
    'HKLM:\Software\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall'
  )
  foreach ($root in $uninstallRoots) {
    if (-not (Test-Path -LiteralPath $root)) { continue }
    foreach ($entry in Get-ChildItem -LiteralPath $root -ErrorAction SilentlyContinue) {
      $properties = Get-ItemProperty -LiteralPath $entry.PSPath -ErrorAction SilentlyContinue
      if ($null -eq $properties) { continue }
      if ($null -eq $properties.PSObject.Properties['DisplayName']) { continue }
      if ($properties.DisplayName -notmatch '^DeepSeek Harness') { continue }
      if ($null -ne $properties.PSObject.Properties['InstallLocation'] -and $properties.InstallLocation) {
        $candidates.Add([string]$properties.InstallLocation)
      }
    }
  }

  if ($null -ne $env:LOCALAPPDATA) { $candidates.Add((Join-Path $env:LOCALAPPDATA 'Programs\DeepSeek Harness')) }
  if ($null -ne $env:ProgramFiles) { $candidates.Add((Join-Path $env:ProgramFiles 'DeepSeek Harness')) }
  if ($null -ne ${env:ProgramFiles(x86)}) { $candidates.Add((Join-Path ${env:ProgramFiles(x86)} 'DeepSeek Harness')) }

  foreach ($directory in $candidates) {
    $launcher = Join-Path $directory 'resources\runtime\cli\bin\dsh.cmd'
    if (Test-Path -LiteralPath $launcher -PathType Leaf) { return $launcher }
  }
  return $null
}

function Resolve-DshLauncher {
  param([string] $RequestedProfile, [string] $Override)

  if ($Override) {
    if (-not (Test-Path -LiteralPath $Override -PathType Leaf)) { throw "The dsh launcher '$Override' does not exist." }
    return (Resolve-Path -LiteralPath $Override).Path
  }

  $onPath = Get-Command dsh -CommandType Application, ExternalScript -ErrorAction SilentlyContinue |
    Select-Object -First 1
  $pathDsh = if ($null -ne $onPath) { $onPath.Source } else { $null }
  $desktopDsh = Find-DesktopDsh

  # The desktop Profile is reserved: an npm-installed CLI refuses it outright,
  # while the bundled desktop CLI is allowed to manage it.
  if ($RequestedProfile -eq 'desktop') {
    if ($null -ne $desktopDsh) { return $desktopDsh }
    if ($null -ne $pathDsh) {
      Write-Warning 'The DeepSeek Harness Desktop installation was not found; falling back to the dsh on PATH. If it refuses the desktop Profile, install DeepSeek Harness Desktop first.'
      return $pathDsh
    }
    throw 'Neither the DeepSeek Harness Desktop installation nor a dsh command on PATH was found. Install DeepSeek Harness first, then run this script again.'
  }

  if ($null -ne $pathDsh) { return $pathDsh }
  if ($null -ne $desktopDsh) { return $desktopDsh }
  throw 'The DSH CLI was not found on PATH. Install DeepSeek Harness first, then run this script again.'
}

$dshLauncher = Resolve-DshLauncher -RequestedProfile $Profile -Override $DshCommand

Write-Host 'Finding the latest DSH Plugin Installer release...'
try {
  $release = Invoke-RestMethod -Uri "https://api.github.com/repos/$repository/releases/latest" -Headers $headers
} catch {
  $hint = if ($headers.ContainsKey('Authorization')) {
    'GitHub rejected the release request.'
  } else {
    'GitHub rejected the release request. If this is an anonymous rate limit, set the GITHUB_TOKEN environment variable and run the script again.'
  }
  throw "$hint $($_.Exception.Message)"
}
$asset = @($release.assets) |
  Where-Object { $_.name -match '^dsh-plugin-installer-.+\.tgz$' } |
  Select-Object -First 1

if ($null -eq $asset) {
  throw "Release $($release.tag_name) does not contain a DSH Plugin Installer package archive."
}

$dshHome = if ($null -ne $env:DSH_HOME -and $env:DSH_HOME.Trim().Length -gt 0) {
  [System.IO.Path]::GetFullPath($env:DSH_HOME)
} else {
  Join-Path ([Environment]::GetFolderPath([Environment+SpecialFolder]::UserProfile)) '.dsh'
}
$archiveDirectory = Join-Path (Join-Path $dshHome 'plugin-archives') 'dsh-plugin-installer'
$archivePath = Join-Path $archiveDirectory $asset.name
$downloadPath = Join-Path $archiveDirectory ".$($asset.name).$([guid]::NewGuid().ToString('N')).download"

try {
  New-Item -ItemType Directory -Path $archiveDirectory -Force | Out-Null

  Write-Host "Downloading $($release.tag_name)..."
  Invoke-WebRequest -Uri $asset.browser_download_url -Headers $headers -OutFile $downloadPath

  if ($asset.PSObject.Properties.Name -contains 'digest' -and $asset.digest -match '^sha256:(?<hash>[0-9a-fA-F]{64})$') {
    $expectedHash = $Matches.hash.ToLowerInvariant()
    $actualHash = (Get-FileHash -LiteralPath $downloadPath -Algorithm SHA256).Hash.ToLowerInvariant()
    if ($actualHash -ne $expectedHash) {
      throw 'The downloaded package checksum does not match the GitHub Release checksum.'
    }
  }

  # `dsh plugin add` preserves a file: dependency. Keep this archive under
  # DSH_HOME instead of a temporary directory so later plugin operations can
  # still resolve the installed package.
  Move-Item -LiteralPath $downloadPath -Destination $archivePath -Force

  Write-Host "Installing into the '$Profile' DSH Profile..."
  & $dshLauncher plugin --profile $Profile add $archivePath
  if ($LASTEXITCODE -ne 0) {
    throw "DSH plugin installation failed with exit code $LASTEXITCODE."
  }

  Write-Host "DSH Plugin Installer $($release.tag_name) was installed successfully."

  if ($NoStart) {
    Write-Host "Installation is complete. Start this Profile with: dsh --profile $Profile"
  } elseif ($Profile -eq 'desktop') {
    # The desktop application composes its Profile at startup, so the new
    # bundle layer only applies after a full restart of the application.
    Write-Host 'Fully quit and reopen DeepSeek Harness Desktop to load the marketplace.'
  } elseif ($Profile -eq 'web') {
    Write-Host 'Starting DSH Web...'
    & $dshLauncher web
    if ($LASTEXITCODE -ne 0) {
      throw "DSH Web exited with code $LASTEXITCODE."
    }
  } else {
    Write-Host "Installation is complete. Start this Profile with: dsh --profile $Profile"
  }
} finally {
  if (Test-Path -LiteralPath $downloadPath) {
    Remove-Item -LiteralPath $downloadPath -Force
  }
}