return {

	{
		"nvim-tree/nvim-tree.lua",
		cond = not env.is_vscode(),
		dependencies = { "nvim-tree/nvim-web-devicons" },
		cmd = { "NvimTreeOpen", "NvimTreeClose", "NvimTreeFocus", "NvimTreeToggle", "NvimTreeFindFile", "NvimTreeRefresh" },
		config = function()
			local api = require("nvim-tree.api")

			-- キーマッピングの設定
			local function on_attach(bufnr)
				local function map(key, action, desc)
					vim.keymap.set("n", key, action, {
						desc = "nvim-tree: " .. desc,
						buffer = bufnr,
						noremap = true,
						silent = true,
						nowait = true,
					})
				end

				-- 基本操作
				map("<CR>", api.node.open.edit, "Open")
				map("o", api.node.open.edit, "Open")
				map("<C-v>", api.node.open.vertical, "Open: Vertical Split")
				map("<C-s>", api.node.open.horizontal, "Open: Horizontal Split")
				map("<BS>", api.node.navigate.parent_close, "Up")
				map("<Tab>", api.node.open.preview, "Open Preview")
				map("-", api.tree.change_root_to_node, "CD")

				-- ナビゲーション
				map(">", api.node.navigate.sibling.next, "Next Sibling")
				map("<", api.node.navigate.sibling.prev, "Previous Sibling")
				map("P", api.node.navigate.parent, "Parent Directory")
				map("J", api.node.navigate.sibling.last, "Last Sibling")
				map("K", api.node.navigate.sibling.first, "First Sibling")

				-- ファイル操作
				map("a", api.fs.create, "Create")
				map("d", api.fs.remove, "Delete")
				map("D", api.fs.trash, "Trash")
				map("r", api.fs.rename, "Rename")
				map("x", api.fs.cut, "Cut")
				map("c", api.fs.copy.node, "Copy")
				map("p", api.fs.paste, "Paste")

				-- その他
				map("R", api.tree.reload, "Refresh")
				map("?", api.tree.toggle_help, "Help")
				map("q", api.tree.close, "Close")

				-- フォルダ展開/折りたたみ
				map("O", api.node.open.no_window_picker, "Open: No Window Picker")
				map("E", api.tree.expand_all, "Expand All")
				map("W", api.tree.collapse_all, "Collapse All")
				map("zo", function()
					local node = api.tree.get_node_under_cursor()
					if node then
						api.tree.expand_all(node)
					end
				end, "Expand Folder Recursively")
				map("zc", api.node.navigate.parent_close, "Collapse Folder")

				-- copy

				map("gy", api.fs.copy.absolute_path, "Copy Absolute Path")

				map("y", api.fs.copy.filename, "Copy Name")
				map("Y", api.fs.copy.relative_path, "Copy Relative Path")
				map("<2-LeftMouse>", api.node.open.edit, "Open")
				map("<2-RightMouse>", api.tree.change_root_to_node, "CD")
			end

			local function setup_diagnostics_refresh()
				-- オリジナルのハンドラを保存
				local original_handler = vim.diagnostic.handlers.virtual_text

				-- 診断情報が更新されたときのハンドラをカスタマイズ
				vim.diagnostic.handlers.virtual_text = {
					show = function(namespace, bufnr, diagnostics, opts)
						original_handler.show(namespace, bufnr, diagnostics, opts)
						-- バッファが有効な場合のみリフレッシュを実行
						if vim.api.nvim_buf_is_valid(bufnr) then
							vim.defer_fn(function()
								api.tree.reload()
							end, 100)
						end
					end,
					hide = function(namespace, bufnr)
						original_handler.hide(namespace, bufnr)
						if vim.api.nvim_buf_is_valid(bufnr) then
							vim.defer_fn(function()
								api.tree.reload()
							end, 100)
						end
					end,
				}

				-- LSPの診断情報変更時のイベントハンドラを設定
				vim.api.nvim_create_autocmd("DiagnosticChanged", {
					group = vim.api.nvim_create_augroup("NvimTreeDiagnostics", { clear = true }),
					callback = function()
						vim.defer_fn(function()
							-- ツリーが表示されている場合のみリフレッシュ
							if api.tree.is_visible() then
								api.tree.reload()
							end
						end, 100)
					end,
				})
			end

			-- auto close: 最後のウィンドウがNvimTreeだけの場合に自動で閉じる
			vim.api.nvim_create_autocmd("QuitPre", {
				callback = function()
					local tree_wins = {}
					local floating_wins = {}
					local wins = vim.api.nvim_list_wins()
					for _, w in ipairs(wins) do
						local bufname = vim.api.nvim_buf_get_name(vim.api.nvim_win_get_buf(w))
						if bufname:match("NvimTree_") ~= nil then
							table.insert(tree_wins, w)
						end
						if vim.api.nvim_win_get_config(w).relative ~= "" then
							table.insert(floating_wins, w)
						end
					end
					if 1 == #wins - #floating_wins - #tree_wins then
						for _, w in ipairs(tree_wins) do
							vim.api.nvim_win_close(w, true)
						end
					end
				end,
			})

			-- nvim-treeの設定
			require("nvim-tree").setup({
				disable_netrw = true,
				hijack_netrw = true,
				hijack_cursor = false,
				sync_root_with_cwd = true,
				filesystem_watchers = {
					enable = true, -- ファイルシステムの監視を有効化
					debounce_delay = 50, -- 更新の遅延時間
					ignore_dirs = { ".git" }, -- 監視から除外するディレクトリ
				},

				-- 自動更新の設定
				auto_reload_on_write = true,
				reload_on_bufenter = true, -- バッファ切り替え時に更新
				update_focused_file = {
					enable = true, -- フォーカスされたファイルの状態を更新
					update_root = false, -- ルートディレクトリは更新しない
					ignore_list = {}, -- 更新を無視するパターン
				},
				view = {
					-- 幅を自動調整（最小30、最大50、内容に合わせて調整）
					width = {
						min = 30,
						max = 50,
						padding = 1,
					},
					side = "left",
					preserve_window_proportions = true,
					-- フローティングウィンドウで表示（左側、上下幅最大）
					float = {
						enable = true,
						quit_on_focus_loss = true,
						open_win_config = function()
							return {
								relative = "editor",
								border = "rounded",
								width = 50,
								height = vim.o.lines - 3, -- ステータスライン等を除いた最大高さ
								row = 0,
								col = 0,
							}
						end,
					},
				},
				renderer = {
					-- 空ディレクトリをグループ化（a/b/c のように表示）
					group_empty = true,
					add_trailing = false,
					highlight_git = true,
					highlight_opened_files = "none",
					indent_markers = {
						enable = true,
					},
					icons = {
						git_placement = "signcolumn",
						show = {
							file = true,
							folder = true,
							folder_arrow = true,
							git = true,
						},
						glyphs = {
							default = "",
							symlink = "",
							git = {
								unstaged = "M",
								staged = "✓",
								unmerged = "",
								renamed = "➜",
								untracked = "★",
								deleted = "",
								ignored = "◌",
							},
							folder = {
								default = "",
								open = "",
								symlink = "",
								empty = "",
								empty_open = "",
								symlink_open = "",
							},
						},
					},
				},
				actions = {
					open_file = {
						window_picker = {
							enable = true,
						},
					},
					change_dir = {
						enable = true,
						global = false,
					},
				},
				modified = {
					enable = true,
					show_on_dirs = true,
					show_on_open_dirs = true,
				},
				diagnostics = {
					enable = true,
					show_on_dirs = true,
					show_on_open_dirs = true, -- 開いているディレクトリでも表示
					debounce_delay = 50, -- 更新の遅延時間
					severity = {
						min = vim.diagnostic.severity.HINT,
						max = vim.diagnostic.severity.ERROR,
					},
					icons = {
						hint = "󱄋",
						info = "",
						warning = "",
						error = "",
					},
				},
				filters = {
					dotfiles = false,
					custom = { "^.git$" },
				},
				git = {
					enable = true,
					ignore = false,
					timeout = 500,
				},
				on_attach = on_attach,
			})
			setup_diagnostics_refresh()
		end,
		doc = "ファイルエクスプローラー",
	},
}