Add tree-mode files to the review side panel

CLAUDE.md

@@ -42,7 +42,8 @@ All plugin code lives under `lua/fude/`. The plugin entry point is `plugin/fude.
   - **`ui/format.lua`** — Pure format/calculation functions with no state or vim API side effects: `calculate_float_dimensions`, `format_comments_for_display`, `normalize_check`, `format_check_status`, `deduplicate_checks`, `sort_checks`, `build_checks_summary`, `format_review_status`, `build_reviewers_list`, `build_reviewers_summary`, `calculate_overview_layout`, `calculate_comments_height`, `calculate_reply_window_dimensions`, `format_reply_comments_for_display`, `build_overview_left_lines`, `build_overview_right_lines`, `calculate_comment_browser_layout`, `format_comment_browser_list`, `format_comment_browser_thread`, `parse_markdown_line`, `build_highlighted_chunks`, `apply_markdown_highlight_to_line`, `normalize_newlines`. Purity is enforced by `scripts/check_purity.lua` (`make check-purity`).
   - **`ui/inline.lua`** — Inline (virt_lines) comment box rendering. `format_comments_for_inline(comments, format_date_fn, opts)` builds bordered comment boxes for use as `nvim_buf_set_extmark` `virt_lines`. Reads the current window's text width via `vim.api`/`vim.fn` to size boxes, which is why it lives outside the pure `ui/format.lua`.
   - **`ui/comment_browser.lua`** — 3-pane floating comment browser for `FudeReviewListComments`. Left pane: comment list (review + PR-level, time-descending), including local drafts via `merge_draft_entries` (existing entries get a `✎draft` marker; new line/suggest/issue drafts appear as `[draft]` rows). Selecting a `type="draft"` row: `line`/`suggest` jumps to the file (`<CR>`), `issue` focuses the lower pane (prefilled). Right upper: thread display (draft body preview for draft rows). Right lower: reply/edit/new comment input. Supports reply, edit, delete, new PR comment, jump to file, and refresh. Does not depend on Telescope.
-  - **`ui/sidepanel.lua`** — Toggleable sidebar showing Review Scope and Changed Files. Pure functions: `format_scope_section`, `format_files_section`, `build_sidepanel_content`, `resolve_entry_at_cursor`. Side-effect functions: `open`, `close`, `toggle`, `refresh`. Uses `nvim_open_win` with `split` for sidebar creation. Uses dedicated `fude_sidepanel` namespace for highlights (avoids `refresh_extmarks` clearing them on BufEnter). Auto-refreshes on scope change and reload. Keymaps: `<CR>` select/open, `<Tab>` toggle reviewed/viewed, `R` reload, `q` close.
+  - **`ui/sidepanel.lua`** — Toggleable sidebar showing Review Scope and Changed Files. Files default to a flat list (`sidepanel.file_tree = "flat"`); `"tree"` groups files by directory via `ui/sidepanel/tree.lua`. Pure functions: `format_scope_section`, `format_files_section`, `format_files_section_tree`, `build_sidepanel_content`, `resolve_entry_at_cursor`. Side-effect functions: `open`, `close`, `toggle`, `refresh`, `toggle_file_tree_mode`. Uses `nvim_open_win` with `split` for sidebar creation. Uses dedicated `fude_sidepanel` namespace for highlights (avoids `refresh_extmarks` clearing them on BufEnter). Auto-refreshes on scope change and reload. Keymaps: `<CR>` select/open, `<Tab>` toggle reviewed/viewed, `t` toggle flat/tree, `R` reload, `q` close.
+  - **`ui/sidepanel/tree.lua`** — Pure tree helpers for the sidepanel Files section: `build_tree`, `collapse_singleton_chains`, `compute_aggregate`, and `flatten_tree`.
   - **`ui/extmarks.lua`** — Extmark management: `flash_line`, `highlight_comment_lines`, `clear_comment_line_highlight`, `refresh_extmarks`, `clear_extmarks`, `clear_all_extmarks`. Uses lazy `require("fude.comments")` to avoid circular dependencies. `refresh_extmarks` also renders the `draft` indicator from `drafts.file_markers(rel_path)` (EOL virt_text, both virtualText and inline modes).
 - **`files.lua`** — Changed files display via Telescope picker, snacks.picker, or quickfix list. All pickers show diff preview and viewed state toggle via `<Tab>`. Shows GitHub viewed status for each file. Exports `apply_viewed_toggle(path, on_done)` as a picker-agnostic state mutator that invokes gh GraphQL mark/unmark, updates `state.viewed_files`, and calls `on_done` with the updated display fields; the Telescope adapter `toggle_viewed_in_telescope` and the snacks adapter `toggle_viewed_in_snacks(picker, item)` both delegate to it. `show()` routes to `show_telescope` / `show_snacks` / `show_quickfix` based on `config.opts.file_list_mode`; snacks falls back to quickfix when snacks.nvim is missing. Also exports `next_file()` / `prev_file()` for jumping between changed files (used by `:FudeReviewNextFile` / `:FudeReviewPrevFile`); both wrap around at the edges and fall back to the first/last entry when the current buffer is not part of the PR. The pure helper `find_adjacent_file_index(changed_files, current_path, direction)` computes the target index.
 - **`scope.lua`** — Review scope selection and navigation. Provides a Telescope picker (or `vim.ui.select` fallback) for choosing between full PR scope and individual commit scope, with commit index display (`[1/10]`) and current scope marker (`▶`). Supports next/prev scope navigation (`next_scope`/`prev_scope`), marking commits as reviewed via `<Tab>` in the Telescope picker (tracked locally in `state.reviewed_commits`), and statusline integration (`statusline()`). On commit scope: checks out the commit, fetches commit-specific changed files, updates gitsigns base to `sha^` (global), and refreshes the diff preview. On full PR scope: restores the original HEAD, re-fetches PR-wide changed files, and computes merge-base (per-buffer gitsigns base is applied via `GitSignsUpdate` autocmd in init.lua). Exports `apply_reviewed_toggle(sha)` as a picker-agnostic state mutator that toggles `state.reviewed_commits[sha]` and returns the updated display fields `{ is_reviewed, reviewed_icon, reviewed_hl }`; both the Telescope adapter `toggle_reviewed_in_telescope` and the snacks adapter `toggle_reviewed_in_snacks(picker, item)` delegate to it. `select_scope()` routes to `show_telescope` / `show_snacks` / `show_vim_select` based on `config.opts.file_list_mode`; snacks falls back to `vim.ui.select` when snacks.nvim is missing.

README.md

@@ -47,7 +47,8 @@ PR code review inside Neovim. Review GitHub pull requests without leaving your e
     "FudeReviewFiles", "FudeReviewNextFile", "FudeReviewPrevFile",
     "FudeReviewScope", "FudeReviewScopeNext", "FudeReviewScopePrev",
     "FudeReviewOverview", "FudeReviewSubmit", "FudeOpenPRURL", "FudeCopyPRURL",
-    "FudeReviewViewed", "FudeReviewUnviewed", "FudeReviewReload", "FudeCreatePR",
+    "FudeReviewViewed", "FudeReviewUnviewed", "FudeReviewReload", "FudeReviewPanel",
+    "FudeReviewToggleFileTree", "FudeCreatePR",
   },
   keys = {
     { "<leader>et", "<cmd>FudeReviewToggle<cr>", desc = "Review: Toggle" },
@@ -123,6 +124,8 @@ PR code review inside Neovim. Review GitHub pull requests without leaving your e
 | `:FudeReviewReload` | Reload review data from GitHub |
 | `:FudeReviewToggleCommentStyle` | Toggle comment display style (virtualText/inline) |
 | `:FudeReviewToggleGitsigns` | Toggle gitsigns between PR base and HEAD |
+| `:FudeReviewPanel` | Toggle review side panel |
+| `:FudeReviewToggleFileTree` | Toggle side panel files between flat list and tree |
 | `:FudeCreatePR` | Create draft PR from template |
 
 ## Configuration
@@ -203,6 +206,12 @@ require("fude").setup({
     label = "[outdated]",  -- Label string for outdated comments
     hl_group = "Comment",  -- Highlight group for outdated label in comment browser
   },
+  -- Side panel options
+  sidepanel = {
+    width = 40,          -- Panel width in columns
+    position = "left",   -- "left" or "right"
+    file_tree = "flat",  -- "flat" or "tree"
+  },
   -- Callback after review start completes (all data fetched)
   -- Receives: { pr_number, base_ref, head_ref, pr_url }
   on_review_start = nil,

doc/fude.txt

@@ -352,6 +352,7 @@ Using lazy.nvim: >lua
     Keymaps (panel):~
       `<CR>`    Select scope entry or open file
       `<Tab>`   Toggle reviewed (scope) / viewed (file)
+      `t`       Toggle files between flat list and tree
       `R`       Reload review data from GitHub
       `q`       Close panel
 
@@ -361,6 +362,12 @@ Using lazy.nvim: >lua
     or viewed/reviewed state is toggled.
     Configurable via `sidepanel` options. Requires an active session.
 
+:FudeReviewToggleFileTree              *:FudeReviewToggleFileTree*
+    Toggle the open side panel's Files section between flat list and
+    directory tree. This changes only the current panel session; the
+    default is controlled by `sidepanel.file_tree`.
+    Requires the side panel to be open.
+
 :FudeReviewToggleGitsigns              *:FudeReviewToggleGitsigns*
     Toggle gitsigns base between PR base and HEAD.
     By default during review mode, gitsigns uses the PR base (or commit
@@ -494,6 +501,7 @@ Default configuration: >lua
     sidepanel = {
       width = 40,       -- Panel width in columns (minimum 20)
       position = "left", -- "left" or "right"
+      file_tree = "flat", -- "flat" or "tree"
     },
     -- Outdated comment display options
     outdated = {
@@ -660,6 +668,12 @@ Options:
                   Side of the editor to open the panel: "left" or "right"
                   (default: "left").
 
+`sidepanel.file_tree`
+                  Files section layout for the side panel: "flat" or "tree"
+                  (default: "flat"). The tree layout groups changed files
+                  by directory and can be toggled for the current panel with
+                  |:FudeReviewToggleFileTree| or `t` in the panel.
+
 `outdated.show`     Show outdated comments (default: true).
                   Outdated comments are those whose position in the code
                   can no longer be tracked due to subsequent changes.

lua/fude/config.lua

@@ -86,6 +86,7 @@ M.defaults = {
 	sidepanel = {
 		width = 40, -- Panel width in columns
 		position = "left", -- "left" or "right"
+		file_tree = "flat", -- "flat" or "tree"
 	},
 	-- Callback invoked after review start completes (all data fetched).
 	-- Receives a table: { pr_number, base_ref, head_ref, pr_url }

lua/fude/ui/sidepanel.lua

@@ -95,6 +95,60 @@ function M.format_files_section(file_entries, width, format_path_fn)
 	return lines, highlights, #file_entries
 end
 
+--- Format the files section lines as a directory tree.
+--- @param tree_entries table[] entries from ui.sidepanel.tree.flatten_tree
+--- @param total_file_count number total number of changed files
+--- @param width number available width in columns
+--- @return string[] lines
+--- @return table[] highlights { { line_0idx, col_start, col_end, hl_group } }
+--- @return number entry_count number of rendered tree entries
+function M.format_files_section_tree(tree_entries, total_file_count, width)
+	local lines = { string.format(" Files (%d)", total_file_count), string.rep("─", width) }
+	local highlights = {
+		{ 0, 0, -1, "Title" },
+	}
+
+	for _, entry in ipairs(tree_entries) do
+		local indent = string.rep("  ", entry.depth)
+		local line_idx = #lines
+
+		if entry.type == "directory" then
+			local viewed_all = entry.total_files > 0 and entry.viewed_files == entry.total_files
+			local viewed_sign = (config.opts.signs and config.opts.signs.viewed) or "✓"
+			local viewed_marker = viewed_all and (" " .. viewed_sign) or ""
+			local text = indent .. entry.name .. viewed_marker
+			table.insert(lines, text)
+
+			local pos = #indent
+			table.insert(highlights, { line_idx, pos, pos + #entry.name, "Directory" })
+			if viewed_all then
+				local viewed_hl = (config.opts.signs and config.opts.signs.viewed_hl) or "DiagnosticOk"
+				local marker_start = pos + #entry.name + 1
+				table.insert(highlights, { line_idx, marker_start, marker_start + #viewed_sign, viewed_hl })
+			end
+		else
+			local f = entry.file or {}
+			local viewed = f.viewed_icon or " "
+			local status = f.status_icon or "?"
+			local adds = string.format("+%-3d", f.additions or 0)
+			local dels = string.format("-%-3d", f.deletions or 0)
+			local text = indent .. viewed .. " " .. status .. " " .. adds .. " " .. dels .. " " .. entry.name
+			table.insert(lines, text)
+
+			local viewed_start = #indent
+			table.insert(highlights, { line_idx, viewed_start, viewed_start + #viewed, f.viewed_hl or "Comment" })
+			local status_start = viewed_start + #viewed + 1
+			table.insert(highlights, { line_idx, status_start, status_start + #status, f.status_hl or "DiffChange" })
+			local adds_start = status_start + #status + 1
+			table.insert(highlights, { line_idx, adds_start, adds_start + #adds, "DiffAdd" })
+			local dels_start = adds_start + #adds + 1
+			table.insert(highlights, { line_idx, dels_start, dels_start + #dels, "DiffDelete" })
+		end
+	end
+
+	return lines, highlights, #tree_entries
+end
+
 --- Build the full sidepanel buffer content from scope and files sections.
 --- @param scope_lines string[]
 --- @param scope_hls table[]
@@ -230,7 +284,18 @@ local function render(panel)
 
 	-- Format sections
 	local scope_lines, scope_hls, scope_count = M.format_scope_section(scope_entries, width)
-	local file_lines, file_hls, file_count = M.format_files_section(file_entries, width, config.format_path)
+	local file_lines, file_hls, file_count
+	local tree_entries
+	if (panel.file_tree_mode or sp_opts.file_tree) == "tree" then
+		local tree_mod = require("fude.ui.sidepanel.tree")
+		local tree = tree_mod.build_tree(file_entries)
+		tree_mod.collapse_singleton_chains(tree)
+		tree_entries = tree_mod.flatten_tree(tree, state.viewed_files)
+		file_lines, file_hls, file_count = M.format_files_section_tree(tree_entries, #file_entries, width)
+	else
+		file_lines, file_hls, file_count = M.format_files_section(file_entries, width, config.format_path)
+	end
+
 	local lines, highlights, section_map =
 		M.build_sidepanel_content(scope_lines, scope_hls, scope_count, file_lines, file_hls, file_count)
 
@@ -252,6 +317,7 @@ local function render(panel)
 	-- Store entries and map for keymap handlers
 	panel.scope_entries = scope_entries
 	panel.file_entries = file_entries
+	panel.tree_entries = tree_entries
 	panel.section_map = section_map
 end
 
@@ -325,8 +391,10 @@ function M.open()
 		buf = buf,
 		scope_entries = {},
 		file_entries = {},
+		tree_entries = nil,
 		section_map = nil,
 		augroup = nil,
+		file_tree_mode = sp_opts.file_tree or "flat",
 	}
 	state.sidepanel = panel
 
@@ -417,6 +485,10 @@ function M.setup_keymaps(panel)
 			M.toggle_file_viewed(panel, entry_info)
 		end
 	end, { buffer = buf, desc = "Toggle reviewed/viewed" })
+
+	vim.keymap.set("n", "t", function()
+		M.toggle_file_tree_mode(panel)
+	end, { buffer = buf, desc = "Toggle tree/flat file list" })
 end
 
 --- Get the entry under the cursor.
@@ -442,9 +514,19 @@ function M.get_current_entry(panel)
 			return { type = "scope", index = result.index, entry = entry }
 		end
 	elseif result.type == "file" then
-		local entry = panel.file_entries[result.index]
-		if entry then
-			return { type = "file", index = result.index, entry = entry }
+		if panel.tree_entries then
+			local tree_entry = panel.tree_entries[result.index]
+			if tree_entry then
+				if tree_entry.type == "directory" then
+					return { type = "directory", index = result.index, entry = tree_entry }
+				end
+				return { type = "file", index = result.index, entry = tree_entry.file, tree_entry = tree_entry }
+			end
+		else
+			local entry = panel.file_entries[result.index]
+			if entry then
+				return { type = "file", index = result.index, entry = entry }
+			end
 		end
 	end
 
@@ -496,6 +578,19 @@ function M.toggle_scope_reviewed(_panel, entry_info)
 	M.refresh()
 end
 
+--- Toggle the panel's file display mode for the current panel session.
+--- @param panel table|nil sidepanel state (defaults to active panel)
+function M.toggle_file_tree_mode(panel)
+	panel = panel or config.state.sidepanel
+	if not panel then
+		vim.notify("fude.nvim: Side panel is not open", vim.log.levels.WARN)
+		return
+	end
+	panel.file_tree_mode = panel.file_tree_mode == "tree" and "flat" or "tree"
+	vim.notify("fude.nvim: File list mode: " .. panel.file_tree_mode, vim.log.levels.INFO)
+	M.refresh()
+end
+
 --- Toggle viewed state for a file entry.
 --- @param panel table sidepanel state
 --- @param entry_info table { type, index, entry }