Feat collapse and expand nodes (#176)

This MR adds the ability to expand and collapse nodes in the discussion tree in bulk. You can now toggle expansion of all nodes, toggle expansion of only resolved discussions, and toggle expansion of only unresolved discussions.

The MR also adjusts keybindings in the discussion tree to support forward and backward searching, as well as the keybinding for the help popup.

Thank you for the contribution @jakubbortlik!

This is a #MINOR bump since it's changing keybindings, although core workflows are unchanged.

lua/gitlab/actions/discussions/init.lua

@@ -389,6 +389,86 @@ M.toggle_node = function(tree)
   tree:render()
 end
 
+---@class ToggleNodesOptions
+---@field toggle_resolved boolean Whether to toggle resolved discussions.
+---@field toggle_unresolved boolean Whether to toggle unresolved discussions.
+---@field keep_current_open boolean Whether to keep the current discussion open even if it should otherwise be closed.
+
+---This function (settings.discussion_tree.toggle_nodes) expands/collapses all nodes and their children according to the opts.
+---@param tree NuiTree
+---@param opts ToggleNodesOptions
+M.toggle_nodes = function(tree, opts)
+  local current_node = tree:get_node()
+  if current_node == nil then
+    return
+  end
+  local root_node = M.get_root_node(tree, current_node)
+  for _, node in ipairs(tree:get_nodes()) do
+    if opts.toggle_resolved then
+      if state.resolved_expanded then
+        M.collapse_recursively(tree, node, root_node, opts.keep_current_open, true)
+      else
+        M.expand_recursively(tree, node, true)
+      end
+    end
+    if opts.toggle_unresolved then
+      if state.unresolved_expanded then
+        M.collapse_recursively(tree, node, root_node, opts.keep_current_open, false)
+      else
+        M.expand_recursively(tree, node, false)
+      end
+    end
+  end
+  if opts.toggle_resolved then
+    state.resolved_expanded = not state.resolved_expanded
+  end
+  if opts.toggle_unresolved then
+    state.unresolved_expanded = not state.unresolved_expanded
+  end
+  tree:render()
+  M.restore_cursor_position(tree, current_node, root_node)
+end
+
+---This function (settings.discussion_tree.collapse_recursively) collapses a node and its children.
+---@param tree NuiTree
+---@param node NuiTree.Node
+---@param current_root_node NuiTree.Node The root node of the current node.
+---@param keep_current_open boolean If true, the current node stays open, even if it should otherwise be collapsed.
+---@param is_resolved boolean If true, collapse resolved discussions. If false, collapse unresolved discussions.
+M.collapse_recursively = function(tree, node, current_root_node, keep_current_open, is_resolved)
+  if node == nil then
+    return
+  end
+  local root_node = M.get_root_node(tree, node)
+  if M.is_node_note(node) and root_node.resolved == is_resolved then
+    if keep_current_open and root_node == current_root_node then
+      return
+    end
+    node:collapse()
+  end
+  local children = node:get_child_ids()
+  for _, child in ipairs(children) do
+    M.collapse_recursively(tree, tree:get_node(child), current_root_node, keep_current_open, is_resolved)
+  end
+end
+
+---This function (settings.discussion_tree.expand_recursively) expands a node and its children.
+---@param tree NuiTree
+---@param node NuiTree.Node
+---@param is_resolved boolean If true, expand resolved discussions. If false, expand unresolved discussions.
+M.expand_recursively = function(tree, node, is_resolved)
+  if node == nil then
+    return
+  end
+  if M.is_node_note(node) and M.get_root_node(tree, node).resolved == is_resolved then
+    node:expand()
+  end
+  local children = node:get_child_ids()
+  for _, child in ipairs(children) do
+    M.expand_recursively(tree, tree:get_node(child), is_resolved)
+  end
+end
+
 --
 -- 🌲 Helper Functions
 --
@@ -560,6 +640,27 @@ M.set_tree_keymaps = function(tree, bufnr, unlinked)
   vim.keymap.set("n", state.settings.discussion_tree.toggle_node, function()
     M.toggle_node(tree)
   end, { buffer = bufnr, desc = "Toggle node" })
+  vim.keymap.set("n", state.settings.discussion_tree.toggle_all_discussions, function()
+    M.toggle_nodes(tree, {
+      toggle_resolved = true,
+      toggle_unresolved = true,
+      keep_current_open = state.settings.discussion_tree.keep_current_open,
+    })
+  end, { buffer = bufnr, desc = "Toggle all nodes" })
+  vim.keymap.set("n", state.settings.discussion_tree.toggle_resolved_discussions, function()
+    M.toggle_nodes(tree, {
+      toggle_resolved = true,
+      toggle_unresolved = false,
+      keep_current_open = state.settings.discussion_tree.keep_current_open,
+    })
+  end, { buffer = bufnr, desc = "Toggle resolved nodes" })
+  vim.keymap.set("n", state.settings.discussion_tree.toggle_unresolved_discussions, function()
+    M.toggle_nodes(tree, {
+      toggle_resolved = false,
+      toggle_unresolved = true,
+      keep_current_open = state.settings.discussion_tree.keep_current_open,
+    })
+  end, { buffer = bufnr, desc = "Toggle unresolved nodes" })
   vim.keymap.set("n", state.settings.discussion_tree.reply, function()
     if M.is_current_node_note(tree) then
       M.reply(tree)
@@ -621,6 +722,18 @@ M.redraw_resolved_status = function(tree, note, mark_resolved)
   tree:render()
 end
 
+---Restore cursor position to the original node if possible
+M.restore_cursor_position = function(tree, original_node, root_node)
+  local _, line_number = tree:get_node("-" .. tostring(original_node.id))
+  -- If current_node is has been collapsed, get line number of root node instead
+  if line_number == nil and root_node then
+    _, line_number = tree:get_node("-" .. tostring(root_node.id))
+  end
+  if line_number ~= nil then
+    vim.api.nvim_win_set_cursor(M.split.winid, { line_number, 0 })
+  end
+end
+
 ---Replace text in discussion after note update.
 ---@param data Discussion[]|UnlinkedDiscussion[]
 ---@param discussion_id string