feat(#3132): add api.node.expand and api.node.collapse (#3133)

* feat: allow passing node to collapse all

* refactor: use snake case

* feat: handle api legacy calls and update signature

* refactor: make sure open is a boolean

* doc: collapse_all

* Revert "doc: collapse_all"

This reverts commit d243da3e14.

* add api.node.collapse

* add api.node.expand

* add api.node.expand

---------

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/actions/tree/modifiers/expand.lua

@@ -0,0 +1,111 @@
+local core = require("nvim-tree.core")
+local Iterator = require("nvim-tree.iterators.node-iterator")
+local notify = require("nvim-tree.notify")
+
+local FileNode = require("nvim-tree.node.file")
+local DirectoryNode = require("nvim-tree.node.directory")
+
+local M = {}
+
+---@param list string[]
+---@return table
+local function to_lookup_table(list)
+  local table = {}
+  for _, element in ipairs(list) do
+    table[element] = true
+  end
+
+  return table
+end
+
+---@param node DirectoryNode
+local function expand(node)
+  node = node:last_group_node()
+  node.open = true
+  if #node.nodes == 0 then
+    core.get_explorer():expand(node)
+  end
+end
+
+---@param expansion_count integer
+---@param node Node
+---@return boolean
+local function should_expand(expansion_count, node)
+  local dir = node:as(DirectoryNode)
+  if not dir then
+    return false
+  end
+  local should_halt = expansion_count >= M.MAX_FOLDER_DISCOVERY
+  local should_exclude = M.EXCLUDE[dir.name]
+  return not should_halt and not dir.open and not should_exclude
+end
+
+local function gen_iterator()
+  local expansion_count = 0
+
+  return function(parent)
+    if parent.parent and parent.nodes and not parent.open then
+      expansion_count = expansion_count + 1
+      expand(parent)
+    end
+
+    Iterator.builder(parent.nodes)
+      :hidden()
+      :applier(function(node)
+        if should_expand(expansion_count, node) then
+          expansion_count = expansion_count + 1
+          node = node:as(DirectoryNode)
+          if node then
+            expand(node)
+          end
+        end
+      end)
+      :recursor(function(node)
+        return expansion_count < M.MAX_FOLDER_DISCOVERY and (node.group_next and { node.group_next } or (node.open and node.nodes))
+      end)
+      :iterate()
+
+    if expansion_count >= M.MAX_FOLDER_DISCOVERY then
+      return true
+    end
+  end
+end
+
+---@param node Node?
+local function expand_node(node)
+  if not node then
+    return
+  end
+
+  if gen_iterator()(node) then
+    notify.warn("expansion iteration was halted after " .. M.MAX_FOLDER_DISCOVERY .. " discovered folders")
+  end
+
+  local explorer = core.get_explorer()
+  if explorer then
+    explorer.renderer:draw()
+  end
+end
+
+---Expand the directory node or the root
+---@param node Node
+function M.all(node)
+  expand_node(node and node:as(DirectoryNode) or core.get_explorer())
+end
+
+---Expand the directory node or parent node
+---@param node Node
+function M.node(node)
+  if not node then
+    return
+  end
+
+  expand_node(node:is(FileNode) and node.parent or node:as(DirectoryNode))
+end
+
+function M.setup(opts)
+  M.MAX_FOLDER_DISCOVERY = opts.actions.expand_all.max_folder_discovery
+  M.EXCLUDE = to_lookup_table(opts.actions.expand_all.exclude)
+end
+
+return M