WIP: collapse/uncollapse all files in tree

Seems like this feature is highly requested #4095 #3554

Did a quick wip pr. I got the core functionality working with files and
had some questions on what can be improved in order to polish it more.
I.e. What keymaps if any to add to these, should the functionality be to
toggle vs collapse and uncollapse separately, and if this should be
added anywhere else (right now it's just for the file tree)

Once I figure this out I can add the tests, documentations and anything
else that's missing. I'm also pretty new to the language so if there's a
way I can structure this better please let me know

pkg/gui/controllers/files_controller.go

@@ -478,6 +478,34 @@ func (self *FilesController) enter() error {
 	return self.EnterFile(types.OnFocusOpts{ClickedWindowName: "", ClickedViewLineIdx: -1})
 }
 
+func (self *FilesController) collapseAll() error {
+	nodes := self.context().GetAllItems()
+
+	dirPaths := lo.FilterMap(nodes, func(file *filetree.FileNode, index int) (string, bool) {
+		return file.Path, !file.IsFile()
+	})
+
+	self.context().FileTreeViewModel.CollapseAll(dirPaths)
+
+	self.c.PostRefreshUpdate(self.c.Contexts().Files)
+
+	return nil
+}
+
+func (self *FilesController) uncollapseAll() error {
+	files := self.context().GetAllFiles()
+
+	filePaths := lo.Map(files, func(file *models.File, index int) string {
+		return file.GetPath()
+	})
+
+	self.context().FileTreeViewModel.UncollapseAll(filePaths)
+
+	self.c.PostRefreshUpdate(self.c.Contexts().Files)
+
+	return nil
+}
+
 func (self *FilesController) EnterFile(opts types.OnFocusOpts) error {
 	node := self.context().GetSelected()
 	if node == nil {

pkg/gui/filetree/file_tree.go

@@ -44,6 +44,8 @@ type IFileTree interface {
 	GetAllFiles() []*models.File
 	GetFilter() FileTreeDisplayFilter
 	GetRoot() *FileNode
+	CollapseAll(paths []string)
+	UncollapseAll(paths []string)
 }
 
 type FileTree struct {
@@ -171,6 +173,18 @@ func (self *FileTree) ToggleCollapsed(path string) {
 	self.collapsedPaths.ToggleCollapsed(path)
 }
 
+func (self *FileTree) CollapseAll(paths []string) {
+	for _, path := range paths {
+		self.collapsedPaths.Collapse(path)
+	}
+}
+
+func (self *FileTree) UncollapseAll(paths []string) {
+	for _, path := range paths {
+		self.collapsedPaths.ExpandToPath(path)
+	}
+}
+
 func (self *FileTree) Tree() *FileNode {
 	return NewFileNode(self.tree)
 }