{ config, lib, ... }:

with lib;

mkIf (elem "emacs::undo-tree" config.machine.pkgs) {
  programs.emacs.init.usePackage.undo-tree = {
    enable = true;
    hook = [ "(after-init . global-undo-tree-mode)" ];
    config = ''
      (setq undo-tree-visualizer-diff 't)
      (setq undo-tree-auto-save-history 't)
      (setq undo-tree-enable-undo-in-region 't)
      (setq undo-tree-history-directory-alist '(("." . "~/.emacs_undo")))
    '';
  };
}