nixpkgs/modules/services/x11/xserver/desktop-managers/kde-environment.nix

{pkgs, config, ...}:

let
  inherit (pkgs.lib) mkOption mkIf;
  kdePackages = config.environment.kdePackages;

  options = {

    kde = {

      extraPackages = mkOption {
        default = [];
        merge = builtins.trace "!!! kde.extraPackages is obsolete, you should use environment.kdePackages." pkgs.lib.mergeDefaultOption;
        description = ''
          ** Obsolete **
          Additional KDE packages to be used when you use KDE as a desktop
          manager.  By default, you only get the KDE base packages.
        '';
      };

    };

    environment = {

      kdePackages = mkOption {
        default = [];
        example = [ pkgs.kde42.kdegames ];
        description = ''
          Additional KDE packages to be used when you use KDE as a desktop
          manager.  By default, you only get the KDE base packages.
        '';
        apply = pkgs: pkgs ++ config.kde.extraPackages;
      };

    };
  };
in

mkIf (kdePackages != []) {
  require = options;

  environment = {
    extraPackages = kdePackages;

    shellInit = ''
      export KDEDIRS="${pkgs.lib.concatStringsSep ":" kdePackages}"
      export XDG_CONFIG_DIRS="${pkgs.lib.makeSearchPath "etc/xdg" kdePackages}"
      export XDG_DATA_DIRS="${pkgs.lib.makeSearchPath "share" kdePackages}"
    '';
  };
}