{ config, pkgs, lib, ... }:
with lib;
let
  cfg = config.programs.custom.zsh;
in
{

  options.programs.custom.zsh = {
    enable = mkEnableOption "enable zsh";
    mainUser = mkOption {
      type = with types; nullOr str;
      default = null;
      description = ''
        the main User if available
      '';
    };
  };

  config = mkIf cfg.enable {

    programs.zsh = {

      enable = true;
      enableCompletion = true;

      syntaxHighlighting.enable = true;

      ohMyZsh = {

        custom = "/etc/zshcustom/";
        enable = false;

        # powerline themes
        # ----------------
        theme = "powerlevel9k/powerlevel9k";

        plugins = [
          "git"
          "git-flow"
          "screen"
          "taskwarrior"
          "systemd"
          "tmux"
          "vi-mode"
          "wd"
        ];
      };

      #loginShellInit = ''
      #  export TERM="xterm-256color"
      #'';

      shellAliases = {
        ls = "ls --color=tty";
        l = "ls -CFh";
        la = "ls -Ah";
        ll = "ls -lh";
        lt = "ls -lct --reverse";
        less = "less -S";
        top = "htop";
        version = "date '+%Y%m%d%H%M%S'";
        vclip = "xclip -selection clipboard";
        df = "df -h";

        timestamp = "date +%Y%m%d%H%M%S";

        #nix-search = "nix-env -qaP";
        #nix-list = ''nix-env -qaP "*" --description'';
        #nix-list-haskell = ''nix-env -f "<nixpkgs>" -qaP -A haskellPackages'';
        #nix-list-node = ''nix-env -f "<nixpkgs>" -qaP -A nodePackages'';
        #nix-list-beam = ''nix-env -f "<nixpkgs>" -qaP -A beamPackages'';
        #nix-find         = "clear ; ${pkgs.nix-index}/bin/nix-locate -1 -w";

        nix-show-garbadge-roots = "ls -lh /nix/var/nix/gcroots/auto/";

      };
    };

    # only used to make quick config changes
    # --------------------------------------
    #environment.etc."zshcustom/mainuser.zsh".source =
    #  pkgs.writeText "mainuser-zsh" (if (cfg.mainUser != null) then ''
    #    source ${config.users.users.mainUser.home}/.zshrc
    #  '' else
    #    "# programs.custom.zsh.mainUser not set ");

    # Theme
    # -----
    #environment.etc."zshcustom/themes/powerlevel9k".source =
    #  pkgs.fetchFromGitHub {
    #    owner = "bhilburn";
    #    repo = "powerlevel9k";
    #    rev = "v0.6.4";
    #    sha256 = "104wvlni3rilpw9v1dk848lnw8cm8qxl64xs70j04ly4s959dyb5";
    #  };
    #environment.etc."zshcustom/powerlevel9kpatch.zsh".source =
    #  pkgs.writeText "powerlevel9kpatch.zsh" ''
    #    # prompt elements
    #    # ---------------
    #    POWERLEVEL9K_LEFT_PROMPT_ELEMENTS=(vi_mode context dir vcs custom_jail background_jobs time status)
    #    POWERLEVEL9K_RIGHT_PROMPT_ELEMENTS=()
    #
    #    # root_indicator
    #    # --------------
    #    POWERLEVEL9K_ROOT_ICON="#"
    #    POWERLEVEL9K_ROOT_INDICATOR_FOREGROUND="black"
    #    POWERLEVEL9K_ROOT_INDICATOR_BACKGROUND="red"
    #  '';
  };
}