{ 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;
      #autosuggestions.enable    = true;
      syntaxHighlighting.enable = true;

      ohMyZsh = {

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

        # powerline themes
        # ----------------
        #theme = "agnoster";
        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";
        todo = "task todo";
        active = "task active";
        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/";

      };
    };

    #environment.systemPackages = [
    #  pkgs.nix-index # make nix-index also available to users
    #];

    # 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
    # -----
    # make sure powerline-fonts is set in `fonts.fonts`

    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" ''

        # this shows all the colors which are available
        # ---------------------------------------------
        # for code ({000..255}) print -P -- "$code: %F{$code}This is how your text would look like%f"

        # prompt elements
        # ---------------
        POWERLEVEL9K_LEFT_PROMPT_ELEMENTS=(vi_mode context dir vcs custom_jail background_jobs time status)
        POWERLEVEL9K_RIGHT_PROMPT_ELEMENTS=()

        # vi mode
        # -------
        POWERLEVEL9K_VI_MODE_INSERT_FOREGROUND="black"
        POWERLEVEL9K_VI_MODE_INSERT_BACKGROUND="blue"
        POWERLEVEL9K_VI_MODE_NORMAL_FOREGROUND="black"
        POWERLEVEL9K_VI_MODE_NORMAL_BACKGROUND="yellow"

        # context
        # -------
        POWERLEVEL9K_CONTEXT_DEFAULT_FOREGROUND="green"
        POWERLEVEL9K_CONTEXT_DEFAULT_BACKGROUND="008"
        POWERLEVEL9K_CONTEXT_ROOT_FOREGROUND="008"
        POWERLEVEL9K_CONTEXT_ROOT_BACKGROUND="red"
        POWERLEVEL9K_CONTEXT_REMOTE_FOREGROUND="008"
        POWERLEVEL9K_CONTEXT_REMOTE_BACKGROUND="red"

        # dir
        # ---
        POWERLEVEL9K_DIR_HOME_FOREGROUND="black"
        POWERLEVEL9K_DIR_HOME_BACKGROUND="yellow"
        POWERLEVEL9K_DIR_HOME_SUBFOLDER_FOREGROUND="black"
        POWERLEVEL9K_DIR_HOME_SUBFOLDER_BACKGROUND="yellow"
        POWERLEVEL9K_DIR_DEFAULT_FOREGROUND="black"
        POWERLEVEL9K_DIR_DEFAULT_BACKGROUND="green"

        # root_indicator
        # --------------
        POWERLEVEL9K_ROOT_ICON="#"
        POWERLEVEL9K_ROOT_INDICATOR_FOREGROUND="black"
        POWERLEVEL9K_ROOT_INDICATOR_BACKGROUND="red"

        # background_jobs
        # ---------------
        POWERLEVEL9K_BACKGROUND_JOBS_ICON=""

        # status
        # ------
        POWERLEVEL9K_STATUS_OK_BACKGROUND="008"
        POWERLEVEL9K_STATUS_ERROR_BACKGROUND="008"

        # time
        # ----
        POWERLEVEL9K_TIME_FOREGROUND="008"
        POWERLEVEL9K_TIME_BACKGROUND="006"


        # jail indicator
        # --------------
        POWERLEVEL9K_CUSTOM_JAIL="[ -z $JAIL ] || echo $JAIL"
        POWERLEVEL9K_CUSTOM_JAIL_BACKGROUND="red"
        POWERLEVEL9K_CUSTOM_JAIL_FOREGROUND="black"


      '';
  };
}