{
  config,
  pkgs,
  lib,
  ...
}:

let
  timezone = config.system.timezone;
  language = config.system.language;
  locale = config.system.locale;

in

{
  options = {
    system = {
      timezone = lib.mkOption {
        default = "Europe/Berlin";
        description = "timezone";
      };
      language = lib.mkOption {
        default = "en_GB.UTF-8";
        description = "language";
      };
      locale = lib.mkOption {
        default = "de_DE.UTF-8";
        description = "locale";
      };
    };
  };

  config = {
    time.timeZone = timezone;
    i18n = {
      defaultLocale = language;
      extraLocaleSettings = {
        LC_ADDRESS = locale;
        LC_IDENTIFICATION = locale;
        LC_MEASUREMENT = locale;
        LC_MONETARY = locale;
        LC_NAME = locale;
        LC_NUMERIC = locale;
        LC_PAPER = locale;
        LC_TELEPHONE = locale;
        LC_TIME = locale;
      };
    };
    console.keyMap = builtins.substring 0 2 locale;
  };
}