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

let
  inherit (lib) mkDefault mkIf mkMerge mkOption mkOverride types;
  cfg = config.beatific;
in {
  options = {
    beatific = {
      # The host name is reused for beatific-specific configuration.
      # The bulk of common config is handled in beatific.defaults below, but
      # having one option without a default ensures that the module cannot be
      # imported accidentally.
      hostName = mkOption {
        type = types.str;
        description = "Hostname";
      };

      # Groups of related defaults can be disabled by flipping off the switches here:
      #   beatific.defaults.${category} = false;
      # They default to true because the point is to do these things by default.
      defaults = {
        time = mkOption {
          type = types.bool;
          description = "Default time zone and NTP";
          default = true;
        };

        i18n = mkOption {
          type = types.bool;
          description = "Default locale settings";
          default = true;
        };

        programs = mkOption {
          type = types.bool;
          description = "Default installed programs";
          default = true;
        };
      };
    };
  };

  config = mkMerge [
    {
      # Options to always set
      networking.hostName = cfg.hostName;
      nix.extraOptions = "experimental-features = nix-command flakes";
    }

    (mkIf cfg.defaults.time {
      # mkDefault time zone to make it easy to configure it to non-UTC
      time.timeZone = mkDefault "UTC";
      services.ntp.enable = true;
      services.ntp.servers = [ "time.nist.gov" ];
    })

    (mkIf cfg.defaults.i18n {
      # en_US.UTF-8
      i18n.defaultLocale = "en_US.UTF-8";
      i18n.extraLocaleSettings = {
        LC_ADDRESS = "en_US.UTF-8";
        LC_IDENTIFICATION = "en_US.UTF-8";
        LC_MEASUREMENT = "en_US.UTF-8";
        LC_MONETARY = "en_US.UTF-8";
        LC_NAME = "en_US.UTF-8";
        LC_NUMERIC = "en_US.UTF-8";
        LC_PAPER = "en_US.UTF-8";
        LC_TELEPHONE = "en_US.UTF-8";
        LC_TIME = "en_US.UTF-8";
      };
    })

    (mkIf cfg.defaults.programs {
      environment.systemPackages = with pkgs; [
        curl
        git
        htop
        python3
        vim
        wget
      ];
      # The nixpkgs default is "nano", so we go one priority higher
      environment.variables.EDITOR = mkOverride 999 "vim";
    })
  ];
}