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

{
  options = {
    system.timezone = lib.mkOption { default = "America/Los_Angeles"; };
    system.extraFonts = lib.mkOption { default = []; };
    system.isNonEFI = lib.mkEnableOption 
      "Enable if you are running a non-EFI system";
    system.users.bigWheels = lib.mkOption { default = []; };
  };
  
  config = lib.mkMerge [
    (lib.mkIf config.system.isNonEFI {
      boot.loader.grub.enable = false;
      boot.loader.generic-extlinux-compatible.enable = true;
    }) 
    (lib.mkIf (!config.system.isNonEFI) {
      boot.kernelPackages = pkgs.linuxPackages_latest;
      boot.loader.systemd-boot.enable = true;
      boot.loader.timeout = 1;
      boot.loader.efi.canTouchEfiVariables = true;
    })
    {
      networking.hostName = hostname;
      system.stateVersion = "23.05";

      time.timeZone = config.system.timezone;
      i18n.defaultLocale = "en_US.UTF-8";

      # Packages & Default Packages
      nixpkgs.config.allowUnfree = true;
      environment.systemPackages = with pkgs; [
        git
        neovim
        nnn
        xdg-user-dirs
      ];

      # XDG Compliance
      nix.settings.use-xdg-base-directories = true;

      users = {
        users = builtins.listToAttrs (map (
          user: {
            name = user;
            value = {
              name = user;
              isNormalUser = true;
              extraGroups = [ "network" ];
            };
          }
        ) usernameList);
        groups = {
          wheel = {
            members = config.system.users.bigWheels;
          };
          network = { };
        };
      };

      fonts = {
        enableDefaultPackages = true;
        packages = with pkgs; [
          cascadia-code
          (nerdfonts.override { fonts = [ "CascadiaCode" ]; })
          source-han-sans # Pan-CJK font
        ] ++ config.system.extraFonts;
      };
    }
  ];
}