nixcfg/nixosModules/apps/steam/default.nix

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

  options = {
    apps.steam.enable = lib.mkEnableOption "Enables Steam for video games.";
  };

  config = lib.mkIf config.apps.steam.enable {
    hardware.steam-hardware.enable = true;
    programs.steam = {
      enable = true;
      remotePlay.openFirewall =
        true; # Open ports in the firewall for Steam Remote Play
      dedicatedServer.openFirewall =
        true; # Open ports in the firewall for Source Dedicated Server
    };
  };
}