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

let
  cfg = config.nomarchy.system.gaming;
in
{
  config = lib.mkIf cfg.enable {
    programs.steam = {
      enable = true;
      remotePlay.openFirewall = lib.mkDefault true;
      localNetworkGameTransfers.openFirewall = lib.mkDefault true;
    };

    # gamemode adjusts CPU governor and reschedules processes when a
    # game requests it. The launching user must be in the `gamemode` group.
    programs.gamemode.enable = true;

    services.flatpak.enable = true;

    # `services.flatpak.enable = true` ships flatpak but does NOT add any
    # remotes — without a remote, `flatpak install` and the Discover GUI
    # can't find anything. nixpkgs has no declarative remote-add API yet,
    # so we run a one-shot system unit after flatpak.service is ready that
    # adds the flathub remote idempotently (`--if-not-exists`). Lives under
    # the gaming preset because Pillar 5 ships flatpak as part of the
    # gaming wiring; if another preset later needs flatpak, lift this to a
    # dedicated module.
    systemd.services.nomarchy-flathub-init = {
      description = "Register the Flathub remote on first start";
      wantedBy = [ "multi-user.target" ];
      after = [ "network-online.target" ];
      wants = [ "network-online.target" ];
      path = [ pkgs.flatpak ];
      serviceConfig = {
        Type = "oneshot";
        RemainAfterExit = true;
      };
      script = ''
        flatpak remote-add --if-not-exists flathub \
          https://dl.flathub.org/repo/flathub.flatpakrepo
      '';
    };
  };
}