{ ... }: {
  flake.nixosModules.systemGaming =
    { config, lib, pkgs, ... }:
    let
      cfg = config.chiasson.system.gaming;
      launcherPkgs =
        with pkgs;
        [
          lutris
          bottles
          wine
          winetricks
          gamemode
          mangohud
          goverlay
        ]
        ++ lib.optionals pkgs.stdenv.isx86_64 [ heroic ];

      steamExtraPkgs =
        if !cfg.steam.steamTinkerLaunch.enable then
          [ ]
        else
          lib.optional (lib.meta.availableOn pkgs.stdenv.hostPlatform pkgs.steamtinkerlaunch) pkgs.steamtinkerlaunch;
    in
    {
      options.chiasson.system.gaming = {
        enable = lib.mkEnableOption ''
          Steam (+ firewall toggles), 32-bit GL/Vulkan, gamemode, JACK via PipeWire, launcher bundle.
        '';

        steam = {
          remotePlay.openFirewall = lib.mkOption {
            type = lib.types.bool;
            default = true;
            description = "Open firewall for Steam Remote Play.";
          };
          dedicatedServer.openFirewall = lib.mkOption {
            type = lib.types.bool;
            default = true;
            description = "Open firewall for Steam dedicated servers.";
          };

          steamTinkerLaunch.enable = lib.mkEnableOption ''
            [SteamTinkerLaunch](https://github.com/frostworx/steamtinkerlaunch) — Steam wrapper for
            custom launch options, Proton helpers, and third-party tools. Adds `pkgs.steamtinkerlaunch`
            next to the launcher package set (`environment.systemPackages` or `launchers.forUsers`).
          '';
        };

        graphics = {
          enable = lib.mkOption {
            type = lib.types.bool;
            default = true;
            description = "`hardware.graphics.enable` (Vulkan/GL stack).";
          };
          enable32Bit = lib.mkOption {
            type = lib.types.bool;
            default = true;
            description = "`hardware.graphics.enable32Bit` (Steam / Proton 32-bit).";
          };
        };

        gamemode.enable = lib.mkOption {
          type = lib.types.bool;
          default = true;
          description = "`programs.gamemode` (Feral GameMode).";
        };

        jack.enable = lib.mkOption {
          type = lib.types.bool;
          default = true;
          description = ''
            Set `chiasson.system.audio.pipewire.jack.enable` (PipeWire JACK). Requires
            `chiasson.system.audio.enable` on the host.
          '';
        };

        launchers = {
          forUsers = lib.mkOption {
            type = lib.types.nullOr (lib.types.listOf lib.types.str);
            default = null;
            description = ''
              Per-user `packages` for launchers; `null` → `environment.systemPackages`.
            '';
          };
          extraPackages = lib.mkOption {
            type = lib.types.listOf lib.types.package;
            default = [ ];
            description = "Additional packages merged with the default launcher set.";
          };
        };
      };

      config = lib.mkIf cfg.enable (lib.mkMerge [
        {
          programs.steam = {
            enable = true;
            remotePlay.openFirewall = cfg.steam.remotePlay.openFirewall;
            dedicatedServer.openFirewall = cfg.steam.dedicatedServer.openFirewall;
          };

          hardware.graphics = lib.mkIf cfg.graphics.enable {
            enable = true;
            enable32Bit = cfg.graphics.enable32Bit;
          };

          programs.gamemode.enable = cfg.gamemode.enable;

          chiasson.system.audio.pipewire.jack.enable = lib.mkIf (cfg.jack.enable) (lib.mkDefault true);

          assertions = [
            {
              assertion = !cfg.enable || !cfg.jack.enable || config.chiasson.system.audio.enable;
              message = "chiasson.system.gaming with JACK requires `chiasson.system.audio.enable` (PipeWire).";
            }
          ];
        }
        (lib.mkIf (cfg.launchers.forUsers == null) {
          environment.systemPackages = launcherPkgs ++ steamExtraPkgs ++ cfg.launchers.extraPackages;
        })
        (lib.mkIf (cfg.launchers.forUsers != null) {
          users.users = lib.genAttrs cfg.launchers.forUsers (_: {
            packages = launcherPkgs ++ steamExtraPkgs ++ cfg.launchers.extraPackages;
          });
        })
      ]);
    };
}