nixpkgs/nixos/modules/programs/steam.nix

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

with lib;

let
  cfg = config.programs.steam;
in {
  options.programs.steam = {
    enable = mkEnableOption (lib.mdDoc "steam");

    package = mkOption {
      type = types.package;
      default = pkgs.steam;
      defaultText = literalExpression "pkgs.steam";
      example = literalExpression ''
        pkgs.steam-small.override {
          extraEnv = {
            MANGOHUD = true;
            OBS_VKCAPTURE = true;
            RADV_TEX_ANISO = 16;
          };
          extraLibraries = p: with p; [
            atk
          ];
        }
      '';
      apply = steam: steam.override (prev: {
        extraLibraries = pkgs: let
          prevLibs = if prev ? extraLibraries then prev.extraLibraries pkgs else [ ];
          additionalLibs = with config.hardware.opengl;
            if pkgs.stdenv.hostPlatform.is64bit
            then [ package ] ++ extraPackages
            else [ package32 ] ++ extraPackages32;
        in prevLibs ++ additionalLibs;
      });
      description = lib.mdDoc ''
        The Steam package to use. Additional libraries are added from the system
        configuration to ensure graphics work properly.

        Use this option to customise the Steam package rather than adding your
        custom Steam to {option}`environment.systemPackages` yourself.
      '';
    };

    remotePlay.openFirewall = mkOption {
      type = types.bool;
      default = false;
      description = lib.mdDoc ''
        Open ports in the firewall for Steam Remote Play.
      '';
    };

    dedicatedServer.openFirewall = mkOption {
      type = types.bool;
      default = false;
      description = lib.mdDoc ''
        Open ports in the firewall for Source Dedicated Server.
      '';
    };
  };

  config = mkIf cfg.enable {
    hardware.opengl = { # this fixes the "glXChooseVisual failed" bug, context: https://github.com/NixOS/nixpkgs/issues/47932
      enable = true;
      driSupport = true;
      driSupport32Bit = true;
    };

    # optionally enable 32bit pulseaudio support if pulseaudio is enabled
    hardware.pulseaudio.support32Bit = config.hardware.pulseaudio.enable;

    hardware.steam-hardware.enable = true;

    environment.systemPackages = [
      cfg.package
      cfg.package.run
    ];

    networking.firewall = lib.mkMerge [
      (mkIf cfg.remotePlay.openFirewall {
        allowedTCPPorts = [ 27036 ];
        allowedUDPPortRanges = [ { from = 27031; to = 27036; } ];
      })

      (mkIf cfg.dedicatedServer.openFirewall {
        allowedTCPPorts = [ 27015 ]; # SRCDS Rcon port
        allowedUDPPorts = [ 27015 ]; # Gameplay traffic
      })
    ];
  };

  meta.maintainers = with maintainers; [ mkg20001 ];
}