software/steam: update from nixpkgs module

modules/modules/software/steam.nix

@@ -3,34 +3,120 @@ with lib;
 with lib.our;
 let
   cfg = config.modules.software.steam;
+  gamescopeCfg = config.programs.gamescope;
 
   hw = config.modules.hardware;
 
-  steam = cfg.package.override {
-    extraLibraries = (pkgs:
-      (with config.hardware.opengl;
-      if pkgs.hostPlatform.is64bit
-      then [ package ] ++ extraPackages
-      else [ package32 ] ++ extraPackages32)
+  steam-gamescope =
+    let
+      exports = builtins.attrValues (builtins.mapAttrs (n: v: "export ${n}=${v}") cfg.gamescopeSession.env);
+    in
+    pkgs.writeShellScriptBin "steam-gamescope" ''
+      ${builtins.concatStringsSep "\n" exports}
+      gamescope --steam ${toString cfg.gamescopeSession.args} -- steam -tenfoot -pipewire-dmabuf
+    '';
 
-      ++ (with pkgs; [ pipewire ]));
-  };
+  gamescopeSessionFile =
+    (pkgs.writeTextDir "share/wayland-sessions/steam.desktop" ''
+      [Desktop Entry]
+      Name=Steam
+      Comment=A digital distribution platform
+      Exec=${steam-gamescope}/bin/steam-gamescope
+      Type=Application
+    '').overrideAttrs (_: { passthru.providedSessions = [ "steam" ]; });
 in
 {
-  options.modules.software.steam = with types; {
-    enable = mkBoolOpt false;
-    package = let pkg = pkgs.steam; in
-      mkOpt package
-        (if hw.gpu.nvidia
-        then
-          pkg.override
-            {
+  options.modules.software.steam = {
+    enable = mkEnableOption (lib.mdDoc "steam");
+
+    package = mkOption {
+      type = types.package;
+      default = pkgs.steam;
+      defaultText = literalExpression "pkgs.steam";
+      example = literalExpression ''
+        pkgs.steam-small.override {
+          extraEnv = {
+            MANGOHUD = true;
+            OBS_VKCAPTURE = true;
+            RADV_TEX_ANISO = 16;
+          };
+          extraLibraries = p: with p; [
+            atk
+          ];
+        }
+      '';
+      apply = steam: steam.override (prev: {
+        extraLibraries = pkgs:
+          let
+            prevLibs = if prev ? extraLibraries then prev.extraLibraries pkgs else [ ];
+            additionalLibs = with config.hardware.opengl;
+              if pkgs.stdenv.hostPlatform.is64bit
+              then [ package ] ++ extraPackages
+              else [ package32 ] ++ extraPackages32;
+          in
+          prevLibs ++ additionalLibs;
+      }
+      // (optionalAttrs (cfg.gamescopeSession.enable && gamescopeCfg.capSysNice) {
+        buildFHSEnv = pkgs.buildFHSEnv.override {
+          # use the setuid wrapped bubblewrap
+          bubblewrap = "${config.security.wrapperDir}/..";
+        };
+      })
+      // (optionalAttrs hw.gpu.nvidia {
         extraProfile = ''
           unset VK_ICD_FILENAMES
           export VK_ICD_FILENAMES=${config.hardware.nvidia.package}/share/vulkan/icd.d/nvidia_icd.json:${config.hardware.nvidia.package.lib32}/share/vulkan/icd.d/nvidia_icd32.json
         '';
-            }
-        else pkg);
+      }));
+      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.
+      '';
+    };
+
+    gamescopeSession = mkOption {
+      description = mdDoc "Run a GameScope driven Steam session from your display-manager";
+      default = { };
+      type = types.submodule {
+        options = {
+          enable = mkEnableOption (mdDoc "GameScope Session");
+          args = mkOption {
+            type = types.listOf types.str;
+            default = [ ];
+            description = mdDoc ''
+              Arguments to be passed to GameScope for the session.
+            '';
+          };
+
+          env = mkOption {
+            type = types.attrsOf types.str;
+            default = { };
+            description = mdDoc ''
+              Environmental variables to be passed to GameScope for the session.
+            '';
+          };
+        };
+      };
+    };
   };
 
   config = mkMerge [
@@ -54,11 +140,35 @@ in
       hardware.steam-hardware.enable = true;
 
       home.home.packages = [
-        steam
-        steam.run
+        cfg.package
+        cfg.package.run
 
         pkgs.protonup
         pkgs.wineWowPackages.stable
+      ] ++ lib.optional cfg.gamescopeSession.enable steam-gamescope;
+
+      security.wrappers = mkIf (cfg.gamescopeSession.enable && gamescopeCfg.capSysNice) {
+        # needed or steam fails
+        bwrap = {
+          owner = "root";
+          group = "root";
+          source = "${pkgs.bubblewrap}/bin/bwrap";
+          setuid = true;
+        };
+      };
+
+      programs.gamescope.enable = mkDefault cfg.gamescopeSession.enable;
+      services.xserver.displayManager.sessionPackages = mkIf cfg.gamescopeSession.enable [ gamescopeSessionFile ];
+      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
+        })
       ];
     })
   ];