software/steam: add steam module

modules/modules/software/steam.nix

@@ -0,0 +1,60 @@
+{ config, lib, pkgs, ... }:
+with lib;
+with lib.hlissner;
+let
+  cfg = config.modules.software.steam;
+
+  hw = config.modules.hardware;
+
+  steam = pkgs.steam.override {
+    extraLibraries = (pkgs:
+      (with config.hardware.opengl;
+      if pkgs.hostPlatform.is64bit
+      then [ package ] ++ extraPackages
+      else [ package32 ] ++ extraPackages32)
+
+      ++ (with pkgs; [ pipewire ]));
+
+
+    extraProfile = mkIf hw.gpu.nvidia ''
+      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
+    '';
+  };
+in
+{
+  options.modules.software.steam = {
+    enable = mkBoolOpt false;
+  };
+
+  config = mkMerge [
+    {
+      assertions = [
+        {
+          assertion = cfg.enable && !config.info.graphical;
+          message = "Steam cannot be enabled in a non-graphical environment";
+        }
+      ];
+    }
+
+    (mkIf cfg.enable {
+      # Taken from the programs.steam option, reimplemented here to move software into userland
+      hardware.opengl = {
+        enable = true;
+        driSupport = true;
+        driSupport32Bit = true;
+      };
+
+      hardware.pulseaudio.support32Bit = config.hardware.pulseaudio.enable;
+
+      hardware.steam-hardware.enable = true;
+
+      home.home.packages = [
+        steam
+        steam.run
+
+        pkgs.protonup
+      ];
+    })
+  ];
+}