[nvidia] Move into module

nixos/modules/default.nix

@@ -1,5 +1,6 @@
 {
   imports = [
+    ./hardware
     ./programs
     ./services
     ./virtualisation

nixos/modules/hardware/default.nix

@@ -0,0 +1,5 @@
+{
+  imports = [
+    ./nvidia
+  ];
+}

nixos/modules/hardware/nvidia/default.nix

@@ -0,0 +1,46 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.sisyphus.hardware.nvidia;
+
+  nvidia-offload = pkgs.writeShellScriptBin "nvidia-offload" ''
+    export __NV_PRIME_RENDER_OFFLOAD=1
+    export __NV_PRIME_RENDER_OFFLOAD_PROVIDER=NVIDIA-G0
+    export __GLX_VENDOR_LIBRARY_NAME=nvidia
+    export __VK_LAYER_NV_optimus=NVIDIA_only
+    exec "$@"
+  '';
+in {
+  options.sisyphus.hardware.nvidia = {
+    enable = lib.mkEnableOption "NVIDIA GPU support";
+    model = lib.mkOption {
+      type = lib.types.enum [ "" "T2000" "RTX 2060" ];
+      default = "";
+      example = "T2000";
+      description = lib.mdDoc "The model of NVIDIA GPU card";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.xserver.videoDrivers = [ "nvidia" ];
+  
+    hardware = {
+      opengl.enable = true;
+      nvidia = {
+        open = true;
+        package = config.boot.kernelPackages.nvidiaPackages.stable;
+        modesetting.enable = true;
+
+        prime = lib.mkIf (cfg.model == "T2000") {
+          offload.enable = true;
+          intelBusId = "PCI::00:02:0";
+          nvidiaBusId = "PCI:01:00:0";
+        };
+      };
+    };
+
+    environment.systemPackages = lib.mkIf (cfg.model != "") [
+      nvidia-offload
+    ];
+  };
+}