feat: auto-patch function

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

patch.nix

@@ -1,19 +1,45 @@
-{nvidia-patch-list}: let
-  createPatch = patchList: object: driverPackage:
-    driverPackage.overrideAttrs ({
+{ nvidia-patch-list }:
+let
+  createPatch =
+    patchList: object: driverPackage:
+    driverPackage.overrideAttrs (
+      {
         version,
         preFixup ? "",
         ...
-    }: let
+      }:
+      let
         patch = patchList.${version};
-    in {
-      preFixup =
-        preFixup
-        + ''
+      in
+      {
+        preFixup = preFixup + ''
           sed -i '${patch}' $out/lib/${object}.${version}
         '';
-    });
-in {
+      }
+    );
+
   patch-nvenc = createPatch nvidia-patch-list.nvenc "libnvidia-encode.so";
   patch-fbc = createPatch nvidia-patch-list.fbc "libnvidia-fbc.so";
+
+  auto-patch =
+    nvidiaPackage:
+    let
+      maybeFbc =
+        if builtins.hasAttr nvidiaPackage.version nvidia-patch-list.fbc then
+          patch-fbc nvidiaPackage
+        else
+          nvidiaPackage;
+
+      maybeNvenc =
+        if builtins.hasAttr maybeFbc.version nvidia-patch-list.nvenc then
+          patch-nvenc maybeFbc
+        else
+          maybeFbc;
+
+      nvidiaPackageFinal = maybeNvenc;
+    in
+    nvidiaPackageFinal;
+in
+{
+  inherit patch-nvenc patch-fbc auto-patch;
 }