fix firefox widevine

flake.nix

@@ -87,6 +87,7 @@
               ];
             }
             ./system/all.nix
+            ./system/widevine/default.nix
             ./system/shell/fish.nix
             ./system/tailscale/default.nix
             ./system/hosts/${hostname}/default.nix

home/browsers/firefox/default.nix

@@ -8,10 +8,6 @@
 }:
 
 {
-  home.sessionVariables = lib.mkIf pkgs.stdenv.hostPlatform.isAarch64 {
-    MOZ_GMP_PATH = "${pkgs.widevine-firefox}/gmp-widevinecdm/system-installed";
-  };
-
   home.file.".mozilla/firefox/default/chrome" = {
     source = ./chrome;
     force = true;

packages/overlay.nix

@@ -25,6 +25,4 @@ final: prev: {
     };
 
   spotifyd = prev.callPackage (builtins.path { path = ./spotifyd/package.nix; }) { };
-
-  widevine-firefox = prev.callPackage (builtins.path { path = ./widevine-firefox/package.nix; }) { };
 }

packages/widevine-firefox/package.nix

@@ -1,21 +0,0 @@
-{
-  stdenv,
-  widevine-cdm,
-}:
-
-stdenv.mkDerivation {
-  name = "widevine-firefox";
-  version = widevine-cdm.version;
-
-  buildCommand = ''
-    mkdir -p $out/gmp-widevinecdm/system-installed
-    ln -s "${widevine-cdm}/share/google/chrome/WidevineCdm/manifest.json" $out/gmp-widevinecdm/system-installed/manifest.json
-    ln -s "${widevine-cdm}/share/google/chrome/WidevineCdm/_platform_specific/linux_arm64/libwidevinecdm.so" $out/gmp-widevinecdm/system-installed/libwidevinecdm.so
-  '';
-
-  meta = widevine-cdm.meta // {
-    platforms = [
-      "aarch64-linux"
-    ];
-  };
-}

system/widevine/default.nix

@@ -0,0 +1,35 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+{
+  nixpkgs.overlays = lib.mkIf (config.nixpkgs.hostPlatform.isLinux) [
+    (final: prev: {
+      wrapFirefox =
+        browser: opts:
+        let
+          extraPrefs = (opts.extraPrefs or "") + ''
+            lockPref("media.gmp-widevinecdm.version", "system-installed");
+            lockPref("media.gmp-widevinecdm.visible", true);
+            lockPref("media.gmp-widevinecdm.enabled", true);
+            lockPref("media.gmp-widevinecdm.autoupdate", false);
+            lockPref("media.eme.enabled", true);
+            lockPref("media.eme.encrypted-media-encryption-scheme.enabled", true);
+          '';
+          widevineCdmDir = "${final.widevine-cdm}/share/google/chrome/WidevineCdm";
+          widevineOutDir = "$out/gmp-widevinecdm/system-installed";
+        in
+        (prev.wrapFirefox browser (opts // { inherit extraPrefs; })).overrideAttrs (previousAttrs: {
+          buildCommand = previousAttrs.buildCommand + ''
+            mkdir -p "${widevineOutDir}"
+            ln -s "${widevineCdmDir}/_platform_specific/linux_arm64/libwidevinecdm.so" "${widevineOutDir}/libwidevinecdm.so"
+            ln -s "${widevineCdmDir}/manifest.json" "${widevineOutDir}/manifest.json"
+            wrapProgram "$oldExe" --set MOZ_GMP_PATH "${widevineOutDir}"
+          '';
+        });
+    })
+  ];
+}