firefox: fix open-in-mpv integration

two parts: add open-in-mpv's config to firefox's sandbox; patch open-in-mpv to forward to xdg-open

hosts/common/programs/firefox.nix

@@ -240,6 +240,7 @@ in
         sandbox.whitelistDbus = [ "user" ];  # mpris
         sandbox.whitelistWayland = true;
         sandbox.extraHomePaths = [
+          ".local/share/applications"  #< this might be needed only for custom schemes (like mpv:// for open-in-mpv)?
           "dev"  # for developing anything web-related
           "tmp"
           "Pictures"
@@ -256,6 +257,8 @@ in
           ".ssh/id_ed25519"
           # ".config/sops"
           "private/knowledge/secrets/accounts"
+        ] ++ lib.optionals cfg.addons.open-in-mpv.enable [
+          ".config/open-in-mpv"
         ];
         fs.".config/sops".dir = lib.mkIf cfg.addons.browserpass-extension.enable {};  #< needs to be created, not *just* added to the sandbox
 

hosts/common/programs/open-in-mpv.nix

@@ -1,18 +1,39 @@
-{ ... }:
+# test: `open-in-mpv 'mpv:///open?url=https://www.youtube.com/watch?v=dQw4w9WgXcQ'`
+{ pkgs, ... }:
 {
   sane.programs.open-in-mpv = {
+    packageUnwrapped = pkgs.open-in-mpv.overrideAttrs (upstream: {
+      patches = (upstream.patches or []) ++ [
+        (pkgs.fetchpatch {
+          # if i want `open-in-mpv 'mpv:///open?...'` to use a different executable than `mpv` (e.g. `xdg-open`),
+          # this patch is required.
+          # TODO: upstream (branch: dev-sane)
+          url = "https://git.uninsane.org/colin/open-in-mpv/commit/4d93d5fbdd3baebb6284c517cfe9fec9970c3002.patch";
+          name = "open-in-mpv: respect the player's `executable` config";
+          hash = "sha256-UkjR58mo4ifqGU2F1YhcJU14gX41XMaXwImbV+v7Tr8=";
+        })
+      ];
+    });
+
     # taken from <https://github.com/Baldomo/open-in-mpv>
     fs.".config/open-in-mpv/config.yml".symlink.text = ''
       players:
         mpv:
           name: mpv
-          executable: mpv
-          fullscreen: "--fs"
-          pip: "--ontop --no-border --autofit=384x216 --geometry=98\\%:98\\%"
+          executable: xdg-open
+          supported_protocols:
+            - http
+            - https
+          fullscreen: ""
+          pip: ""
           enqueue: ""
           new_window: ""
-          needs_ipc: true
+          needs_ipc: false
           flag_overrides: {}
     '';
+
+    mime.associations = {
+      "x-scheme-handler/mpv" = "open-in-mpv.desktop";
+    };
   };
 }