From 68cc9eeb3875ae9682c04629f20738e1e79d72aa Mon Sep 17 00:00:00 2001
From: YTG1234 <ytg1234@pm.me>
Date: Tue, 3 Jun 2025 21:37:43 +0300
Subject: [PATCH] jellyfin-mpv-shim: merge settings with existing config file

The Nix-defined settings take priority over the existing settings, but
any new keys added by the user are preserved.
---
 modules/services/jellyfin-mpv-shim.nix | 46 +++++++++++++++++---------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/modules/services/jellyfin-mpv-shim.nix b/modules/services/jellyfin-mpv-shim.nix
index 037750d9..849247b2 100644
--- a/modules/services/jellyfin-mpv-shim.nix
+++ b/modules/services/jellyfin-mpv-shim.nix
@@ -107,22 +107,6 @@ in
     ];
 
     xdg.configFile = {
-      # jellyfin-mpv-shim errors if the config file isn't writeable
-      # so, as a temporary workaround, we generate a hidden file (.conf.json)
-      # and make a writeable copy.
-      "jellyfin-mpv-shim/conf.json" = lib.mkIf (cfg.settings != { }) {
-        source = jsonFormat.generate "jellyfin-mpv-shim-conf" cfg.settings;
-        target = "jellyfin-mpv-shim/.conf.json";
-        onChange =
-          let
-            dir = "${config.xdg.configHome}/jellyfin-mpv-shim";
-          in
-          ''
-            cp --dereference ${dir}/.conf.json ${dir}/conf.json
-            chmod u+w ${dir}/conf.json
-          '';
-      };
-
       "jellyfin-mpv-shim/mpv.conf" = lib.mkIf (cfg.mpvConfig != null) {
         text = renderOptions cfg.mpvConfig;
       };
@@ -148,5 +132,35 @@ in
         WantedBy = [ "graphical-session.target" ];
       };
     };
+
+    # Yoinked from programs/zed-editor.nix
+    # jellyfin-mpv-shim can't load the configuration file if it's not
+    # writeable. So we merge the settings defined here in Nix with the existing
+    # configuration, if any.
+    home.activation.jellyfinMpvShimSettingsActivation =
+      let
+        path = lib.escapeShellArg "${config.xdg.configHome}/jellyfin-mpv-shim/conf.json";
+        staticSettings = lib.escapeShellArg (jsonFormat.generate "jellyfin-mpv-shim-conf" cfg.settings);
+        cmd = "${lib.getExe pkgs.jq} -s '.[0] * .[1]' ${path} ${staticSettings}";
+      in
+      lib.mkIf (cfg.settings != { }) (
+        lib.hm.dag.entryAfter [ "linkGeneration" ] ''
+          run mkdir -p "$(dirname ${path})"
+          if [ ! -e ${path} ]; then
+            # Create the file
+            if [[ -v DRY_RUN ]]; then
+              run echo '{}' '>' ${path}
+            else
+              echo '{}' > ${path}
+            fi
+          fi
+          if [[ -v DRY_RUN ]]; then
+            run ${cmd} '>' ${path}
+          else
+            config="$(${cmd})"
+            printf '%s\n' "$config" > ${path}
+          fi
+        ''
+      );
   };
 }