feat(playback): add useRemoteControl dispatch hook

hooks/useRemoteControl.ts

@@ -0,0 +1,62 @@
+/**
+ * Dispatches Jellyfin remote-control WebSocket messages to the active
+ * PlaybackController. DisplayMessage is shown as an in-app toast and needs no
+ * controller.
+ */
+
+import { useAtomValue } from "jotai";
+import { useEffect } from "react";
+import { toast } from "sonner-native";
+import { activePlaybackControllerAtom } from "@/utils/playback/playbackController";
+import {
+  mapRemoteCommand,
+  type RemoteWsMessage,
+} from "@/utils/playback/remoteCommands";
+
+/** Handle one remote-control message (call it whenever a new WS message arrives). */
+export const useRemoteControl = (lastMessage: RemoteWsMessage | null): void => {
+  const controller = useAtomValue(activePlaybackControllerAtom);
+
+  useEffect(() => {
+    if (!lastMessage) return;
+    const action = mapRemoteCommand(lastMessage);
+    if (!action) return;
+
+    if (action.kind === "displayMessage") {
+      toast(action.text);
+      return;
+    }
+
+    if (!controller) return;
+
+    switch (action.kind) {
+      case "playPause":
+        controller.playPause();
+        break;
+      case "pause":
+        controller.pause();
+        break;
+      case "unpause":
+        controller.unpause();
+        break;
+      case "stop":
+        controller.stop();
+        break;
+      case "seek":
+        controller.seek(action.positionMs);
+        break;
+      case "next":
+        controller.next();
+        break;
+      case "previous":
+        controller.previous();
+        break;
+      case "setVolume":
+        controller.setVolume(action.level);
+        break;
+      case "toggleMute":
+        controller.toggleMute();
+        break;
+    }
+  }, [lastMessage, controller]);
+};