initial scaffold

src/audio/playbackController.ts

@@ -0,0 +1,59 @@
+import TrackPlayer, { isPlaying } from 'react-native-track-player';
+import { setupPlayer } from './trackPlayer';
+import { SAMPLE_TRACKS, toRntpTrack } from './sampleTracks';
+
+/**
+ * Transport actions screens call. Thin wrappers over RNTP so the UI never
+ * imports the engine directly — at M3/M4 this is where a custom Media3 module
+ * would slot in behind the same function signatures.
+ */
+
+/**
+ * Set up the player and load the demo queue. Setup is deferred to here (a
+ * user-initiated play) rather than app launch: RNTP starts a foreground
+ * MediaSession service on setup, and Android only permits starting a foreground
+ * service while the app is in the foreground.
+ */
+async function ensurePlayerReady(): Promise<void> {
+  await setupPlayer();
+  const queue = await TrackPlayer.getQueue();
+  if (queue.length === 0) {
+    await TrackPlayer.add(SAMPLE_TRACKS.map(toRntpTrack));
+  }
+}
+
+/** M0 entry point: ensure the player is ready, then start playback. */
+export async function playSample(): Promise<void> {
+  await ensurePlayerReady();
+  await TrackPlayer.play();
+}
+
+export const play = (): Promise<void> => TrackPlayer.play();
+export const pause = (): Promise<void> => TrackPlayer.pause();
+export const seekTo = (seconds: number): Promise<void> => TrackPlayer.seekTo(seconds);
+
+export async function togglePlay(): Promise<void> {
+  const { playing } = await isPlaying();
+  if (playing) {
+    await TrackPlayer.pause();
+  } else {
+    await ensurePlayerReady();
+    await TrackPlayer.play();
+  }
+}
+
+export async function skipToNext(): Promise<void> {
+  try {
+    await TrackPlayer.skipToNext();
+  } catch {
+    // no next track — ignore
+  }
+}
+
+export async function skipToPrevious(): Promise<void> {
+  try {
+    await TrackPlayer.skipToPrevious();
+  } catch {
+    // no previous track — ignore
+  }
+}