import type { AviationStore } from '../store';
import type { PlaybackState } from '../specs/types.nitro';

/**
 * Subscribe to every store channel that a playback snapshot derives from:
 * state, current item, error, and position (playback reads `isLive` off the
 * position). Returns a single unsubscribe. Shared by {@link usePlayback} and
 * {@link usePlaybackFor}; both must subscribe to the same set or a transition
 * (e.g. on-demand → live) wouldn't re-evaluate the snapshot.
 */
export function subscribePlaybackChannels(
  store: AviationStore,
  cb: () => void
): () => void {
  const unsubs = [
    store.subscribeState(cb),
    store.subscribeCurrentItem(cb),
    store.subscribeError(cb),
    store.subscribePosition(cb),
  ];
  return () => unsubs.forEach((u) => u());
}

/** Boolean playback flags derived from a raw {@link PlaybackState}. */
export function playbackFlags(state: PlaybackState): {
  isPlaying: boolean;
  isPaused: boolean;
  isLoaded: boolean;
  isBuffering: boolean;
} {
  return {
    isPlaying: state === 'playing',
    isPaused: state === 'paused',
    isLoaded:
      state === 'ready' ||
      state === 'playing' ||
      state === 'paused' ||
      state === 'buffering',
    isBuffering: state === 'buffering',
  };
}