musicland/src/hooks/useTrackController.js

import { useCallback, useMemo } from "react";
import usePlayer from "./usePlayer";

const useTrackController = (descriptor) => {
  const {
    currentTrack,
    play,
    pause,
    resume,
    isPlaying,
    positionMs,
    durationMs,
    seekTo,
    seekBy,
  } = usePlayer();

  const normalizedDescriptor = useMemo(() => {
    if (!descriptor || !descriptor.id) return null;
    return descriptor;
  }, [descriptor]);

  const trackId = normalizedDescriptor?.id || null;
  const isCurrent = trackId ? currentTrack?.id === trackId : false;
  const effectivePositionMs = isCurrent ? positionMs : 0;
  const effectiveDurationMs = isCurrent ? durationMs : 0;
  const effectiveIsPlaying = isCurrent && isPlaying;

  const ensureLoaded = useCallback(
    async ({ startPositionMs = 0, autoPlay = true } = {}) => {
      if (!normalizedDescriptor) return;
      await play(normalizedDescriptor, {
        startPositionMs,
        autoPlay,
        context: normalizedDescriptor.context,
      });
    },
    [normalizedDescriptor, play]
  );

  const playNow = useCallback(
    async ({ startPositionMs = 0 } = {}) => {
      await ensureLoaded({ startPositionMs, autoPlay: true });
    },
    [ensureLoaded]
  );

  const pauseNow = useCallback(async () => {
    if (isCurrent) {
      await pause();
    }
  }, [isCurrent, pause]);

  const resumeNow = useCallback(
    async ({ startPositionMs } = {}) => {
      if (!normalizedDescriptor) return;
      if (!isCurrent) {
        await ensureLoaded({
          startPositionMs: startPositionMs ?? effectivePositionMs,
          autoPlay: true,
        });
        return;
      }
      if (typeof startPositionMs === "number") {
        await seekTo(Math.max(0, startPositionMs));
      }
      await resume();
    },
    [
      normalizedDescriptor,
      isCurrent,
      ensureLoaded,
      effectivePositionMs,
      seekTo,
      resume,
    ]
  );

  const seekToPosition = useCallback(
    async (targetMs, { autoPlay = false } = {}) => {
      const bounded = Math.max(0, Number(targetMs) || 0);
      if (!normalizedDescriptor) return;
      if (!isCurrent) {
        await ensureLoaded({ startPositionMs: bounded, autoPlay });
        return;
      }
      await seekTo(bounded);
      if (autoPlay && !effectiveIsPlaying) {
        await resume();
      }
    },
    [
      normalizedDescriptor,
      isCurrent,
      ensureLoaded,
      seekTo,
      effectiveIsPlaying,
      resume,
    ]
  );

  const seekByDelta = useCallback(
    async (deltaMs, { autoPlay = false } = {}) => {
      const delta = Number(deltaMs || 0);
      if (!normalizedDescriptor) return;
      if (!isCurrent) {
        const next = Math.max(0, effectivePositionMs + delta);
        await ensureLoaded({ startPositionMs: next, autoPlay });
        return;
      }
      await seekBy(delta);
      if (autoPlay && !effectiveIsPlaying) {
        await resume();
      }
    },
    [
      normalizedDescriptor,
      isCurrent,
      ensureLoaded,
      effectivePositionMs,
      seekBy,
      effectiveIsPlaying,
      resume,
    ]
  );

  return {
    trackId,
    descriptor: normalizedDescriptor,
    isCurrent,
    isPlaying: effectiveIsPlaying,
    positionMs: effectivePositionMs,
    durationMs: effectiveDurationMs,
    ensureLoaded,
    play: playNow,
    pause: pauseNow,
    resume: resumeNow,
    seekTo: seekToPosition,
    seekBy: seekByDelta,
  };
};

export default useTrackController;