// Local playlist and shared audio controls. Files never leave the browser.
export function initMusic({ storage, toast }) {
    const $ = selector => document.querySelector(selector);
  const audio = $('#audio');
  let tracks = [], selected = -1;
  let shuffle = storage.get('shuffle') === 'true', shuffleBag = [], playbackHistory = [];
  $('#immersive-shuffle').setAttribute('aria-pressed', String(shuffle));
  $('#immersive-shuffle').onclick = () => {
    shuffle = !shuffle; shuffleBag = []; playbackHistory = [];
    storage.set('shuffle', String(shuffle));
    $('#immersive-shuffle').setAttribute('aria-pressed', String(shuffle));
    toast(shuffle ? 'Lecture aléatoire activée' : 'Lecture aléatoire désactivée');
  };
  function nextTrack() {
    if (!shuffle || tracks.length < 2) return selectTrack(selected + 1, true);
    if (!shuffleBag.length) {
      shuffleBag = tracks.map((_, index) => index).filter(index => index !== selected);
      for (let i = shuffleBag.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [shuffleBag[i], shuffleBag[j]] = [shuffleBag[j], shuffleBag[i]];
      }
    }
    selectTrack(shuffleBag.pop(), true);
  }
  function renderPlaylist() {
    $('#playlist').replaceChildren();
    tracks.forEach((track, index) => {
      const li = document.createElement('li'), button = document.createElement('button');
      const number = document.createElement('span'), name = document.createElement('b');
      number.textContent = String(index + 1).padStart(2, '0'); name.textContent = track.name;
      button.append(number, name); button.classList.toggle('selected', index === selected);
      button.setAttribute('aria-pressed', String(index === selected)); button.onclick = () => selectTrack(index, true);
      li.append(button); $('#playlist').append(li);
    });
    $('#track-count').textContent = `${tracks.length} TITRE${tracks.length > 1 ? 'S' : ''}`;
    $('#empty-library').hidden = tracks.length > 0;
    ['#play', '#previous', '#next'].forEach(id => $(id).disabled = tracks.length === 0);
  }
  async function playAudio() {
    try { await audio.play(); $('#audio-message').textContent = 'Lecture locale · aucun fichier envoyé au serveur.'; }
    catch { $('#audio-message').textContent = 'Lecture impossible : réessayez ou choisissez un format audio pris en charge.'; }
  }
  function selectTrack(index, play = false, remember = true) {
    if (!tracks.length) return;
    previousTap = -Infinity;
    if (remember && selected >= 0 && index !== selected) {
      playbackHistory.push(selected);
      if (playbackHistory.length > 256) playbackHistory.shift();
    }
    selected = (index + tracks.length) % tracks.length;
    shuffleBag = shuffleBag.filter(index => index !== selected);
    audio.src = tracks[selected].url;
    $('#track-title').textContent = tracks[selected].name;
    $('#home-track').textContent = tracks[selected].name;
    $('#track-subtitle').textContent = `Morceau ${selected + 1} sur ${tracks.length} · Bibliothèque locale`;
    $('#home-track-sub').textContent = 'Bibliothèque locale';
    renderPlaylist(); if (play) playAudio();
  }
  $('#music-files').addEventListener('change', event => {
    let added = 0;
    for (const file of event.target.files) {
      if (!file.type.startsWith('audio/') && !/\.(mp3|flac|ogg|wav|m4a|aac|opus)$/i.test(file.name)) continue;
      tracks.push({ name: file.name.replace(/\.[^.]+$/, ''), url: URL.createObjectURL(file) }); added++;
    }
    shuffleBag = [];
    renderPlaylist();
    if (selected === -1 && tracks.length) selectTrack(0);
    toast(added ? `${added} morceau${added > 1 ? 'x' : ''} ajouté${added > 1 ? 's' : ''}` : 'Aucun fichier audio reconnu');
    event.target.value = '';
  });
  $('#play').onclick = () => { if (selected === -1) return; if (audio.paused) playAudio(); else audio.pause(); };
  let previousTap = -Infinity;
  $('#previous').onclick = () => {
    const now = performance.now(), twice = now - previousTap < 600;
    previousTap = twice ? -Infinity : now;
    if (!twice) { audio.currentTime = 0; return; }
    if (shuffle) { shuffleBag = []; selectTrack(playbackHistory.pop() ?? selected, true, false); }
    else selectTrack(selected - 1, true);
  };
  $('#next').onclick = nextTrack;
  audio.addEventListener('play', () => $('#play').textContent = 'Pause');
  audio.addEventListener('pause', () => $('#play').textContent = 'Lecture');
  audio.addEventListener('ended', () => { if (audio.loop) return; if (shuffle || selected + 1 < tracks.length) nextTrack(); else $('#play').textContent = 'Lecture'; });
  audio.addEventListener('error', () => $('#audio-message').textContent = 'Ce fichier ne peut pas être lu. Essayez un autre format audio.');
  window.addEventListener('pagehide', event => { if (!event.persisted) tracks.forEach(track => URL.revokeObjectURL(track.url)); });
  renderPlaylist();
  
}