import { getLibraries, getArtists, getArtistAlbums, getAlbumTracks, audioStreamUrl } from '../embyApi.js';
import { leaveParty, connectParty, addTrackToQueue } from '../party.js';
import { navigate } from '../router.js';
import { escapeHtml, formatDuration, colorForName, initialsFor } from '../tiles.js';

/**
 * Music half of the party route (see player.js's dispatcher). Deliberately
 * NOT full-viewport/theater-mode like the video player: there's no image
 * to declutter around, so the sidebar stays up and this renders as a
 * normal page - which also means "browse and add a track" can happen
 * inline, right here, instead of navigating away and losing player state.
 *
 * Permission model (chosen, not assumed - see session history): anyone can
 * add a track to the shared queue at any time; anyone can pause/resume;
 * skipping the current track needs a strict majority vote of currently
 * connected members. No host-only controls at all - see
 * server/src/musicQueueService.js for the full reasoning and the
 * server-authoritative auto-advance timer that drives this without any
 * single client having to be "in charge".
 */
export function renderMusicPlayer(root, partyId, party) {
  root.innerHTML = `
    <div class="pageHeader">
      <h1>Écoute partagée</h1>
      <button class="linklike" id="leaveBtn">Quitter</button>
    </div>

    <div id="presenceOverlay" class="presenceOverlay musicPresence"></div>

    <div class="nowPlaying" id="nowPlaying">
      <img id="trackImage" class="nowPlayingImage" alt="" onerror="this.classList.add('noImage')" />
      <div class="nowPlayingInfo">
        <strong id="trackName">-</strong>
        <span class="hint" id="trackArtist"></span>
        <div class="nowPlayingControls">
          <button class="iconBtn" id="playPauseBtn" title="Lecture / pause" aria-label="Lecture / pause">&#9654;</button>
          <span id="trackPosition" class="hint">0:00 / 0:00</span>
          <button class="linklike" id="voteSkipBtn">Passer (vote)</button>
        </div>
      </div>
    </div>
    <audio id="audio"></audio>

    <div class="pageHeader">
      <h2>File d'attente</h2>
      <button class="linklike" id="toggleBrowseBtn">Ajouter des morceaux</button>
    </div>
    <div id="queueList" class="trackList"><p class="hint">Rien en attente.</p></div>

    <div id="browsePanel" class="browsePanel hide"></div>`;

  const audio = root.querySelector('#audio');
  const presenceOverlay = root.querySelector('#presenceOverlay');
  const trackImage = root.querySelector('#trackImage');
  const trackName = root.querySelector('#trackName');
  const trackArtist = root.querySelector('#trackArtist');
  const playPauseBtn = root.querySelector('#playPauseBtn');
  const trackPosition = root.querySelector('#trackPosition');
  const voteSkipBtn = root.querySelector('#voteSkipBtn');
  const queueList = root.querySelector('#queueList');
  const browsePanel = root.querySelector('#browsePanel');

  let conn = null;
  let hls = null;
  let currentItemId = null;
  let currentDurationSeconds = 0;
  let suppressLocalEvents = false; // avoid feeding our own correction back as a new event - same pattern as player.js
  let positionTicker = null;
  let latestMembers = [];

  // Same HLS pipeline as the video player (player.js's loadVideo) - Emby's
  // PlaybackInfo negotiation isn't video-specific, so its TranscodingUrl
  // for a music track just as plausibly comes back HLS-shaped, and most
  // browsers (everything but Safari) have no native .m3u8 support at all -
  // an <audio src="...m3u8"> alone would silently just not play anywhere
  // but Safari. `elapsedSeconds`/`isPaused` are applied once the manifest
  // is actually parsed, not immediately after setting src - setting
  // currentTime before a fresh source has loaded metadata is unreliable
  // and gets silently reset by most browsers.
  function loadTrack(track, elapsedSeconds, isPaused) {
    currentItemId = track.itemId;
    currentDurationSeconds = track.durationSeconds || 0;
    trackImage.src = track.itemImageUrl || '';
    trackImage.classList.remove('noImage');
    trackName.textContent = track.itemName || '';
    trackArtist.textContent = [track.artistName, track.albumName].filter(Boolean).join(' - ');

    if (hls) {
      hls.destroy();
      hls = null;
    }

    const src = audioStreamUrl(track.itemId);
    const resume = () => {
      suppressLocalEvents = true;
      audio.currentTime = elapsedSeconds || 0;
      if (!isPaused) audio.play().catch(() => {});
      setTimeout(() => { suppressLocalEvents = false; }, 250);
    };

    // Caught, not left to propagate: this runs from inside applyMusicState,
    // which every "queueUpdated" push calls - an uncaught throw here would
    // abort that entire handler (and, the first time it happens, the
    // player's whole synchronous init - see player.js's dispatcher), taking
    // the queue list and vote button down with a problem that's really
    // just "this one track's audio failed to load". A skip vote is still
    // this feature's actual recovery path (see musicQueueService.js) - this
    // just needs to not crash on the way there.
    try {
      if (window.Hls && window.Hls.isSupported()) {
        hls = new window.Hls();
        hls.on(window.Hls.Events.MANIFEST_PARSED, resume);
        hls.on(window.Hls.Events.ERROR, (event, data) => {
          if (data.fatal) console.error('[watchparty musicPlayer] HLS error', data);
        });
        hls.loadSource(src);
        hls.attachMedia(audio);
      } else if (audio.canPlayType('application/vnd.apple.mpegurl')) {
        audio.src = src;
        audio.addEventListener('loadedmetadata', resume, { once: true });
      } else {
        console.error('[watchparty musicPlayer] no HLS support and hls.js unavailable');
      }
    } catch (err) {
      console.error('[watchparty musicPlayer] failed to load track audio', err);
    }
  }

  function applyMusicState(music) {
    // Queue/vote-button/play-icon updates happen first, unconditionally -
    // deliberately BEFORE the track-loading branch below, which touches
    // hls.js and could throw (a bad manifest, a network hiccup). Same
    // ordering the video player already uses (see onItemChanged in
    // player.js, which updates the title/next-button before calling
    // loadVideo): a media-loading failure should never also take the
    // queue list and vote tally down with it, since they're not actually
    // related to whether THIS particular track's audio loaded.
    playPauseBtn.textContent = music.current && !music.current.isPaused ? '⏸' : '▶';
    playPauseBtn.disabled = !music.current;
    voteSkipBtn.disabled = !music.current;
    // "needed" mirrors the exact math musicQueueService.js uses server-side
    // (strict majority of currently connected members) - computed here from
    // the member list the "members" event already provides, rather than
    // MusicQueueService's own broadcast repeating that count on every
    // single queue change (see its getState()'s own comment on this).
    const connectedCount = latestMembers.filter((m) => m.connected).length || 1;
    const needed = Math.floor(connectedCount / 2) + 1;
    voteSkipBtn.textContent = music.current ? `Passer (vote) - ${music.skipVotes}/${needed}` : 'Passer (vote)';

    queueList.innerHTML = music.queue.length
      ? music.queue.map((t) => `
        <div class="trackRow">
          <span class="trackName">${escapeHtml(t.itemName)}</span>
          <span class="hint">${escapeHtml([t.artistName, t.albumName].filter(Boolean).join(' - '))}</span>
          <span class="trackDuration">${t.durationSeconds ? formatDuration(t.durationSeconds) : ''}</span>
          <span class="hint">Ajouté par ${escapeHtml(t.addedByUserName)}</span>
        </div>`).join('')
      : '<p class="hint">Rien en attente.</p>';

    if (!music.current) {
      currentItemId = null;
      trackName.textContent = 'Rien ne joue pour le moment.';
      trackArtist.textContent = '';
      trackImage.src = '';
      if (hls) { hls.destroy(); hls = null; }
      audio.pause();
      audio.removeAttribute('src');
    } else if (music.current.itemId !== currentItemId) {
      loadTrack(music.current, music.current.elapsedSeconds, music.current.isPaused);
    } else {
      // Same track still playing - just resync pause state/position, don't reload the source.
      suppressLocalEvents = true;
      if (Math.abs(audio.currentTime - music.current.elapsedSeconds) > 2) {
        audio.currentTime = music.current.elapsedSeconds;
      }
      if (music.current.isPaused && !audio.paused) audio.pause();
      if (!music.current.isPaused && audio.paused) audio.play().catch(() => {});
      setTimeout(() => { suppressLocalEvents = false; }, 250);
    }
  }

  function sendLocalPlaystate() {
    if (suppressLocalEvents || !conn) return;
    conn.setMusicPaused(audio.paused);
  }
  audio.addEventListener('play', sendLocalPlaystate);
  audio.addEventListener('pause', sendLocalPlaystate);

  playPauseBtn.addEventListener('click', () => {
    if (!conn) return;
    conn.setMusicPaused(!audio.paused);
  });

  voteSkipBtn.addEventListener('click', () => { if (conn) conn.voteSkip(); });

  // Ticks the visible position label between server updates - the same
  // "derive it client-side from a snapshot" approach as the home page's
  // party-elapsed-time labels, rather than the server pushing this every
  // second for every listener.
  positionTicker = setInterval(() => {
    if (!currentItemId) return;
    trackPosition.textContent = `${formatDuration(audio.currentTime)} / ${formatDuration(currentDurationSeconds)}`;
  }, 500);

  function renderMembers(members) {
    latestMembers = members;
    presenceOverlay.innerHTML = members.map((m) => `
      <div class="avatar" style="background:${colorForName(m.userName)}" title="${escapeHtml(m.userName)}">
        ${escapeHtml(initialsFor(m.userName))}
      </div>`).join('');
  }

  // --- Inline "add tracks" browser: artist -> album -> tracks, entirely
  // within this page (see class comment for why not a route navigation). ---
  let browsing = false;

  root.querySelector('#toggleBrowseBtn').addEventListener('click', () => {
    browsing = !browsing;
    browsePanel.classList.toggle('hide', !browsing);
    if (browsing) loadMusicLibraries();
  });

  async function loadMusicLibraries() {
    browsePanel.innerHTML = '<p class="hint">Chargement...</p>';
    try {
      const libraries = (await getLibraries()).filter((l) => l.collectionType === 'music');
      if (!libraries.length) {
        browsePanel.innerHTML = '<p class="hint">Aucune bibliothèque musicale.</p>';
        return;
      }
      // Almost always exactly one - skip straight to its artists rather
      // than making the common case click through a one-item list.
      if (libraries.length === 1) {
        loadArtists(libraries[0].id);
      } else {
        browsePanel.innerHTML = renderBrowseList(libraries.map((l) => ({ id: l.id, name: l.name })), null);
        wireBrowseList((id) => loadArtists(id));
      }
    } catch (err) {
      browsePanel.innerHTML = '<p class="error">Impossible de charger les bibliothèques.</p>';
    }
  }

  async function loadArtists(libraryId) {
    browsePanel.innerHTML = '<p class="hint">Chargement...</p>';
    try {
      const artists = await getArtists(libraryId);
      browsePanel.innerHTML = renderBrowseList(artists.map((a) => ({ id: a.id, name: a.name })), null);
      wireBrowseList((id) => loadAlbums(id));
    } catch (err) {
      browsePanel.innerHTML = '<p class="error">Impossible de charger les artistes.</p>';
    }
  }

  async function loadAlbums(artistId) {
    browsePanel.innerHTML = '<p class="hint">Chargement...</p>';
    try {
      const albums = await getArtistAlbums(artistId);
      browsePanel.innerHTML = renderBrowseList(albums.map((a) => ({ id: a.id, name: a.year ? `${a.name} (${a.year})` : a.name })), () => loadMusicLibraries());
      wireBrowseList((id) => loadTracks(id));
    } catch (err) {
      browsePanel.innerHTML = '<p class="error">Impossible de charger les albums.</p>';
    }
  }

  async function loadTracks(albumId) {
    browsePanel.innerHTML = '<p class="hint">Chargement...</p>';
    try {
      const tracks = await getAlbumTracks(albumId);
      browsePanel.innerHTML = `
        <button class="linklike browseBack">&larr; Retour</button>
        ${tracks.map((t) => `
          <div class="trackRow">
            <span class="trackIndex">${t.indexNumber != null ? t.indexNumber : ''}</span>
            <span class="trackName">${escapeHtml(t.name)}</span>
            <span class="trackDuration">${t.durationTicks ? formatDuration(t.durationTicks / 10000000) : ''}</span>
            <button class="addTrackBtn" data-track="${encodeURIComponent(JSON.stringify({
              itemId: t.id, itemName: t.name, artistName: t.artistName, albumName: t.albumName,
              itemImageUrl: t.imageUrl, durationTicks: t.durationTicks
            }))}">Ajouter</button>
          </div>`).join('')}`;
      browsePanel.querySelector('.browseBack').addEventListener('click', () => loadMusicLibraries());
      browsePanel.querySelectorAll('.addTrackBtn').forEach((btn) => {
        btn.addEventListener('click', async () => {
          btn.disabled = true;
          const originalLabel = btn.textContent;
          try {
            await addTrackToQueue(partyId, JSON.parse(decodeURIComponent(btn.dataset.track)));
            btn.textContent = 'Ajouté !';
            setTimeout(() => { btn.textContent = originalLabel; btn.disabled = false; }, 1500);
          } catch (err) {
            alert(err.message);
            btn.disabled = false;
          }
        });
      });
    } catch (err) {
      browsePanel.innerHTML = '<p class="error">Impossible de charger les morceaux.</p>';
    }
  }

  function renderBrowseList(items, onBack) {
    const back = onBack ? '<button class="linklike browseBack">&larr; Retour</button>' : '';
    const body = items.length
      ? items.map((i) => `<button class="linklike browseItem" data-id="${escapeHtml(i.id)}">${escapeHtml(i.name)}</button>`).join('')
      : '<p class="hint">Rien à afficher.</p>';
    return `${back}<div class="browseList">${body}</div>`;
  }

  function wireBrowseList(onPick) {
    const back = browsePanel.querySelector('.browseBack');
    if (back) back.addEventListener('click', () => loadMusicLibraries());
    browsePanel.querySelectorAll('.browseItem').forEach((btn) => {
      btn.addEventListener('click', () => onPick(btn.dataset.id));
    });
  }

  // --- Init ---
  applyMusicState(party.music);

  conn = connectParty(partyId, {
    onMembers: renderMembers,
    onQueueUpdated: applyMusicState,
    onError: (message) => alert(message),
    onClose: () => {}
  });

  root.querySelector('#leaveBtn').addEventListener('click', () => navigate('/home'));

  return function cleanup() {
    if (positionTicker) clearInterval(positionTicker);
    if (hls) hls.destroy();
    audio.pause();
    audio.removeAttribute('src');
    if (conn) conn.leave();
    leaveParty(partyId).catch(() => {});
  };
}