/* ============================================================================
 * YT Player — frontend logic
 * Talks to the native (Zig) side over the zero-native bridge: window.zero.invoke
 * Handlers (implemented in src/bridge.zig):
 *   yt.search   { query }            -> { ok, results:[{id,title,channel,duration,thumbnail}] }
 *   yt.streams  { videoId }          -> { ok, data:{ meta, audioUrl, qualities:[{label,height,url,hasAudio,ext}] } }
 *   store.load  {}                   -> { playlists, history, settings }
 *   store.save  { data }             -> { ok }
 * ========================================================================== */

// ---------- Native bridge adapter ----------
async function invoke(command, payload = {}) {
  if (window.zero && typeof window.zero.invoke === 'function') {
    return await window.zero.invoke(command, payload);
  }
  throw new Error('Native bridge unavailable — run this inside zero-native (zig build run).');
}

const API = {
  search: (query) => invoke('yt.search', { query }),
  getStreams: (videoId) => invoke('yt.streams', { videoId }),
  loadData: () => invoke('store.load', {}),
  // data is sent pre-stringified so the native side can write it verbatim.
  saveData: (data) => invoke('store.save', { data: JSON.stringify(data) }),
};

// ---------- State ----------
let data = { playlists: [], history: [], settings: { quality: 'auto', volume: 1, audioOnly: false } };
let view = { type: 'search' };          // 'search' | 'history' | 'playlist'
let searchResults = [];
let queue = [];                          // list of video objects for autoplay
let queueIndex = -1;
let current = null;                      // { meta, qualities, audioUrl }
let saveTimer = null;

// ---------- DOM ----------
const $ = (id) => document.getElementById(id);
const els = {
  video: $('video'),
  audio: $('audio'),
  art: $('artFallback'),
  artImg: $('artImg'),
  placeholder: $('playerPlaceholder'),
  spinner: $('bufferSpinner'),
  controls: $('controls'),
  playerPane: $('playerPane'),
  nowMeta: $('nowPlayingMeta'),
  npTitle: $('npTitle'),
  npChannel: $('npChannel'),
  seek: $('seek'),
  curTime: $('curTime'),
  durTime: $('durTime'),
  playBtn: $('playBtn'),
  prevBtn: $('prevBtn'),
  nextBtn: $('nextBtn'),
  muteBtn: $('muteBtn'),
  volume: $('volume'),
  speed: $('speedSelect'),
  quality: $('qualitySelect'),
  fsBtn: $('fsBtn'),
  cards: $('cards'),
  listTitle: $('listTitle'),
  listActions: $('listActions'),
  status: $('status'),
  searchForm: $('searchForm'),
  searchInput: $('searchInput'),
  playlistList: $('playlistList'),
  newPlaylistBtn: $('newPlaylistBtn'),
  audioOnlyToggle: $('audioOnlyToggle'),
};

// ---------- Persistence ----------
function persist() {
  clearTimeout(saveTimer);
  saveTimer = setTimeout(() => API.saveData(data).catch(() => {}), 400);
}

// ---------- Helpers ----------
function fmtTime(sec) {
  if (!sec || !isFinite(sec)) return '0:00';
  sec = Math.floor(sec);
  const h = Math.floor(sec / 3600);
  const m = Math.floor((sec % 3600) / 60);
  const s = sec % 60;
  const mm = h ? String(m).padStart(2, '0') : String(m);
  return (h ? h + ':' : '') + mm + ':' + String(s).padStart(2, '0');
}
function toast(msg) {
  const t = $('toast');
  t.textContent = msg;
  t.classList.remove('hidden');
  clearTimeout(toast._t);
  toast._t = setTimeout(() => t.classList.add('hidden'), 2200);
}
function uid() { return Date.now().toString(36) + Math.random().toString(36).slice(2, 7); }

// ============================================================================
// Player engine — single video, or video+audio synced (adaptive), or audio-only
// ============================================================================
const Player = {
  mode: 'progressive', // 'progressive' | 'dual' | 'audio'
  master: els.video,
  secondary: null,     // synced audio element in dual mode
  driftTimer: null,

  get soundEl() {
    return this.mode === 'dual' ? els.audio : this.master;
  },

  async loadVideo(videoObj) {
    showSpinner(true);
    els.placeholder.classList.add('hidden');
    try {
      const res = await API.getStreams(videoObj.id);
      if (!res || !res.ok) throw new Error(res?.error || 'Could not load streams');
      current = res.data;
      // Merge richer metadata we may already have from the list card.
      current.meta = { ...videoObj, ...current.meta };

      addToHistory(current.meta);
      buildQualityMenu();
      els.playerPane.classList.remove('empty');
      els.controls.classList.remove('hidden');
      els.nowMeta.classList.remove('hidden');
      els.npTitle.textContent = current.meta.title;
      els.npChannel.textContent = current.meta.channel || '';
      markPlayingCard();

      const q = chooseQuality();
      this.attach(q);
    } catch (err) {
      showSpinner(false);
      toast('⚠ ' + err.message);
    }
  },

  attach(quality) {
    const V = els.video, A = els.audio;
    const audioOnly = data.settings.audioOnly;

    // Reset
    V.pause(); A.pause();
    this.stopDrift();

    if (audioOnly) {
      // Play only audio; show cover art.
      this.mode = 'audio';
      this.master = A;
      this.secondary = null;
      A.src = current.audioUrl || (quality && quality.url) || '';
      V.removeAttribute('src'); V.load();
      els.art.classList.remove('hidden');
      els.artImg.src = current.meta.thumbnail || '';
    } else if (quality && quality.hasAudio) {
      // Progressive single stream (video already carries audio).
      this.mode = 'progressive';
      this.master = V;
      this.secondary = null;
      V.muted = false;
      V.src = quality.url;
      A.removeAttribute('src'); A.load();
      els.art.classList.add('hidden');
    } else if (quality && current.audioUrl) {
      // Adaptive: muted video + synced audio for high quality without muxing.
      this.mode = 'dual';
      this.master = V;
      this.secondary = A;
      V.muted = true;
      V.src = quality.url;
      A.src = current.audioUrl;
      els.art.classList.add('hidden');
    } else {
      showSpinner(false);
      toast('No playable stream found for this video.');
      return;
    }

    this.applyVolume();
    this.applySpeed();
    this.master.load();
    if (this.secondary) this.secondary.load();

    const onReady = () => {
      this.play();
      this.master.removeEventListener('canplay', onReady);
    };
    this.master.addEventListener('canplay', onReady);
    this.startDrift();
  },

  play() {
    this.master.play().catch(() => {});
    if (this.secondary) {
      this.secondary.currentTime = this.master.currentTime;
      this.secondary.play().catch(() => {});
    }
  },
  pause() {
    this.master.pause();
    if (this.secondary) this.secondary.pause();
  },
  toggle() {
    if (this.master.paused) this.play(); else this.pause();
  },
  seek(t) {
    this.master.currentTime = t;
    if (this.secondary) this.secondary.currentTime = t;
  },
  applyVolume() {
    const v = data.settings.volume;
    this.soundEl.volume = v;
    this.soundEl.muted = v === 0;
    // make sure the non-sound elements stay muted
    if (this.mode === 'dual') els.video.muted = true;
  },
  applySpeed() {
    const r = parseFloat(els.speed.value) || 1;
    this.master.playbackRate = r;
    if (this.secondary) this.secondary.playbackRate = r;
  },

  startDrift() {
    this.stopDrift();
    this.driftTimer = setInterval(() => {
      if (this.mode !== 'dual' || this.master.paused) return;
      const drift = Math.abs(this.secondary.currentTime - this.master.currentTime);
      if (drift > 0.3) this.secondary.currentTime = this.master.currentTime;
    }, 1000);
  },
  stopDrift() {
    if (this.driftTimer) clearInterval(this.driftTimer);
    this.driftTimer = null;
  },
};

function showSpinner(on) {
  els.spinner.classList.toggle('hidden', !on);
}

function chooseQuality() {
  const qs = current.qualities || [];
  if (!qs.length) return null;
  const pref = data.settings.quality;
  if (pref && pref !== 'auto') {
    const match = qs.find((q) => q.label === pref);
    if (match) return match;
  }
  // auto: best quality at or below 720p, else the lowest available.
  const sorted = [...qs].sort((a, b) => b.height - a.height);
  return sorted.find((q) => q.height <= 720) || sorted[sorted.length - 1];
}

function buildQualityMenu() {
  const qs = current.qualities || [];
  els.quality.innerHTML = '';
  const auto = document.createElement('option');
  auto.value = 'auto';
  auto.textContent = 'Auto';
  els.quality.appendChild(auto);
  const seen = new Set();
  for (const q of qs) {
    if (seen.has(q.label)) continue;
    seen.add(q.label);
    const o = document.createElement('option');
    o.value = q.label;
    o.textContent = q.label + (q.hasAudio ? '' : '');
    els.quality.appendChild(o);
  }
  els.quality.value = data.settings.quality || 'auto';
}

// ---------- Player media events (master mirrors to secondary) ----------
function wirePlayerEvents() {
  const V = els.video, A = els.audio;

  const masterIs = (el) => Player.master === el;

  function bind(el) {
    el.addEventListener('play', () => { if (masterIs(el) && Player.secondary && Player.secondary.paused) { Player.secondary.currentTime = el.currentTime; Player.secondary.play().catch(() => {}); } updatePlayBtn(); });
    el.addEventListener('pause', () => { if (masterIs(el) && Player.secondary) Player.secondary.pause(); updatePlayBtn(); });
    el.addEventListener('seeking', () => { if (masterIs(el) && Player.secondary) Player.secondary.currentTime = el.currentTime; });
    el.addEventListener('waiting', () => { if (masterIs(el)) { showSpinner(true); if (Player.secondary) Player.secondary.pause(); } });
    el.addEventListener('playing', () => { if (masterIs(el)) { showSpinner(false); if (Player.secondary && !el.paused) { Player.secondary.currentTime = el.currentTime; Player.secondary.play().catch(() => {}); } } });
    el.addEventListener('canplay', () => { if (masterIs(el)) showSpinner(false); });
    el.addEventListener('timeupdate', () => { if (masterIs(el)) updateProgress(); });
    el.addEventListener('loadedmetadata', () => { if (masterIs(el)) updateProgress(); });
    el.addEventListener('ended', () => { if (masterIs(el)) playNext(); });
    el.addEventListener('error', () => { if (masterIs(el)) { showSpinner(false); } });
  }
  bind(V);
  bind(A);
}

function updatePlayBtn() {
  els.playBtn.textContent = Player.master.paused ? '▶' : '⏸';
}
function updateProgress() {
  const cur = Player.master.currentTime || 0;
  const dur = Player.master.duration || current?.meta?.duration || 0;
  els.curTime.textContent = fmtTime(cur);
  els.durTime.textContent = fmtTime(dur);
  if (dur) els.seek.value = String((cur / dur) * 1000);
}

// ============================================================================
// History
// ============================================================================
function addToHistory(meta) {
  data.history = data.history.filter((v) => v.id !== meta.id);
  data.history.unshift({
    id: meta.id, title: meta.title, channel: meta.channel,
    duration: meta.duration, thumbnail: meta.thumbnail,
  });
  if (data.history.length > 200) data.history.length = 200;
  persist();
  if (view.type === 'history') renderList();
}

// ============================================================================
// Queue / navigation
// ============================================================================
function playFromList(list, index) {
  queue = list;
  queueIndex = index;
  Player.loadVideo(list[index]);
}
function playNext() {
  if (queueIndex >= 0 && queueIndex < queue.length - 1) {
    queueIndex++;
    Player.loadVideo(queue[queueIndex]);
  } else {
    updatePlayBtn();
  }
}
function playPrev() {
  if (Player.master.currentTime > 3) { Player.seek(0); return; }
  if (queueIndex > 0) {
    queueIndex--;
    Player.loadVideo(queue[queueIndex]);
  }
}

// ============================================================================
// Rendering
// ============================================================================
function renderSidebar() {
  els.playlistList.innerHTML = '';
  for (const pl of data.playlists) {
    const item = document.createElement('div');
    item.className = 'playlist-item' + (view.type === 'playlist' && view.id === pl.id ? ' active' : '');
    item.innerHTML = `<span class="pl-name"></span><span class="pl-count">${pl.videos.length}</span>`;
    item.querySelector('.pl-name').textContent = pl.name;
    item.addEventListener('click', () => { view = { type: 'playlist', id: pl.id }; render(); });
    els.playlistList.appendChild(item);
  }
  document.querySelectorAll('.nav-item').forEach((b) => {
    b.classList.toggle('active', b.dataset.view === view.type);
  });
}

function currentList() {
  if (view.type === 'search') return searchResults;
  if (view.type === 'history') return data.history;
  if (view.type === 'playlist') {
    const pl = data.playlists.find((p) => p.id === view.id);
    return pl ? pl.videos : [];
  }
  return [];
}

function renderList() {
  const list = currentList();
  els.cards.innerHTML = '';
  els.listActions.innerHTML = '';

  if (view.type === 'search') {
    els.listTitle.textContent = 'Search results';
  } else if (view.type === 'history') {
    els.listTitle.textContent = 'History';
    if (list.length) {
      const clear = document.createElement('button');
      clear.textContent = 'Clear';
      clear.onclick = () => { data.history = []; persist(); renderList(); };
      els.listActions.appendChild(clear);
    }
  } else if (view.type === 'playlist') {
    const pl = data.playlists.find((p) => p.id === view.id);
    els.listTitle.textContent = pl ? pl.name : 'Playlist';
    if (pl) {
      const playAll = document.createElement('button');
      playAll.textContent = '▶ Play all';
      playAll.onclick = () => { if (pl.videos.length) playFromList(pl.videos, 0); };
      const rename = document.createElement('button');
      rename.textContent = 'Rename';
      rename.onclick = () => renamePlaylist(pl);
      const del = document.createElement('button');
      del.textContent = 'Delete';
      del.onclick = () => deletePlaylist(pl);
      els.listActions.append(playAll, rename, del);
    }
  }

  if (!list.length) {
    els.status.classList.remove('hidden');
    els.status.textContent =
      view.type === 'search' ? 'Search for something to begin.'
      : view.type === 'history' ? 'Nothing watched yet.'
      : 'This playlist is empty. Add videos from search.';
    return;
  }
  els.status.classList.add('hidden');

  list.forEach((v, i) => els.cards.appendChild(renderCard(v, i, list)));
  markPlayingCard();
}

function renderCard(v, index, list) {
  const card = document.createElement('div');
  card.className = 'card';
  card.dataset.id = v.id;
  card.innerHTML = `
    <div class="thumb">
      <img loading="lazy" src="${v.thumbnail || ''}" alt="" />
      ${v.duration ? `<span class="dur">${fmtTime(v.duration)}</span>` : ''}
    </div>
    <div class="card-info">
      <div class="card-title"></div>
      <div class="card-channel"></div>
    </div>
    <button class="card-menu" title="Add to playlist / remove">⋯</button>`;
  card.querySelector('.card-title').textContent = v.title;
  card.querySelector('.card-channel').textContent = v.channel || '';
  card.addEventListener('click', (e) => {
    if (e.target.closest('.card-menu')) return;
    playFromList(list, index);
  });
  card.querySelector('.card-menu').addEventListener('click', (e) => {
    e.stopPropagation();
    openCardMenu(v);
  });
  return card;
}

function markPlayingCard() {
  document.querySelectorAll('.card').forEach((c) => {
    c.classList.toggle('playing', current && c.dataset.id === current.meta.id);
  });
}

function render() {
  renderSidebar();
  renderList();
}

// ============================================================================
// Playlists
// ============================================================================
function openCardMenu(video) {
  const inPlaylistView = view.type === 'playlist';
  const body = document.createElement('div');
  body.className = 'modal-list';

  data.playlists.forEach((pl) => {
    const has = pl.videos.some((x) => x.id === video.id);
    const btn = document.createElement('button');
    btn.textContent = (has ? '✓ ' : '+ ') + pl.name;
    btn.onclick = () => {
      if (has) pl.videos = pl.videos.filter((x) => x.id !== video.id);
      else pl.videos.push(slim(video));
      persist();
      closeModal();
      toast(has ? `Removed from ${pl.name}` : `Added to ${pl.name}`);
      render();
    };
    body.appendChild(btn);
  });

  const newBtn = document.createElement('button');
  newBtn.textContent = '＋ New playlist…';
  newBtn.onclick = () => { closeModal(); newPlaylist(video); };
  body.appendChild(newBtn);

  const actions = [{ label: 'Close', onClick: closeModal }];
  if (inPlaylistView) {
    actions.unshift({
      label: 'Remove from this playlist', danger: true, onClick: () => {
        const pl = data.playlists.find((p) => p.id === view.id);
        if (pl) { pl.videos = pl.videos.filter((x) => x.id !== video.id); persist(); }
        closeModal(); render();
      },
    });
  }
  showModal('Add to playlist', body, actions);
}

function slim(v) {
  return { id: v.id, title: v.title, channel: v.channel, duration: v.duration, thumbnail: v.thumbnail };
}

function newPlaylist(addVideo) {
  const input = document.createElement('input');
  input.type = 'text';
  input.placeholder = 'Playlist name';
  showModal('New playlist', input, [
    { label: 'Cancel', onClick: closeModal },
    {
      label: 'Create', primary: true, onClick: () => {
        const name = input.value.trim();
        if (!name) return;
        const pl = { id: uid(), name, videos: addVideo ? [slim(addVideo)] : [] };
        data.playlists.push(pl);
        persist();
        closeModal();
        view = { type: 'playlist', id: pl.id };
        render();
        toast(`Created “${name}”`);
      },
    },
  ]);
  setTimeout(() => input.focus(), 50);
}

function renamePlaylist(pl) {
  const input = document.createElement('input');
  input.type = 'text';
  input.value = pl.name;
  showModal('Rename playlist', input, [
    { label: 'Cancel', onClick: closeModal },
    {
      label: 'Save', primary: true, onClick: () => {
        const name = input.value.trim();
        if (name) { pl.name = name; persist(); }
        closeModal(); render();
      },
    },
  ]);
  setTimeout(() => { input.focus(); input.select(); }, 50);
}

function deletePlaylist(pl) {
  showModal(`Delete “${pl.name}”?`, document.createTextNode('This cannot be undone.'), [
    { label: 'Cancel', onClick: closeModal },
    {
      label: 'Delete', danger: true, onClick: () => {
        data.playlists = data.playlists.filter((p) => p.id !== pl.id);
        persist();
        closeModal();
        view = { type: 'search' };
        render();
      },
    },
  ]);
}

// ---------- Modal ----------
function showModal(title, bodyNode, actions) {
  $('modalTitle').textContent = title;
  const body = $('modalBody');
  body.innerHTML = '';
  body.appendChild(bodyNode);
  const act = $('modalActions');
  act.innerHTML = '';
  actions.forEach((a) => {
    const b = document.createElement('button');
    b.className = 'btn' + (a.primary ? ' primary' : '') + (a.danger ? ' danger' : '');
    b.textContent = a.label;
    b.onclick = a.onClick;
    act.appendChild(b);
  });
  $('modal').classList.remove('hidden');
}
function closeModal() { $('modal').classList.add('hidden'); }

// ============================================================================
// Events
// ============================================================================
function wireUI() {
  els.searchForm.addEventListener('submit', async (e) => {
    e.preventDefault();
    const q = els.searchInput.value.trim();
    if (!q) return;
    view = { type: 'search' };
    render();
    els.status.classList.remove('hidden');
    els.status.textContent = 'Searching…';
    els.cards.innerHTML = '';
    try {
      const res = await API.search(q);
      if (!res || !res.ok) throw new Error(res?.error || 'Search failed');
      searchResults = res.results || [];
      renderList();
    } catch (err) {
      els.status.textContent = '⚠ ' + err.message;
    }
  });

  document.querySelectorAll('.nav-item').forEach((b) => {
    b.addEventListener('click', () => { view = { type: b.dataset.view }; render(); });
  });

  els.newPlaylistBtn.addEventListener('click', () => newPlaylist(null));

  // Controls
  els.playBtn.addEventListener('click', () => Player.toggle());
  els.nextBtn.addEventListener('click', playNext);
  els.prevBtn.addEventListener('click', playPrev);
  els.fsBtn.addEventListener('click', () => {
    const stage = els.video.parentElement;
    if (document.fullscreenElement) document.exitFullscreen();
    else stage.requestFullscreen?.();
  });

  els.seek.addEventListener('input', () => {
    const dur = Player.master.duration || 0;
    if (dur) Player.seek((parseFloat(els.seek.value) / 1000) * dur);
  });

  els.volume.addEventListener('input', () => {
    data.settings.volume = parseFloat(els.volume.value);
    Player.applyVolume();
    els.muteBtn.textContent = data.settings.volume === 0 ? '🔇' : '🔊';
    persist();
  });
  els.muteBtn.addEventListener('click', () => {
    if (data.settings.volume > 0) { els.muteBtn.dataset.prev = data.settings.volume; data.settings.volume = 0; }
    else { data.settings.volume = parseFloat(els.muteBtn.dataset.prev || '1'); }
    els.volume.value = String(data.settings.volume);
    Player.applyVolume();
    els.muteBtn.textContent = data.settings.volume === 0 ? '🔇' : '🔊';
    persist();
  });

  els.speed.addEventListener('change', () => Player.applySpeed());

  els.quality.addEventListener('change', () => {
    data.settings.quality = els.quality.value;
    persist();
    if (!current) return;
    // reload at the new quality, preserving position + play state
    const t = Player.master.currentTime;
    const wasPlaying = !Player.master.paused;
    const q = chooseQuality();
    Player.attach(q);
    const restore = () => {
      Player.seek(t);
      if (!wasPlaying) Player.pause();
      Player.master.removeEventListener('canplay', restore);
    };
    Player.master.addEventListener('canplay', restore);
  });

  els.audioOnlyToggle.addEventListener('change', () => {
    data.settings.audioOnly = els.audioOnlyToggle.checked;
    persist();
    if (!current) return;
    const t = Player.master.currentTime;
    const q = chooseQuality();
    Player.attach(q);
    const restore = () => { Player.seek(t); Player.master.removeEventListener('canplay', restore); };
    Player.master.addEventListener('canplay', restore);
  });

  // Keyboard
  document.addEventListener('keydown', (e) => {
    if (e.target.tagName === 'INPUT') return;
    if (e.code === 'Space') { e.preventDefault(); Player.toggle(); }
    else if (e.code === 'ArrowRight') Player.seek(Player.master.currentTime + 5);
    else if (e.code === 'ArrowLeft') Player.seek(Math.max(0, Player.master.currentTime - 5));
    else if (e.key === 'f') els.fsBtn.click();
    else if (e.key === 'm') els.muteBtn.click();
  });

  $('modal').addEventListener('click', (e) => { if (e.target.id === 'modal') closeModal(); });
}

// ============================================================================
// Boot
// ============================================================================
async function boot() {
  wirePlayerEvents();
  wireUI();
  try {
    const loaded = await API.loadData();
    if (loaded && typeof loaded === 'object') {
      data = {
        playlists: loaded.playlists || [],
        history: loaded.history || [],
        settings: { quality: 'auto', volume: 1, audioOnly: false, ...(loaded.settings || {}) },
      };
    }
  } catch {
    // first run / bridge not ready — start with defaults
  }
  els.volume.value = String(data.settings.volume ?? 1);
  els.quality.value = data.settings.quality || 'auto';
  els.audioOnlyToggle.checked = !!data.settings.audioOnly;
  render();
  els.searchInput.focus();
}

document.addEventListener('DOMContentLoaded', boot);