'use strict';

// ── Compatibility: fetch polyfill via XMLHttpRequest ─────────────────────────
// fetch() is available from Safari 10.1 / iOS 10.3 onwards.
// For iOS 9 (iPad 2) we fall back to a minimal XHR wrapper that matches the
// subset of the fetch API we actually use: .json() and { method, headers, body }.
function apiFetch(url, opts) {
  if (window.fetch) return fetch(url, opts);
  opts = opts || {};
  return new Promise(function(resolve, reject) {
    var xhr = new XMLHttpRequest();
    xhr.open(opts.method || 'GET', url);
    var headers = opts.headers || {};
    Object.keys(headers).forEach(function(k) { xhr.setRequestHeader(k, headers[k]); });
    xhr.onload = function() {
      var text = xhr.responseText;
      resolve({
        ok:   xhr.status >= 200 && xhr.status < 300,
        json: function() { return JSON.parse(text); },
        text: function() { return text; }
      });
    };
    xhr.onerror = function() { reject(new Error('XHR error')); };
    xhr.send(opts.body || null);
  });
}

// ── DOM refs ──────────────────────────────────────────────────────────────────
const $ = id => document.getElementById(id);

const statusDot      = $('winamp-status');
const stateLabel     = $('state-label');
const trackTitle     = $('track-title');
const playlistPos    = $('playlist-pos');
const progressFill   = $('progress-fill');
const timeCurrent    = $('time-current');
const timeLength     = $('time-length');
const volumeFill     = $('volume-fill');
const volumePct      = $('volume-pct');
const btnMute        = $('btn-mute');
const btnPlay        = $('btn-play');
const killistPanel   = $('killist-panel');
const killistItems   = $('killist-items');
const playlistOverlay = $('playlist-overlay');
const playlistList   = $('playlist-list');
const canvas         = $('viz');
const ctx2d          = canvas.getContext('2d');

// ── State ─────────────────────────────────────────────────────────────────────
let currentVolume      = 50;
let currentPlaylistPos = 0;   // 1-based, updated from status
let currentRating      = -1;  // -1 = not yet loaded
let lastRatedTitle     = '';  // track we last fetched rating for
let ws = null;
let reconnectTimer = null;

// Viz state
const NUM_BARS  = 64;
const peaks     = new Float32Array(NUM_BARS);
let   lastBars  = new Float32Array(NUM_BARS);
let   rafId     = null;
let   lastVizAt = 0;       // timestamp of last received viz frame
let   winampPlaying = false;

// Canvas display mode — cycles on click: viz → actual → remaining → viz
const VIZ_MODES = ['viz', 'actual', 'remaining'];
let   vizMode   = 'viz';
let   currentPosition = 0;
let   currentLength   = 0;

// ── WebSocket ─────────────────────────────────────────────────────────────────
function connect() {
  const proto = location.protocol === 'https:' ? 'wss' : 'ws';
  ws = new WebSocket(`${proto}://${location.host}/ws`);

  ws.addEventListener('open', () => {
    statusDot.className = 'ok';
    stateLabel.textContent = 'Verbunden';
    clearTimeout(reconnectTimer);
  });

  ws.addEventListener('close', () => {
    statusDot.className = 'err';
    stateLabel.textContent = 'Verbindung unterbrochen…';
    ws = null;
    reconnectTimer = setTimeout(connect, 3000);
  });

  ws.addEventListener('error', () => ws.close());

  ws.addEventListener('message', e => {
    let msg;
    try { msg = JSON.parse(e.data); } catch { return; }

    if (msg.type === 'status') applyStatus(msg);
    if (msg.type === 'viz')    applyViz(msg.bars);
  });
}

function send(obj) {
  if (ws && ws.readyState === WebSocket.OPEN) {
    ws.send(JSON.stringify(obj));
  }
}

// ── Status handler ────────────────────────────────────────────────────────────
function applyStatus(st) {
  if (!st.running) {
    statusDot.className = 'err';
    stateLabel.textContent = 'Winamp nicht gestartet';
    trackTitle.textContent = '–';
    playlistPos.textContent = '';
    return;
  }

  statusDot.className = 'ok';
  const stateMap = { playing: '▶ Spielt', paused: '⏸ Pause', stopped: '⏹ Stop' };
  stateLabel.textContent = stateMap[st.state] ?? st.state;

  trackTitle.textContent = st.title || '–';

  // Fetch rating whenever the track changes
  if (st.title && st.title !== lastRatedTitle) {
    lastRatedTitle = st.title;
    fetchRating();
  }
  if (!st.title || !st.running) {
    lastRatedTitle = '';
    renderStars(0);
  }

  playlistPos.textContent = st.playlist_length
    ? `${st.playlist_pos} / ${st.playlist_length}` : '';

  if (st.playlist_pos !== currentPlaylistPos) {
    currentPlaylistPos = st.playlist_pos;
    updatePlaylistHighlight();
  }

  if (st.length > 0) {
    currentPosition = st.position;
    currentLength   = st.length;
    progressFill.style.width = (st.position / st.length * 100).toFixed(1) + '%';
    timeCurrent.textContent  = fmtTime(st.position);
    timeLength.textContent   = '-' + fmtTime(st.length - st.position);
  } else {
    progressFill.style.width = '0%';
    timeCurrent.textContent  = '0:00';
    timeLength.textContent   = '-0:00';
  }

  btnPlay.textContent = st.state === 'playing' ? '⏸' : '▶';
  winampPlaying = st.state === 'playing';

  if (typeof st.volume === 'number') {
    currentVolume = st.volume;
    updateVolumeFill(st.muted);
    updateMuteBtn(st.muted);
  }
}

// ── Controls ──────────────────────────────────────────────────────────────────
btnPlay.addEventListener('click', () => {
  // Optimistic toggle — server will push the real state back immediately.
  const playing = btnPlay.textContent === '⏸';
  send({ cmd: playing ? 'pause' : 'play' });
});

$('btn-stop').addEventListener('click', () => send({ cmd: 'stop' }));
$('btn-next').addEventListener('click', () => send({ cmd: 'next' }));
$('btn-prev').addEventListener('click', () => send({ cmd: 'prev' }));

document.querySelectorAll('.btn-seek').forEach(btn => {
  btn.addEventListener('click', () =>
    send({ cmd: 'seek', delta: parseInt(btn.dataset.delta, 10) }));
});

$('progress-bar').addEventListener('click', async e => {
  // Derive total from current + remaining (timeLength shows "-mm:ss").
  const current = parseTime(timeCurrent.textContent);
  const remaining = parseTime(timeLength.textContent.replace('-', ''));
  const total = current + remaining;
  if (!total) return;
  const rect = e.currentTarget.getBoundingClientRect();
  const target = Math.round((e.clientX - rect.left) / rect.width * total);
  send({ cmd: 'seek', delta: target - current });
});

// ── Volume ────────────────────────────────────────────────────────────────────
$('btn-vol-up').addEventListener('click', () => {
  currentVolume = Math.min(100, currentVolume + 5);
  send({ cmd: 'volume', level: currentVolume });
  updateVolumeFill();
});
$('btn-vol-down').addEventListener('click', () => {
  currentVolume = Math.max(0, currentVolume - 5);
  send({ cmd: 'volume', level: currentVolume });
  updateVolumeFill();
});
$('volume-bar').addEventListener('click', e => {
  const rect = e.currentTarget.getBoundingClientRect();
  currentVolume = Math.round((e.clientX - rect.left) / rect.width * 100);
  send({ cmd: 'volume', level: currentVolume });
  updateVolumeFill();
});
btnMute.addEventListener('click', () => {
  const nowMuted = btnMute.classList.contains('muted');
  send({ cmd: 'mute', muted: !nowMuted });
  updateMuteBtn(!nowMuted);
  updateVolumeFill(!nowMuted);
});

function updateVolumeFill(muted = btnMute.classList.contains('muted')) {
  volumeFill.style.width  = currentVolume + '%';
  volumePct.textContent   = currentVolume + ' %';
  volumeFill.classList.toggle('muted', muted);
}
function updateMuteBtn(muted) {
  btnMute.textContent = muted ? '🔇' : '🔊';
  btnMute.classList.toggle('muted', muted);
}

// ── Rating (stars) ────────────────────────────────────────────────────────────
const starEls = document.querySelectorAll('.star');

async function fetchRating() {
  try {
    const r = await apiFetch('/api/rating').then(r => r.json());
    currentRating = r.stars ?? 0;
    renderStars(currentRating);
  } catch {
    renderStars(0);
  }
}

function renderStars(n) {
  currentRating = n;
  starEls.forEach(s => {
    const v = parseInt(s.dataset.v, 10);
    const lit = v <= n;
    s.textContent = lit ? '★' : '☆';
    s.classList.toggle('lit', lit);
  });
}

starEls.forEach(s => {
  s.addEventListener('click', async () => {
    const v = parseInt(s.dataset.v, 10);
    // Tap the current rating again → remove it (set to 0)
    const newRating = v === currentRating ? 0 : v;
    renderStars(newRating);
    try {
      await apiFetch('/api/rating', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ stars: newRating }),
      });
    } catch {
      // Revert on error
      renderStars(currentRating);
    }
  });
});

// ── KillList ──────────────────────────────────────────────────────────────────
$('btn-kill').addEventListener('click', () => {
  send({ cmd: 'killist_add' });
  showToast('🚫 Track zur Skip-Liste hinzugefügt');
});

$('btn-show-killist').addEventListener('click', async () => {
  const list = await apiFetch('/api/killist').then(r => r.json()).catch(() => []);
  killistItems.innerHTML = '';
  (list || []).forEach(title => {
    const li  = document.createElement('li');
    li.innerHTML = `<span>${escHtml(title)}</span>`;
    const btn = document.createElement('button');
    btn.textContent = '✕';
    btn.onclick = () => {
      send({ cmd: 'killist_remove', title });
      li.remove();
    };
    li.appendChild(btn);
    killistItems.appendChild(li);
  });
  killistPanel.classList.remove('hidden');
});

$('btn-close-killist').addEventListener('click', () =>
  killistPanel.classList.add('hidden'));

// ── Visualisation (Canvas) ────────────────────────────────────────────────────
canvas.addEventListener('click', () => {
  vizMode = VIZ_MODES[(VIZ_MODES.indexOf(vizMode) + 1) % VIZ_MODES.length];
});

function applyViz(bars) {
  if (!bars || bars.length === 0) return;
  lastBars = new Float32Array(bars);
  lastVizAt = performance.now();
}

function renderFrame(ts = 0) {
  rafId = requestAnimationFrame(renderFrame);

  // Resize canvas to CSS size (handles window resize / DPR).
  // Setting canvas.width resets the transform, so we re-apply scale.
  const dpr  = window.devicePixelRatio || 1;
  const cssW = canvas.clientWidth;
  const cssH = canvas.clientHeight;
  if (canvas.width !== Math.round(cssW * dpr) || canvas.height !== Math.round(cssH * dpr)) {
    canvas.width  = Math.round(cssW * dpr);
    canvas.height = Math.round(cssH * dpr);
    ctx2d.scale(dpr, dpr);
  }

  const w = cssW;
  const h = cssH;
  if (w === 0 || h === 0) return;

  // Background
  ctx2d.fillStyle = '#000';
  ctx2d.fillRect(0, 0, w, h);

  // ── Time display modes ──────────────────────────────────────────────────────
  if (vizMode === 'actual' || vizMode === 'remaining') {
    const isActual = vizMode === 'actual';
    const secs     = isActual ? currentPosition : Math.max(0, currentLength - currentPosition);
    const prefix   = isActual ? '' : '-';
    const timeStr  = prefix + fmtTimeLong(secs);
    const label    = isActual ? 'ELAPSED' : 'REMAINING';

    ctx2d.textAlign    = 'center';
    ctx2d.textBaseline = 'middle';

    // Large time
    ctx2d.font      = `bold ${Math.round(h * 0.52)}px monospace`;
    ctx2d.fillStyle = isActual ? '#e0e0e0' : '#e94560';
    ctx2d.fillText(timeStr, w / 2, h * 0.48);

    // Small label below
    ctx2d.font      = `${Math.round(h * 0.18)}px monospace`;
    ctx2d.fillStyle = '#444';
    ctx2d.fillText(label, w / 2, h * 0.82);
    return;
  }

  // ── Spectrum mode ───────────────────────────────────────────────────────────
  // Check if real viz data is fresh (< 1.5 s old) and Winamp is playing.
  const hasSignal = winampPlaying && (performance.now() - lastVizAt) < 1500;

  // Classic fixed vertical gradient: green at bottom → yellow → red at top.
  // Defined in canvas coords so every bar shows the same colour at the same
  // height — no per-frame hue calculation, no flicker.
  const grad = ctx2d.createLinearGradient(0, h, 0, 0);
  if (hasSignal) {
    grad.addColorStop(0,    '#00aa00');
    grad.addColorStop(0.6,  '#aaaa00');
    grad.addColorStop(1,    '#cc0000');
  } else {
    // Idle: same palette but much dimmer
    grad.addColorStop(0,    '#003300');
    grad.addColorStop(0.6,  '#333300');
    grad.addColorStop(1,    '#330000');
  }

  const n    = NUM_BARS;
  const gap  = 1;
  const barW = Math.max(1, (w - gap * (n - 1)) / n);

  for (let i = 0; i < n; i++) {
    let val;

    if (hasSignal) {
      val = lastBars[i] || 0;
      if (val > peaks[i]) peaks[i] = val;
      else peaks[i] = Math.max(0, peaks[i] - 0.008); // gentle decay
    } else {
      // Idle: slow sine breathing
      const phase  = (ts / 1800) + (i / n) * Math.PI * 2;
      const breath = (Math.sin(ts / 2000) * 0.5 + 0.5) * 0.08;
      val = Math.max(0, Math.sin(phase) * breath);
      peaks[i] = Math.max(0, peaks[i] - 0.02);
    }

    const x    = Math.round(i * (barW + gap));
    const barH = val * h;

    if (barH > 0.5) {
      ctx2d.fillStyle = grad;
      ctx2d.fillRect(x, h - barH, barW, barH);
    }

    // Peak dot — 1 px taller slice of the same gradient, slightly brighter
    if (peaks[i] > 0.02) {
      const py = Math.round(h - peaks[i] * h) - 1;
      ctx2d.fillStyle = hasSignal ? 'rgba(255,255,255,0.6)' : 'rgba(255,255,255,0.15)';
      ctx2d.fillRect(x, py, barW, 2);
    }
  }

  // "No signal" label when disconnected or stopped
  if (!ws || ws.readyState !== WebSocket.OPEN) {
    drawLabel(ctx2d, w, h, '● NO SIGNAL', '#333');
  } else if (!winampPlaying) {
    drawLabel(ctx2d, w, h, '▶ PLAY', '#1a3a1a');
  }
}

function drawLabel(ctx, w, h, text, color) {
  ctx.font = `bold ${Math.round(h * 0.22)}px monospace`;
  ctx.textAlign = 'center';
  ctx.textBaseline = 'middle';
  ctx.fillStyle = color;
  ctx.fillText(text, w / 2, h / 2);
}

// ── Helpers ───────────────────────────────────────────────────────────────────
function fmtTime(secs) {
  const m = Math.floor(secs / 60);
  const s = String(Math.floor(secs % 60)).padStart(2, '0');
  return `${m}:${s}`;
}

// Like fmtTime but always zero-pads to hh:mm:ss for the canvas display.
function fmtTimeLong(secs) {
  secs = Math.floor(secs);
  const h = Math.floor(secs / 3600);
  const m = Math.floor((secs % 3600) / 60);
  const s = secs % 60;
  return `${String(h).padStart(2,'0')}:${String(m).padStart(2,'0')}:${String(s).padStart(2,'0')}`;
}

function parseTime(str) {
  const [m, s] = (str || '0:00').split(':').map(Number);
  return m * 60 + (s || 0);
}

function escHtml(s) {
  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
}

let toastTimer;
function showToast(msg) {
  let el = $('toast');
  if (!el) {
    el = document.createElement('div');
    el.id = 'toast';
    el.style.cssText = [
      'position:fixed', 'bottom:24px', 'left:50%', 'transform:translateX(-50%)',
      'background:#333', 'color:#fff', 'padding:10px 20px', 'border-radius:8px',
      'font-size:14px', 'z-index:999', 'opacity:0', 'transition:opacity .2s',
      'pointer-events:none',
    ].join(';');
    document.body.appendChild(el);
  }
  el.textContent = msg;
  el.style.opacity = '1';
  clearTimeout(toastTimer);
  toastTimer = setTimeout(() => { el.style.opacity = '0'; }, 2500);
}

// ── Playlist ──────────────────────────────────────────────────────────────────
$('btn-show-playlist').addEventListener('click', openPlaylist);
$('btn-close-playlist').addEventListener('click', () => {
  playlistOverlay.classList.add('hidden');
});

async function openPlaylist() {
  playlistOverlay.classList.remove('hidden');
  playlistList.innerHTML = '<li id="playlist-loading">Lade…</li>';

  let tracks;
  try {
    tracks = await apiFetch('/api/playlist').then(r => r.json());
  } catch {
    playlistList.innerHTML = '<li id="playlist-loading">Fehler beim Laden</li>';
    return;
  }

  if (!tracks || tracks.length === 0) {
    playlistList.innerHTML = '<li id="playlist-loading">Playlist leer</li>';
    return;
  }

  const frag = document.createDocumentFragment();
  tracks.forEach(t => {
    const li = document.createElement('li');
    li.dataset.index = t.index - 1; // store 0-based for jump
    if (t.index === currentPlaylistPos) li.classList.add('current');

    const idx = document.createElement('span');
    idx.className = 'pl-idx';
    idx.textContent = t.index;

    const title = document.createElement('span');
    title.className = 'pl-title';
    title.textContent = t.title || '–';

    li.appendChild(idx);
    li.appendChild(title);
    li.addEventListener('click', () => {
      send({ cmd: 'jump', index: parseInt(li.dataset.index, 10) });
      playlistOverlay.classList.add('hidden');
    });
    frag.appendChild(li);
  });

  playlistList.innerHTML = '';
  playlistList.appendChild(frag);
  scrollToCurrentTrack();
}

function updatePlaylistHighlight() {
  if (playlistOverlay.classList.contains('hidden')) return;
  playlistList.querySelectorAll('li').forEach(li => {
    const isCurrent = parseInt(li.dataset.index, 10) === currentPlaylistPos - 1;
    li.classList.toggle('current', isCurrent);
  });
  scrollToCurrentTrack();
}

function scrollToCurrentTrack() {
  const current = playlistList.querySelector('li.current');
  if (current) current.scrollIntoView({ block: 'center', behavior: 'smooth' });
}

// ── Boot ──────────────────────────────────────────────────────────────────────
connect();
renderFrame();