/* 词页共用计时器＋浏览器内合成环境声（2026-10-23 关键词引流批次）。
   为什么合成而不是放音频文件：/pomodoro-timer-with-sounds 这页要承诺"无下载、无文件、
   锁屏笔记本也能用"，用 mp3 就要么加几百 KB 要么写假话。这里全部用 WebAudio 现算：
   white=白噪，pink=粉噪（Paul Kellet 算法），rain=白噪过带通＋慢调制，ocean=棕噪过低通＋LFO。
   首页 index.html 的五声（forest/rain/whitenoise/pinknoise/ocean）是另一套实现，这页不冒充它，
   也不发新埋点事件名（埋点新事件要过 track.js＋RPC＋表 CHECK 三道白名单门，动它得抬全站 ?v=）。

   用法（页内必须有这块骨架，id 逐字对齐）：
     <div id="wt" data-modes="25,50,10" data-labels="Focus 25,Deep 50,Quick 10"
          data-default="25" data-done="Done!" data-sounds="white,pink,rain,ocean"></div>
     <script src="/assets/wordtimer.js?v=1"></script>
*/
(function () {
  var root = document.getElementById('wt');
  if (!root) return;
  var modes = (root.dataset.modes || '25').split(',').map(function (x) { return parseInt(x, 10) || 25; });
  var labels = (root.dataset.labels || modes.join(',')).split(',');
  var def = parseInt(root.dataset.default, 10) || modes[0];
  var doneMsg = root.dataset.done || 'Done!';
  var soundDefs = (root.dataset.sounds || '').split(',').filter(Boolean);

  root.innerHTML =
    '<div class="bird">' + (root.dataset.bird || '🐦') + '</div>' +
    '<div class="timer" id="wtT">' + fmt(def * 60) + '</div>' +
    '<div class="modes" id="wtM"></div>' +
    '<div class="controls">' +
    '<button class="btn btn-start" id="wtGo" aria-label="Start or pause">▶</button>' +
    '<button class="btn btn-reset" id="wtRe" aria-label="Reset">↺</button>' +
    '</div>' +
    (soundDefs.length ? '<div class="sounds" id="wtS"></div>' : '') +
    '<p class="hint">' + (root.dataset.hint || 'Press play. Nothing is uploaded — the countdown runs in this tab.') + '</p>';

  var total = def * 60, rem = total, int = null, run = false;
  var tEl = document.getElementById('wtT'), go = document.getElementById('wtGo');
  var baseTitle = document.title;

  function fmt(s) {
    var m = Math.floor(s / 60), ss = s % 60;
    return String(m).padStart(2, '0') + ':' + String(ss).padStart(2, '0');
  }
  function tickTitle() {
    document.title = run ? fmt(rem) + ' · ' + baseTitle : baseTitle;
  }
  function pick(m, btn) {
    stop();
    total = m * 60; rem = total;
    tEl.textContent = fmt(rem);
    Array.prototype.forEach.call(document.querySelectorAll('#wtM .mode-btn'), function (x) { x.classList.remove('active'); });
    if (btn) btn.classList.add('active');
  }
  var mBox = document.getElementById('wtM');
  modes.forEach(function (m, i) {
    var b = document.createElement('button');
    b.className = 'mode-btn' + (m === def ? ' active' : '');
    b.textContent = (labels[i] || (m + ' min')).trim();
    b.onclick = function () { pick(m, b); };
    mBox.appendChild(b);
  });
  function stop() {
    if (int) clearInterval(int);
    int = null; run = false;
    go.textContent = '▶';
  }
  function start() {
    run = true; go.textContent = '⏸';
    int = setInterval(function () {
      rem = Math.max(0, rem - 1);
      tEl.textContent = fmt(rem);
      tickTitle();
      if (rem <= 0) {
        stop(); rem = total; tEl.textContent = fmt(rem);
        document.title = baseTitle;
        try { new Function('')(); } catch (e) {}
        flash();
      }
    }, 1000);
  }
  function flash() {
    var prev = tEl.textContent;
    tEl.textContent = '✓';
    setTimeout(function () { tEl.textContent = fmt(rem); }, 900);
    if (window.console) console.log(doneMsg);
    try { Notification && Notification.permission === 'granted' && new Notification('Timerbird', { body: doneMsg }); } catch (e) {}
  }
  go.onclick = function () { run ? stop() : start(); tickTitle(); };
  document.getElementById('wtRe').onclick = function () { stop(); rem = total; tEl.textContent = fmt(rem); document.title = baseTitle; };

  /* ---- 合成环境声 ---- */
  var actx = null, src = null, gain = null, lfo = null, cur = null;
  var sBox = document.getElementById('wtS');
  function noiseBuffer(kind) {
    var len = actx.sampleRate * 2, buf = actx.createBuffer(1, len, actx.sampleRate), d = buf.getChannelData(0);
    var i, last = 0, b0 = 0, b1 = 0, b2 = 0, b3 = 0, b4 = 0, b5 = 0, b6 = 0;
    for (i = 0; i < len; i++) {
      var w = Math.random() * 2 - 1;
      if (kind === 'pink') {
        b0 = 0.99886 * b0 + w * 0.0555179; b1 = 0.99332 * b1 + w * 0.0750759;
        b2 = 0.96900 * b2 + w * 0.1538520; b3 = 0.86650 * b3 + w * 0.3104856;
        b4 = 0.55000 * b4 + w * 0.5329522; b5 = -0.7616 * b5 - w * 0.0168980;
        d[i] = (b0 + b1 + b2 + b3 + b4 + b5 + b6 + w * 0.5362) * 0.11; b6 = w * 0.115926;
      } else if (kind === 'brown') {
        last = (last + 0.02 * w) / 1.02; d[i] = last * 3.5;
      } else {
        d[i] = w * 0.6;
      }
    }
    return buf;
  }
  function setSound(id, btn) {
    if (!actx) {
      var AC = window.AudioContext || window.webkitAudioContext;
      if (!AC) return;
      actx = new AC();
    }
    if (cur === id) { off(); btn.classList.remove('on'); cur = null; return; }
    off();
    var need = (id === 'ocean') ? 'brown' : 'white', kind = (id === 'pink') ? 'pink' : need;
    src = actx.createBufferSource(); src.buffer = noiseBuffer(kind); src.loop = true;
    var tail = actx.createGain(); tail.gain.value = 0.55;
    if (id === 'rain') {
      var bp = actx.createBiquadFilter(); bp.type = 'bandpass'; bp.frequency.value = 1100; bp.Q.value = 0.7;
      var mod = actx.createOscillator(); mod.frequency.value = 0.22;
      var modG = actx.createGain(); modG.gain.value = 0.18;
      mod.connect(modG); modG.connect(tail.gain); mod.start(); lfo = mod;
      src.connect(bp); bp.connect(tail);
    } else if (id === 'ocean') {
      var lp = actx.createBiquadFilter(); lp.type = 'lowpass'; lp.frequency.value = 420;
      var sw = actx.createOscillator(); sw.frequency.value = 0.11;
      var swG = actx.createGain(); swG.gain.value = 0.25;
      sw.connect(swG); swG.connect(tail.gain); sw.start(); lfo = sw;
      src.connect(lp); lp.connect(tail);
    } else {
      src.connect(tail);
    }
    gain = actx.createGain(); gain.gain.value = 0;
    tail.connect(gain); gain.connect(actx.destination);
    src.start();
    gain.gain.linearRampToValueAtTime(0.5, actx.currentTime + 0.4);
    cur = id;
    Array.prototype.forEach.call(document.querySelectorAll('#wtS .snd'), function (x) { x.classList.remove('on'); });
    btn.classList.add('on');
  }
  function off() {
    try { if (src) { src.stop(); src.disconnect(); } } catch (e) {}
    try { if (lfo) { lfo.stop(); lfo.disconnect(); } } catch (e) {}
    src = null; lfo = null;
  }
  var NAMES = { white: 'White noise', pink: 'Pink noise', rain: 'Rain', ocean: 'Ocean', forest: 'Forest' };
  if (sBox) {
    soundDefs.forEach(function (id) {
      var b = document.createElement('button');
      b.className = 'snd'; b.textContent = NAMES[id] || id; b.dataset.id = id;
      b.onclick = function () { setSound(id, b); };
      sBox.appendChild(b);
    });
  }
  document.addEventListener('visibilitychange', function () { if (document.hidden) off(), cur = null; });
})();