// CDJ-900NXS Mods — small helpers: theme toggle, before/after slider, docs TOC highlight.
(function () {
  var root = document.documentElement;

  function storedTheme() {
    try { return localStorage.getItem('theme'); } catch (e) { return null; }
  }
  var t = storedTheme();
  if (t === 'light' || t === 'dark') root.setAttribute('data-theme', t);

  document.addEventListener('DOMContentLoaded', function () {
    var btn = document.querySelector('.theme-btn');
    function label() {
      if (btn) btn.textContent = root.getAttribute('data-theme') === 'light' ? '☾' : '☀';
    }
    label();
    if (btn) btn.addEventListener('click', function () {
      var next = root.getAttribute('data-theme') === 'light' ? 'dark' : 'light';
      root.setAttribute('data-theme', next);
      try { localStorage.setItem('theme', next); } catch (e) { /* private mode */ }
      label();
    });

    // version badge and changelog (assets/versions.js, made by tools/make_builder_data.py)
    var V = window.CDJ_VERSIONS;
    var head = document.querySelector('.top .wrap');
    if (V && head) {
      var esc = function (t) { return String(t).replace(/[&<>]/g, function (c) { return { '&': '&amp;', '<': '&lt;', '>': '&gt;' }[c]; }); };
      var vb = document.createElement('button');
      vb.type = 'button'; vb.className = 'ver-btn'; vb.textContent = 'v' + V.site;
      vb.setAttribute('aria-haspopup', 'dialog'); vb.title = 'Changelog';
      var brand = head.querySelector('.brand');
      if (brand && brand.nextSibling) head.insertBefore(vb, brand.nextSibling); else head.appendChild(vb);
      var pop = document.createElement('div');
      pop.className = 'ver-pop'; pop.setAttribute('role', 'dialog'); pop.setAttribute('aria-label', 'Changelog');
      var html = '<div class="ver-box"><button class="close" type="button" aria-label="Close">✕</button>' +
        '<h2>Changelog</h2><p class="sub">Site ' + esc(V.site) + ' · ' + esc(V.date) + ' · Semantic Versioning, dates ISO 8601</p>';
      V.log.forEach(function (e) {
        html += '<h3>' + esc(e.version) + '<span class="d">' + esc(e.date) + '</span></h3><ul>' +
          e.changes.map(function (c) { return '<li>' + esc(c) + '</li>'; }).join('') + '</ul>';
      });
      html += '<h3>Mods</h3><div class="ver-mods">' + Object.keys(V.mods).map(function (m) {
        return '<code>' + esc(m) + '</code><span>' + esc(V.mods[m]) + '</span>';
      }).join('') + '</div></div>';
      pop.innerHTML = html;
      document.body.appendChild(pop);
      var close = function () { pop.classList.remove('open'); vb.focus(); };
      vb.addEventListener('click', function () { pop.classList.add('open'); pop.querySelector('.close').focus(); });
      pop.querySelector('.close').addEventListener('click', close);
      pop.addEventListener('click', function (e) { if (e.target === pop) close(); });
      document.addEventListener('keydown', function (e) { if (e.key === 'Escape' && pop.classList.contains('open')) close(); });
      // every mod card's version beside its name
      document.querySelectorAll('.card h3 code').forEach(function (c) {
        var v = V.mods[c.textContent.trim()];
        if (v) { var s = document.createElement('span'); s.className = 'ver'; s.textContent = 'v' + v; c.parentNode.appendChild(s); }
      });
    }

    // before / after
    document.querySelectorAll('.compare').forEach(function (box) {
      var range = box.querySelector('input[type="range"]');
      if (!range) return;
      function set() { box.style.setProperty('--pos', range.value + '%'); }
      range.addEventListener('input', set);
      set();
    });

    // docs: highlight the section in view
    var links = Array.prototype.slice.call(document.querySelectorAll('.toc a[href^="#"]'));
    if (links.length && 'IntersectionObserver' in window) {
      var byId = {};
      links.forEach(function (a) { byId[a.getAttribute('href').slice(1)] = a; });
      var obs = new IntersectionObserver(function (entries) {
        entries.forEach(function (e) {
          if (e.isIntersecting && byId[e.target.id]) {
            links.forEach(function (a) { a.classList.remove('active'); });
            byId[e.target.id].classList.add('active');
          }
        });
      }, { rootMargin: '-80px 0px -70% 0px' });
      Object.keys(byId).forEach(function (id) {
        var el = document.getElementById(id);
        if (el) obs.observe(el);
      });
    }
  });
})();

// Background: a record turning at the top right, a 3-band waveform (lows blue,
// mids amber, highs white) running along the bottom at 128 BPM; --beat pulses
// with it. Quiet when the system asks for reduced motion or the tab is hidden.
(function () {
  var BPM = 128, COL = 4, SPEED = 0.3, still = window.matchMedia && matchMedia('(prefers-reduced-motion: reduce)').matches;
  function rnd(k) { var x = Math.sin(k * 127.1 + 311.7) * 43758.5453; return x - Math.floor(x); }
  // one column of the waveform: k counts columns, 16 to a beat
  function band(k) {
    var beat = k % 16, bar = Math.floor(k / 64) % 16, drop = bar % 8 >= 2 && bar % 8 < 7;
    var kick = drop ? Math.exp(-beat / 3.2) : 0;
    var low = 0.12 + 0.8 * kick + 0.08 * rnd(k);
    var mid = (drop ? 0.32 : 0.45) + 0.25 * rnd(k + 9) * (0.6 + 0.4 * Math.sin(k / 40));
    var high = (beat >= 7 && beat <= 9 ? 0.45 : 0.08) * (0.5 + rnd(k + 3));
    return [low, mid, high];
  }
  document.addEventListener('DOMContentLoaded', function () {
    var c = document.createElement('canvas'), x = c.getContext('2d');
    if (!x) return;
    c.className = 'bg-fx'; c.setAttribute('aria-hidden', 'true');
    document.body.insertBefore(c, document.body.firstChild);
    var w, h, dpr, last = 0, t0 = performance.now();
    function size() {
      dpr = Math.min(window.devicePixelRatio || 1, 1.5);
      w = innerWidth; h = innerHeight;
      c.width = Math.round(w * dpr); c.height = Math.round(h * dpr);
    }
    size(); addEventListener('resize', size);
    function draw(now) {
      var light = document.documentElement.getAttribute('data-theme') === 'light', a = light ? 0.5 : 1;
      var t = (now - t0) / 1000 * SPEED, beats = t * BPM / 60;   // slowed down: calm, not a real 128 BPM
      x.setTransform(dpr, 0, 0, dpr, 0, 0);
      x.clearRect(0, 0, w, h);
      // the record
      var r = Math.max(w, h) * 0.32, cx = w - r * 0.35, cy = r * 0.25, turn = still ? 0.6 : t * Math.PI * 2 * 0.09;
      x.save(); x.translate(cx, cy);
      for (var g = 0.36; g < 1; g += 0.022) {
        x.beginPath(); x.arc(0, 0, r * g, 0, Math.PI * 2);
        x.strokeStyle = light ? 'rgba(20,24,33,' + 0.05 * a + ')' : 'rgba(255,255,255,' + 0.035 + ')';
        x.lineWidth = 1; x.stroke();
      }
      x.rotate(turn);
      var sheen = x.createLinearGradient(-r, 0, r, 0);
      sheen.addColorStop(0.42, 'rgba(255,255,255,0)');
      sheen.addColorStop(0.5, light ? 'rgba(20,24,33,' + 0.06 * a + ')' : 'rgba(255,255,255,0.06)');
      sheen.addColorStop(0.58, 'rgba(255,255,255,0)');
      x.beginPath(); x.arc(0, 0, r, 0, Math.PI * 2); x.arc(0, 0, r * 0.33, 0, Math.PI * 2, true);
      x.fillStyle = sheen; x.fill();
      x.beginPath(); x.arc(0, 0, r * 0.3, 0, Math.PI * 2);
      x.fillStyle = 'rgba(0,97,197,' + 0.06 * a + ')'; x.fill();
      x.beginPath(); x.arc(r * 0.18, 0, r * 0.012, 0, Math.PI * 2);
      x.fillStyle = 'rgba(255,255,255,' + 0.25 * a + ')'; x.fill();
      x.restore();
      // the waveform, 16 columns to a beat, scrolling left
      var y0 = h - Math.min(110, h * 0.13), amp = Math.min(70, h * 0.085);
      var shift = still ? 0 : beats * 16 * COL, first = Math.floor(shift / COL), off = shift - first * COL;
      for (var i = 0; i * COL - off < w + COL; i++) {
        var b = band(first + i), px = i * COL - off;
        var hl = b[0] * amp, hm = b[1] * amp * 0.85, hh = b[2] * amp;
        x.fillStyle = 'rgba(40,110,255,' + 0.22 * a + ')'; x.fillRect(px, y0 - hl, COL - 1, hl * 2);
        x.fillStyle = 'rgba(255,150,30,' + 0.22 * a + ')'; x.fillRect(px, y0 - hm, COL - 1, hm * 2);
        x.fillStyle = 'rgba(255,255,255,' + 0.20 * a + ')'; x.fillRect(px, y0 - hh, COL - 1, hh * 2);
      }
      document.documentElement.style.setProperty('--beat', still ? 0 : Math.pow(1 - (beats % 1), 3).toFixed(3));
    }
    function loop(now) {
      if (!document.hidden && now - last > 33) { last = now; draw(now); }
      if (!still) requestAnimationFrame(loop);
    }
    if (still) draw(performance.now()); else requestAnimationFrame(loop);
    addEventListener('resize', function () { if (still) draw(performance.now()); });
  });
})();