/* ============================================================
   About Us V3 — NIO-style animations
   文字/Logo = 触发式(到达阈值 → 播完)
   蒙版/背景缩放 = scrub 式(随滚动持续变化)
   ============================================================ */
(function () {
  'use strict';

  var s1 = document.getElementById('au-1');
  var s3 = document.getElementById('au-3');
  if (!s1) return;

  if (window.matchMedia('(prefers-reduced-motion: reduce)').matches) {
    document.documentElement.classList.add('rm');
    return;
  }

  var pin1 = s1.closest('.au-pin');
  var pin3 = s3 ? s3.closest('.au-pin') : null;
  var mask1 = s1.querySelector('.au-mask');
  var bg1   = s1.querySelector('.au-bg');
  var mask3 = s3 ? s3.querySelector('.au-zoom-mask') : null;

  function clamp(v, a, b) { return Math.max(a, Math.min(b, v)); }

  function check() {
    var y = window.scrollY;
    var vh = window.innerHeight;

    /* ---- au-1 ---- */
    // 文字:触发式(过 30% → 加 .play)
    var t1 = pin1.offsetTop + vh * 0.3;
    s1.classList.toggle('play', y > t1);

    // 蒙版:scrub 式(随滚动持续加深,0 → 1 跨 1.5 屏)
    var p1 = clamp((y - pin1.offsetTop) / (vh * 1.5), 0, 1);
    mask1.style.opacity = p1.toFixed(3);

    // 背景:scrub 式(随滚动持续微缩 1.04 → 1)
    bg1.style.transform = 'scale(' + (1.04 - 0.04 * p1).toFixed(4) + ')';

    /* ---- au-3 ---- */
    if (pin3) {
      // 文字/Logo:触发式
      var t3 = pin3.offsetTop + vh * 1.0;
      s3.classList.toggle('play', y > t3);

      // 黑幕:scrub 式(随滚动持续加深,0 → 0.8 跨 1.5 屏)
      if (mask3) {
        var p3 = clamp((y - pin3.offsetTop - vh * 0.5) / (vh * 1.5), 0, 1);
        mask3.style.opacity = (p3 * 0.8).toFixed(3);
      }
    }
  }

  var ticking = false;
  window.addEventListener('scroll', function () {
    if (ticking) return;
    ticking = true;
    requestAnimationFrame(function () { check(); ticking = false; });
  }, { passive: true });

  window.addEventListener('resize', function () {
    pin1 = s1.closest('.au-pin');
    pin3 = s3 ? s3.closest('.au-pin') : null;
    check();
  }, { passive: true });

  check();
})();

/* GPS carousel */
(function () {
  'use strict';
  var viewport = document.querySelector('.au-gps__viewport');
  var track = document.querySelector('.au-gps__track');
  var dotsWrap = document.querySelector('.au-gps__dots');
  if (!viewport || !track || !dotsWrap) return;
  var cards = Array.prototype.slice.call(track.children);
  if (cards.length < 2) return;
  var idx = 0, timer = null;

  cards.forEach(function (_, i) {
    var b = document.createElement('button');
    b.setAttribute('aria-label', 'Slide ' + (i + 1));
    b.addEventListener('click', function () { goTo(i); restart(); });
    dotsWrap.appendChild(b);
  });
  var dots = Array.prototype.slice.call(dotsWrap.children);

  function render() {
    track.style.transform = 'translateX(' + (-idx * 100) + '%)';
    dots.forEach(function (d, i) { d.classList.toggle('active', i === idx); });
  }
  function goTo(i) { idx = ((i % cards.length) + cards.length) % cards.length; render(); }
  function next() { goTo(idx + 1); }
  function start() { if (!timer) timer = setInterval(next, 4000); }
  function stop()  { clearInterval(timer); timer = null; }
  function restart(){ stop(); start(); }

  render(); start();
  viewport.addEventListener('mouseenter', stop);
  viewport.addEventListener('mouseleave', start);
  document.addEventListener('visibilitychange', function () {
    document.hidden ? stop() : start();
  });
  var x0 = null;
  viewport.addEventListener('pointerdown', function (e) { x0 = e.clientX; });
  window.addEventListener('pointerup', function (e) {
    if (x0 === null) return;
    var dx = e.clientX - x0; x0 = null;
    if (Math.abs(dx) > 40) { dx < 0 ? next() : goTo(idx - 1); restart(); }
  });
})();