/**
 * AKSRT Effects — count-up / countdown / marquee / 3D tilt / FPS detection
 *
 * 全部渐进增强，尊重 prefers-reduced-motion。
 *
 * @package AKSRT
 */

(function () {
  'use strict';

  var reducedMotion = window.matchMedia && window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  /* ============================================================
   * 1. 数字递增 (count-up) — IntersectionObserver 触发
   *    用法：<span data-aksrt-countup data-target="1234" data-duration="2000">0</span>
   * ============================================================ */
  function initCountUp() {
    if (reducedMotion) return;
    if (!('IntersectionObserver' in window)) return;

    var els = document.querySelectorAll('[data-aksrt-countup]');
    if (!els.length) return;

    var observer = new IntersectionObserver(function (entries) {
      entries.forEach(function (entry) {
        if (!entry.isIntersecting) return;
        var el = entry.target;
        observer.unobserve(el);

        var target = parseFloat(el.dataset.target || '0');
        var duration = parseInt(el.dataset.duration || '2000', 10);
        var decimals = (el.dataset.decimals || '0|').split('|');
        var prefix = decimals[1] || '';
        var dec = parseInt(decimals[0], 10) || 0;
        var start = 0;
        var startTime = null;

        function step(timestamp) {
          if (!startTime) startTime = timestamp;
          var progress = Math.min((timestamp - startTime) / duration, 1);
          // ease-out cubic
          var eased = 1 - Math.pow(1 - progress, 3);
          var current = start + (target - start) * eased;
          el.textContent = prefix + current.toFixed(dec).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
          if (progress < 1) {
            requestAnimationFrame(step);
          } else {
            el.textContent = prefix + target.toFixed(dec).replace(/\B(?=(\d{3})+(?!\d))/g, ',');
          }
        }

        requestAnimationFrame(step);
      });
    }, { threshold: 0.3 });

    els.forEach(function (el) { observer.observe(el); });
  }

  /* ============================================================
   * 2. 倒计时组件
   *    用法：<span data-aksrt-countdown data-end="2026-12-31T23:59:59">--:--:--</span>
   * ============================================================ */
  function initCountdown() {
    var els = document.querySelectorAll('[data-aksrt-countdown]');
    if (!els.length) return;

    function pad(n) { return n < 10 ? '0' + n : '' + n; }

    function update() {
      var now = Date.now();
      els.forEach(function (el) {
        var end = new Date(el.dataset.end).getTime();
        var diff = end - now;
        if (diff <= 0) {
          el.textContent = el.dataset.expired || '已结束';
          return;
        }
        var d = Math.floor(diff / 86400000);
        var h = Math.floor((diff % 86400000) / 3600000);
        var m = Math.floor((diff % 3600000) / 60000);
        var s = Math.floor((diff % 60000) / 1000);
        var format = el.dataset.format || 'dhms';
        if (format === 'dhms') {
          el.textContent = (d > 0 ? d + '天 ' : '') + pad(h) + ':' + pad(m) + ':' + pad(s);
        } else if (format === 'hms') {
          el.textContent = pad(h + d * 24) + ':' + pad(m) + ':' + pad(s);
        } else {
          el.textContent = (d > 0 ? d + '天 ' : '') + pad(h) + '时' + pad(m) + '分' + pad(s) + '秒';
        }
      });
    }

    update();
    setInterval(update, 1000);
  }

  /* ============================================================
   * 4. 3D 悬停倾斜 (vanilla tilt)
   *    用法：<div data-aksrt-tilt data-tilt-max="15">...</div>
   * ============================================================ */
  function initTilt() {
    if (reducedMotion) return;

    document.querySelectorAll('[data-aksrt-tilt]').forEach(function (el) {
      if (el.dataset.tiltBound) return;
      el.dataset.tiltBound = '1';

      var maxDeg = parseFloat(el.dataset.tiltMax || '10');
      var perspective = parseFloat(el.dataset.tiltPerspective || '800');
      var scale = parseFloat(el.dataset.tiltScale || '1.03');
      var glare = el.dataset.tiltGlare === '1';
      var glareEl = null;

      if (glare) {
        glareEl = document.createElement('div');
        glareEl.style.cssText = 'position:absolute;inset:0;border-radius:inherit;pointer-events:none;background:linear-gradient(135deg,rgba(255,255,255,0) 0%,rgba(255,255,255,0.25) 100%);opacity:0;transition:opacity 0.2s;';
        el.style.position = el.style.position || 'relative';
        el.style.overflow = 'hidden';
        el.appendChild(glareEl);
      }

      el.addEventListener('mousemove', function (e) {
        var rect = el.getBoundingClientRect();
        var x = (e.clientX - rect.left) / rect.width;
        var y = (e.clientY - rect.top) / rect.height;
        var rotateX = (0.5 - y) * maxDeg;
        var rotateY = (x - 0.5) * maxDeg;
        el.style.transform = 'perspective(' + perspective + 'px) rotateX(' + rotateX + 'deg) rotateY(' + rotateY + 'deg) scale3d(' + scale + ',' + scale + ',' + scale + ')';
        if (glareEl) glareEl.style.opacity = '1';
      });

      el.addEventListener('mouseleave', function () {
        el.style.transform = 'perspective(' + perspective + 'px) rotateX(0deg) rotateY(0deg) scale3d(1,1,1)';
        if (glareEl) glareEl.style.opacity = '0';
      });
    });
  }

  /* ============================================================
   * 5. FPS 检测 + 低端设备降级
   * ============================================================ */
  function initFpsDetection() {
    if (!('requestAnimationFrame' in window)) return;

    var frames = 0;
    var startTime = performance.now();

    function countFrames() {
      frames++;
      var elapsed = performance.now() - startTime;
      if (elapsed >= 1000) {
        var fps = Math.round(frames * 1000 / elapsed);
        if (fps < 24) {
          document.body.classList.add('fps-accelerat');
        }
        return; // 只检测一次
      }
      requestAnimationFrame(countFrames);
    }

    requestAnimationFrame(countFrames);
  }

  /* ============================================================
   * 初始化入口
   * ============================================================ */
  document.addEventListener('DOMContentLoaded', function () {
    initCountUp();
    initCountdown();
    if (typeof initMarquee === 'function') {
      initMarquee();
    }
    initTilt();
    initFpsDetection();
  });

})();