$(function () {

  // WebP支持检测（首次运行时缓存结果）
  function checkWebPSupport(callback) {
    if (typeof localStorage !== 'undefined' && localStorage.getItem('webpSupport') !== null) {
      return callback(localStorage.getItem('webpSupport') === 'true');
    }

    const img = new Image();
    img.onload = function () {
      const result = img.width > 0 && img.height > 0;
      localStorage.setItem('webpSupport', result);
      callback(result);
    };
    img.onerror = function () {
      localStorage.setItem('webpSupport', false);
      callback(false);
    };

    img.src =
      'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=';
  }
  checkWebPSupport(function (isSupported) {
    $('img').each(function () {
      const $img = $(this);
      const webpSrc = $img.closest('picture').find('source[type="image/webp"]').data('srcset');
      const fallbackSrc = $img.data('src');

      // 动态设置真实图片路径
      $img.data('original', isSupported ? webpSrc : fallbackSrc);
    });

    $('img').lazyload({
      threshold: 200,
      effect: 'fadeIn',
      appear: function () {
        const realSrc = $(this).data('original');
        $(this).attr('src', realSrc);
        $(this).addClass('lazy-loaded');
      },
      load: function () {
        $(this).addClass('lazy-loaded');
      },
      error: function () {
        $(this).attr('src', 'img/error.jpg');
      },
    });
  });

  // 初始化懒加载
  $('img').lazyload({
    effect: 'fadeIn', // 淡入效果
    threshold: 100, // 提前300px加载
    failure_limit: 15, // 最大容错数量
    skip_invisible: true, // 加载隐藏图片
    appear: function () {
      // 加载前回调
      $(this).css('background', 'transparent');
      $(this).removeClass('lazyload');
    },
    load: function () {
      // 加载完成回调
      $(this).addClass('lazy-loaded');
    },
  });
});