(function ($) {
  'use strict';

  const CLS = {
    lazy: '.ei-lazy',
    lazyBg: '.ei-lazy-bg',
    scrollContainer: '.ei-top-article .ei-row',
    loaded: 'ei-lazy-loaded',
    loadedBg: 'ei-lazy-bg-loaded',
  };
  const DATA = {
    boundImg: 'eiLazyBound',
    boundBg: 'eiLazyBgBound',
    scrollBound: 'eiScrollBound',
  };

  const OPT = { effect: 'fadeIn', effectTime: 300, threshold: 0 };
  const OPT_IMG = OPT;
  const OPT_BG  = Object.assign({ attribute: 'data-bg' }, OPT);

  function hasLazy() { return !!($.fn && $.fn.Lazy); }

  function runLazy($els, options, boundKey, loadedClass) {
    if (!hasLazy() || !$els || !$els.length) return;

    const $targets = $els.filter(function () { return !this.dataset[boundKey]; });
    if (!$targets.length) return;

    $targets.each(function () { this.dataset[boundKey] = '1'; });
    $targets.Lazy(Object.assign({}, options, {
      afterLoad: function (element) { element.addClass(loadedClass); }
    }));
  }

  function bindScroll($containers) {
    if (!$containers || !$containers.length) return;

    $containers.each(function () {
      const $c = $(this);
      if ($c.data(DATA.scrollBound)) return;

      $c.on('scroll', function () {
        runLazy($c.find(CLS.lazy),   OPT_IMG, DATA.boundImg, CLS.loaded);
        runLazy($c.find(CLS.lazyBg), OPT_BG,  DATA.boundBg,  CLS.loadedBg);
      });

      $c.data(DATA.scrollBound, true);
    });
  }

  function boot(root) {
    const $root = $(root || document);
    runLazy($root.find(CLS.lazy),   OPT_IMG, DATA.boundImg, CLS.loaded);
    runLazy($root.find(CLS.lazyBg), OPT_BG,  DATA.boundBg,  CLS.loadedBg);
    bindScroll($root.find(CLS.scrollContainer));
  }

  // Frontend (DOM Ready)
  $(function () { boot(document); });

  // Elementor Live Editor
  $(window).on('elementor/frontend/init', function () {
    if (window.elementorFrontend && elementorFrontend.hooks) {
      elementorFrontend.hooks.addAction('frontend/element_ready/global', function ($scope) {
        boot($scope && $scope[0] ? $scope[0] : document);
      });
    }
  });

})(jQuery);