(function ($) {

  /**
   * initializeBlock
   *
   * Adds custom JavaScript to the block HTML.
   *
   * @date    15/4/19
   * @since   1.0.0
   *
   * @param   object $block The block jQuery element.
   * @param   object attributes The block attributes (only available when editing).
   * @return  void
   */
  var initializeBlock = function ($block) {

    function isInViewport() {
      var pageHeight = $(document).height();
      var windowScroll = $(window).scrollTop();
      var windowHeight = $(window).height();
      var scrollTreshold = windowScroll + (windowHeight * .95);
      var elementTop = $($block).offset().top;
      var elementHeight = $($block).outerHeight();
      var elementBottom = elementTop + elementHeight;

      if (elementTop < scrollTreshold && windowScroll < elementBottom) {
        window.removeEventListener('scroll', initStatCounters);
        return true;
      } else {
        return false;
      }
    };

    var countDecimals = function (value) {
      if ((value % 1) != 0)
        return value.toString().split(".")[1].length;
      return 0;
    };

    function initStatCounters() {
      window.addEventListener('scroll', initStatCounters);
      if (isInViewport() || window.acf) {
        var animate_start_delay = 200;
        var animate_start_stagger = 500; // each stat counter delays slightly longer than the last
        var animate_length = 3000;
        $('.stat-value[stat-value]').each(function () {
          var statValue = $(this).attr('stat-value');
          statValue = statValue.replace(/,/g, "");
          statValue = parseFloat(statValue);
          var decimals = countDecimals(statValue);

          $(this).prop('Counter', 0).delay(animate_start_delay).animate({
            Counter: statValue
          }, {
            duration: animate_length,
            easing: 'swing',
            step: function (now) {
              if (decimals) {
                $(this).text(now.toFixed(decimals));
              } else {
                $(this).text(Math.ceil(now).toLocaleString('en'));
              }

            },
            complete: function () {
            }
          });

          animate_start_delay += animate_start_stagger;
        });
      }
    }

    initStatCounters();
  }

  // Initialize each block on page load (front end).
  setTimeout(function () {
    $(function () {
      $('.stat-section').each(function () {
        initializeBlock($(this));
      });
    });
  }, 1000);

  // Initialize dynamic block preview (editor).
  if (window.acf) {
    window.acf.addAction('render_block_preview/type=stat-section', initializeBlock);
  }

})(jQuery);