(function ($) {
  if (!$ || $.fn.steps) {
    return;
  }

  $.fn.steps = function (options) {
    var settings = $.extend(
      {
        onFinish: function () {}
      },
      options || {}
    );

    return this.each(function () {
      var $wizard = $(this);
      var $steps = $wizard.find('.step-steps > li');
      var $panels = $wizard.find('.step-content > .step-tab-panel');
      var $footer = $wizard.find('.step-footer');
      var $prev = $footer.find('[data-direction="prev"]');
      var $next = $footer.find('[data-direction="next"]');
      var $finish = $footer.find('[data-direction="finish"]');
      var targets = $steps
        .map(function () {
          return $(this).find('a').attr('href');
        })
        .get();

      if (!$steps.length || !$panels.length) {
        return;
      }

      var currentIndex = $steps.index($steps.filter('.active').first());
      if (currentIndex < 0) {
        currentIndex = 0;
      }

      function setStep(index) {
        if (index < 0 || index >= targets.length) {
          return;
        }
        currentIndex = index;

        $steps.removeClass('active done').each(function (i) {
          var $step = $(this);
          if (i < index) {
            $step.addClass('done');
          }
          if (i === index) {
            $step.addClass('active');
          }
        });

        $steps.find('a').attr('aria-selected', 'false');
        $steps.eq(index).find('a').attr('aria-selected', 'true');

        $panels.removeClass('active').hide();
        var target = targets[index];
        if (target && target.charAt(0) === '#') {
          $wizard.find(target).addClass('active').show();
        }

        $footer.toggleClass('is-first', index === 0);
        $footer.toggleClass('is-last', index === targets.length - 1);
        $prev.prop('disabled', index === 0);
        $next.prop('disabled', index >= targets.length - 1);
      }

      $steps.find('a').on('click', function (event) {
        event.preventDefault();
        var target = $(this).attr('href');
        var index = targets.indexOf(target);
        if (index !== -1) {
          setStep(index);
        }
      });

      $prev.on('click', function (event) {
        event.preventDefault();
        setStep(currentIndex - 1);
      });

      $next.on('click', function (event) {
        event.preventDefault();
        setStep(currentIndex + 1);
      });

      $finish.on('click', function (event) {
        event.preventDefault();
        if (currentIndex === targets.length - 1) {
          settings.onFinish.call($wizard[0]);
        } else {
          setStep(targets.length - 1);
        }
      });

      setStep(currentIndex);
    });
  };
})(jQuery);