(function ($) {
  "use strict";

  if (jQuery().startTimer) {
    $('.timer').startTimer({
      onComplete: function onComplete(element) {
        element.addClass('text-danger');
        $('.quiz-form form').trigger('submit');
      }
    });
  }

  var question_step = 1;
  var current_fs, next_fs, previous_fs; //fieldsets

  var opacity;

  function handleButtonDisable() {
    var question_count = $('.js-quiz-question-count').val();

    if (question_step >= question_count) {
      $(".next").prop('disabled', true);
    } else {
      $(".next").prop('disabled', false);
    }

    if (question_step <= 1) {
      $(".previous").prop('disabled', true);
    } else {
      $(".previous").prop('disabled', false);
    }
  }

  $("body").on('click', '.next', function () {
    current_fs = $('.question-step-' + question_step);
    next_fs = $('.question-step-' + (question_step + 1));

    if (next_fs.length < 1) {
      return;
    }

    next_fs.show();
    current_fs.animate({
      opacity: 0
    }, {
      step: function step(now) {
        opacity = 1 - now;
        current_fs.css({
          'display': 'none',
          'position': 'relative'
        });
        next_fs.css({
          'opacity': opacity
        });
      },
      duration: 600
    });
    question_step += 1;
    handleButtonDisable();
  });
  $("body").on('click', '.previous', function () {
    current_fs = $('.question-step-' + question_step);
    previous_fs = $('.question-step-' + (question_step - 1));

    if (previous_fs.length < 1) {
      return;
    }

    previous_fs.show();
    current_fs.animate({
      opacity: 0
    }, {
      step: function step(now) {
        opacity = 1 - now;
        current_fs.css({
          'display': 'none',
          'position': 'relative'
        });
        previous_fs.css({
          'opacity': opacity
        });
      },
      duration: 600
    });
    question_step--;
    handleButtonDisable();
  });
  var videoOptions = {
    autoplay: false,
    preload: 'auto'
  };
  var videoItems = $('.video-js');

  if (videoItems.length) {
    videoItems.each(function (key) {
      var el = videoItems[key];
      var id = $(el).attr('id');
      videojs(id, videoOptions);
    });
  }
})(jQuery);