$( function() {

  // Show and hide loader
  var activityIndicatorOn = function() {
      $('<div id="imagelightbox-loading"><div></div></div>' ).appendTo('body');
    },
    activityIndicatorOff = function() {
      $('#imagelightbox-loading').remove();
    },

    // Show and hide overlay
    overlayOn = function() {
      $('<div id="imagelightbox-overlay"></div>').appendTo('body');
    },
    overlayOff = function() {
      $('#imagelightbox-overlay').remove();
    },

    // Show and hide close button
    closeButtonOn = function(instance) {
      $('<a href="#" id="imagelightbox-close">Close</a>').appendTo('body').on('click touchend', function(){ $(this).remove(); instance.quitImageLightbox(); return false; });
    },
    closeButtonOff = function() {
      $('#imagelightbox-close').remove();
    },

    // Show and hide caption
    captionOn = function() {
      var description = $('a[href="' + $('#imagelightbox').attr('src') + '"] img').attr('alt');
      if(description.length > 0)
        $('<div id="imagelightbox-caption">' + description + '</div>').appendTo('body');
    },
    captionOff = function() {
      $('#imagelightbox-caption').remove();
    },

    // Show, hide and keep navigation boubble updated
    navigationOn = function(instance, selector) {
      var images = $(selector);
      if (images.length) {
        var nav = $('<div id="imagelightbox-nav"></div>');
        for(var i = 0; i < images.length; i++)
          nav.append('<a href="#"></a>');

        nav.appendTo('body');
        nav.on('click touchend', function(){ return false; });

        var navItems = nav.find('a');
        navItems.on('click touchend', function() {
          var $this = $(this);
          if (images.eq($this.index()).attr('href') != $('#imagelightbox').attr('src'))
            instance.switchImageLightbox($this.index());

          navItems.removeClass('active');
          navItems.eq($this.index()).addClass('active');

          return false;
        })
        .on('touchend', function(){ return false; });
      }
    },
    navigationUpdate = function(selector) {
      var items = $('#imagelightbox-nav a');
      items.removeClass('active');
      items.eq( $( selector ).filter('[href="' + $('#imagelightbox').attr('src') + '"]').index( selector ) ).addClass('active');
    },
    navigationOff = function() {
      $('#imagelightbox-nav').remove();
    };

  //  WITH ACTIVITY INDICATION
  $('a[data-imagelightbox="0"]').imageLightbox(
  {
    onLoadStart:  function() { activityIndicatorOn(); },
    onLoadEnd:    function() { activityIndicatorOff(); },
    onEnd:        function() { activityIndicatorOff(); }
  });

  //  WITH OVERLAY & ACTIVITY INDICATION
  $('a[data-imagelightbox="1"]').imageLightbox(
  {
    onStart:      function() { overlayOn(); },
    onEnd:        function() { overlayOff(); activityIndicatorOff(); },
    onLoadStart:  function() { activityIndicatorOn(); },
    onLoadEnd:    function() { activityIndicatorOff(); }
  });

  //  WITH "CLOSE" BUTTON & ACTIVITY INDICATION
  var instanceTwo = $('a[data-imagelightbox="2"]').imageLightbox(
  {
    quitOnDocClick: false,
    onStart:      function() { closeButtonOn( instanceTwo ); },
    onEnd:        function() { closeButtonOff(); activityIndicatorOff(); },
    onLoadStart:  function() { activityIndicatorOn(); },
    onLoadEnd:    function() { activityIndicatorOff(); }
  });

  //  WITH CAPTION & ACTIVITY INDICATION
  $('a[data-imagelightbox="3"]').imageLightbox(
  {
    onLoadStart:  function() { captionOff(); activityIndicatorOn(); },
    onLoadEnd:    function() { captionOn(); activityIndicatorOff(); },
    onEnd:        function() { captionOff(); activityIndicatorOff(); }
  });

  //  WITH DIRECTION REFERENCE
  var selectorFour = 'a[data-imagelightbox="4"]';
  var instanceFour = $(selectorFour).imageLightbox(
  {
    onStart:      function() { navigationOn( instanceFour, selectorFour ); },
    onEnd:        function() { navigationOff(); activityIndicatorOff(); },
    onLoadStart:  function() { activityIndicatorOn(); },
    onLoadEnd:    function() { navigationUpdate( selectorFour ); activityIndicatorOff(); }
  });

  //  ALL COMBINED
  var instanceF = $('a[data-imagelightbox="5"]').imageLightbox(
  {
    onStart:      function() { overlayOn(); closeButtonOn( instanceF ); },
    onEnd:        function() { overlayOff(); captionOff(); closeButtonOff(); activityIndicatorOff(); },
    onLoadStart:  function() { captionOff(); activityIndicatorOn(); },
    onLoadEnd:    function() { captionOn(); activityIndicatorOff(); }
  });

});