
/**
 * Plugin written by the great jqueryfordesigners.com
 * http://jqueryfordesigners.com/jquery-infinite-carousel/
 *
 * Slightly addapted for our use case
 */
(function ($) {
  $.fn.infiniteCarousel = function () {

      function repeat(str, num) {
          return new Array( num + 1 ).join( str );
      }

      return this.each(function () {

          var $wrapper = $('> div', this).css('overflow', 'hidden'),
              $slider = $wrapper.find('> ul'),
              $items = $slider.find('> li'),
              $single = $items.filter(':first'),

              singleWidth = $single.outerWidth(),
              visible = Math.ceil($wrapper.innerWidth() / singleWidth), // note: doesn't include padding or border
              currentPage = 1,
              pages = Math.ceil($items.length / visible);


          // 1. Pad so that 'visible' number will always be seen, otherwise create empty items
          if (($items.length % visible) != 0) {
              $slider.append(repeat('<li class="empty" />', visible - ($items.length % visible)));
              $items = $slider.find('> li');
          }

          // 2. Top and tail the list with 'visible' number of items, top has the last section, and tail has the first
          $items.filter(':first').before($items.slice(- visible).clone().addClass('cloned'));
          $items.filter(':last').after($items.slice(0, visible).clone().addClass('cloned'));
          $items = $slider.find('> li'); // reselect

          // 3. Set the left position to the first 'real' item
          $wrapper.scrollLeft(singleWidth * visible);

          // 4. paging function
          function gotoPage(page) {
              var dir = page < currentPage ? -1 : 1,
                  n = Math.abs(currentPage - page),
                  left = singleWidth * dir * visible * n;

              $wrapper.filter(':not(:animated)').animate({
                  scrollLeft : '+=' + left
              }, 500, function () {
                  if (page == 0) {
                      $wrapper.scrollLeft(singleWidth * visible * pages);
                      page = pages;
                  } else if (page > pages) {
                      $wrapper.scrollLeft(singleWidth * visible);
                      // reset back to start position
                      page = 1;
                  }

                  currentPage = page;
              });

              return false;
          }

          $wrapper.after('<a class="arrow back" title="'+ Drupal.t('Previous page') +'">&lt;</a><a class="arrow forward" title="'+ Drupal.t('Next page') +'">&gt;</a>');

          // 5. Bind to the forward and back buttons
          $('a.back', this).click(function () {
              return gotoPage(currentPage - 1);
          });

          $('a.forward', this).click(function () {
              return gotoPage(currentPage + 1);
          });

          // create a public interface to move to a specific page
          $(this).bind('goto', function (event, page) {
              gotoPage(page);
          });

          // custom events to trigger next and prev pages
          $(this).bind('next', function () {
            gotoPage(currentPage + 1);
          });
          $(this).bind('prev', function () {
            gotoPage(currentPage - 1);
          })
      });
  };
})(jQuery);
