javascripts/foundation/foundation.magellan.js

/*jslint unparam: true, browser: true, indent: 2 */

;(function ($, window, document, undefined) {
  'use strict';

  Foundation.libs.magellan = {
    name : 'magellan',

    version : '4.3.2',

    settings : {
      activeClass: 'active',
      threshold: 0
    },

    init : function (scope, method, options) {
      this.scope = scope || this.scope;
      Foundation.inherit(this, 'data_options');

      if (typeof method === 'object') {
        $.extend(true, this.settings, method);
      }

      if (typeof method !== 'string') {
        if (!this.settings.init) {
          this.fixed_magellan = $("[data-magellan-expedition]");
          this.set_threshold();
          this.last_destination = $('[data-magellan-destination]').last();
          this.events();
        }

        return this.settings.init;
      } else {
        return this[method].call(this, options);
      }
    },

    events : function () {
      var self = this;
      $(this.scope).on('arrival.fndtn.magellan', '[data-magellan-arrival]', function (e) {
        var $destination = $(this),
            $expedition = $destination.closest('[data-magellan-expedition]'),
            activeClass = $expedition.attr('data-magellan-active-class') 
              || self.settings.activeClass;

          $destination
            .closest('[data-magellan-expedition]')
            .find('[data-magellan-arrival]')
            .not($destination)
            .removeClass(activeClass);
          $destination.addClass(activeClass);
      });

      this.fixed_magellan
        .on('update-position.fndtn.magellan', function(){
          var $el = $(this);
          // $el.data("magellan-fixed-position","");
          // $el.data("magellan-top-offset", "");
        })
        .trigger('update-position');

      $(window)
        .on('resize.fndtn.magellan', function() {
          this.fixed_magellan.trigger('update-position');
        }.bind(this))

        .on('scroll.fndtn.magellan', function() {
          var windowScrollTop = $(window).scrollTop();
          self.fixed_magellan.each(function() {
            var $expedition = $(this);
            if (typeof $expedition.data('magellan-top-offset') === 'undefined') {
              $expedition.data('magellan-top-offset', $expedition.offset().top);
            }
            if (typeof $expedition.data('magellan-fixed-position') === 'undefined') {
              $expedition.data('magellan-fixed-position', false)
            }
            var fixed_position = (windowScrollTop + self.settings.threshold) > $expedition.data("magellan-top-offset");
            var attr = $expedition.attr('data-magellan-top-offset');

            if ($expedition.data("magellan-fixed-position") != fixed_position) {
              $expedition.data("magellan-fixed-position", fixed_position);
              if (fixed_position) {
                $expedition.addClass('fixed');
                $expedition.css({position:"fixed", top:0});
              } else {
                $expedition.removeClass('fixed');
                $expedition.css({position:"", top:""});
              }
              if (fixed_position && typeof attr != 'undefined' && attr != false) {
                $expedition.css({position:"fixed", top:attr + "px"});
              }
            }
          });
        });


      if (this.last_destination.length > 0) {
        $(window).on('scroll.fndtn.magellan', function (e) {
          var windowScrollTop = $(window).scrollTop(),
              scrolltopPlusHeight = windowScrollTop + $(window).height(),
              lastDestinationTop = Math.ceil(self.last_destination.offset().top);

          $('[data-magellan-destination]').each(function () {
            var $destination = $(this),
                destination_name = $destination.attr('data-magellan-destination'),
                topOffset = $destination.offset().top - windowScrollTop;

            if (topOffset <= self.settings.threshold) {
              $("[data-magellan-arrival='" + destination_name + "']").trigger('arrival');
            }
            // In large screens we may hit the bottom of the page and dont reach the top of the last magellan-destination, so lets force it
            if (scrolltopPlusHeight >= $(self.scope).height() && lastDestinationTop > windowScrollTop && lastDestinationTop < scrolltopPlusHeight) {
              $('[data-magellan-arrival]').last().trigger('arrival');
            }
          });
        });
      }

      this.settings.init = true;
    },

    set_threshold : function () {
      if (typeof this.settings.threshold !== 'number') {
        this.settings.threshold = (this.fixed_magellan.length > 0) ? 
          this.outerHeight(this.fixed_magellan, true) : 0;
      }
    },

    off : function () {
      $(this.scope).off('.fndtn.magellan');
      $(window).off('.fndtn.magellan');
    },

    reflow : function () {}
  };
}(Foundation.zj, this, this.document));