;(function ($, window, document, undefined) {

  'use strict';

  Foundation.libs['magellan-expedition'] = {

    name : 'magellan-expedition',

    version : '5.5.2',

    settings : {

      active_class : 'active',

      threshold : 0, // pixels from the top of the expedition for it to become fixes

      destination_threshold : 20, // pixels from the top of destination for it to be considered active

      throttle_delay : 30, // calculation throttling to increase framerate

      fixed_top : 0, // top distance in pixels assigend to the fixed element on scroll

      offset_by_height : true,  // whether to offset the destination by the expedition height. Usually you want this to be true, unless your expedition is on the side.

      duration : 700, // animation duration time

      easing : 'swing' // animation easing

    },

    init : function (scope, method, options) {

      Foundation.inherit(this, 'throttle');

      this.bindings(method, options);

    },

    events : function () {

      var self = this,

          S = self.S,

          settings = self.settings;

      // initialize expedition offset

      self.set_expedition_position();

      S(self.scope)

        .off('.magellan')

        .on('click.fndtn.magellan', '[' + self.add_namespace('data-magellan-arrival') + '] a[href*=#]', function (e) {

          var sameHost = ((this.hostname === location.hostname) || !this.hostname),

              samePath = self.filterPathname(location.pathname) === self.filterPathname(this.pathname),

              testHash = this.hash.replace(/(:|\.|\/)/g, '\\$1'),

              anchor = this;

          if (sameHost && samePath && testHash) {

            e.preventDefault();

            var expedition = $(this).closest('[' + self.attr_name() + ']'),

                settings = expedition.data('magellan-expedition-init'),

                hash = this.hash.split('#').join(''),

                target = $('a[name="' + hash + '"]');

            if (target.length === 0) {

              target = $('#' + hash);

            }

            // Account for expedition height if fixed position

            var scroll_top = target.offset().top - settings.destination_threshold + 1;

            if (settings.offset_by_height) {

              scroll_top = scroll_top - expedition.outerHeight();

            }

            $('html, body').stop().animate({

              'scrollTop' : scroll_top

            }, settings.duration, settings.easing, function () {

              if (history.pushState) {

                        history.pushState(null, null, anchor.pathname + '#' + hash);

              }

                    else {

                        location.hash = anchor.pathname + '#' + hash;

                    }

            });

          }

        })

        .on('scroll.fndtn.magellan', self.throttle(this.check_for_arrivals.bind(this), settings.throttle_delay));

    },

    check_for_arrivals : function () {

      var self = this;

      self.update_arrivals();

      self.update_expedition_positions();

    },

    set_expedition_position : function () {

      var self = this;

      $('[' + this.attr_name() + '=fixed]', self.scope).each(function (idx, el) {

        var expedition = $(this),

            settings = expedition.data('magellan-expedition-init'),

            styles = expedition.attr('styles'), // save styles

            top_offset, fixed_top;

        expedition.attr('style', '');

        top_offset = expedition.offset().top + settings.threshold;

        //set fixed-top by attribute

        fixed_top = parseInt(expedition.data('magellan-fixed-top'));

        if (!isNaN(fixed_top)) {

          self.settings.fixed_top = fixed_top;

        }

        expedition.data(self.data_attr('magellan-top-offset'), top_offset);

        expedition.attr('style', styles);

      });

    },

    update_expedition_positions : function () {

      var self = this,

          window_top_offset = $(window).scrollTop();

      $('[' + this.attr_name() + '=fixed]', self.scope).each(function () {

        var expedition = $(this),

            settings = expedition.data('magellan-expedition-init'),

            styles = expedition.attr('style'), // save styles

            top_offset = expedition.data('magellan-top-offset');

        //scroll to the top distance

        if (window_top_offset + self.settings.fixed_top >= top_offset) {

          // Placeholder allows height calculations to be consistent even when

          // appearing to switch between fixed/non-fixed placement

          var placeholder = expedition.prev('[' + self.add_namespace('data-magellan-expedition-clone') + ']');

          if (placeholder.length === 0) {

            placeholder = expedition.clone();

            placeholder.removeAttr(self.attr_name());

            placeholder.attr(self.add_namespace('data-magellan-expedition-clone'), '');

            expedition.before(placeholder);

          }

          expedition.css({position :'fixed', top : settings.fixed_top}).addClass('fixed');

        } else {

          expedition.prev('[' + self.add_namespace('data-magellan-expedition-clone') + ']').remove();

          expedition.attr('style', styles).css('position', '').css('top', '').removeClass('fixed');

        }

      });

    },

    update_arrivals : function () {

      var self = this,

          window_top_offset = $(window).scrollTop();

      $('[' + this.attr_name() + ']', self.scope).each(function () {

        var expedition = $(this),

            settings = expedition.data(self.attr_name(true) + '-init'),

            offsets = self.offsets(expedition, window_top_offset),

            arrivals = expedition.find('[' + self.add_namespace('data-magellan-arrival') + ']'),

            active_item = false;

        offsets.each(function (idx, item) {

          if (item.viewport_offset >= item.top_offset) {

            var arrivals = expedition.find('[' + self.add_namespace('data-magellan-arrival') + ']');

            arrivals.not(item.arrival).removeClass(settings.active_class);

            item.arrival.addClass(settings.active_class);

            active_item = true;

            return true;

          }

        });

        if (!active_item) {

          arrivals.removeClass(settings.active_class);

        }

      });

    },

    offsets : function (expedition, window_offset) {

      var self = this,

          settings = expedition.data(self.attr_name(true) + '-init'),

          viewport_offset = window_offset;

      return expedition.find('[' + self.add_namespace('data-magellan-arrival') + ']').map(function (idx, el) {

        var name = $(this).data(self.data_attr('magellan-arrival')),

            dest = $('[' + self.add_namespace('data-magellan-destination') + '=' + name + ']');

        if (dest.length > 0) {

          var top_offset = dest.offset().top - settings.destination_threshold;

          if (settings.offset_by_height) {

            top_offset = top_offset - expedition.outerHeight();

          }

          top_offset = Math.floor(top_offset);

          return {

            destination : dest,

            arrival : $(this),

            top_offset : top_offset,

            viewport_offset : viewport_offset

          }

        }

      }).sort(function (a, b) {

        if (a.top_offset < b.top_offset) {

          return -1;

        }

        if (a.top_offset > b.top_offset) {

          return 1;

        }

        return 0;

      });

    },

    data_attr : function (str) {

      if (this.namespace.length > 0) {

        return this.namespace + '-' + str;

      }

      return str;

    },

    off : function () {

      this.S(this.scope).off('.magellan');

      this.S(window).off('.magellan');

    },

    filterPathname : function (pathname) {

      pathname = pathname || '';

      return pathname

          .replace(/^\//,'')

          .replace(/(?:index|default).[a-zA-Z]{3,4}$/,'')

          .replace(/\/$/,'');

    },

    reflow : function () {

      var self = this;

      // remove placeholder expeditions used for height calculation purposes

      $('[' + self.add_namespace('data-magellan-expedition-clone') + ']', self.scope).remove();

    }

  };

}(jQuery, window, window.document));