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

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

    version : '{{VERSION}}',

    settings : {
      active_class : 'active',
      callback : function () {},
      deep_linking : false,
      scroll_to_content : true,
      is_hover : false
    },

    default_tab_hashes : [],

    init : function (scope, method, options) {
      var self = this,
          S = this.S;

  	  // Store the default active tabs which will be referenced when the
  	  // location hash is absent, as in the case of navigating the tabs and
  	  // returning to the first viewing via the browser Back button.
  	  S('[' + this.attr_name() + '] > .active > a', this.scope).each(function () {
  	    self.default_tab_hashes.push(this.hash);
  	  });

      this.bindings(method, options);
      this.handle_location_hash_change();
    },

    events : function () {
      var self = this,
          S = this.S;

      var usual_tab_behavior =  function (e, target) {
        var settings = S(target).closest('[' + self.attr_name() + ']').data(self.attr_name(true) + '-init');
        if (!settings.is_hover || Modernizr.touch) {
          // if user did not pressed tab key, prevent default action
          var keyCode = e.keyCode || e.which;
          if (keyCode !== 9) { 
            e.preventDefault();
            e.stopPropagation();
          }
          self.toggle_active_tab(S(target).parent());
          
        }
      };

      S(this.scope)
        .off('.tab')
        // Key event: focus/tab key
        .on('keydown.fndtn.tab', '[' + this.attr_name() + '] > * > a', function(e) {
          var keyCode = e.keyCode || e.which;
          // if user pressed tab key
          if (keyCode === 13 || keyCode === 32) { // enter or space
            var el = this;
            usual_tab_behavior(e, el);
          } 
        })
        // Click event: tab title
        .on('click.fndtn.tab', '[' + this.attr_name() + '] > * > a', function(e) {
          var el = this;
          usual_tab_behavior(e, el);
        })
        // Hover event: tab title
        .on('mouseenter.fndtn.tab', '[' + this.attr_name() + '] > * > a', function (e) {
          var settings = S(this).closest('[' + self.attr_name() + ']').data(self.attr_name(true) + '-init');
          if (settings.is_hover) {
            self.toggle_active_tab(S(this).parent());
          }
        });

      // Location hash change event
      S(window).on('hashchange.fndtn.tab', function (e) {
        e.preventDefault();
        self.handle_location_hash_change();
      });
    },

    handle_location_hash_change : function () {

      var self = this,
          S = this.S;

      S('[' + this.attr_name() + ']', this.scope).each(function () {
        var settings = S(this).data(self.attr_name(true) + '-init');
        if (settings.deep_linking) {
          // Match the location hash to a label
          var hash;
          if (settings.scroll_to_content) {
            hash = self.scope.location.hash;
          } else {
            // prefix the hash to prevent anchor scrolling
            hash = self.scope.location.hash.replace('fndtn-', '');
          }
          if (hash != '') {
            // Check whether the location hash references a tab content div or
            // another element on the page (inside or outside the tab content div)
            var hash_element = S(hash);
            if (hash_element.hasClass('content') && hash_element.parent().hasClass('tabs-content')) {
              // Tab content div
              self.toggle_active_tab($('[' + self.attr_name() + '] > * > a[href=\\' + hash + ']').parent());
            } else {
              // Not the tab content div. If inside the tab content, find the
              // containing tab and toggle it as active.
              var hash_tab_container_id = hash_element.closest('.content').attr('id');
              if (hash_tab_container_id != undefined) {
                self.toggle_active_tab($('[' + self.attr_name() + '] > * > a[href=\\#' + hash_tab_container_id + ']').parent(), hash);
              }
            }
          } else {
            // Reference the default tab hashes which were initialized in the init function
            for (var ind = 0; ind < self.default_tab_hashes.length; ind++) {
              self.toggle_active_tab($('[' + self.attr_name() + '] > * > a[href=\\' + self.default_tab_hashes[ind] + ']').parent());
            }
          }
        }
       });
     },

    toggle_active_tab : function (tab, location_hash) {
      var self = this,
          S = self.S,
          tabs = tab.closest('[' + this.attr_name() + ']'),
          tab_link = tab.find('a'),
          anchor = tab.children('a').first(),
          target_hash = '#' + anchor.attr('href').split('#')[1],
          target = S(target_hash),
          siblings = tab.siblings(),
          settings = tabs.data(this.attr_name(true) + '-init'),
          interpret_keyup_action = function (e) {
            // Light modification of Heydon Pickering's Practical ARIA Examples: http://heydonworks.com/practical_aria_examples/js/a11y.js

            // define current, previous and next (possible) tabs

            var $original = $(this);
            var $prev = $(this).parents('li').prev().children('[role="tab"]');
            var $next = $(this).parents('li').next().children('[role="tab"]');
            var $target;

            // find the direction (prev or next)

            switch (e.keyCode) {
              case 37:
                $target = $prev;
                break;
              case 39:
                $target = $next;
                break;
              default:
                $target = false
                  break;
            }

            if ($target.length) {
              $original.attr({
                'tabindex' : '-1',
                'aria-selected' : null
              });
              $target.attr({
                'tabindex' : '0',
                'aria-selected' : true
              }).focus();
            }

            // Hide panels

            $('[role="tabpanel"]')
              .attr('aria-hidden', 'true');

            // Show panel which corresponds to target

            $('#' + $(document.activeElement).attr('href').substring(1))
              .attr('aria-hidden', null);

          },
          go_to_hash = function(hash) {
            // This function allows correct behaviour of the browser's back button when deep linking is enabled. Without it
            // the user would get continually redirected to the default hash.
            var default_hash = settings.scroll_to_content ? self.default_tab_hashes[0] : 'fndtn-' + self.default_tab_hashes[0].replace('#', '');

            if (hash !== default_hash || window.location.hash) {
              window.location.hash = hash;
            }
          };

      // allow usage of data-tab-content attribute instead of href
      if (anchor.data('tab-content')) {
        target_hash = '#' + anchor.data('tab-content').split('#')[1];
        target = S(target_hash);
      }

      if (settings.deep_linking) {

        if (settings.scroll_to_content) {

          // retain current hash to scroll to content
          go_to_hash(location_hash || target_hash);

          if (location_hash == undefined || location_hash == target_hash) {
            tab.parent()[0].scrollIntoView();
          } else {
            S(target_hash)[0].scrollIntoView();
          }
        } else {
          // prefix the hashes so that the browser doesn't scroll down
          if (location_hash != undefined) {
            go_to_hash('fndtn-' + location_hash.replace('#', ''));
          } else {
            go_to_hash('fndtn-' + target_hash.replace('#', ''));
          }
        }
      }

      // WARNING: The activation and deactivation of the tab content must
      // occur after the deep linking in order to properly refresh the browser
      // window (notably in Chrome).
      // Clean up multiple attr instances to done once
      tab.addClass(settings.active_class).triggerHandler('opened');
      tab_link.attr({'aria-selected' : 'true',  tabindex : 0});
      siblings.removeClass(settings.active_class)
      siblings.find('a').attr({'aria-selected' : 'false'/*,  tabindex : -1*/});
      target.siblings().removeClass(settings.active_class).attr({'aria-hidden' : 'true'/*,  tabindex : -1*/});
      target.addClass(settings.active_class).attr('aria-hidden', 'false').removeAttr('tabindex');
      settings.callback(tab);
      target.triggerHandler('toggled', [target]);
      tabs.triggerHandler('toggled', [tab]);

      tab_link.off('keydown').on('keydown', interpret_keyup_action );
    },

    data_attr : function (str) {
      if (this.namespace.length > 0) {
        return this.namespace + '-' + str;
      }

      return str;
    },

    off : function () {},

    reflow : function () {}
  };
}(jQuery, window, window.document));