/*!

 * Bootstrap Table of Contents v0.4.1 (http://afeld.github.io/bootstrap-toc/)

 * Copyright 2015 Aidan Feldman

 * Licensed under MIT (https://github.com/afeld/bootstrap-toc/blob/gh-pages/LICENSE.md) */

(function() {

  'use strict';

  window.Toc = {

    helpers: {

      // return all matching elements in the set, or their descendants

      findOrFilter: function($el, selector) {

        // http://danielnouri.org/notes/2011/03/14/a-jquery-find-that-also-finds-the-root-element/

        // http://stackoverflow.com/a/12731439/358804

        var $descendants = $el.find(selector);

        return $el.filter(selector).add($descendants).filter(':not([data-toc-skip])');

      },

      generateUniqueIdBase: function(el) {

        var text = $(el).text();

        var anchor = text.trim().toLowerCase().replace(/[^A-Za-z0-9]+/g, '-');

        return anchor || el.tagName.toLowerCase();

      },

      generateUniqueId: function(el) {

        var anchorBase = this.generateUniqueIdBase(el);

        for (var i = 0; ; i++) {

          var anchor = anchorBase;

          if (i > 0) {

            // add suffix

            anchor += '-' + i;

          }

          // check if ID already exists

          if (!document.getElementById(anchor)) {

            return anchor;

          }

        }

      },

      generateAnchor: function(el) {

        if (el.id) {

          return el.id;

        } else {

          var anchor = this.generateUniqueId(el);

          el.id = anchor;

          return anchor;

        }

      },

      createNavList: function() {

        return $('<ul class="nav"></ul>');

      },

      createChildNavList: function($parent) {

        var $childList = this.createNavList();

        $parent.append($childList);

        return $childList;

      },

      generateNavEl: function(anchor, text) {

        var $a = $('<a></a>');

        $a.attr('href', '#' + anchor);

        $a.text(text);

        var $li = $('<li></li>');

        $li.append($a);

        return $li;

      },

      generateNavItem: function(headingEl) {

        var anchor = this.generateAnchor(headingEl);

        var $heading = $(headingEl);

        var text = $heading.data('toc-text') || $heading.text();

        return this.generateNavEl(anchor, text);

      },

      // Find the first heading level (`<h1>`, then `<h2>`, etc.) that has more than one element. Defaults to 1 (for `<h1>`).

      getTopLevel: function($scope) {

        for (var i = 1; i <= 6; i++) {

          var $headings = this.findOrFilter($scope, 'h' + i);

          if ($headings.length > 1) {

            return i;

          }

        }

        return 1;

      },

      // returns the elements for the top level, and the next below it

      getHeadings: function($scope, topLevel) {

        var topSelector = 'h' + topLevel;

        var secondaryLevel = topLevel + 1;

        var secondarySelector = 'h' + secondaryLevel;

        return this.findOrFilter($scope, topSelector + ',' + secondarySelector);

      },

      getNavLevel: function(el) {

        return parseInt(el.tagName.charAt(1), 10);

      },

      populateNav: function($topContext, topLevel, $headings) {

        var $context = $topContext;

        var $prevNav;

        var helpers = this;

        $headings.each(function(i, el) {

          var $newNav = helpers.generateNavItem(el);

          var navLevel = helpers.getNavLevel(el);

          // determine the proper $context

          if (navLevel === topLevel) {

            // use top level

            $context = $topContext;

          } else if ($prevNav && $context === $topContext) {

            // create a new level of the tree and switch to it

            $context = helpers.createChildNavList($prevNav);

          } // else use the current $context

          $context.append($newNav);

          $prevNav = $newNav;

        });

      },

      parseOps: function(arg) {

        var opts;

        if (arg.jquery) {

          opts = {

            $nav: arg

          };

        } else {

          opts = arg;

        }

        opts.$scope = opts.$scope || $(document.body);

        return opts;

      }

    },

    // accepts a jQuery object, or an options object

    init: function(opts) {

      opts = this.helpers.parseOps(opts);

      // ensure that the data attribute is in place for styling

      opts.$nav.attr('data-toggle', 'toc');

      var $topContext = this.helpers.createChildNavList(opts.$nav);

      var topLevel = this.helpers.getTopLevel(opts.$scope);

      var $headings = this.helpers.getHeadings(opts.$scope, topLevel);

      this.helpers.populateNav($topContext, topLevel, $headings);

    }

  };

  $(function() {

    $('nav[data-toggle="toc"]').each(function(i, el) {

      var $nav = $(el);

      Toc.init($nav);

    });

  });

})();