// github.com/ghiculescu/jekyll-table-of-contents (function($){

$.fn.toc = function(options) {
  var defaults = {
    noBackToTopLinks: false,
    title: '<h3><i>Jump to...</i></h3>',
    minimumHeaders: 3,
    headers: 'h1, h2, h3, h4, h5, h6',
    listType: 'ol', // values: [ol|ul]
    showEffect: 'show', // values: [show|slideDown|fadeIn|none]
    showSpeed: 'slow' // set to 0 to deactivate effect
  },
  settings = $.extend(defaults, options);

  function fixedEncodeURIComponent (str) {
    return encodeURIComponent(str).replace(/[!'()*]/g, function(c) {
      return '%' + c.charCodeAt(0).toString(16);
    });
  }

  var headers = $(settings.headers).filter(function() {
    // get all headers with an ID
    var previousSiblingName = $(this).prev().attr( "name" );
    if (!this.id && previousSiblingName) {
      this.id = $(this).attr( "id", previousSiblingName.replace(/\./g, "-") );
    }
    return this.id;
  }), output = $(this);
  if (!headers.length || headers.length < settings.minimumHeaders || !output.length) {
    return;
  }

  if (0 === settings.showSpeed) {
    settings.showEffect = 'none';
  }

  var render = {
    show: function() { output.hide().html(html).show(settings.showSpeed); },
    slideDown: function() { output.hide().html(html).slideDown(settings.showSpeed); },
    fadeIn: function() { output.hide().html(html).fadeIn(settings.showSpeed); },
    none: function() { output.html(html); }
  };

  var get_level = function(ele) { return parseInt(ele.nodeName.replace("H", ""), 10); }
  var highest_level = headers.map(function(_, ele) { return get_level(ele); }).get().sort()[0];
  var return_to_top = '<i class="icon-arrow-up back-to-top"> </i>';

  var level = get_level(headers[0]),
    this_level,
    html = settings.title + " <"+settings.listType+">";
  headers.on('click', function() {
    if (!settings.noBackToTopLinks) {
      window.location.hash = this.id;
    }
  })
  .addClass('clickable-header')
  .each(function(_, header) {
    this_level = get_level(header);
    if (!settings.noBackToTopLinks && this_level === highest_level) {
      $(header).addClass('top-level-header').after(return_to_top);
    }
    if (this_level === level) // same level as before; same indenting
      html += "<li><a href='#" + fixedEncodeURIComponent(header.id) + "'>" + header.innerHTML + "</a>";
    else if (this_level <= level){ // higher level than before; end parent ol
      for(i = this_level; i < level; i++) {
        html += "</li></"+settings.listType+">"
      }
      html += "<li><a href='#" + fixedEncodeURIComponent(header.id) + "'>" + header.innerHTML + "</a>";
    }
    else if (this_level > level) { // lower level than before; expand the previous to contain a ol
      for(i = this_level; i > level; i--) {
        html += "<"+settings.listType+"><li>"
      }
      html += "<a href='#" + fixedEncodeURIComponent(header.id) + "'>" + header.innerHTML + "</a>";
    }
    level = this_level; // update for the next one
  });
  html += "</"+settings.listType+">";
  if (!settings.noBackToTopLinks) {
    $(document).on('click', '.back-to-top', function() {
      $(window).scrollTop(0);
      window.location.hash = '';
    });
  }

  render[settings.showEffect]();
};

})(jQuery);