// https://github.com/ghiculescu/jekyll-table-of-contents
// Updated by https://chyblog.cn
(function ($) {
  $.fn.toc = function (options) {
    var defaults = {
      noBackToTopLinks: false,
      title: '文章目录',
      minimumHeaders: 2,
      headers: 'h1, h2, h3, h4, h5, h6',
      listType: 'ul', // values: [ol|ul]
      showEffect: 'show', // values: [show|slideDown|fadeIn|none]
      showSpeed: 0 // 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 = $(settings.headers).filter(function () {
      if ($(this).parent('blockquote').length > 0) {
        return false;
      }
      // 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) {
      $(this).hide();
      $('.post-directory-title').css('display', 'none');
      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 = "<p><strong class=\"toc-title\">" + settings.title + "</strong></p>\n";
    html += " <" + settings.listType + " class=\"toc\">";
    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 class=\"toc-item toc-level-" + this_level + "\">";
          html += "<a class=\"jumper\" href='#" + fixedEncodeURIComponent(header.id) + "'>";
          html += "<span class='toc-text'>" + header.innerHTML + "</span>";
          html += "</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 class='toc-item toc-level-" + this_level + "'><a class=\"jumper\" href='#" + fixedEncodeURIComponent(header.id) + "'>";
          html += "<span class='toc-text'>" + header.innerHTML + "</span>";
          html += "</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 + " class='toc-child'><li class='toc-item toc-level-" + i + "'>"
          }
          html += "<a class=\"jumper\" href='#" + fixedEncodeURIComponent(header.id) + "'>";
          html += "<span class='toc-text'>" + header.innerHTML + "</span>";
          html += "</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);

$(document).ready(function () {
  $('.post-directory').toc();

  var fixmeTop = $('#post-directory-module').offset().top;
  var tocSections = $('.clickable-header');
  var tocSectionOffsets = [];

  var calculateTocSections = function () {
    tocSectionOffsets = [];
    tocSections.each(function (index, section) {
      tocSectionOffsets.push(section.offsetTop);
    })
  }
  calculateTocSections();
  // Calculates the toc section offsets, which can change as images get loaded
  $(window).bind('load', calculateTocSections);

  var highlightTocSection = function () {
    var highlightIndex = 0;
    var sectionsCount = tocSectionOffsets.length;
    var currentScroll = $(window).scrollTop();

    if (currentScroll + 60 > tocSectionOffsets[sectionsCount - 1]) {
      highlightIndex = sectionsCount;
    } else {
      for (var i = 0; i < sectionsCount; i++) {
        if (currentScroll + 60 <= tocSectionOffsets[i]) {
          highlightIndex = i;
          break;
        }
      }
    }
    if (highlightIndex == 0) {
      highlightIndex += 1;
    }
    $('.toc-item .jumper').removeClass('on');
    $('.toc-item .jumper').eq(highlightIndex - 1).addClass('on');
  }
  highlightTocSection();

  var updateTocHeight = function () {
    var height = document.documentElement.clientHeight;
    height = height || 'auto';
    $('.post-directory').css('max-height', height);
  }

  $(window).scroll(function () {
    var currentScroll = $(window).scrollTop();
    if (currentScroll >= fixmeTop) {
      $('#post-directory-module').css({
        top: '0',
        position: 'fixed',
        width: 'inherit'
      });
      $('.post-directory').css('overflow', 'auto');
    } else {
      $('#post-directory-module').css({
        position: 'inherit',
        width: 'inherit'
      });
      $('.post-directory').css('overflow', 'hidden');
      $('.post-directory').scrollTop(0);
    }

    highlightTocSection();
  });

  updateTocHeight();

  $(window).on("resize", function () {
    updateTocHeight();
  });
});

$(".jumper").on("click", function (e) {
  e.preventDefault();
  $("body, html").animate({
    scrollTop: $($(this).attr('href')).offset().top
  }, 600);
});
