text: /* global window, document, $, hljs, elasticlunr, base_url, is_top_frame */
  /* exported getParam, onIframeLoad */
  "use strict";
  
  // The full page consists of a main window with navigation and table of contents, and an inner
  // iframe containing the current article. Which article is shown is determined by the main
  // window's #hash portion of the URL. In fact, we use the simple rule: main window's URL of
  // "rootUrl#relPath" corresponds to iframe's URL of "rootUrl/relPath".
  //
  // The main frame and the contents of the index page actually live in a single generated html
  // file: the outer frame hides one half, and the inner hides the other. TODO: this should be
  // possible to greatly simplify after mkdocs-1.0 release.
  
  var mainWindow = is_top_frame ? window : (window.parent !== window ? window.parent : null);
  var iframeWindow = null;
  var rootUrl = qualifyUrl(base_url);
  var searchIndex = null;
  var showPageToc = true;
  var MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
  
  var Keys = {
    ENTER:  13,
    ESCAPE: 27,
    UP:     38,
    DOWN:   40,
  };
  
  function startsWith(str, prefix) { return str.lastIndexOf(prefix, 0) === 0; }
  function endsWith(str, suffix) { return str.indexOf(suffix, str.length - suffix.length) !== -1; }
  
  /**
   * Returns whether to use small-screen mode. Note that the same size is used in css @media block.
   */
  function isSmallScreen() {
    return window.matchMedia("(max-width: 600px)").matches;
  }
  
  /**
   * Given a relative URL, returns the absolute one, relying on the browser to convert it.
   */
  function qualifyUrl(url) {
    var a = document.createElement('a');
    a.href = url;
    return a.href;
  }
  
  /**
   * Turns an absolute path to relative, stripping out rootUrl + separator.
   */
  function getRelPath(separator, absUrl) {
    var prefix = rootUrl + (endsWith(rootUrl, separator) ? '' : separator);
    return startsWith(absUrl, prefix) ? absUrl.slice(prefix.length) : null;
  }
  
  /**
   * Turns a relative path to absolute, adding a prefix of rootUrl + separator.
   */
  function getAbsUrl(separator, relPath) {
    var sep = endsWith(rootUrl, separator) ? '' : separator;
    return relPath === null ? null : rootUrl + sep + relPath;
  }
  
  /**
   * Redirects the iframe to reflect the path represented by the main window's current URL.
   * (In our design, nothing should change iframe's src except via updateIframe(), or back/forward
   * history is likely to get messed up.)
   */
  function updateIframe(enableForwardNav) {
    // Grey out the "forward" button if we don't expect 'forward' to work.
    $('#hist-fwd').toggleClass('greybtn', !enableForwardNav);
  
    var targetRelPath = getRelPath('#', mainWindow.location.href) || '';
    var targetIframeUrl = getAbsUrl('/', targetRelPath);
    var loc = iframeWindow.location;
    var currentIframeUrl = _safeGetLocationHref(loc);
  
    console.log("updateIframe: %s -> %s (%s)", currentIframeUrl, targetIframeUrl,
      currentIframeUrl === targetIframeUrl ? "same" : "replacing");
  
    if (currentIframeUrl !== targetIframeUrl) {
      loc.replace(targetIframeUrl);
      onIframeBeforeLoad(targetIframeUrl);
    }
    document.body.scrollTop = 0;
  }
  
  /**
   * Returns location.href, catching exception that's triggered if the iframe is on a different domain.
   */
  function _safeGetLocationHref(location) {
    try {
      return location.href;
    } catch (e) {
      return null;
    }
  }
  
  /**
   * Returns the value of the given parameter in the URL's query portion.
   */
  function getParam(key) {
    var params = window.location.search.substring(1).split('&');
    for (var i = 0; i < params.length; i++) {
      var param = params[i].split('=');
      if (param[0] === key) {
        return decodeURIComponent(param[1].replace(/\+/g, '%20'));
      }
    }
  }
  
  /**
   * Update the state of the button toggling table-of-contents. TOC has different behavior
   * depending on screen size, so the button's behavior depends on that too.
   */
  function updateTocButtonState() {
    var shown;
    if (isSmallScreen()) {
      shown = $('.wm-toc-pane').hasClass('wm-toc-dropdown');
    } else {
      shown = !$('#main-content').hasClass('wm-toc-hidden');
    }
    $('#wm-toc-button').toggleClass('active', shown);
  }
  
  /**
   * Update the height of the iframe container. On small screens, we adjust it to fit the iframe
   * contents, so that the page scrolls as a whole rather than inside the iframe.
   */
  function updateContentHeight() {
    if (isSmallScreen()) {
      $('.wm-content-pane').height(iframeWindow.document.body.offsetHeight + 20);
      $('.wm-article').attr('scrolling', 'no');
    } else {
      $('.wm-content-pane').height('');
      $('.wm-article').attr('scrolling', 'auto');
    }
  }
  
  /**
   * When TOC is a dropdown (on small screens), close it.
   */
  function closeTempItems() {
    $('.wm-toc-dropdown').removeClass('wm-toc-dropdown');
    $('#mkdocs-search-query').closest('.wm-top-tool').removeClass('wm-top-tool-expanded');
    updateTocButtonState();
  }
  
  /**
   * Visit the given URL. This changes the hash of the top page to reflect the new URL's relative
   * path, and points the iframe to the new URL.
   */
  function visitUrl(url, event) {
    var relPath = getRelPath('/', url);
    if (relPath !== null) {
      event.preventDefault();
      var newUrl = getAbsUrl('#', relPath);
      if (newUrl !== mainWindow.location.href) {
        mainWindow.history.pushState(null, '', newUrl);
        updateIframe(false);
      }
      closeTempItems();
      iframeWindow.focus();
    }
  }
  
  /**
   * Adjusts link to point to a top page, converting URL from "base/path" to "base#path". It also
   * sets a data-adjusted attribute on the link, to skip adjustments on future clicks.
   */
  function adjustLink(linkEl) {
    if (!linkEl.hasAttribute('data-wm-adjusted')) {
      linkEl.setAttribute('data-wm-adjusted', 'done');
      var relPath = getRelPath('/', linkEl.href);
      if (relPath !== null) {
        var newUrl = getAbsUrl('#', relPath);
        linkEl.href = newUrl;
      }
    }
  }
  
  /**
   * Given a URL, strips query and fragment, returning just the path.
   */
  function cleanUrlPath(relUrl) {
    return relUrl.replace(/[#?].*/, '');
  }
  
  /**
   * Initialize the main window.
   */
  function initMainWindow() {
    // wm-toc-button either opens the table of contents in the side-pane, or (on smaller screens)
    // shows the side-pane as a drop-down.
    $('#wm-toc-button').on('click', function(e) {
      if (isSmallScreen()) {
        $('.wm-toc-pane').toggleClass('wm-toc-dropdown');
        $('#wm-main-content').removeClass('wm-toc-hidden');
      } else {
        $('#main-content').toggleClass('wm-toc-hidden');
        closeTempItems();
      }
      updateTocButtonState();
    });
  
    // Update the state of the wm-toc-button
    updateTocButtonState();
    $(window).on('resize', function() {
      updateTocButtonState();
      updateContentHeight();
    });
  
    // Connect up the Back and Forward buttons (if present).
    $('#hist-back').on('click', function(e) { window.history.back(); });
    $('#hist-fwd').on('click', function(e) { window.history.forward(); });
  
    // When the side-pane is a dropdown, hide it on click-away.
    $(window).on('blur', closeTempItems);
  
    // When we click on an opener in the table of contents, open it.
    $('.wm-toc-pane').on('click', '.wm-toc-opener', function(e) {
      $(this).toggleClass('wm-toc-open');
      $(this).next('.wm-toc-li-nested').collapse('toggle');
    });
    $('.wm-toc-pane').on('click', '.wm-page-toc-opener', function(e) {
      // Ignore clicks while transitioning.
      if ($(this).next('.wm-page-toc').hasClass('collapsing')) { return; }
      showPageToc = !showPageToc;
      $(this).toggleClass('wm-page-toc-open', showPageToc);
      $(this).next('.wm-page-toc').collapse(showPageToc ? 'show' : 'hide');
    });
  
    // Once the article loads in the side-pane, close the dropdown.
    $('.wm-article').on('load', function() {
      document.title = iframeWindow.document.title;
      updateContentHeight();
  
      // We want to update content height whenever the height of the iframe's content changes.
      // Using MutationObserver seems to be the best way to do that.
      var observer = new MutationObserver(updateContentHeight);
      observer.observe(iframeWindow.document.body, {
        attributes: true,
        childList: true,
        characterData: true,
        subtree: true
      });
  
      iframeWindow.focus();
    });
  
    // Initialize search functionality.
    initSearch();
  
    // Load the iframe now, and whenever we navigate the top frame.
    setTimeout(function() { updateIframe(false); }, 0);
    // For our usage, 'popstate' or 'hashchange' would work, but only 'hashchange' work on IE.
    $(window).on('hashchange', function() { updateIframe(true); });
  }
  
  function onIframeBeforeLoad(url) {
    $('.wm-current').removeClass('wm-current');
    closeTempItems();
  
    var tocLi = getTocLi(url);
    tocLi.addClass('wm-current');
    tocLi.parents('.wm-toc-li-nested')
      // It's better to open parent items immediately without a transition.
      .removeClass('collapsing').addClass('collapse in').height('')
      .prev('.wm-toc-opener').addClass('wm-toc-open');
  }
  
  function getTocLi(url) {
    var relPath = getAbsUrl('#', getRelPath('/', cleanUrlPath(url)));
    var selector = '.wm-article-link[href="' + relPath + '"]';
    return $(selector).closest('.wm-toc-li');
  }
  
  function onIframeLoad() {
    var url = iframeWindow.location.href;
    onIframeBeforeLoad(url);
  
    if (iframeWindow.pageToc) {
      var relPath = getAbsUrl('#', getRelPath('/', cleanUrlPath(url)));
      renderPageToc(getTocLi(url), relPath, iframeWindow.pageToc);
    }
    iframeWindow.focus();
  }
  
  /**
   * Hides a bootstrap collapsible element, and removes it from DOM once hidden.
   */
  function collapseAndRemove(collapsibleElem) {
    if (!collapsibleElem.hasClass('in')) {
      // If the element is already hidden, just remove it immediately.
      collapsibleElem.remove();
    } else {
      collapsibleElem.on('hidden.bs.collapse', function() {
        collapsibleElem.remove();
      })
      .collapse('hide');
    }
  }
  
  function renderPageToc(parentElem, pageUrl, pageToc) {
    var ul = $('<ul class="wm-toctree">');
    function addItem(tocItem) {
      ul.append($('<li class="wm-toc-li">')
        .append($('<a class="wm-article-link wm-page-toc-text">')
          .attr('href', pageUrl + tocItem.url)
          .attr('data-wm-adjusted', 'done')
          .text(tocItem.title)));
      if (tocItem.children) {
        tocItem.children.forEach(addItem);
      }
    }
    pageToc.forEach(addItem);
  
    $('.wm-page-toc-opener').removeClass('wm-page-toc-opener wm-page-toc-open');
    collapseAndRemove($('.wm-page-toc'));
  
    parentElem.addClass('wm-page-toc-opener').toggleClass('wm-page-toc-open', showPageToc);
    $('<li class="wm-page-toc wm-toc-li-nested collapse">').append(ul).insertAfter(parentElem)
      .collapse(showPageToc ? 'show' : 'hide');
  }
  
  
  if (!mainWindow) {
    // This is a page that ought to be in an iframe. Redirect to load the top page instead.
    var topUrl = getAbsUrl('#', getRelPath('/', window.location.href));
    if (topUrl) {
      window.location.href = topUrl;
    }
  
  } else {
    // Adjust all links to point to the top page with the right hash fragment.
    $(document).ready(function() {
      $('a').each(function() { adjustLink(this); });
    });
  
    // For any dynamically-created links, adjust them on click.
    $(document).on('click', 'a:not([data-wm-adjusted])', function(e) { adjustLink(this); });
  }
  
  if (is_top_frame) {
    // Main window.
    $(document).ready(function() {
      iframeWindow = $('.wm-article')[0].contentWindow;
      initMainWindow();
    });
  
  } else {
    // Article contents.
    iframeWindow = window;
    if (mainWindow) {
      mainWindow.onIframeLoad();
    }
  
    // Other initialization of iframe contents.
    hljs.initHighlightingOnLoad();
    $(document).ready(function() {
      $('table').addClass('table table-striped table-hover table-bordered table-condensed');
    });
  }
  
  
  var searchIndexReady = false;
  
  
  /**
   * Initialize search functionality.
   */
  function initSearch() {
    // Create elasticlunr index.
    searchIndex = elasticlunr(function() {
      this.setRef('location');
      this.addField('title');
      this.addField('text');
    });
  
    var searchBox = $('#mkdocs-search-query');
    var searchResults = $('#mkdocs-search-results');
  
    // Fetch the prebuilt index data, and add to the index.
    $.getJSON(base_url + '/search/search_index.json')
    .done(function(data) {
      data.docs.forEach(function(doc) {
        doc.location = base_url + '/' + doc.location;
        searchIndex.addDoc(doc);
      });
      searchIndexReady = true;
      $(document).trigger('searchIndexReady');
    });
  
    function showSearchResults(optShow) {
      var show = (optShow === false ? false : Boolean(searchBox.val()));
      if (show) {
        doSearch({
          resultsElem: searchResults,
          query: searchBox.val(),
          snippetLen: 100,
          limit: 10
        });
      }
      searchResults.parent().toggleClass('open', show);
      return show;
    }
  
    searchBox.on('click', function(e) {
      if (!searchResults.parent().hasClass('open')) {
        if (showSearchResults()) {
          e.stopPropagation();
        }
      }
    });
  
    // Search automatically and show results on keyup event.
    searchBox.on('keyup', function(e) {
      var show = (e.which !== Keys.ESCAPE && e.which !== Keys.ENTER);
      showSearchResults(show);
    });
  
    // Open the search box (and run the search) on up/down arrow keys.
    searchBox.on('keydown', function(e) {
      if (e.which === Keys.UP || e.which === Keys.DOWN) {
        if (showSearchResults()) {
          e.stopPropagation();
          e.preventDefault();
          setTimeout(function() {
            searchResults.find('a').eq(e.which === Keys.UP ? -1 : 0).focus();
          }, 0);
        }
      }
    });
  
    searchResults.on('keydown', function(e) {
      if (e.which === Keys.UP || e.which === Keys.DOWN) {
        if (searchResults.find('a').eq(e.which === Keys.UP ? 0 : -1)[0] === e.target) {
          searchBox.focus();
          e.stopPropagation();
          e.preventDefault();
        }
      }
    });
  
    $(searchResults).on('click', '.search-all', function(e) {
      e.stopPropagation();
      e.preventDefault();
      $('#wm-search-form').trigger('submit');
    });
  
    // Redirect to the search page on Enter or button-click (form submit).
    $('#wm-search-form').on('submit', function(e) {
      var url = this.action + '?' + $(this).serialize();
      visitUrl(url, e);
      searchResults.parent().removeClass('open');
    });
  
    $('#wm-search-show,#wm-search-go').on('click', function(e) {
      if (isSmallScreen()) {
        e.preventDefault();
        var el = $('#mkdocs-search-query').closest('.wm-top-tool')
        el.toggleClass('wm-top-tool-expanded');
        if (el.hasClass('wm-top-tool-expanded')) {
          setTimeout(function() {
            $('#mkdocs-search-query').focus();
            showSearchResults();
          }, 0);
          $('#mkdocs-search-query').focus();
        }
      }
    });
  }
  
  function escapeRegex(s) {
    return s.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
  }
  
  /**
   * This helps construct useful snippets to show in search results, and highlight matches.
   */
  function SnippetBuilder(query) {
    var termsPattern = elasticlunr.tokenizer(query).map(escapeRegex).join("|");
    this._termsRegex = termsPattern ? new RegExp(termsPattern, "gi") : null;
  }
  
  SnippetBuilder.prototype.getSnippet = function(text, len) {
    if (!this._termsRegex) {
      return text.slice(0, len);
    }
  
    // Find a position that includes something we searched for.
    var pos = text.search(this._termsRegex);
    if (pos < 0) { pos = 0; }
  
    // Find a period before that position (a good starting point).
    var start = text.lastIndexOf('.', pos) + 1;
    if (pos - start > 30) {
      // If too long to previous period, give it 30 characters, and find a space before that.
      start = text.lastIndexOf(' ', pos - 30) + 1;
    }
    var rawSnippet = text.slice(start, start + len);
    return rawSnippet.replace(this._termsRegex, '<b>$&</b>');
  };
  
  /**
   * Search the elasticlunr index for the given query, and populate the dropdown with results.
   */
  function doSearch(options) {
    var resultsElem = options.resultsElem;
    resultsElem.empty();
  
    // If the index isn't ready, wait for it, and search again when ready.
    if (!searchIndexReady) {
      resultsElem.append($('<li class="disabled"><a class="search-link">SEARCHING...</a></li>'));
      $(document).one('searchIndexReady', function() { doSearch(options); });
      return;
    }
  
    var query = options.query;
    var snippetLen = options.snippetLen;
    var limit = options.limit;
  
    if (query === '') { return; }
  
    var results = searchIndex.search(query, {
      fields: { title: {boost: 10}, text: { boost: 1 } },
      expand: true,
      bool: "AND"
    });
  
    var snippetBuilder = new SnippetBuilder(query);
    if (results.length > 0){
      var len = Math.min(results.length, limit || Infinity);
      for (var i = 0; i < len; i++) {
        var doc = searchIndex.documentStore.getDoc(results[i].ref);
        var snippet = snippetBuilder.getSnippet(doc.text, snippetLen);
  
        resultsElem.append(
          $('<li>').append($('<a class="search-link">').attr('href', doc.location)
            .append($('<div class="search-title">').text(doc.title))
            .append($('<div class="search-text">').html(snippet)))
        );
      }
      if (limit) {
        resultsElem.append($('<li role="separator" class="divider"></li>'));
        resultsElem.append($(
          '<li><a class="search-link search-all" href="' + base_url + '/search.html">' +
          '<div class="search-title">SEE ALL RESULTS</div></a></li>'));
      }
    } else {
      resultsElem.append($('<li class="disabled"><a class="search-link">NO RESULTS FOUND</a></li>'));
    }
  }
  