(function() {
  if (!window.rangy) {
    window.rangy = {};
  }
  if (window.rangy.serializeRange && window.rangy.deserializeRange) {
    return;
  }

  function normalizeHref(rawHref) {
    if (!rawHref) { return ''; }
    var value = String(rawHref);
    value = value.replace(/^.*?:\/\/[^/]+\//, '');
    value = value.split('#')[0];
    value = value.replace(/^\/+/, '');
    try {
      value = decodeURIComponent(value);
    } catch (error) {
    }
    return value;
  }

  function nodePath(node) {
    var path = [];
    var current = node;
    while (current && current !== current.ownerDocument) {
      var parent = current.parentNode;
      if (!parent) { break; }
      var index = Array.prototype.indexOf.call(parent.childNodes, current);
      path.unshift(index);
      current = parent;
    }
    return path;
  }

  function nodeFromPath(doc, path) {
    var current = doc;
    for (var index = 0; index < path.length; index += 1) {
      if (!current || !current.childNodes || current.childNodes.length <= path[index]) {
        return null;
      }
      current = current.childNodes[path[index]];
    }
    return current;
  }

  function documentContexts(rootDoc) {
    var items = [];
    if (!rootDoc) { return items; }
    items.push(rootDoc);
    var frames = rootDoc.querySelectorAll ? rootDoc.querySelectorAll('iframe') : [];
    Array.prototype.forEach.call(frames, function(frame) {
      try {
        if (!frame.contentDocument) { return; }
        documentContexts(frame.contentDocument).forEach(function(item) {
          items.push(item);
        });
      } catch (error) {
      }
    });
    return items;
  }

  window.rangy.serializeRange = function(range, doc) {
    var ownerDocument = doc || (range && range.startContainer && range.startContainer.ownerDocument) || document;
    return JSON.stringify({
      kind: 'dom-range',
      documentHref: normalizeHref(ownerDocument.location && ownerDocument.location.href),
      startPath: nodePath(range.startContainer),
      startOffset: range.startOffset,
      endPath: nodePath(range.endContainer),
      endOffset: range.endOffset
    });
  };

  window.rangy.deserializeRange = function(rangeInfo, rootDoc) {
    try {
      var payload = typeof rangeInfo === 'string' ? JSON.parse(rangeInfo) : rangeInfo;
      var documentHref = normalizeHref(payload.documentHref);
      var resolvedDocument = (documentContexts(rootDoc || document).find(function(candidate) {
        return normalizeHref(candidate.location && candidate.location.href) === documentHref;
      })) || (rootDoc || document);
      var startNode = nodeFromPath(resolvedDocument, payload.startPath || []);
      var endNode = nodeFromPath(resolvedDocument, payload.endPath || []);
      if (!startNode || !endNode) { return null; }
      var range = resolvedDocument.createRange();
      range.setStart(startNode, payload.startOffset || 0);
      range.setEnd(endNode, payload.endOffset || 0);
      return range;
    } catch (error) {
      return null;
    }
  };
})();