text: 'use strict';
  
  var defaultTreeAdapter = require('../tree_adapters/default'),
      mergeOptions = require('../utils/merge_options'),
      doctype = require('../common/doctype'),
      HTML = require('../common/html');
  
  //Aliases
  var $ = HTML.TAG_NAMES,
      NS = HTML.NAMESPACES;
  
  //Default serializer options
  var DEFAULT_OPTIONS = {
      treeAdapter: defaultTreeAdapter
  };
  
  //Escaping regexes
  var AMP_REGEX = /&/g,
      NBSP_REGEX = /\u00a0/g,
      DOUBLE_QUOTE_REGEX = /"/g,
      LT_REGEX = /</g,
      GT_REGEX = />/g;
  
  //Serializer
  var Serializer = module.exports = function (node, options) {
      this.options = mergeOptions(DEFAULT_OPTIONS, options);
      this.treeAdapter = this.options.treeAdapter;
  
      this.html = '';
      this.startNode = node;
  };
  
  // NOTE: exported as static method for the testing purposes
  Serializer.escapeString = function (str, attrMode) {
      str = str
          .replace(AMP_REGEX, '&amp;')
          .replace(NBSP_REGEX, '&nbsp;');
  
      if (attrMode)
          str = str.replace(DOUBLE_QUOTE_REGEX, '&quot;');
  
      else {
          str = str
              .replace(LT_REGEX, '&lt;')
              .replace(GT_REGEX, '&gt;');
      }
  
      return str;
  };
  
  
  //API
  Serializer.prototype.serialize = function () {
      this._serializeChildNodes(this.startNode);
  
      return this.html;
  };
  
  
  //Internals
  Serializer.prototype._serializeChildNodes = function (parentNode) {
      var childNodes = this.treeAdapter.getChildNodes(parentNode);
  
      if (childNodes) {
          for (var i = 0, cnLength = childNodes.length; i < cnLength; i++) {
              var currentNode = childNodes[i];
  
              if (this.treeAdapter.isElementNode(currentNode))
                  this._serializeElement(currentNode);
  
              else if (this.treeAdapter.isTextNode(currentNode))
                  this._serializeTextNode(currentNode);
  
              else if (this.treeAdapter.isCommentNode(currentNode))
                  this._serializeCommentNode(currentNode);
  
              else if (this.treeAdapter.isDocumentTypeNode(currentNode))
                  this._serializeDocumentTypeNode(currentNode);
          }
      }
  };
  
  Serializer.prototype._serializeElement = function (node) {
      var tn = this.treeAdapter.getTagName(node),
          ns = this.treeAdapter.getNamespaceURI(node);
  
      this.html += '<' + tn;
      this._serializeAttributes(node);
      this.html += '>';
  
      if (tn !== $.AREA && tn !== $.BASE && tn !== $.BASEFONT && tn !== $.BGSOUND && tn !== $.BR && tn !== $.BR &&
          tn !== $.COL && tn !== $.EMBED && tn !== $.FRAME && tn !== $.HR && tn !== $.IMG && tn !== $.INPUT &&
          tn !== $.KEYGEN && tn !== $.LINK && tn !== $.MENUITEM && tn !== $.META && tn !== $.PARAM && tn !== $.SOURCE &&
          tn !== $.TRACK && tn !== $.WBR) {
  
          var childNodesHolder = tn === $.TEMPLATE && ns === NS.HTML ?
              this.treeAdapter.getTemplateContent(node) :
              node;
  
          this._serializeChildNodes(childNodesHolder);
          this.html += '</' + tn + '>';
      }
  };
  
  Serializer.prototype._serializeAttributes = function (node) {
      var attrs = this.treeAdapter.getAttrList(node);
  
      for (var i = 0, attrsLength = attrs.length; i < attrsLength; i++) {
          var attr = attrs[i],
              value = Serializer.escapeString(attr.value, true);
  
          this.html += ' ';
  
          if (!attr.namespace)
              this.html += attr.name;
  
          else if (attr.namespace === NS.XML)
              this.html += 'xml:' + attr.name;
  
          else if (attr.namespace === NS.XMLNS) {
              if (attr.name !== 'xmlns')
                  this.html += 'xmlns:';
  
              this.html += attr.name;
          }
  
          else if (attr.namespace === NS.XLINK)
              this.html += 'xlink:' + attr.name;
  
          else
              this.html += attr.namespace + ':' + attr.name;
  
          this.html += '="' + value + '"';
      }
  };
  
  Serializer.prototype._serializeTextNode = function (node) {
      var content = this.treeAdapter.getTextNodeContent(node),
          parent = this.treeAdapter.getParentNode(node),
          parentTn = void 0;
  
      if (parent && this.treeAdapter.isElementNode(parent))
          parentTn = this.treeAdapter.getTagName(parent);
  
      if (parentTn === $.STYLE || parentTn === $.SCRIPT || parentTn === $.XMP || parentTn === $.IFRAME ||
          parentTn === $.NOEMBED || parentTn === $.NOFRAMES || parentTn === $.PLAINTEXT || parentTn === $.NOSCRIPT)
  
          this.html += content;
  
      else
          this.html += Serializer.escapeString(content, false);
  };
  
  Serializer.prototype._serializeCommentNode = function (node) {
      this.html += '<!--' + this.treeAdapter.getCommentNodeContent(node) + '-->';
  };
  
  Serializer.prototype._serializeDocumentTypeNode = function (node) {
      var name = this.treeAdapter.getDocumentTypeNodeName(node);
  
      this.html += '<' + doctype.serializeContent(name, null, null) + '>';
  };
  