var conventions = require("./conventions");

var find = conventions.find;
var NAMESPACE = conventions.NAMESPACE;

/**
 * A prerequisite for `[].filter`, to drop elements that are empty
 * @param {string} input
 * @returns {boolean}
 */
function notEmptyString (input) {
	return input !== ''
}
/**
 * @see https://infra.spec.whatwg.org/#split-on-ascii-whitespace
 * @see https://infra.spec.whatwg.org/#ascii-whitespace
 *
 * @param {string} input
 * @returns {string[]} (can be empty)
 */
function splitOnASCIIWhitespace(input) {
	// U+0009 TAB, U+000A LF, U+000C FF, U+000D CR, U+0020 SPACE
	return input ? input.split(/[\t\n\f\r ]+/).filter(notEmptyString) : []
}

/**
 * Adds element as a key to current if it is not already present.
 *
 * @param {Record<string, boolean | undefined>} current
 * @param {string} element
 * @returns {Record<string, boolean | undefined>}
 */
function orderedSetReducer (current, element) {
	if (!current.hasOwnProperty(element)) {
		current[element] = true;
	}
	return current;
}

/**
 * @see https://infra.spec.whatwg.org/#ordered-set
 * @param {string} input
 * @returns {string[]}
 */
function toOrderedSet(input) {
	if (!input) return [];
	var list = splitOnASCIIWhitespace(input);
	return Object.keys(list.reduce(orderedSetReducer, {}))
}

/**
 * Uses `list.indexOf` to implement something like `Array.prototype.includes`,
 * which we can not rely on being available.
 *
 * @param {any[]} list
 * @returns {function(any): boolean}
 */
function arrayIncludes (list) {
	return function(element) {
		return list && list.indexOf(element) !== -1;
	}
}

function copy(src,dest){
	for(var p in src){
		if (Object.prototype.hasOwnProperty.call(src, p)) {
			dest[p] = src[p];
		}
	}
}

/**
^\w+\.prototype\.([_\w]+)\s*=\s*((?:.*\{\s*?[\r\n][\s\S]*?^})|\S.*?(?=[;\r\n]));?
^\w+\.prototype\.([_\w]+)\s*=\s*(\S.*?(?=[;\r\n]));?
 */
function _extends(Class,Super){
	var pt = Class.prototype;
	if(!(pt instanceof Super)){
		function t(){};
		t.prototype = Super.prototype;
		t = new t();
		copy(pt,t);
		Class.prototype = pt = t;
	}
	if(pt.constructor != Class){
		if(typeof Class != 'function'){
			console.error("unknown Class:"+Class)
		}
		pt.constructor = Class
	}
}

// Node Types
var NodeType = {}
var ELEMENT_NODE                = NodeType.ELEMENT_NODE                = 1;
var ATTRIBUTE_NODE              = NodeType.ATTRIBUTE_NODE              = 2;
var TEXT_NODE                   = NodeType.TEXT_NODE                   = 3;
var CDATA_SECTION_NODE          = NodeType.CDATA_SECTION_NODE          = 4;
var ENTITY_REFERENCE_NODE       = NodeType.ENTITY_REFERENCE_NODE       = 5;
var ENTITY_NODE                 = NodeType.ENTITY_NODE                 = 6;
var PROCESSING_INSTRUCTION_NODE = NodeType.PROCESSING_INSTRUCTION_NODE = 7;
var COMMENT_NODE                = NodeType.COMMENT_NODE                = 8;
var DOCUMENT_NODE               = NodeType.DOCUMENT_NODE               = 9;
var DOCUMENT_TYPE_NODE          = NodeType.DOCUMENT_TYPE_NODE          = 10;
var DOCUMENT_FRAGMENT_NODE      = NodeType.DOCUMENT_FRAGMENT_NODE      = 11;
var NOTATION_NODE               = NodeType.NOTATION_NODE               = 12;

// ExceptionCode
var ExceptionCode = {}
var ExceptionMessage = {};
var INDEX_SIZE_ERR              = ExceptionCode.INDEX_SIZE_ERR              = ((ExceptionMessage[1]="Index size error"),1);
var DOMSTRING_SIZE_ERR          = ExceptionCode.DOMSTRING_SIZE_ERR          = ((ExceptionMessage[2]="DOMString size error"),2);
var HIERARCHY_REQUEST_ERR       = ExceptionCode.HIERARCHY_REQUEST_ERR       = ((ExceptionMessage[3]="Hierarchy request error"),3);
var WRONG_DOCUMENT_ERR          = ExceptionCode.WRONG_DOCUMENT_ERR          = ((ExceptionMessage[4]="Wrong document"),4);
var INVALID_CHARACTER_ERR       = ExceptionCode.INVALID_CHARACTER_ERR       = ((ExceptionMessage[5]="Invalid character"),5);
var NO_DATA_ALLOWED_ERR         = ExceptionCode.NO_DATA_ALLOWED_ERR         = ((ExceptionMessage[6]="No data allowed"),6);
var NO_MODIFICATION_ALLOWED_ERR = ExceptionCode.NO_MODIFICATION_ALLOWED_ERR = ((ExceptionMessage[7]="No modification allowed"),7);
var NOT_FOUND_ERR               = ExceptionCode.NOT_FOUND_ERR               = ((ExceptionMessage[8]="Not found"),8);
var NOT_SUPPORTED_ERR           = ExceptionCode.NOT_SUPPORTED_ERR           = ((ExceptionMessage[9]="Not supported"),9);
var INUSE_ATTRIBUTE_ERR         = ExceptionCode.INUSE_ATTRIBUTE_ERR         = ((ExceptionMessage[10]="Attribute in use"),10);
//level2
var INVALID_STATE_ERR        	= ExceptionCode.INVALID_STATE_ERR        	= ((ExceptionMessage[11]="Invalid state"),11);
var SYNTAX_ERR               	= ExceptionCode.SYNTAX_ERR               	= ((ExceptionMessage[12]="Syntax error"),12);
var INVALID_MODIFICATION_ERR 	= ExceptionCode.INVALID_MODIFICATION_ERR 	= ((ExceptionMessage[13]="Invalid modification"),13);
var NAMESPACE_ERR            	= ExceptionCode.NAMESPACE_ERR           	= ((ExceptionMessage[14]="Invalid namespace"),14);
var INVALID_ACCESS_ERR       	= ExceptionCode.INVALID_ACCESS_ERR      	= ((ExceptionMessage[15]="Invalid access"),15);

/**
 * DOM Level 2
 * Object DOMException
 * @see http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/ecma-script-binding.html
 * @see http://www.w3.org/TR/REC-DOM-Level-1/ecma-script-language-binding.html
 */
function DOMException(code, message) {
	if(message instanceof Error){
		var error = message;
	}else{
		error = this;
		Error.call(this, ExceptionMessage[code]);
		this.message = ExceptionMessage[code];
		if(Error.captureStackTrace) Error.captureStackTrace(this, DOMException);
	}
	error.code = code;
	if(message) this.message = this.message + ": " + message;
	return error;
};
DOMException.prototype = Error.prototype;
copy(ExceptionCode,DOMException)

/**
 * @see http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/core.html#ID-536297177
 * The NodeList interface provides the abstraction of an ordered collection of nodes, without defining or constraining how this collection is implemented. NodeList objects in the DOM are live.
 * The items in the NodeList are accessible via an integral index, starting from 0.
 */
function NodeList() {
};
NodeList.prototype = {
	/**
	 * The number of nodes in the list. The range of valid child node indices is 0 to length-1 inclusive.
	 * @standard level1
	 */
	length:0,
	/**
	 * Returns the indexth item in the collection. If index is greater than or equal to the number of nodes in the list, this returns null.
	 * @standard level1
	 * @param index  unsigned long
	 *   Index into the collection.
	 * @return Node
	 * 	The node at the indexth position in the NodeList, or null if that is not a valid index.
	 */
	item: function(index) {
		return this[index] || null;
	},
	toString:function(isHTML,nodeFilter){
		for(var buf = [], i = 0;i<this.length;i++){
			serializeToString(this[i],buf,isHTML,nodeFilter);
		}
		return buf.join('');
	},
	/**
	 * @private
	 * @param {function (Node):boolean} predicate
	 * @returns {Node[]}
	 */
	filter: function (predicate) {
		return Array.prototype.filter.call(this, predicate);
	},
	/**
	 * @private
	 * @param {Node} item
	 * @returns {number}
	 */
	indexOf: function (item) {
		return Array.prototype.indexOf.call(this, item);
	},
};

function LiveNodeList(node,refresh){
	this._node = node;
	this._refresh = refresh
	_updateLiveList(this);
}
function _updateLiveList(list){
	var inc = list._node._inc || list._node.ownerDocument._inc;
	if(list._inc != inc){
		var ls = list._refresh(list._node);
		//console.log(ls.length)
		__set__(list,'length',ls.length);
		copy(ls,list);
		list._inc = inc;
	}
}
LiveNodeList.prototype.item = function(i){
	_updateLiveList(this);
	return this[i];
}

_extends(LiveNodeList,NodeList);

/**
 * Objects implementing the NamedNodeMap interface are used
 * to represent collections of nodes that can be accessed by name.
 * Note that NamedNodeMap does not inherit from NodeList;
 * NamedNodeMaps are not maintained in any particular order.
 * Objects contained in an object implementing NamedNodeMap may also be accessed by an ordinal index,
 * but this is simply to allow convenient enumeration of the contents of a NamedNodeMap,
 * and does not imply that the DOM specifies an order to these Nodes.
 * NamedNodeMap objects in the DOM are live.
 * used for attributes or DocumentType entities
 */
function NamedNodeMap() {
};

function _findNodeIndex(list,node){
	var i = list.length;
	while(i--){
		if(list[i] === node){return i}
	}
}

function _addNamedNode(el,list,newAttr,oldAttr){
	if(oldAttr){
		list[_findNodeIndex(list,oldAttr)] = newAttr;
	}else{
		list[list.length++] = newAttr;
	}
	if(el){
		newAttr.ownerElement = el;
		var doc = el.ownerDocument;
		if(doc){
			oldAttr && _onRemoveAttribute(doc,el,oldAttr);
			_onAddAttribute(doc,el,newAttr);
		}
	}
}
function _removeNamedNode(el,list,attr){
	//console.log('remove attr:'+attr)
	var i = _findNodeIndex(list,attr);
	if(i>=0){
		var lastIndex = list.length-1
		while(i<lastIndex){
			list[i] = list[++i]
		}
		list.length = lastIndex;
		if(el){
			var doc = el.ownerDocument;
			if(doc){
				_onRemoveAttribute(doc,el,attr);
				attr.ownerElement = null;
			}
		}
	}else{
		throw new DOMException(NOT_FOUND_ERR,new Error(el.tagName+'@'+attr))
	}
}
NamedNodeMap.prototype = {
	length:0,
	item:NodeList.prototype.item,
	getNamedItem: function(key) {
//		if(key.indexOf(':')>0 || key == 'xmlns'){
//			return null;
//		}
		//console.log()
		var i = this.length;
		while(i--){
			var attr = this[i];
			//console.log(attr.nodeName,key)
			if(attr.nodeName == key){
				return attr;
			}
		}
	},
	setNamedItem: function(attr) {
		var el = attr.ownerElement;
		if(el && el!=this._ownerElement){
			throw new DOMException(INUSE_ATTRIBUTE_ERR);
		}
		var oldAttr = this.getNamedItem(attr.nodeName);
		_addNamedNode(this._ownerElement,this,attr,oldAttr);
		return oldAttr;
	},
	/* returns Node */
	setNamedItemNS: function(attr) {// raises: WRONG_DOCUMENT_ERR,NO_MODIFICATION_ALLOWED_ERR,INUSE_ATTRIBUTE_ERR
		var el = attr.ownerElement, oldAttr;
		if(el && el!=this._ownerElement){
			throw new DOMException(INUSE_ATTRIBUTE_ERR);
		}
		oldAttr = this.getNamedItemNS(attr.namespaceURI,attr.localName);
		_addNamedNode(this._ownerElement,this,attr,oldAttr);
		return oldAttr;
	},

	/* returns Node */
	removeNamedItem: function(key) {
		var attr = this.getNamedItem(key);
		_removeNamedNode(this._ownerElement,this,attr);
		return attr;


	},// raises: NOT_FOUND_ERR,NO_MODIFICATION_ALLOWED_ERR

	//for level2
	removeNamedItemNS:function(namespaceURI,localName){
		var attr = this.getNamedItemNS(namespaceURI,localName);
		_removeNamedNode(this._ownerElement,this,attr);
		return attr;
	},
	getNamedItemNS: function(namespaceURI, localName) {
		var i = this.length;
		while(i--){
			var node = this[i];
			if(node.localName == localName && node.namespaceURI == namespaceURI){
				return node;
			}
		}
		return null;
	}
};

/**
 * The DOMImplementation interface represents an object providing methods
 * which are not dependent on any particular document.
 * Such an object is returned by the `Document.implementation` property.
 *
 * __The individual methods describe the differences compared to the specs.__
 *
 * @constructor
 *
 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation MDN
 * @see https://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-102161490 DOM Level 1 Core (Initial)
 * @see https://www.w3.org/TR/DOM-Level-2-Core/core.html#ID-102161490 DOM Level 2 Core
 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-102161490 DOM Level 3 Core
 * @see https://dom.spec.whatwg.org/#domimplementation DOM Living Standard
 */
function DOMImplementation() {
}

DOMImplementation.prototype = {
	/**
	 * The DOMImplementation.hasFeature() method returns a Boolean flag indicating if a given feature is supported.
	 * The different implementations fairly diverged in what kind of features were reported.
	 * The latest version of the spec settled to force this method to always return true, where the functionality was accurate and in use.
	 *
	 * @deprecated It is deprecated and modern browsers return true in all cases.
	 *
	 * @param {string} feature
	 * @param {string} [version]
	 * @returns {boolean} always true
	 *
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation/hasFeature MDN
	 * @see https://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#ID-5CED94D7 DOM Level 1 Core
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-hasfeature DOM Living Standard
	 */
	hasFeature: function(feature, version) {
			return true;
	},
	/**
	 * Creates an XML Document object of the specified type with its document element.
	 *
	 * __It behaves slightly different from the description in the living standard__:
	 * - There is no interface/class `XMLDocument`, it returns a `Document` instance.
	 * - `contentType`, `encoding`, `mode`, `origin`, `url` fields are currently not declared.
	 * - this implementation is not validating names or qualified names
	 *   (when parsing XML strings, the SAX parser takes care of that)
	 *
	 * @param {string|null} namespaceURI
	 * @param {string} qualifiedName
	 * @param {DocumentType=null} doctype
	 * @returns {Document}
	 *
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation/createDocument MDN
	 * @see https://www.w3.org/TR/DOM-Level-2-Core/core.html#Level-2-Core-DOM-createDocument DOM Level 2 Core (initial)
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-createdocument  DOM Level 2 Core
	 *
	 * @see https://dom.spec.whatwg.org/#validate-and-extract DOM: Validate and extract
	 * @see https://www.w3.org/TR/xml/#NT-NameStartChar XML Spec: Names
	 * @see https://www.w3.org/TR/xml-names/#ns-qualnames XML Namespaces: Qualified names
	 */
	createDocument: function(namespaceURI,  qualifiedName, doctype){
		var doc = new Document();
		doc.implementation = this;
		doc.childNodes = new NodeList();
		doc.doctype = doctype || null;
		if (doctype){
			doc.appendChild(doctype);
		}
		if (qualifiedName){
			var root = doc.createElementNS(namespaceURI, qualifiedName);
			doc.appendChild(root);
		}
		return doc;
	},
	/**
	 * Returns a doctype, with the given `qualifiedName`, `publicId`, and `systemId`.
	 *
	 * __This behavior is slightly different from the in the specs__:
	 * - this implementation is not validating names or qualified names
	 *   (when parsing XML strings, the SAX parser takes care of that)
	 *
	 * @param {string} qualifiedName
	 * @param {string} [publicId]
	 * @param {string} [systemId]
	 * @returns {DocumentType} which can either be used with `DOMImplementation.createDocument` upon document creation
	 * 				  or can be put into the document via methods like `Node.insertBefore()` or `Node.replaceChild()`
	 *
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMImplementation/createDocumentType MDN
	 * @see https://www.w3.org/TR/DOM-Level-2-Core/core.html#Level-2-Core-DOM-createDocType DOM Level 2 Core
	 * @see https://dom.spec.whatwg.org/#dom-domimplementation-createdocumenttype DOM Living Standard
	 *
	 * @see https://dom.spec.whatwg.org/#validate-and-extract DOM: Validate and extract
	 * @see https://www.w3.org/TR/xml/#NT-NameStartChar XML Spec: Names
	 * @see https://www.w3.org/TR/xml-names/#ns-qualnames XML Namespaces: Qualified names
	 */
	createDocumentType: function(qualifiedName, publicId, systemId){
		var node = new DocumentType();
		node.name = qualifiedName;
		node.nodeName = qualifiedName;
		node.publicId = publicId || '';
		node.systemId = systemId || '';

		return node;
	}
};


/**
 * @see http://www.w3.org/TR/2000/REC-DOM-Level-2-Core-20001113/core.html#ID-1950641247
 */

function Node() {
};

Node.prototype = {
	firstChild : null,
	lastChild : null,
	previousSibling : null,
	nextSibling : null,
	attributes : null,
	parentNode : null,
	childNodes : null,
	ownerDocument : null,
	nodeValue : null,
	namespaceURI : null,
	prefix : null,
	localName : null,
	// Modified in DOM Level 2:
	insertBefore:function(newChild, refChild){//raises
		return _insertBefore(this,newChild,refChild);
	},
	replaceChild:function(newChild, oldChild){//raises
		_insertBefore(this, newChild,oldChild, assertPreReplacementValidityInDocument);
		if(oldChild){
			this.removeChild(oldChild);
		}
	},
	removeChild:function(oldChild){
		return _removeChild(this,oldChild);
	},
	appendChild:function(newChild){
		return this.insertBefore(newChild,null);
	},
	hasChildNodes:function(){
		return this.firstChild != null;
	},
	cloneNode:function(deep){
		return cloneNode(this.ownerDocument||this,this,deep);
	},
	// Modified in DOM Level 2:
	normalize:function(){
		var child = this.firstChild;
		while(child){
			var next = child.nextSibling;
			if(next && next.nodeType == TEXT_NODE && child.nodeType == TEXT_NODE){
				this.removeChild(next);
				child.appendData(next.data);
			}else{
				child.normalize();
				child = next;
			}
		}
	},
  	// Introduced in DOM Level 2:
	isSupported:function(feature, version){
		return this.ownerDocument.implementation.hasFeature(feature,version);
	},
    // Introduced in DOM Level 2:
    hasAttributes:function(){
    	return this.attributes.length>0;
    },
	/**
	 * Look up the prefix associated to the given namespace URI, starting from this node.
	 * **The default namespace declarations are ignored by this method.**
	 * See Namespace Prefix Lookup for details on the algorithm used by this method.
	 *
	 * _Note: The implementation seems to be incomplete when compared to the algorithm described in the specs._
	 *
	 * @param {string | null} namespaceURI
	 * @returns {string | null}
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-lookupNamespacePrefix
	 * @see https://www.w3.org/TR/DOM-Level-3-Core/namespaces-algorithms.html#lookupNamespacePrefixAlgo
	 * @see https://dom.spec.whatwg.org/#dom-node-lookupprefix
	 * @see https://github.com/xmldom/xmldom/issues/322
	 */
    lookupPrefix:function(namespaceURI){
    	var el = this;
    	while(el){
    		var map = el._nsMap;
    		//console.dir(map)
    		if(map){
    			for(var n in map){
					if (Object.prototype.hasOwnProperty.call(map, n) && map[n] === namespaceURI) {
						return n;
					}
    			}
    		}
    		el = el.nodeType == ATTRIBUTE_NODE?el.ownerDocument : el.parentNode;
    	}
    	return null;
    },
    // Introduced in DOM Level 3:
    lookupNamespaceURI:function(prefix){
    	var el = this;
    	while(el){
    		var map = el._nsMap;
    		//console.dir(map)
    		if(map){
    			if(prefix in map){
					if(Object.prototype.hasOwnProperty.call(map, prefix)){
						return map[prefix] ;
					}
    			}
    		}
    		el = el.nodeType == ATTRIBUTE_NODE?el.ownerDocument : el.parentNode;
    	}
    	return null;
    },
    // Introduced in DOM Level 3:
    isDefaultNamespace:function(namespaceURI){
    	var prefix = this.lookupPrefix(namespaceURI);
    	return prefix == null;
    }
};


function _xmlEncoder(c){
	return c == '<' && '&lt;' ||
         c == '>' && '&gt;' ||
         c == '&' && '&amp;' ||
         c == '"' && '&quot;' ||
         '&#'+c.charCodeAt()+';'
}


copy(NodeType,Node);
copy(NodeType,Node.prototype);

/**
 * @param callback return true for continue,false for break
 * @return boolean true: break visit;
 */
function _visitNode(node,callback){
	if(callback(node)){
		return true;
	}
	if(node = node.firstChild){
		do{
			if(_visitNode(node,callback)){return true}
        }while(node=node.nextSibling)
    }
}



function Document(){
	this.ownerDocument = this;
}

function _onAddAttribute(doc,el,newAttr){
	doc && doc._inc++;
	var ns = newAttr.namespaceURI ;
	if(ns === NAMESPACE.XMLNS){
		//update namespace
		el._nsMap[newAttr.prefix?newAttr.localName:''] = newAttr.value
	}
}

function _onRemoveAttribute(doc,el,newAttr,remove){
	doc && doc._inc++;
	var ns = newAttr.namespaceURI ;
	if(ns === NAMESPACE.XMLNS){
		//update namespace
		delete el._nsMap[newAttr.prefix?newAttr.localName:'']
	}
}

function _onUpdateChild(doc,el,newChild){
	if(doc && doc._inc){
		doc._inc++;
		//update childNodes
		var cs = el.childNodes;
		if(newChild){
			cs[cs.length++] = newChild;
		}else{
			//console.log(1)
			var child = el.firstChild;
			var i = 0;
			while(child){
				cs[i++] = child;
				child =child.nextSibling;
			}
			cs.length = i;
			delete cs[cs.length];
		}
	}
}

/**
 * attributes;
 * children;
 *
 * writeable properties:
 * nodeValue,Attr:value,CharacterData:data
 * prefix
 */
function _removeChild(parentNode,child){
	var previous = child.previousSibling;
	var next = child.nextSibling;
	if(previous){
		previous.nextSibling = next;
	}else{
		parentNode.firstChild = next
	}
	if(next){
		next.previousSibling = previous;
	}else{
		parentNode.lastChild = previous;
	}
	child.parentNode = null;
	child.previousSibling = null;
	child.nextSibling = null;
	_onUpdateChild(parentNode.ownerDocument,parentNode);
	return child;
}

/**
 * Returns `true` if `node` can be a parent for insertion.
 * @param {Node} node
 * @returns {boolean}
 */
function hasValidParentNodeType(node) {
	return (
		node &&
		(node.nodeType === Node.DOCUMENT_NODE || node.nodeType === Node.DOCUMENT_FRAGMENT_NODE || node.nodeType === Node.ELEMENT_NODE)
	);
}

/**
 * Returns `true` if `node` can be inserted according to it's `nodeType`.
 * @param {Node} node
 * @returns {boolean}
 */
function hasInsertableNodeType(node) {
	return (
		node &&
		(isElementNode(node) ||
			isTextNode(node) ||
			isDocTypeNode(node) ||
			node.nodeType === Node.DOCUMENT_FRAGMENT_NODE ||
			node.nodeType === Node.COMMENT_NODE ||
			node.nodeType === Node.PROCESSING_INSTRUCTION_NODE)
	);
}

/**
 * Returns true if `node` is a DOCTYPE node
 * @param {Node} node
 * @returns {boolean}
 */
function isDocTypeNode(node) {
	return node && node.nodeType === Node.DOCUMENT_TYPE_NODE;
}

/**
 * Returns true if the node is an element
 * @param {Node} node
 * @returns {boolean}
 */
function isElementNode(node) {
	return node && node.nodeType === Node.ELEMENT_NODE;
}
/**
 * Returns true if `node` is a text node
 * @param {Node} node
 * @returns {boolean}
 */
function isTextNode(node) {
	return node && node.nodeType === Node.TEXT_NODE;
}

/**
 * Check if en element node can be inserted before `child`, or at the end if child is falsy,
 * according to the presence and position of a doctype node on the same level.
 *
 * @param {Document} doc The document node
 * @param {Node} child the node that would become the nextSibling if the element would be inserted
 * @returns {boolean} `true` if an element can be inserted before child
 * @private
 * https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity
 */
function isElementInsertionPossible(doc, child) {
	var parentChildNodes = doc.childNodes || [];
	if (find(parentChildNodes, isElementNode) || isDocTypeNode(child)) {
		return false;
	}
	var docTypeNode = find(parentChildNodes, isDocTypeNode);
	return !(child && docTypeNode && parentChildNodes.indexOf(docTypeNode) > parentChildNodes.indexOf(child));
}

/**
 * Check if en element node can be inserted before `child`, or at the end if child is falsy,
 * according to the presence and position of a doctype node on the same level.
 *
 * @param {Node} doc The document node
 * @param {Node} child the node that would become the nextSibling if the element would be inserted
 * @returns {boolean} `true` if an element can be inserted before child
 * @private
 * https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity
 */
function isElementReplacementPossible(doc, child) {
	var parentChildNodes = doc.childNodes || [];

	function hasElementChildThatIsNotChild(node) {
		return isElementNode(node) && node !== child;
	}

	if (find(parentChildNodes, hasElementChildThatIsNotChild)) {
		return false;
	}
	var docTypeNode = find(parentChildNodes, isDocTypeNode);
	return !(child && docTypeNode && parentChildNodes.indexOf(docTypeNode) > parentChildNodes.indexOf(child));
}

/**
 * @private
 * Steps 1-5 of the checks before inserting and before replacing a child are the same.
 *
 * @param {Node} parent the parent node to insert `node` into
 * @param {Node} node the node to insert
 * @param {Node=} child the node that should become the `nextSibling` of `node`
 * @returns {Node}
 * @throws DOMException for several node combinations that would create a DOM that is not well-formed.
 * @throws DOMException if `child` is provided but is not a child of `parent`.
 * @see https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity
 * @see https://dom.spec.whatwg.org/#concept-node-replace
 */
function assertPreInsertionValidity1to5(parent, node, child) {
	// 1. If `parent` is not a Document, DocumentFragment, or Element node, then throw a "HierarchyRequestError" DOMException.
	if (!hasValidParentNodeType(parent)) {
		throw new DOMException(HIERARCHY_REQUEST_ERR, 'Unexpected parent node type ' + parent.nodeType);
	}
	// 2. If `node` is a host-including inclusive ancestor of `parent`, then throw a "HierarchyRequestError" DOMException.
	// not implemented!
	// 3. If `child` is non-null and its parent is not `parent`, then throw a "NotFoundError" DOMException.
	if (child && child.parentNode !== parent) {
		throw new DOMException(NOT_FOUND_ERR, 'child not in parent');
	}
	if (
		// 4. If `node` is not a DocumentFragment, DocumentType, Element, or CharacterData node, then throw a "HierarchyRequestError" DOMException.
		!hasInsertableNodeType(node) ||
		// 5. If either `node` is a Text node and `parent` is a document,
		// the sax parser currently adds top level text nodes, this will be fixed in 0.9.0
		// || (node.nodeType === Node.TEXT_NODE && parent.nodeType === Node.DOCUMENT_NODE)
		// or `node` is a doctype and `parent` is not a document, then throw a "HierarchyRequestError" DOMException.
		(isDocTypeNode(node) && parent.nodeType !== Node.DOCUMENT_NODE)
	) {
		throw new DOMException(
			HIERARCHY_REQUEST_ERR,
			'Unexpected node type ' + node.nodeType + ' for parent node type ' + parent.nodeType
		);
	}
}

/**
 * @private
 * Step 6 of the checks before inserting and before replacing a child are different.
 *
 * @param {Document} parent the parent node to insert `node` into
 * @param {Node} node the node to insert
 * @param {Node | undefined} child the node that should become the `nextSibling` of `node`
 * @returns {Node}
 * @throws DOMException for several node combinations that would create a DOM that is not well-formed.
 * @throws DOMException if `child` is provided but is not a child of `parent`.
 * @see https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity
 * @see https://dom.spec.whatwg.org/#concept-node-replace
 */
function assertPreInsertionValidityInDocument(parent, node, child) {
	var parentChildNodes = parent.childNodes || [];
	var nodeChildNodes = node.childNodes || [];

	// DocumentFragment
	if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE) {
		var nodeChildElements = nodeChildNodes.filter(isElementNode);
		// If node has more than one element child or has a Text node child.
		if (nodeChildElements.length > 1 || find(nodeChildNodes, isTextNode)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'More than one element or text in fragment');
		}
		// Otherwise, if `node` has one element child and either `parent` has an element child,
		// `child` is a doctype, or `child` is non-null and a doctype is following `child`.
		if (nodeChildElements.length === 1 && !isElementInsertionPossible(parent, child)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Element in fragment can not be inserted before doctype');
		}
	}
	// Element
	if (isElementNode(node)) {
		// `parent` has an element child, `child` is a doctype,
		// or `child` is non-null and a doctype is following `child`.
		if (!isElementInsertionPossible(parent, child)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Only one element can be added and only after doctype');
		}
	}
	// DocumentType
	if (isDocTypeNode(node)) {
		// `parent` has a doctype child,
		if (find(parentChildNodes, isDocTypeNode)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Only one doctype is allowed');
		}
		var parentElementChild = find(parentChildNodes, isElementNode);
		// `child` is non-null and an element is preceding `child`,
		if (child && parentChildNodes.indexOf(parentElementChild) < parentChildNodes.indexOf(child)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Doctype can only be inserted before an element');
		}
		// or `child` is null and `parent` has an element child.
		if (!child && parentElementChild) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Doctype can not be appended since element is present');
		}
	}
}

/**
 * @private
 * Step 6 of the checks before inserting and before replacing a child are different.
 *
 * @param {Document} parent the parent node to insert `node` into
 * @param {Node} node the node to insert
 * @param {Node | undefined} child the node that should become the `nextSibling` of `node`
 * @returns {Node}
 * @throws DOMException for several node combinations that would create a DOM that is not well-formed.
 * @throws DOMException if `child` is provided but is not a child of `parent`.
 * @see https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity
 * @see https://dom.spec.whatwg.org/#concept-node-replace
 */
function assertPreReplacementValidityInDocument(parent, node, child) {
	var parentChildNodes = parent.childNodes || [];
	var nodeChildNodes = node.childNodes || [];

	// DocumentFragment
	if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE) {
		var nodeChildElements = nodeChildNodes.filter(isElementNode);
		// If `node` has more than one element child or has a Text node child.
		if (nodeChildElements.length > 1 || find(nodeChildNodes, isTextNode)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'More than one element or text in fragment');
		}
		// Otherwise, if `node` has one element child and either `parent` has an element child that is not `child` or a doctype is following `child`.
		if (nodeChildElements.length === 1 && !isElementReplacementPossible(parent, child)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Element in fragment can not be inserted before doctype');
		}
	}
	// Element
	if (isElementNode(node)) {
		// `parent` has an element child that is not `child` or a doctype is following `child`.
		if (!isElementReplacementPossible(parent, child)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Only one element can be added and only after doctype');
		}
	}
	// DocumentType
	if (isDocTypeNode(node)) {
		function hasDoctypeChildThatIsNotChild(node) {
			return isDocTypeNode(node) && node !== child;
		}

		// `parent` has a doctype child that is not `child`,
		if (find(parentChildNodes, hasDoctypeChildThatIsNotChild)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Only one doctype is allowed');
		}
		var parentElementChild = find(parentChildNodes, isElementNode);
		// or an element is preceding `child`.
		if (child && parentChildNodes.indexOf(parentElementChild) < parentChildNodes.indexOf(child)) {
			throw new DOMException(HIERARCHY_REQUEST_ERR, 'Doctype can only be inserted before an element');
		}
	}
}

/**
 * @private
 * @param {Node} parent the parent node to insert `node` into
 * @param {Node} node the node to insert
 * @param {Node=} child the node that should become the `nextSibling` of `node`
 * @returns {Node}
 * @throws DOMException for several node combinations that would create a DOM that is not well-formed.
 * @throws DOMException if `child` is provided but is not a child of `parent`.
 * @see https://dom.spec.whatwg.org/#concept-node-ensure-pre-insertion-validity
 */
function _insertBefore(parent, node, child, _inDocumentAssertion) {
	// To ensure pre-insertion validity of a node into a parent before a child, run these steps:
	assertPreInsertionValidity1to5(parent, node, child);

	// If parent is a document, and any of the statements below, switched on the interface node implements,
	// are true, then throw a "HierarchyRequestError" DOMException.
	if (parent.nodeType === Node.DOCUMENT_NODE) {
		(_inDocumentAssertion || assertPreInsertionValidityInDocument)(parent, node, child);
	}

	var cp = node.parentNode;
	if(cp){
		cp.removeChild(node);//remove and update
	}
	if(node.nodeType === DOCUMENT_FRAGMENT_NODE){
		var newFirst = node.firstChild;
		if (newFirst == null) {
			return node;
		}
		var newLast = node.lastChild;
	}else{
		newFirst = newLast = node;
	}
	var pre = child ? child.previousSibling : parent.lastChild;

	newFirst.previousSibling = pre;
	newLast.nextSibling = child;


	if(pre){
		pre.nextSibling = newFirst;
	}else{
		parent.firstChild = newFirst;
	}
	if(child == null){
		parent.lastChild = newLast;
	}else{
		child.previousSibling = newLast;
	}
	do{
		newFirst.parentNode = parent;
	}while(newFirst !== newLast && (newFirst= newFirst.nextSibling))
	_onUpdateChild(parent.ownerDocument||parent, parent);
	//console.log(parent.lastChild.nextSibling == null)
	if (node.nodeType == DOCUMENT_FRAGMENT_NODE) {
		node.firstChild = node.lastChild = null;
	}
	return node;
}
function _appendSingleChild(parentNode,newChild){
	if (newChild.parentNode) {
		newChild.parentNode.removeChild(newChild);
	}
	newChild.parentNode = parentNode;
	newChild.previousSibling = parentNode.lastChild;
	newChild.nextSibling = null;
	if (newChild.previousSibling) {
		newChild.previousSibling.nextSibling = newChild;
	}else{
		parentNode.firstChild = newChild;
	}
	parentNode.lastChild = newChild;
	_onUpdateChild(parentNode.ownerDocument,parentNode,newChild);
	return newChild;
}

Document.prototype = {
	//implementation : null,
	nodeName :  '#document',
	nodeType :  DOCUMENT_NODE,
	/**
	 * The DocumentType node of the document.
	 *
	 * @readonly
	 * @type DocumentType
	 */
	doctype :  null,
	documentElement :  null,
	_inc : 1,

	insertBefore :  function(newChild, refChild){//raises
		if(newChild.nodeType == DOCUMENT_FRAGMENT_NODE){
			var child = newChild.firstChild;
			while(child){
				var next = child.nextSibling;
				this.insertBefore(child,refChild);
				child = next;
			}
			return newChild;
		}
		_insertBefore(this, newChild, refChild);
		newChild.ownerDocument = this;
		if (this.documentElement === null && newChild.nodeType === ELEMENT_NODE) {
			this.documentElement = newChild;
		}

		return newChild;
	},
	removeChild :  function(oldChild){
		if(this.documentElement == oldChild){
			this.documentElement = null;
		}
		return _removeChild(this,oldChild);
	},
	replaceChild: function (newChild, oldChild) {
		//raises
		_insertBefore(this, newChild, oldChild, assertPreReplacementValidityInDocument);
		newChild.ownerDocument = this;
		if (oldChild) {
			this.removeChild(oldChild);
		}
		if (isElementNode(newChild)) {
			this.documentElement = newChild;
		}
	},
	// Introduced in DOM Level 2:
	importNode : function(importedNode,deep){
		return importNode(this,importedNode,deep);
	},
	// Introduced in DOM Level 2:
	getElementById :	function(id){
		var rtv = null;
		_visitNode(this.documentElement,function(node){
			if(node.nodeType == ELEMENT_NODE){
				if(node.getAttribute('id') == id){
					rtv = node;
					return true;
				}
			}
		})
		return rtv;
	},

	/**
	 * The `getElementsByClassName` method of `Document` interface returns an array-like object
	 * of all child elements which have **all** of the given class name(s).
	 *
	 * Returns an empty list if `classeNames` is an empty string or only contains HTML white space characters.
	 *
	 *
	 * Warning: This is a live LiveNodeList.
	 * Changes in the DOM will reflect in the array as the changes occur.
	 * If an element selected by this array no longer qualifies for the selector,
	 * it will automatically be removed. Be aware of this for iteration purposes.
	 *
	 * @param {string} classNames is a string representing the class name(s) to match; multiple class names are separated by (ASCII-)whitespace
	 *
	 * @see https://developer.mozilla.org/en-US/docs/Web/API/Document/getElementsByClassName
	 * @see https://dom.spec.whatwg.org/#concept-getelementsbyclassname
	 */
	getElementsByClassName: function(classNames) {
		var classNamesSet = toOrderedSet(classNames)
		return new LiveNodeList(this, function(base) {
			var ls = [];
			if (classNamesSet.length > 0) {
				_visitNode(base.documentElement, function(node) {
					if(node !== base && node.nodeType === ELEMENT_NODE) {
						var nodeClassNames = node.getAttribute('class')
						// can be null if the attribute does not exist
						if (nodeClassNames) {
							// before splitting and iterating just compare them for the most common case
							var matches = classNames === nodeClassNames;
							if (!matches) {
								var nodeClassNamesSet = toOrderedSet(nodeClassNames)
								matches = classNamesSet.every(arrayIncludes(nodeClassNamesSet))
							}
							if(matches) {
								ls.push(node);
							}
						}
					}
				});
			}
			return ls;
		});
	},

	//document factory method:
	createElement :	function(tagName){
		var node = new Element();
		node.ownerDocument = this;
		node.nodeName = tagName;
		node.tagName = tagName;
		node.localName = tagName;
		node.childNodes = new NodeList();
		var attrs	= node.attributes = new NamedNodeMap();
		attrs._ownerElement = node;
		return node;
	},
	createDocumentFragment :	function(){
		var node = new DocumentFragment();
		node.ownerDocument = this;
		node.childNodes = new NodeList();
		return node;
	},
	createTextNode :	function(data){
		var node = new Text();
		node.ownerDocument = this;
		node.appendData(data)
		return node;
	},
	createComment :	function(data){
		var node = new Comment();
		node.ownerDocument = this;
		node.appendData(data)
		return node;
	},
	createCDATASection :	function(data){
		var node = new CDATASection();
		node.ownerDocument = this;
		node.appendData(data)
		return node;
	},
	createProcessingInstruction :	function(target,data){
		var node = new ProcessingInstruction();
		node.ownerDocument = this;
		node.tagName = node.target = target;
		node.nodeValue= node.data = data;
		return node;
	},
	createAttribute :	function(name){
		var node = new Attr();
		node.ownerDocument	= this;
		node.name = name;
		node.nodeName	= name;
		node.localName = name;
		node.specified = true;
		return node;
	},
	createEntityReference :	function(name){
		var node = new EntityReference();
		node.ownerDocument	= this;
		node.nodeName	= name;
		return node;
	},
	// Introduced in DOM Level 2:
	createElementNS :	function(namespaceURI,qualifiedName){
		var node = new Element();
		var pl = qualifiedName.split(':');
		var attrs	= node.attributes = new NamedNodeMap();
		node.childNodes = new NodeList();
		node.ownerDocument = this;
		node.nodeName = qualifiedName;
		node.tagName = qualifiedName;
		node.namespaceURI = namespaceURI;
		if(pl.length == 2){
			node.prefix = pl[0];
			node.localName = pl[1];
		}else{
			//el.prefix = null;
			node.localName = qualifiedName;
		}
		attrs._ownerElement = node;
		return node;
	},
	// Introduced in DOM Level 2:
	createAttributeNS :	function(namespaceURI,qualifiedName){
		var node = new Attr();
		var pl = qualifiedName.split(':');
		node.ownerDocument = this;
		node.nodeName = qualifiedName;
		node.name = qualifiedName;
		node.namespaceURI = namespaceURI;
		node.specified = true;
		if(pl.length == 2){
			node.prefix = pl[0];
			node.localName = pl[1];
		}else{
			//el.prefix = null;
			node.localName = qualifiedName;
		}
		return node;
	}
};
_extends(Document,Node);


function Element() {
	this._nsMap = {};
};
Element.prototype = {
	nodeType : ELEMENT_NODE,
	hasAttribute : function(name){
		return this.getAttributeNode(name)!=null;
	},
	getAttribute : function(name){
		var attr = this.getAttributeNode(name);
		return attr && attr.value || '';
	},
	getAttributeNode : function(name){
		return this.attributes.getNamedItem(name);
	},
	setAttribute : function(name, value){
		var attr = this.ownerDocument.createAttribute(name);
		attr.value = attr.nodeValue = "" + value;
		this.setAttributeNode(attr)
	},
	removeAttribute : function(name){
		var attr = this.getAttributeNode(name)
		attr && this.removeAttributeNode(attr);
	},

	//four real opeartion method
	appendChild:function(newChild){
		if(newChild.nodeType === DOCUMENT_FRAGMENT_NODE){
			return this.insertBefore(newChild,null);
		}else{
			return _appendSingleChild(this,newChild);
		}
	},
	setAttributeNode : function(newAttr){
		return this.attributes.setNamedItem(newAttr);
	},
	setAttributeNodeNS : function(newAttr){
		return this.attributes.setNamedItemNS(newAttr);
	},
	removeAttributeNode : function(oldAttr){
		//console.log(this == oldAttr.ownerElement)
		return this.attributes.removeNamedItem(oldAttr.nodeName);
	},
	//get real attribute name,and remove it by removeAttributeNode
	removeAttributeNS : function(namespaceURI, localName){
		var old = this.getAttributeNodeNS(namespaceURI, localName);
		old && this.removeAttributeNode(old);
	},

	hasAttributeNS : function(namespaceURI, localName){
		return this.getAttributeNodeNS(namespaceURI, localName)!=null;
	},
	getAttributeNS : function(namespaceURI, localName){
		var attr = this.getAttributeNodeNS(namespaceURI, localName);
		return attr && attr.value || '';
	},
	setAttributeNS : function(namespaceURI, qualifiedName, value){
		var attr = this.ownerDocument.createAttributeNS(namespaceURI, qualifiedName);
		attr.value = attr.nodeValue = "" + value;
		this.setAttributeNode(attr)
	},
	getAttributeNodeNS : function(namespaceURI, localName){
		return this.attributes.getNamedItemNS(namespaceURI, localName);
	},

	getElementsByTagName : function(tagName){
		return new LiveNodeList(this,function(base){
			var ls = [];
			_visitNode(base,function(node){
				if(node !== base && node.nodeType == ELEMENT_NODE && (tagName === '*' || node.tagName == tagName)){
					ls.push(node);
				}
			});
			return ls;
		});
	},
	getElementsByTagNameNS : function(namespaceURI, localName){
		return new LiveNodeList(this,function(base){
			var ls = [];
			_visitNode(base,function(node){
				if(node !== base && node.nodeType === ELEMENT_NODE && (namespaceURI === '*' || node.namespaceURI === namespaceURI) && (localName === '*' || node.localName == localName)){
					ls.push(node);
				}
			});
			return ls;

		});
	}
};
Document.prototype.getElementsByTagName = Element.prototype.getElementsByTagName;
Document.prototype.getElementsByTagNameNS = Element.prototype.getElementsByTagNameNS;


_extends(Element,Node);
function Attr() {
};
Attr.prototype.nodeType = ATTRIBUTE_NODE;
_extends(Attr,Node);


function CharacterData() {
};
CharacterData.prototype = {
	data : '',
	substringData : function(offset, count) {
		return this.data.substring(offset, offset+count);
	},
	appendData: function(text) {
		text = this.data+text;
		this.nodeValue = this.data = text;
		this.length = text.length;
	},
	insertData: function(offset,text) {
		this.replaceData(offset,0,text);

	},
	appendChild:function(newChild){
		throw new Error(ExceptionMessage[HIERARCHY_REQUEST_ERR])
	},
	deleteData: function(offset, count) {
		this.replaceData(offset,count,"");
	},
	replaceData: function(offset, count, text) {
		var start = this.data.substring(0,offset);
		var end = this.data.substring(offset+count);
		text = start + text + end;
		this.nodeValue = this.data = text;
		this.length = text.length;
	}
}
_extends(CharacterData,Node);
function Text() {
};
Text.prototype = {
	nodeName : "#text",
	nodeType : TEXT_NODE,
	splitText : function(offset) {
		var text = this.data;
		var newText = text.substring(offset);
		text = text.substring(0, offset);
		this.data = this.nodeValue = text;
		this.length = text.length;
		var newNode = this.ownerDocument.createTextNode(newText);
		if(this.parentNode){
			this.parentNode.insertBefore(newNode, this.nextSibling);
		}
		return newNode;
	}
}
_extends(Text,CharacterData);
function Comment() {
};
Comment.prototype = {
	nodeName : "#comment",
	nodeType : COMMENT_NODE
}
_extends(Comment,CharacterData);

function CDATASection() {
};
CDATASection.prototype = {
	nodeName : "#cdata-section",
	nodeType : CDATA_SECTION_NODE
}
_extends(CDATASection,CharacterData);


function DocumentType() {
};
DocumentType.prototype.nodeType = DOCUMENT_TYPE_NODE;
_extends(DocumentType,Node);

function Notation() {
};
Notation.prototype.nodeType = NOTATION_NODE;
_extends(Notation,Node);

function Entity() {
};
Entity.prototype.nodeType = ENTITY_NODE;
_extends(Entity,Node);

function EntityReference() {
};
EntityReference.prototype.nodeType = ENTITY_REFERENCE_NODE;
_extends(EntityReference,Node);

function DocumentFragment() {
};
DocumentFragment.prototype.nodeName =	"#document-fragment";
DocumentFragment.prototype.nodeType =	DOCUMENT_FRAGMENT_NODE;
_extends(DocumentFragment,Node);


function ProcessingInstruction() {
}
ProcessingInstruction.prototype.nodeType = PROCESSING_INSTRUCTION_NODE;
_extends(ProcessingInstruction,Node);
function XMLSerializer(){}
XMLSerializer.prototype.serializeToString = function(node,isHtml,nodeFilter){
	return nodeSerializeToString.call(node,isHtml,nodeFilter);
}
Node.prototype.toString = nodeSerializeToString;
function nodeSerializeToString(isHtml,nodeFilter){
	var buf = [];
	var refNode = this.nodeType == 9 && this.documentElement || this;
	var prefix = refNode.prefix;
	var uri = refNode.namespaceURI;

	if(uri && prefix == null){
		//console.log(prefix)
		var prefix = refNode.lookupPrefix(uri);
		if(prefix == null){
			//isHTML = true;
			var visibleNamespaces=[
			{namespace:uri,prefix:null}
			//{namespace:uri,prefix:''}
			]
		}
	}
	serializeToString(this,buf,isHtml,nodeFilter,visibleNamespaces);
	//console.log('###',this.nodeType,uri,prefix,buf.join(''))
	return buf.join('');
}

function needNamespaceDefine(node, isHTML, visibleNamespaces) {
	var prefix = node.prefix || '';
	var uri = node.namespaceURI;
	// According to [Namespaces in XML 1.0](https://www.w3.org/TR/REC-xml-names/#ns-using) ,
	// and more specifically https://www.w3.org/TR/REC-xml-names/#nsc-NoPrefixUndecl :
	// > In a namespace declaration for a prefix [...], the attribute value MUST NOT be empty.
	// in a similar manner [Namespaces in XML 1.1](https://www.w3.org/TR/xml-names11/#ns-using)
	// and more specifically https://www.w3.org/TR/xml-names11/#nsc-NSDeclared :
	// > [...] Furthermore, the attribute value [...] must not be an empty string.
	// so serializing empty namespace value like xmlns:ds="" would produce an invalid XML document.
	if (!uri) {
		return false;
	}
	if (prefix === "xml" && uri === NAMESPACE.XML || uri === NAMESPACE.XMLNS) {
		return false;
	}

	var i = visibleNamespaces.length
	while (i--) {
		var ns = visibleNamespaces[i];
		// get namespace prefix
		if (ns.prefix === prefix) {
			return ns.namespace !== uri;
		}
	}
	return true;
}
/**
 * Well-formed constraint: No < in Attribute Values
 * The replacement text of any entity referred to directly or indirectly in an attribute value must not contain a <.
 * @see https://www.w3.org/TR/xml/#CleanAttrVals
 * @see https://www.w3.org/TR/xml/#NT-AttValue
 */
function addSerializedAttribute(buf, qualifiedName, value) {
	buf.push(' ', qualifiedName, '="', value.replace(/[<&"]/g,_xmlEncoder), '"')
}

function serializeToString(node,buf,isHTML,nodeFilter,visibleNamespaces){
	if (!visibleNamespaces) {
		visibleNamespaces = [];
	}

	if(nodeFilter){
		node = nodeFilter(node);
		if(node){
			if(typeof node == 'string'){
				buf.push(node);
				return;
			}
		}else{
			return;
		}
		//buf.sort.apply(attrs, attributeSorter);
	}

	switch(node.nodeType){
	case ELEMENT_NODE:
		var attrs = node.attributes;
		var len = attrs.length;
		var child = node.firstChild;
		var nodeName = node.tagName;

		isHTML = NAMESPACE.isHTML(node.namespaceURI) || isHTML

		var prefixedNodeName = nodeName
		if (!isHTML && !node.prefix && node.namespaceURI) {
			var defaultNS
			// lookup current default ns from `xmlns` attribute
			for (var ai = 0; ai < attrs.length; ai++) {
				if (attrs.item(ai).name === 'xmlns') {
					defaultNS = attrs.item(ai).value
					break
				}
			}
			if (!defaultNS) {
				// lookup current default ns in visibleNamespaces
				for (var nsi = visibleNamespaces.length - 1; nsi >= 0; nsi--) {
					var namespace = visibleNamespaces[nsi]
					if (namespace.prefix === '' && namespace.namespace === node.namespaceURI) {
						defaultNS = namespace.namespace
						break
					}
				}
			}
			if (defaultNS !== node.namespaceURI) {
				for (var nsi = visibleNamespaces.length - 1; nsi >= 0; nsi--) {
					var namespace = visibleNamespaces[nsi]
					if (namespace.namespace === node.namespaceURI) {
						if (namespace.prefix) {
							prefixedNodeName = namespace.prefix + ':' + nodeName
						}
						break
					}
				}
			}
		}

		buf.push('<', prefixedNodeName);

		for(var i=0;i<len;i++){
			// add namespaces for attributes
			var attr = attrs.item(i);
			if (attr.prefix == 'xmlns') {
				visibleNamespaces.push({ prefix: attr.localName, namespace: attr.value });
			}else if(attr.nodeName == 'xmlns'){
				visibleNamespaces.push({ prefix: '', namespace: attr.value });
			}
		}

		for(var i=0;i<len;i++){
			var attr = attrs.item(i);
			if (needNamespaceDefine(attr,isHTML, visibleNamespaces)) {
				var prefix = attr.prefix||'';
				var uri = attr.namespaceURI;
				addSerializedAttribute(buf, prefix ? 'xmlns:' + prefix : "xmlns", uri);
				visibleNamespaces.push({ prefix: prefix, namespace:uri });
			}
			serializeToString(attr,buf,isHTML,nodeFilter,visibleNamespaces);
		}

		// add namespace for current node
		if (nodeName === prefixedNodeName && needNamespaceDefine(node, isHTML, visibleNamespaces)) {
			var prefix = node.prefix||'';
			var uri = node.namespaceURI;
			addSerializedAttribute(buf, prefix ? 'xmlns:' + prefix : "xmlns", uri);
			visibleNamespaces.push({ prefix: prefix, namespace:uri });
		}

		if(child || isHTML && !/^(?:meta|link|img|br|hr|input)$/i.test(nodeName)){
			buf.push('>');
			//if is cdata child node
			if(isHTML && /^script$/i.test(nodeName)){
				while(child){
					if(child.data){
						buf.push(child.data);
					}else{
						serializeToString(child, buf, isHTML, nodeFilter, visibleNamespaces.slice());
					}
					child = child.nextSibling;
				}
			}else
			{
				while(child){
					serializeToString(child, buf, isHTML, nodeFilter, visibleNamespaces.slice());
					child = child.nextSibling;
				}
			}
			buf.push('</',prefixedNodeName,'>');
		}else{
			buf.push('/>');
		}
		// remove added visible namespaces
		//visibleNamespaces.length = startVisibleNamespaces;
		return;
	case DOCUMENT_NODE:
	case DOCUMENT_FRAGMENT_NODE:
		var child = node.firstChild;
		while(child){
			serializeToString(child, buf, isHTML, nodeFilter, visibleNamespaces.slice());
			child = child.nextSibling;
		}
		return;
	case ATTRIBUTE_NODE:
		return addSerializedAttribute(buf, node.name, node.value);
	case TEXT_NODE:
		/**
		 * The ampersand character (&) and the left angle bracket (<) must not appear in their literal form,
		 * except when used as markup delimiters, or within a comment, a processing instruction, or a CDATA section.
		 * If they are needed elsewhere, they must be escaped using either numeric character references or the strings
		 * `&amp;` and `&lt;` respectively.
		 * The right angle bracket (>) may be represented using the string " &gt; ", and must, for compatibility,
		 * be escaped using either `&gt;` or a character reference when it appears in the string `]]>` in content,
		 * when that string is not marking the end of a CDATA section.
		 *
		 * In the content of elements, character data is any string of characters
		 * which does not contain the start-delimiter of any markup
		 * and does not include the CDATA-section-close delimiter, `]]>`.
		 *
		 * @see https://www.w3.org/TR/xml/#NT-CharData
		 */
		return buf.push(node.data
			.replace(/[<&]/g,_xmlEncoder)
			.replace(/]]>/g, ']]&gt;')
		);
	case CDATA_SECTION_NODE:
		return buf.push( '<![CDATA[',node.data,']]>');
	case COMMENT_NODE:
		return buf.push( "<!--",node.data,"-->");
	case DOCUMENT_TYPE_NODE:
		var pubid = node.publicId;
		var sysid = node.systemId;
		buf.push('<!DOCTYPE ',node.name);
		if(pubid){
			buf.push(' PUBLIC ', pubid);
			if (sysid && sysid!='.') {
				buf.push(' ', sysid);
			}
			buf.push('>');
		}else if(sysid && sysid!='.'){
			buf.push(' SYSTEM ', sysid, '>');
		}else{
			var sub = node.internalSubset;
			if(sub){
				buf.push(" [",sub,"]");
			}
			buf.push(">");
		}
		return;
	case PROCESSING_INSTRUCTION_NODE:
		return buf.push( "<?",node.target," ",node.data,"?>");
	case ENTITY_REFERENCE_NODE:
		return buf.push( '&',node.nodeName,';');
	//case ENTITY_NODE:
	//case NOTATION_NODE:
	default:
		buf.push('??',node.nodeName);
	}
}
function importNode(doc,node,deep){
	var node2;
	switch (node.nodeType) {
	case ELEMENT_NODE:
		node2 = node.cloneNode(false);
		node2.ownerDocument = doc;
		//var attrs = node2.attributes;
		//var len = attrs.length;
		//for(var i=0;i<len;i++){
			//node2.setAttributeNodeNS(importNode(doc,attrs.item(i),deep));
		//}
	case DOCUMENT_FRAGMENT_NODE:
		break;
	case ATTRIBUTE_NODE:
		deep = true;
		break;
	//case ENTITY_REFERENCE_NODE:
	//case PROCESSING_INSTRUCTION_NODE:
	////case TEXT_NODE:
	//case CDATA_SECTION_NODE:
	//case COMMENT_NODE:
	//	deep = false;
	//	break;
	//case DOCUMENT_NODE:
	//case DOCUMENT_TYPE_NODE:
	//cannot be imported.
	//case ENTITY_NODE:
	//case NOTATION_NODE：
	//can not hit in level3
	//default:throw e;
	}
	if(!node2){
		node2 = node.cloneNode(false);//false
	}
	node2.ownerDocument = doc;
	node2.parentNode = null;
	if(deep){
		var child = node.firstChild;
		while(child){
			node2.appendChild(importNode(doc,child,deep));
			child = child.nextSibling;
		}
	}
	return node2;
}
//
//var _relationMap = {firstChild:1,lastChild:1,previousSibling:1,nextSibling:1,
//					attributes:1,childNodes:1,parentNode:1,documentElement:1,doctype,};
function cloneNode(doc,node,deep){
	var node2 = new node.constructor();
	for (var n in node) {
		if (Object.prototype.hasOwnProperty.call(node, n)) {
			var v = node[n];
			if (typeof v != "object") {
				if (v != node2[n]) {
					node2[n] = v;
				}
			}
		}
	}
	if(node.childNodes){
		node2.childNodes = new NodeList();
	}
	node2.ownerDocument = doc;
	switch (node2.nodeType) {
	case ELEMENT_NODE:
		var attrs	= node.attributes;
		var attrs2	= node2.attributes = new NamedNodeMap();
		var len = attrs.length
		attrs2._ownerElement = node2;
		for(var i=0;i<len;i++){
			node2.setAttributeNode(cloneNode(doc,attrs.item(i),true));
		}
		break;;
	case ATTRIBUTE_NODE:
		deep = true;
	}
	if(deep){
		var child = node.firstChild;
		while(child){
			node2.appendChild(cloneNode(doc,child,deep));
			child = child.nextSibling;
		}
	}
	return node2;
}

function __set__(object,key,value){
	object[key] = value
}
//do dynamic
try{
	if(Object.defineProperty){
		Object.defineProperty(LiveNodeList.prototype,'length',{
			get:function(){
				_updateLiveList(this);
				return this.$$length;
			}
		});

		Object.defineProperty(Node.prototype,'textContent',{
			get:function(){
				return getTextContent(this);
			},

			set:function(data){
				switch(this.nodeType){
				case ELEMENT_NODE:
				case DOCUMENT_FRAGMENT_NODE:
					while(this.firstChild){
						this.removeChild(this.firstChild);
					}
					if(data || String(data)){
						this.appendChild(this.ownerDocument.createTextNode(data));
					}
					break;

				default:
					this.data = data;
					this.value = data;
					this.nodeValue = data;
				}
			}
		})

		function getTextContent(node){
			switch(node.nodeType){
			case ELEMENT_NODE:
			case DOCUMENT_FRAGMENT_NODE:
				var buf = [];
				node = node.firstChild;
				while(node){
					if(node.nodeType!==7 && node.nodeType !==8){
						buf.push(getTextContent(node));
					}
					node = node.nextSibling;
				}
				return buf.join('');
			default:
				return node.nodeValue;
			}
		}

		__set__ = function(object,key,value){
			//console.log(value)
			object['$$'+key] = value
		}
	}
}catch(e){//ie8
}

//if(typeof require == 'function'){
	exports.DocumentType = DocumentType;
	exports.DOMException = DOMException;
	exports.DOMImplementation = DOMImplementation;
	exports.Element = Element;
	exports.Node = Node;
	exports.NodeList = NodeList;
	exports.XMLSerializer = XMLSerializer;
//}