var conventions = require("./conventions");
var dom = require('./dom')
var entities = require('./entities');
var sax = require('./sax');

var DOMImplementation = dom.DOMImplementation;

var NAMESPACE = conventions.NAMESPACE;

var ParseError = sax.ParseError;
var XMLReader = sax.XMLReader;

/**
 * Normalizes line ending according to https://www.w3.org/TR/xml11/#sec-line-ends:
 *
 * > XML parsed entities are often stored in computer files which,
 * > for editing convenience, are organized into lines.
 * > These lines are typically separated by some combination
 * > of the characters CARRIAGE RETURN (#xD) and LINE FEED (#xA).
 * >
 * > To simplify the tasks of applications, the XML processor must behave
 * > as if it normalized all line breaks in external parsed entities (including the document entity)
 * > on input, before parsing, by translating all of the following to a single #xA character:
 * >
 * > 1. the two-character sequence #xD #xA
 * > 2. the two-character sequence #xD #x85
 * > 3. the single character #x85
 * > 4. the single character #x2028
 * > 5. any #xD character that is not immediately followed by #xA or #x85.
 *
 * @param {string} input
 * @returns {string}
 */
function normalizeLineEndings(input) {
	return input
		.replace(/\r[\n\u0085]/g, '\n')
		.replace(/[\r\u0085\u2028]/g, '\n')
}

/**
 * @typedef Locator
 * @property {number} [columnNumber]
 * @property {number} [lineNumber]
 */

/**
 * @typedef DOMParserOptions
 * @property {DOMHandler} [domBuilder]
 * @property {Function} [errorHandler]
 * @property {(string) => string} [normalizeLineEndings] used to replace line endings before parsing
 * 						defaults to `normalizeLineEndings`
 * @property {Locator} [locator]
 * @property {Record<string, string>} [xmlns]
 *
 * @see normalizeLineEndings
 */

/**
 * The DOMParser interface provides the ability to parse XML or HTML source code
 * from a string into a DOM `Document`.
 *
 * _xmldom is different from the spec in that it allows an `options` parameter,
 * to override the default behavior._
 *
 * @param {DOMParserOptions} [options]
 * @constructor
 *
 * @see https://developer.mozilla.org/en-US/docs/Web/API/DOMParser
 * @see https://html.spec.whatwg.org/multipage/dynamic-markup-insertion.html#dom-parsing-and-serialization
 */
function DOMParser(options){
	this.options = options ||{locator:{}};
}

DOMParser.prototype.parseFromString = function(source,mimeType){
	var options = this.options;
	var sax =  new XMLReader();
	var domBuilder = options.domBuilder || new DOMHandler();//contentHandler and LexicalHandler
	var errorHandler = options.errorHandler;
	var locator = options.locator;
	var defaultNSMap = options.xmlns||{};
	var isHTML = /\/x?html?$/.test(mimeType);//mimeType.toLowerCase().indexOf('html') > -1;
  	var entityMap = isHTML ? entities.HTML_ENTITIES : entities.XML_ENTITIES;
	if(locator){
		domBuilder.setDocumentLocator(locator)
	}

	sax.errorHandler = buildErrorHandler(errorHandler,domBuilder,locator);
	sax.domBuilder = options.domBuilder || domBuilder;
	if(isHTML){
		defaultNSMap[''] = NAMESPACE.HTML;
	}
	defaultNSMap.xml = defaultNSMap.xml || NAMESPACE.XML;
	var normalize = options.normalizeLineEndings || normalizeLineEndings;
	if (source && typeof source === 'string') {
		sax.parse(
			normalize(source),
			defaultNSMap,
			entityMap
		)
	} else {
		sax.errorHandler.error('invalid doc source')
	}
	return domBuilder.doc;
}
function buildErrorHandler(errorImpl,domBuilder,locator){
	if(!errorImpl){
		if(domBuilder instanceof DOMHandler){
			return domBuilder;
		}
		errorImpl = domBuilder ;
	}
	var errorHandler = {}
	var isCallback = errorImpl instanceof Function;
	locator = locator||{}
	function build(key){
		var fn = errorImpl[key];
		if(!fn && isCallback){
			fn = errorImpl.length == 2?function(msg){errorImpl(key,msg)}:errorImpl;
		}
		errorHandler[key] = fn && function(msg){
			fn('[xmldom '+key+']\t'+msg+_locator(locator));
		}||function(){};
	}
	build('warning');
	build('error');
	build('fatalError');
	return errorHandler;
}

//console.log('#\n\n\n\n\n\n\n####')
/**
 * +ContentHandler+ErrorHandler
 * +LexicalHandler+EntityResolver2
 * -DeclHandler-DTDHandler
 *
 * DefaultHandler:EntityResolver, DTDHandler, ContentHandler, ErrorHandler
 * DefaultHandler2:DefaultHandler,LexicalHandler, DeclHandler, EntityResolver2
 * @link http://www.saxproject.org/apidoc/org/xml/sax/helpers/DefaultHandler.html
 */
function DOMHandler() {
    this.cdata = false;
}
function position(locator,node){
	node.lineNumber = locator.lineNumber;
	node.columnNumber = locator.columnNumber;
}
/**
 * @see org.xml.sax.ContentHandler#startDocument
 * @link http://www.saxproject.org/apidoc/org/xml/sax/ContentHandler.html
 */
DOMHandler.prototype = {
	startDocument : function() {
    	this.doc = new DOMImplementation().createDocument(null, null, null);
    	if (this.locator) {
        	this.doc.documentURI = this.locator.systemId;
    	}
	},
	startElement:function(namespaceURI, localName, qName, attrs) {
		var doc = this.doc;
	    var el = doc.createElementNS(namespaceURI, qName||localName);
	    var len = attrs.length;
	    appendElement(this, el);
	    this.currentElement = el;

		this.locator && position(this.locator,el)
	    for (var i = 0 ; i < len; i++) {
	        var namespaceURI = attrs.getURI(i);
	        var value = attrs.getValue(i);
	        var qName = attrs.getQName(i);
			var attr = doc.createAttributeNS(namespaceURI, qName);
			this.locator &&position(attrs.getLocator(i),attr);
			attr.value = attr.nodeValue = value;
			el.setAttributeNode(attr)
	    }
	},
	endElement:function(namespaceURI, localName, qName) {
		var current = this.currentElement
		var tagName = current.tagName;
		this.currentElement = current.parentNode;
	},
	startPrefixMapping:function(prefix, uri) {
	},
	endPrefixMapping:function(prefix) {
	},
	processingInstruction:function(target, data) {
	    var ins = this.doc.createProcessingInstruction(target, data);
	    this.locator && position(this.locator,ins)
	    appendElement(this, ins);
	},
	ignorableWhitespace:function(ch, start, length) {
	},
	characters:function(chars, start, length) {
		chars = _toString.apply(this,arguments)
		//console.log(chars)
		if(chars){
			if (this.cdata) {
				var charNode = this.doc.createCDATASection(chars);
			} else {
				var charNode = this.doc.createTextNode(chars);
			}
			if(this.currentElement){
				this.currentElement.appendChild(charNode);
			}else if(/^\s*$/.test(chars)){
				this.doc.appendChild(charNode);
				//process xml
			}
			this.locator && position(this.locator,charNode)
		}
	},
	skippedEntity:function(name) {
	},
	endDocument:function() {
		this.doc.normalize();
	},
	setDocumentLocator:function (locator) {
	    if(this.locator = locator){// && !('lineNumber' in locator)){
	    	locator.lineNumber = 0;
	    }
	},
	//LexicalHandler
	comment:function(chars, start, length) {
		chars = _toString.apply(this,arguments)
	    var comm = this.doc.createComment(chars);
	    this.locator && position(this.locator,comm)
	    appendElement(this, comm);
	},

	startCDATA:function() {
	    //used in characters() methods
	    this.cdata = true;
	},
	endCDATA:function() {
	    this.cdata = false;
	},

	startDTD:function(name, publicId, systemId) {
		var impl = this.doc.implementation;
	    if (impl && impl.createDocumentType) {
	        var dt = impl.createDocumentType(name, publicId, systemId);
	        this.locator && position(this.locator,dt)
	        appendElement(this, dt);
					this.doc.doctype = dt;
	    }
	},
	/**
	 * @see org.xml.sax.ErrorHandler
	 * @link http://www.saxproject.org/apidoc/org/xml/sax/ErrorHandler.html
	 */
	warning:function(error) {
		console.warn('[xmldom warning]\t'+error,_locator(this.locator));
	},
	error:function(error) {
		console.error('[xmldom error]\t'+error,_locator(this.locator));
	},
	fatalError:function(error) {
		throw new ParseError(error, this.locator);
	}
}
function _locator(l){
	if(l){
		return '\n@'+(l.systemId ||'')+'#[line:'+l.lineNumber+',col:'+l.columnNumber+']'
	}
}
function _toString(chars,start,length){
	if(typeof chars == 'string'){
		return chars.substr(start,length)
	}else{//java sax connect width xmldom on rhino(what about: "? && !(chars instanceof String)")
		if(chars.length >= start+length || start){
			return new java.lang.String(chars,start,length)+'';
		}
		return chars;
	}
}

/*
 * @link http://www.saxproject.org/apidoc/org/xml/sax/ext/LexicalHandler.html
 * used method of org.xml.sax.ext.LexicalHandler:
 *  #comment(chars, start, length)
 *  #startCDATA()
 *  #endCDATA()
 *  #startDTD(name, publicId, systemId)
 *
 *
 * IGNORED method of org.xml.sax.ext.LexicalHandler:
 *  #endDTD()
 *  #startEntity(name)
 *  #endEntity(name)
 *
 *
 * @link http://www.saxproject.org/apidoc/org/xml/sax/ext/DeclHandler.html
 * IGNORED method of org.xml.sax.ext.DeclHandler
 * 	#attributeDecl(eName, aName, type, mode, value)
 *  #elementDecl(name, model)
 *  #externalEntityDecl(name, publicId, systemId)
 *  #internalEntityDecl(name, value)
 * @link http://www.saxproject.org/apidoc/org/xml/sax/ext/EntityResolver2.html
 * IGNORED method of org.xml.sax.EntityResolver2
 *  #resolveEntity(String name,String publicId,String baseURI,String systemId)
 *  #resolveEntity(publicId, systemId)
 *  #getExternalSubset(name, baseURI)
 * @link http://www.saxproject.org/apidoc/org/xml/sax/DTDHandler.html
 * IGNORED method of org.xml.sax.DTDHandler
 *  #notationDecl(name, publicId, systemId) {};
 *  #unparsedEntityDecl(name, publicId, systemId, notationName) {};
 */
"endDTD,startEntity,endEntity,attributeDecl,elementDecl,externalEntityDecl,internalEntityDecl,resolveEntity,getExternalSubset,notationDecl,unparsedEntityDecl".replace(/\w+/g,function(key){
	DOMHandler.prototype[key] = function(){return null}
})

/* Private static helpers treated below as private instance methods, so don't need to add these to the public API; we might use a Relator to also get rid of non-standard public properties */
function appendElement (hander,node) {
    if (!hander.currentElement) {
        hander.doc.appendChild(node);
    } else {
        hander.currentElement.appendChild(node);
    }
}//appendChild and setAttributeNS are preformance key

exports.__DOMHandler = DOMHandler;
exports.normalizeLineEndings = normalizeLineEndings;
exports.DOMParser = DOMParser;