YAHOO.util.Connect =
{

	_msxml_progid:[
		'MSXML2.XMLHTTP.3.0',
		'MSXML2.XMLHTTP',
		'Microsoft.XMLHTTP'
		],

	_http_header:{},


	_has_http_headers:false,


    _use_default_post_header:true,


    _default_post_header:'application/x-www-form-urlencoded',

    _isFormSubmit:false,


    _isFileUpload:false,


    _formNode:null,

    _sFormData:null,


    _poll:{},

    _timeOut:{},


     _polling_interval:50,

     _transaction_id:0,


	setProgId:function(id)
	{
		this._msxml_progid.unshift(id);
	},


	setDefaultPostHeader:function(b)
	{
		this._use_default_post_header = b;
	},


	setPollingInterval:function(i)
	{
		if(typeof i == 'number' && isFinite(i)){
			this._polling_interval = i;
		}
	},

	createXhrObject:function(transactionId)
	{
		var obj,http;
		try
		{
			http = new XMLHttpRequest();
			obj = { conn:http, tId:transactionId };
		}
		catch(e)
		{
			for(var i=0; i<this._msxml_progid.length; ++i){
				try
				{
					http = new ActiveXObject(this._msxml_progid[i]);
					obj = { conn:http, tId:transactionId };
					break;
				}
				catch(e){}
			}
		}
		finally
		{
			return obj;
		}
	},
	getConnectionObject:function()
	{
		var o;
		var tId = this._transaction_id;

		try
		{
			o = this.createXhrObject(tId);
			if(o){
				this._transaction_id++;
			}
		}
		catch(e){}
		finally
		{
			return o;
		}
	},
	asyncRequest:function(method, uri, callback, postData)
	{
		var o = this.getConnectionObject();

		if(!o){
			return null;
		}
		else{
			if(this._isFormSubmit){
				if(this._isFileUpload){
					this.uploadFile(o.tId, callback, uri, postData);
					this.releaseObject(o);

					return;
				}
				if(method == 'GET'){
					if(this._sFormData.length != 0){
						uri += ((uri.indexOf('?') == -1)?'?':'&') + this._sFormData;
					}
					else{
						uri += "?" + this._sFormData;
					}
				}
				else if(method == 'POST'){
					postData = postData?this._sFormData + "&" + postData:this._sFormData;
				}
			}

			o.conn.open(method, uri, true);

			if(this._isFormSubmit || (postData && this._use_default_post_header)){
				this.initHeader('Content-Type', this._default_post_header);
				if(this._isFormSubmit){
					this.resetFormState();
				}
			}

			if(this._has_http_headers){
				this.setHeader(o);
			}

			this.handleReadyState(o, callback);
			o.conn.send(postData || null);

			return o;
		}
	},
    handleReadyState:function(o, callback)
    {
		var oConn = this;

		if(callback && callback.timeout){
			this._timeOut[o.tId] = window.setTimeout(function(){ oConn.abort(o, callback, true); }, callback.timeout);
		}

		this._poll[o.tId] = window.setInterval(
			function(){
				if(o.conn && o.conn.readyState == 4){
					window.clearInterval(oConn._poll[o.tId]);
					delete oConn._poll[o.tId];

					if(callback && callback.timeout){
						delete oConn._timeOut[o.tId];
					}

					oConn.handleTransactionResponse(o, callback);
				}
			}
		,this._polling_interval);
    },
    handleTransactionResponse:function(o, callback, isAbort)
    {
		if(!callback){
			this.releaseObject(o);
			return;
		}

		var httpStatus, responseObject;

		try
		{
			if(o.conn.status !== undefined && o.conn.status != 0){
				httpStatus = o.conn.status;
			}
			else{
				httpStatus = 13030;
			}
		}
		catch(e){
			httpStatus = 13030;
		}

		if(httpStatus >= 200 && httpStatus < 300){
			try
			{
				responseObject = this.createResponseObject(o, callback.argument);
				if(callback.success){
					if(!callback.scope){
						callback.success(responseObject);
					}
					else{
						callback.success.apply(callback.scope, [responseObject]);
					}
				}
			}
			catch(e){}
		}
		else{
			try
			{
				switch(httpStatus){
					case 12002:
					case 12029:
					case 12030:
					case 12031:
					case 12152:
					case 13030:
						responseObject = this.createExceptionObject(o.tId, callback.argument, (isAbort?isAbort:false));
						if(callback.failure){
							if(!callback.scope){
								callback.failure(responseObject);
							}
							else{
								callback.failure.apply(callback.scope, [responseObject]);
							}
						}
						break;
					default:
						responseObject = this.createResponseObject(o, callback.argument);
						if(callback.failure){
							if(!callback.scope){
								callback.failure(responseObject);
							}
							else{
								callback.failure.apply(callback.scope, [responseObject]);
							}
						}
				}
			}
			catch(e){}
		}

		this.releaseObject(o);
		responseObject = null;
    },

    createResponseObject:function(o, callbackArg)
    {
		var obj = {};
		var headerObj = {};

		try
		{
			var headerStr = o.conn.getAllResponseHeaders();
			var header = headerStr.split('\n');
			for(var i=0; i<header.length; i++){
				var delimitPos = header[i].indexOf(':');
				if(delimitPos != -1){
					headerObj[header[i].substring(0,delimitPos)] = header[i].substring(delimitPos+2);
				}
			}
		}
		catch(e){}

		obj.tId = o.tId;
		obj.status = o.conn.status;
		obj.statusText = o.conn.statusText;
		obj.getResponseHeader = headerObj;
		obj.getAllResponseHeaders = headerStr;
		obj.responseText = o.conn.responseText;
		obj.responseXML = o.conn.responseXML;

		if(typeof callbackArg !== undefined){
			obj.argument = callbackArg;
		}

		return obj;
    },
    createExceptionObject:function(tId, callbackArg, isAbort)
    {
		var COMM_CODE = 0;
		var COMM_ERROR = 'communication failure';
		var ABORT_CODE = -1;
		var ABORT_ERROR = 'transaction aborted';

		var obj = {};

		obj.tId = tId;
		if(isAbort){
			obj.status = ABORT_CODE;
			obj.statusText = ABORT_ERROR;
		}
		else{
			obj.status = COMM_CODE;
			obj.statusText = COMM_ERROR;
		}

		if(callbackArg){
			obj.argument = callbackArg;
		}

		return obj;
    },
	initHeader:function(label,value)
	{
		if(this._http_header[label] === undefined){
			this._http_header[label] = value;
		}
		else{
			this._http_header[label] =  value + "," + this._http_header[label];
		}

		this._has_http_headers = true;
	},

	setHeader:function(o)
	{
		for(var prop in this._http_header){
			if(this._http_header.hasOwnProperty(prop)){
				o.conn.setRequestHeader(prop, this._http_header[prop]);
			}
		}
		delete this._http_header;

		this._http_header = {};
		this._has_http_headers = false;
	},
	setForm:function(formId, isUpload, secureUri)
	{
		this.resetFormState();
		var oForm;
		if(typeof formId == 'string'){
			oForm = (document.getElementById(formId) || document.forms[formId]);
		}
		else if(typeof formId == 'object'){
			oForm = formId;
		}
		else{
			return;
		}


		if(isUpload){

			this.createFrame(secureUri?secureUri:null);

			this._isFormSubmit = true;
			this._isFileUpload = true;
			this._formNode = oForm;

			return;
		}

		var oElement, oName, oValue, oDisabled;
		var hasSubmit = false;


		for (var i=0; i<oForm.elements.length; i++){
			oElement = oForm.elements[i];
			oDisabled = oForm.elements[i].disabled;
			oName = oForm.elements[i].name;
			oValue = oForm.elements[i].value;
			if(!oDisabled && oName)
			{
				switch (oElement.type)
				{
					case 'select-one':
					case 'select-multiple':
						for(var j=0; j<oElement.options.length; j++){
							if(oElement.options[j].selected){
								if(window.ActiveXObject){
									this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oElement.options[j].attributes['value'].specified?oElement.options[j].value:oElement.options[j].text) + '&';
								}
								else{
									this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oElement.options[j].hasAttribute('value')?oElement.options[j].value:oElement.options[j].text) + '&';
								}

							}
						}
						break;
					case 'radio':
					case 'checkbox':
						if(oElement.checked){
							this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
						}
						break;
					case 'file':

					case undefined:
					case 'reset':
					case 'button':
						break;
					case 'submit':
						if(hasSubmit == false){
							this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
							hasSubmit = true;
						}
						break;
					default:
						this._sFormData += encodeURIComponent(oName) + '=' + encodeURIComponent(oValue) + '&';
						break;
				}
			}
		}

		this._isFormSubmit = true;
		this._sFormData = this._sFormData.substr(0, this._sFormData.length - 1);

		return this._sFormData;
	},

	resetFormState:function(){
		this._isFormSubmit = false;
		this._isFileUpload = false;
		this._formNode = null;
		this._sFormData = "";
	},
	createFrame:function(secureUri){

		var frameId = 'yuiIO' + this._transaction_id;
		if(window.ActiveXObject){
			var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');

			if(typeof secureUri == 'boolean'){
				io.src = 'javascript:false';
			}
			else if(typeof secureURI == 'string'){

				io.src = secureUri;
			}
		}
		else{
			var io = document.createElement('iframe');
			io.id = frameId;
			io.name = frameId;
		}

		io.style.position = 'absolute';
		io.style.top = '-1000px';
		io.style.left = '-1000px';

		document.body.appendChild(io);
	},

	appendPostData:function(postData)
	{
		var formElements = new Array();
		var postMessage = postData.split('&');
		for(var i=0; i < postMessage.length; i++){
			var delimitPos = postMessage[i].indexOf('=');
			if(delimitPos != -1){
				formElements[i] = document.createElement('input');
				formElements[i].type = 'hidden';
				formElements[i].name = postMessage[i].substring(0,delimitPos);
				formElements[i].value = postMessage[i].substring(delimitPos+1);
				this._formNode.appendChild(formElements[i]);
			}
		}

		return formElements;
	},

	uploadFile:function(id, callback, uri, postData){


		var frameId = 'yuiIO' + id;
		var io = document.getElementById(frameId);

		this._formNode.action = uri;
		this._formNode.method = 'POST';
		this._formNode.target = frameId;

		if(this._formNode.encoding){

			this._formNode.encoding = 'multipart/form-data';
		}
		else{
			this._formNode.enctype = 'multipart/form-data';
		}

		if(postData){
			var oElements = this.appendPostData(postData);
		}

		this._formNode.submit();

		if(oElements && oElements.length > 0){
			try
			{
				for(var i=0; i < oElements.length; i++){
					this._formNode.removeChild(oElements[i]);
				}
			}
			catch(e){}
		}

		this.resetFormState();
		var uploadCallback = function()
		{
			var obj = {};
			obj.tId = id;
			obj.argument = callback.argument;

			try
			{
				obj.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
				obj.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;
			}
			catch(e){}

			if(callback.upload){
				if(!callback.scope){
					callback.upload(obj);
				}
				else{
					callback.upload.apply(callback.scope, [obj]);
				}
			}

			if(YAHOO.util.Event){
				YAHOO.util.Event.removeListener(io, "load", uploadCallback);
			}
			else if(window.detachEvent){
				io.detachEvent('onload', uploadCallback);
			}
			else{
				io.removeEventListener('load', uploadCallback, false);
			}
			setTimeout(function(){ document.body.removeChild(io); }, 100);
		};

		if(YAHOO.util.Event){
			YAHOO.util.Event.addListener(io, "load", uploadCallback);
		}
		else if(window.attachEvent){
			io.attachEvent('onload', uploadCallback);
		}
		else{
			io.addEventListener('load', uploadCallback, false);
		}
	},

	abort:function(o, callback, isTimeout)
	{
		if(this.isCallInProgress(o)){
			o.conn.abort();
			window.clearInterval(this._poll[o.tId]);
			delete this._poll[o.tId];
			if(isTimeout){
				delete this._timeOut[o.tId];
			}

			this.handleTransactionResponse(o, callback, true);

			return true;
		}
		else{
			return false;
		}
	},

	isCallInProgress:function(o)
	{
		if(o.conn){
			return o.conn.readyState != 4 && o.conn.readyState != 0;
		}
		else{
			return false;
		}
	},

	releaseObject:function(o)
	{
		o.conn = null;
		o = null;
	}
};