/*
 * ***** BEGIN LICENSE BLOCK *****
 * Version: ZAPL 1.1
 * 
 * The contents of this file are subject to the Zimbra AJAX Public
 * License Version 1.1 ("License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.zimbra.com/license
 * 
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 * 
 * The Original Code is: Zimbra AJAX Toolkit.
 * 
 * The Initial Developer of the Original Code is Zimbra, Inc.
 * Portions created by Zimbra are Copyright (C) 2005 Zimbra, Inc.
 * All Rights Reserved.
 * 
 * Contributor(s):
 * 
 * ***** END LICENSE BLOCK *****
 */

/**
* class AjxRpcRequest encapsulates XMLHttpRequest as _httpReq
*
**/
function AjxRpcRequest(init) {
	if (arguments.length == 0) return;
	
	if (!AjxRpcRequest._inited) 
		AjxRpcRequest._init();	
	
	if (AjxEnv.isIE) {
		this._httpReq = new ActiveXObject(AjxRpcRequest._msxmlVers);
	} else if (AjxEnv.isSafari || AjxEnv.isNav) {
		this._httpReq =  new XMLHttpRequest();
	}
	this.busy=false;
}

AjxRpcRequest._inited = false;
AjxRpcRequest._msxmlVers = null;


AjxRpcRequest.prototype.toString = 
function() {
	return "AjxRpcRequest";
}

/**
* @method public AjxRpcRequest.prototype.invoke
* @param requestStr - http request string
* @param serverUrl - URI for HTTP request
* @requestHeaders - HTTP request headers
* @param callback - AjxCallback instance. if call back is null, then the call is synchronous
**/
AjxRpcRequest.prototype.invoke =
function(requestStr, serverUrl, requestHeaders, callback) {
	// TODO Allow arbritatry request headers to be passed in
	this._httpReq.open("post", serverUrl, (callback != null) );
	if (callback) {
		var tempThis = this;
		DBG.println(AjxDebug.DBG1, "Have callback");
		this._httpReq.onreadystatechange = function (evt) {
			DBG.println(AjxDebug.DBG1, "ReadyState changed");
			if(!tempThis) {
				//IE sometimes looses objects
				callback.run( {text: null, xml: null, success: false, status: null} );				
			}
			DBG.println(AjxDebug.DBG1, "ready state = " + tempThis._httpReq.readyState);
			if(tempThis._httpReq.readyState==4) {
				DBG.println(AjxDebug.DBG1, "status = " + tempThis._httpReq.status);				
				if(tempThis._httpReq.status==200) {
					callback.run( {text: tempThis._httpReq.responseText, xml: tempThis._httpReq.responseXML, success: true} );				
				} else {
					callback.run( {text: tempThis._httpReq.responseText, xml: tempThis._httpReq.responseXML, success: false, status: tempThis._httpReq.status} );				
				}
				tempThis.busy = false;
				tempThis = null;
			}
		}
	}	

	if (requestHeaders) {
		for (var i in requestHeaders) {
			this._httpReq.setRequestHeader(i, requestHeaders[i]);
			DBG.println("REQ. HEADER: " + i + " - " + requestHeaders[i]);
		}
	}
	this._httpReq.send(requestStr);
	if (callback) {
		return;
	} else {
		return {text: this._httpReq.responseText, xml: this._httpReq.responseXML};
	}
}

AjxRpcRequest._init =
function() {
	if (AjxEnv.isIE) {
		var msxmlVers = ["MSXML2.XMLHTTP.4.0", "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP"];
		for (var i = 0; i < msxmlVers.length; i++) {
			try {
				// search for the xml version on user's machine
				var x = new ActiveXObject(msxmlVers[i]);
				AjxRpcRequest._msxmlVers = msxmlVers[i];
				break;
			} catch (ex) {
				// do nothing
			}
		}
		if (AjxRpcRequest._msxmlVers == null)
			throw new AjxException("MSXML not installed", AjxException.INTERNAL_ERROR, "AjxRpc._init");
	}
	AjxRpcRequest._inited = true;
}