/*
 * ***** 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 *****
 */

AjxRpc._rpcCache = new Array();
AjxRpc._RPC_CACHE_MAX = 10;

function AjxRpc() {
}

/**
* @method public static AjxRpc.invoke
* @param requestStr - http request string
* @param serverUrl - URI for HTTP request
* @requestHeaders - HTTP request headers
* @param callback - AjxCallback instance
**/
AjxRpc.invoke =
function(requestStr, serverUrl, requestHeaders, callback) {
	var rpcCtxt = AjxRpc._getRpcCtxt();

	try {
	 	var response = rpcCtxt.rpcRequestObj.invoke(requestStr, serverUrl, requestHeaders, callback);
	} catch (ex) {
		var newEx = new AjxException();
		newEx.method = "AjxRpc.prototype._invoke";
		if (ex instanceof Error) {
			newEx.detail = ex.message;
			newEx.code = AjxException.NETWORK_ERROR;
			newEx.msg = "Network error";
		} else {
			newEx.detail = ex.toString();
			newEx.code = AjxException.UNKNOWN_ERROR;
			newEx.msg = "Unknown Error";
		}
		if(!callback)		
			rpcCtxt.rpcRequestObj.busy = false;
		throw newEx;
	}
	if(!callback)
		rpcCtxt.rpcRequestObj.busy = false;
	return response;
}


/**
* inner class _RpcCtxt
 members:
 	rpcRequestObj : AjxRpcRequest
**/
function _RpcCtxt() {
	this.rpcRequestObj = new AjxRpcRequest(true);
}

/**
* singleton factory of _RpcCtxt objects
**/
AjxRpc._getRpcCtxt = 
function() {
	var rpcCtxt = null
	for (var i = 0; i < AjxRpc._rpcCache.length; i++) {
		rpcCtxt = AjxRpc._rpcCache[i];
		if (!rpcCtxt.rpcRequestObj.busy) {
			DBG.println(AjxDebug.DBG1, "Found free Rpc Context in cache");
			break;
		}
	}
	
	// if we didnt find a non-busy rpc cache, create new one
	if (i == AjxRpc._rpcCache.length) {
		if (AjxRpc._rpcCache.length == AjxRpc._RPC_CACHE_MAX) {
			DBG.println(AjxDebug.DBG1, "Out of RPC Contexts");
			throw new AjxException("Out of RPC cache", AjxException.OUT_OF_RPC_CACHE, "ZmCsfeCommand._getRpcCtxt");	
		}
		rpcCtxt = new _RpcCtxt();
		AjxRpc._rpcCache.push(rpcCtxt);
		
		// XXX: this should never eval to true in synchronous mode
		//      REMOVE THIS CHECK WHEN ASYNCH HAS BEEN IMPLEMENTED
		if (AjxRpc._rpcCache.length > 1)
			DBG.println("XXXX: ---- more than one rpc cache created ---- :XXXX");
	}
	rpcCtxt.rpcRequestObj.busy = true;
	return rpcCtxt;
}