//
//  JavaScript Refactoring for safer, faster, better AJAX.
//
//  Copyright 2005, Pavel Simakov, 
//  http://www.softwaresecretweapons.com
//
//  former function name: oyXMLRPCProvider()
//

function RpcProvider()
{	
	var version = "1.0.1";
	var status = null;
	var url = null;	
	var req = null;
	var msgCount = 0;	
	var inProgress = false;
	var isComplete = false;
		
	var oThis = this;
	
	// checks to see if we have too many messages in log
	var internalCanMsg = function()
	{
		++msgCount;
		return msgCount < 100;
	}
	
	// adds message to internal log
	var alert = function(msg)
	{
		if( oThis.onLog && internalCanMsg() )
		{
			oThis.onLog( msg );
		}
	}
	
	// adds message to internal error handler
	var internalOnError = function( msg )
	{
		if( oThis.onError && internalCanMsg() )
		{
			oThis.onError( msg );
		}
	}
	
	// tell us whether we are busy waiting for the response to another request
	var internalIsBusy = function()
	{
		return inProgress && !isComplete;
	}	
	
	// internal callback function for the browser; 
	// it is called when a state of a request object changes
	var internalRequestComplete = function()
	{
		var STATE_COMPLETED = 4;
		var STATUS_200 = 200;
				
		if( ! internalIsBusy() )
		{
			internalOnError( "internalRequestComplete: error - no request submitted" );
		}
		
//		alert( "internalRequestComplete: readyState " + req.readyState );
		
		if( req.readyState == STATE_COMPLETED )
		{
			status = req.status;
			inProgress = false;
			isComplete = true;

//			alert( "internalRequestComplete: status " + status );
			
			if( status == STATUS_200 )
			{
//				alert( "internalRequestComplete: calling callback on content with length " + req.responseText.length + " chars" );			
				if( oThis.onComplete )
				{
					oThis.onComplete( req.responseText , req.responseXML );
				}				 
//				alert( "internalRequestComplete: complete on " + new Date() );
			} 
			else
			{
				internalOnError( "internalRequestComplete: error - bad status while fetching " + url );
			}
		}
		else
		{
			// we need to review other state codes for XMLRPC provider
		}
	}	
	
	// call this function to figure out version of this class
	this.getVersion = function()
	{
		return version;
	}
	
	// call this function to figure out if current browser supports XML HTTP Requests
	this.isSupported = function()
	{
		var nonEI = window.XMLHttpRequest;
		var onIE = window.ActiveXObject;
		
		if( onIE )
		{	    		
			onIE = new ActiveXObject("Microsoft.XMLHTTP") != null;
		}
		
		return window.XMLHttpRequest || onIE;
	}
	
	// call this function to find out if more calls are possible and if request has been completely received 
	this.isBusy = function()
	{
		return internalIsBusy();
	}		

	//  call this function to submit new request
	this.submit = function(_url)
	{	
		if( internalIsBusy() )
		{
			internalOnError( "submit: error - busy processing another request " + _url );			
		}	
		
		msgCount = 0;
//		alert( "submit: started on " + new Date() + " for " + _url );
				
		url = _url;	
		status = null;
		inProgress = true;
		isComplete = false;
		
	    if( window.XMLHttpRequest)
	    {
	    	// branch for native XMLHttpRequest object
//			alert("submit: using XMLHttpRequest()");
	    
	        req = new XMLHttpRequest();
	        req.onreadystatechange = internalRequestComplete;
	        req.open( "GET" , url , true );
	                
        	req.send( null );	
	    }
	    else
	    { 
	    	// branch for IE/Windows ActiveX version
	    	if( window.ActiveXObject )
	    	{	    		
		        req = new ActiveXObject( "Microsoft.XMLHTTP" );
		        if( req )
		        {
//					alert( "submit: using Microsoft.XMLHTTP" );
		        
		            req.onreadystatechange = internalRequestComplete;
		            req.open( "GET" , url , true );
			    	req.setrequestheader( "Pragma" , "no-cache" );
		   	    	req.setrequestheader( "Cache-control" , "no-cache" );
		           
		        	req.send();	
		        }
		        else
		        {
//					alert( "submit: error - unable to create Microsoft.XMLHTTP" );
		        }
		    }
		    else
		    {
//				alert( "submit: error - browser does not support XML HTTP Request" );
		    }
	    }
//		alert( "submit: complete" );
	}
	
	// call this function to abort current request
	this.abort = function()
	{
//		alert( "abort: " + url );
		
		if( ! internalIsBusy() )
		{
			internalOnError( "abort: error - no request submitted" );			
		}
	
		onComplete = null;		
		req.abort();
	}	

	// call this function to find out current url
	this.getUrl = function()
	{
		return url;
	}
	
	// call this function to find out HTTP status code after response completes
	this.getStatus = function()
	{
		return status;
	}	
	
	// user can override this; this is function called when fatal error occurs
	this.onError = function( msg )
	{
		
	} 
	
	// user can override this; this function is called when log message is created	
	this.onLog = function( msg )
	{
	
	}	
	
	// user can override this; this function is called when response is received without errors
	this.onComplete = function( responseText , responseXML )
	{
		
	}
}

function ajax( url , div )
{
	if( ! div ) div = "";
		
//	document.getElementById(div).innerHTML = "Aguarde enquanto os dados são carregados.";

	var objRpc1 = new RpcProvider();
	
	objRpc1.onComplete = function( responseText , responseXML )
	{			
		if( ! div == "" )
		{
			document.getElementById( div ).innerHTML = responseText;
		}
	}

	objRpc1.onError = function( msg )
	{
		if( ! div == "" )
		{
			document.getElementById( div ).innerHTML = "Ocorreu um erro de sistema.";
		}
	}

	objRpc1.submit( url );
	
	return strReturn;
}

/**
 * Chama requisição em ajax e ao completar submete funcao
 */
function ajaxFunction( url , functionReturn )
{
	var objRpc1 = new RpcProvider();
	
	objRpc1.onComplete = function( responseText , responseXML )
	{
		eval( functionReturn + "( responseText , responseXML )" );
	}

	objRpc1.onError = function( msg )
	{
		alert( "Ocorreu um erro de sistema." );
	}

	objRpc1.submit( url );
}