#property indicator_chart_window
#property indicator_buffers 4
#property indicator_color1 Blue
#property indicator_color2 Red
#property indicator_color3 Aqua
#property indicator_color4 Orange

//---- input parameters
extern int FastEMA=12;
extern int SlowEMA=26;
extern int SignalSMA=9;
extern bool      alertsOn      = true;
extern bool      alertsMessage = true;
extern bool      alertsSound   = true;
extern bool      alertsEmail   = false;

//---- buffers
double Cross_Up[];
double Cross_Down[];
double ZeroCross_Up[];
double ZeroCross_Down[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
{
	IndicatorBuffers(4);

	SetIndexBuffer(0,Cross_Up);
	SetIndexStyle(0,DRAW_ARROW);
	SetIndexArrow(0,108);

	SetIndexBuffer(1,Cross_Down);
	SetIndexStyle(1,DRAW_ARROW);
	SetIndexArrow(1,108);     

	SetIndexBuffer(2,ZeroCross_Up);
	SetIndexStyle(2,DRAW_ARROW);
	SetIndexArrow(2,233);

	SetIndexBuffer(3,ZeroCross_Down);
	SetIndexStyle(3,DRAW_ARROW);
	SetIndexArrow(3,234);  
	
	return(0);
}
//+------------------------------------------------------------------+
//| Relative Strength Index                                          |
//+------------------------------------------------------------------+
int start()
{
	int limit;
	int counted_bars=IndicatorCounted();
	//---- check for possible errors
	if(counted_bars<0) return(-1);
	//---- the last counted bar will be recounted
	if(counted_bars>0) counted_bars--;
	limit=Bars-counted_bars;

	for(int i=1; i<limit; i++)
	{
		double Range=0.0;
		double AvgRange=0.0;
		
		for (int j = i; j<=i+9; j++) AvgRange=AvgRange+MathAbs(High[j]-Low[j]);
		Range=AvgRange/10;

		double Signal_1 = iMACD(NULL,0,FastEMA,SlowEMA,SignalSMA,PRICE_CLOSE,MODE_SIGNAL,i);
		double Signal_2 = iMACD(NULL,0,FastEMA,SlowEMA,SignalSMA,PRICE_CLOSE,MODE_SIGNAL,i+1);

		double MACD_1 = iMACD(NULL,0,FastEMA,SlowEMA,SignalSMA,PRICE_CLOSE,MODE_MAIN,i);
		double MACD_2 = iMACD(NULL,0,FastEMA,SlowEMA,SignalSMA,PRICE_CLOSE,MODE_MAIN,i+1);

		if ( MACD_1>Signal_1 && MACD_2<= Signal_2 )  {Cross_Up[i] = Low[i]-Range;}
		if ( MACD_1<Signal_1 && MACD_2>= Signal_2 )  {Cross_Down[i] = High[i]+Range;}

		if ( Signal_1>0 && Signal_2 < 0 )
		{
			ZeroCross_Up[i] = Low[i]-Range;
			if (alertsOn) doAlert(" crossed up");
		}
		if ( Signal_1<0 && Signal_2 > 0 )
		{
			ZeroCross_Down[i] = High[i]+Range;
			if (alertsOn) doAlert(" crossed down");
		}
	} 

	return(0);
}

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+

void doAlert(string doWhat)
{
	static string previousAlert = "nothing";
	static datetime previousTime;
	string message;

	if (previousAlert != doWhat || previousTime != Time[0])
	{
		previousAlert = doWhat;
		previousTime = Time[0];

		message = StringConcatenate(Symbol(), " at ", TimeToStr(TimeLocal(), TIME_SECONDS), " MACD ", doWhat);
		if (alertsMessage) Alert(message);
		if (alertsSound) PlaySound("alert2.wav");
		if (alertsEmail) SendMail(StringConcatenate(Symbol(), " MACD crossing"), message);
	}     
}