//+------------------------------------------------------------------+
//|                                        simple_trading_system.mq4 |
//|                                                         evillive |
//|                                                                  |
//+------------------------------------------------------------------+
#property copyright "2014, Vitalie Postolache"
#property link        "http://www.mql4.com"
#property version   "1.0"
#property strict
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Aqua
#property indicator_color2 Magenta

//+------------------------------------------------------------------+
//| User parameters                                                  |
//+------------------------------------------------------------------+

extern int period = 2;                             //MA period
extern ENUM_MA_METHOD method = MODE_SMA;           //MA method
extern ENUM_APPLIED_PRICE price = PRICE_CLOSE;     //Applied price   
extern int shift = 4;                              //Bar shift for second MA value
extern double ashift=0.3;                          //Arrow vertical shift
extern bool ocb=false;                             //Only completed bars counted
//----
extern string _alerts_="alerts section";
extern bool alertsON     =false;                   //Allow alerts globally 
extern bool alert  =false;                         //Pop-up alert
extern bool sound  =false;                         //Play sound
extern bool email  =false;                         //Send e-mail
extern bool notify =false;                         //Send push notification
extern string soundname = "news.wav";              //Sound file name
//----
double ma00,ma01,atr;
double Up[];
double Dn[];
double Hlv[];
string name;
int m=0;

//+------------------------------------------------------------------+
//|  Custom indicator initialization function                        |
//+------------------------------------------------------------------+

int OnInit()
  {
   IndicatorBuffers(3);
   SetIndexStyle(0,DRAW_ARROW);
   SetIndexArrow(0,225);
   SetIndexBuffer(0,Up);
   SetIndexStyle(1,DRAW_ARROW);
   SetIndexArrow(1,226);
   SetIndexBuffer(1,Dn);
   SetIndexLabel(0,"BUY!");
   SetIndexLabel(1,"SELL!");
   SetIndexBuffer(2,Hlv);
   name = MQLInfoString(MQL_PROGRAM_NAME);
   IndicatorShortName(name);
   IndicatorDigits(_Digits);
   if(ocb==true) m=1;
   return(INIT_SUCCEEDED);
  }
  
//+------------------------------------------------------------------+
//|  Main program body                                               |
//+------------------------------------------------------------------+

int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//----
   int i;
   int limit;
//----
   if(rates_total-1 < (period+shift))  
      return(0);
//----
   if(prev_calculated<1)
     {
      for(i=0; i<=rates_total-1-(period+shift); i++)
        {
         Up[i]=0.0;
         Dn[i]=0.0;
         Hlv[i]=0.0;
        }
     }
//----
   if(prev_calculated>1)
      limit=rates_total-1-prev_calculated;
   else
      limit=rates_total-1-(period+shift);
//---- starting calculation
   for(i=m; i<=limit; i++)
    {
      Up[i]=0.0;
      Dn[i]=0.0;
      Hlv[i]=0.0;
      
      ma00 = iMA(NULL,0,period,0,method,price,i);
      ma01 = iMA(NULL,0,period,0,method,price,i+shift);
      atr  = iATR(NULL,0,period,i);
      
      if(ma00<=ma01 && Close[i]>=Close[i+shift] && Close[i]<=Close[i+period+shift] && Close[i]<Open[i])
        {
         Up[i]=Low[i]-atr*ashift;
         Hlv[i]=1;
        }
      if(ma00>=ma01 && Close[i]<=Close[i+shift] && Close[i]>=Close[i+period+shift] && Close[i]>Open[i])
        {
         Dn[i]=High[i]+atr*ashift;
         Hlv[i]=-1;
        }
     }
//----
   if (alertsON)
      if (Hlv[m]!=0.0 && Hlv[m]!=Hlv[m+1])
      {
         if (Hlv[m]==1.0) doAlert(Up[m],"'UP'");
         else  doAlert(Dn[m],"'DOWN'");
      }
//----
   return(rates_total);
  }
  
//+------------------------------------------------------------------+
//|  Alerts section                                                  |
//+------------------------------------------------------------------+

void doAlert(double pr, string doWhat)
{
   static string   previousAlert="nothing";
   static datetime previousTime;
   string message;
//----
     if (!IsTesting() && (previousAlert!=doWhat || previousTime!=Time[0]))
     {
      previousAlert =doWhat;
      previousTime  =Time[0];
//----
      message= StringConcatenate(MQLInfoString(MQL_PROGRAM_NAME)," indicator direction changed to ",doWhat,", value: ",DoubleToStr(pr,_Digits),
      ", symbol: ",Symbol(),", time: ",TimeToStr(TimeCurrent(),TIME_DATE|TIME_SECONDS));
      if (alert)  Alert(message);
      if (email)  SendMail(StringConcatenate(MQLInfoString(MQL_PROGRAM_NAME), " on ",Symbol(),", at ",TimeToStr(TimeCurrent(),TIME_DATE|TIME_SECONDS)),message);
      if (notify) SendNotification(message);
      if (sound)  PlaySound(soundname);
     }
}