//+------------------------------------------------------------------+
//|                                                          IRB.mq4 |
//|                   Copyright 2009-2020, MetaQuotes Software Corp. |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2009-2020, MetaQuotes Software Corp."
#property link      "http://www.mql5.com"
//--- indicator settings
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_type1   DRAW_ARROW
#property indicator_type2   DRAW_ARROW
#property indicator_width1  2
#property indicator_width2  2
#property indicator_color1  clrLimeGreen
#property indicator_color2  clrRed
#property indicator_label1  "IRB Up"
#property indicator_label2  "IRB Down"

input double retracementBuy = 45;    //retracement amount buys (in %)
input double retracementSell = 45;   //retracement amount sells (in %)
//--- indicator buffers
double ExtUpperBuffer[];
double ExtLowerBuffer[];
//--- 10 pixels upper from high price
int    ExtArrowShift=-10;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
void OnInit()
  {
//--- indicator buffers mapping
   SetIndexBuffer(0,ExtUpperBuffer,INDICATOR_DATA);
   SetIndexBuffer(1,ExtLowerBuffer,INDICATOR_DATA);
   SetIndexArrow(0,217);
   SetIndexArrow(1,218);
   SetIndexEmptyValue(0,EMPTY_VALUE);
   SetIndexEmptyValue(1,EMPTY_VALUE);
  }
//+------------------------------------------------------------------+
//|  Fractals on 5 bars                                              |
//+------------------------------------------------------------------+
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[])
  {
   if(rates_total<5)
      return(0);

   int start;
//--- clean up arrays
   if(prev_calculated<7)
     {
      start=2;
      ArrayInitialize(ExtUpperBuffer,EMPTY_VALUE);
      ArrayInitialize(ExtLowerBuffer,EMPTY_VALUE);
     }
   else
      start=rates_total-5;
//--- main cycle of calculations
   for(int i=start; i<rates_total-3 && !IsStopped(); i++)
     {
      //--- Upper Fractal
      if(high[i] - MathMax(open[i], close[i]) > (high[i]-low[i]) * retracementBuy / 100.0)
         ExtLowerBuffer[i]=high[i];
      else
         ExtLowerBuffer[i]=EMPTY_VALUE;

      //--- Lower Fractal
      if(MathMin(open[i], close[i]) - low[i] > (high[i]-low[i]) * retracementSell / 100.0)
         ExtUpperBuffer[i]=low[i];
      else
         ExtUpperBuffer[i]=EMPTY_VALUE;
     }
//--- OnCalculate done. Return new prev_calculated.
   return(rates_total);
  }

//+------------------------------------------------------------------+