//+------------------------------------------------------------------+
//|                                                 Mirror_Bands.mq4 |
//|                           Copyright © 2011, Andy Tjatur Pramono. |
//|                                            andy.tjatur@gmail.com |
//+------------------------------------------------------------------+
#property  copyright "Copyright © 2011, Andy Tjatur Pramono."
#property  link      "andy.tjatur@gmail.com"

#property indicator_chart_window
#property indicator_buffers 5
#property indicator_color1 White
#property indicator_color2 Aqua
#property indicator_color3 Aqua
#property indicator_color4 Red
#property indicator_color5 Blue

#property  indicator_width1  2
#property  indicator_width2  1
#property  indicator_width3  1
#property  indicator_width4  2
#property  indicator_width5  2

//---- indicator parameters
extern int    BandsPeriod=9;
extern int    BandsPeriod2=2;
extern int    BandsShift=0;
extern double BandsDeviations=2.0;
//---- buffers
double MovingBuffer[];
double UpperBuffer[];
double LowerBuffer[];
double UpperMirror[];
double LowerMirror[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0,DRAW_LINE);
   SetIndexBuffer(0,MovingBuffer);
   SetIndexStyle(1,DRAW_LINE);
   SetIndexBuffer(1,UpperBuffer);
   SetIndexStyle(2,DRAW_LINE);
   SetIndexBuffer(2,LowerBuffer);
   SetIndexStyle(3,DRAW_LINE);
   SetIndexBuffer(3,UpperMirror);
   SetIndexStyle(4,DRAW_LINE);
   SetIndexBuffer(4,LowerMirror);
//----
   SetIndexDrawBegin(0,BandsPeriod+BandsShift);
   SetIndexDrawBegin(1,BandsPeriod+BandsShift);
   SetIndexDrawBegin(2,BandsPeriod+BandsShift);
   SetIndexDrawBegin(3,BandsPeriod2+BandsShift);
   SetIndexDrawBegin(4,BandsPeriod2+BandsShift);
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Bollinger Bands                                                  |
//+------------------------------------------------------------------+
int start()
  {
   int    i,k,counted_bars=IndicatorCounted();
   double deviation;
   double sum,oldval,newres;
//----
   if(Bars<=BandsPeriod) return(0);
//---- initial zero
   if(counted_bars<1)
      for(i=1;i<=BandsPeriod;i++)
        {
         MovingBuffer[Bars-i]=EMPTY_VALUE;
         UpperBuffer[Bars-i]=EMPTY_VALUE;
         LowerBuffer[Bars-i]=EMPTY_VALUE;
        }
//----
   int limit=Bars-counted_bars;
   if(counted_bars>0) limit++;
   for(i=0; i<limit; i++)
      MovingBuffer[i]=iMA(NULL,0,BandsPeriod,BandsShift,MODE_SMA,PRICE_CLOSE,i);
//----
   i=Bars-BandsPeriod+1;
   if(counted_bars>BandsPeriod-1) i=Bars-counted_bars-1;
   while(i>=0)
     {
      sum=0.0;
      k=i+BandsPeriod-1;
      oldval=MovingBuffer[i];
      while(k>=i)
        {
         newres=Close[k]-oldval;
         sum+=newres*newres;
         k--;
        }
      deviation=BandsDeviations*MathSqrt(sum/BandsPeriod);
      UpperBuffer[i]=oldval+deviation;
      LowerBuffer[i]=oldval-deviation;
      UpperMirror[i]=iMA(NULL,0,BandsPeriod2,BandsShift,MODE_SMA,PRICE_CLOSE,i);
      LowerMirror[i]=iMA(NULL,0,BandsPeriod,BandsShift,MODE_SMA,PRICE_CLOSE,i)+(iMA(NULL,0,BandsPeriod,BandsShift,MODE_SMA,PRICE_CLOSE,i)-iMA(NULL,0,BandsPeriod2,BandsShift,MODE_SMA,PRICE_CLOSE,i));
      i--;
     }
//----
   return(0);
  }
//+------------------------------------------------------------------+