//------------------------------------------------------------------
#property copyright   "mladen"
#property link        "mladenfx@gmail.com"
#property description "Keltner channel - smooth ATR"
//+------------------------------------------------------------------
#property indicator_chart_window
#property indicator_buffers 9
#property indicator_plots   5
#property indicator_label1  "upper filling"
#property indicator_type1   DRAW_FILLING
#property indicator_color1  C'207,243,207'
#property indicator_label2  "lower filling"
#property indicator_type2   DRAW_FILLING
#property indicator_color2  C'252,225,205'
#property indicator_label3  "Upper band"
#property indicator_type3   DRAW_COLOR_LINE
#property indicator_color3  clrLimeGreen,clrSandyBrown
#property indicator_width3  2
#property indicator_label4  "Lower band"
#property indicator_type4   DRAW_COLOR_LINE
#property indicator_color4  clrLimeGreen,clrSandyBrown
#property indicator_width4  2
#property indicator_label5  "Middle value"
#property indicator_type5   DRAW_LINE
#property indicator_color5  clrDarkGray
#property indicator_width5  1
//
//
//
//
//

enum enMaTypes
  {
   ma_sma,    // Simple moving average
   ma_ema,    // Exponential moving average
   ma_smma,   // Smoothed MA
   ma_lwma    // Linear weighted MA
  };
input int                 inpPeriods    = 20;           // Keltner channel period
input double              inpMulti      = 2.0;          // Channel multiplicator
input enMaTypes           inpMaMethod   = ma_sma;       // Keltner channel median value average method
input ENUM_APPLIED_PRICE  inpPrice      = PRICE_MEDIAN; // Price
//
//---
//
double bufferUp[],bufferUpc[],bufferDn[],bufferDnc[],bufferMe[],fupu[],fupd[],fdnd[],fdnu[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
   SetIndexBuffer(0,fupu,INDICATOR_DATA);     SetIndexBuffer(1,fupd,INDICATOR_DATA);
   SetIndexBuffer(2,fdnu,INDICATOR_DATA);     SetIndexBuffer(3,fdnd,INDICATOR_DATA);
   SetIndexBuffer(4,bufferUp,INDICATOR_DATA); SetIndexBuffer(5,bufferUpc,INDICATOR_COLOR_INDEX);
   SetIndexBuffer(6,bufferDn,INDICATOR_DATA); SetIndexBuffer(7,bufferDnc,INDICATOR_COLOR_INDEX);
   SetIndexBuffer(8,bufferMe,INDICATOR_DATA);
   return(0);
  }
void OnDeinit(const int reason) { return; }
//+------------------------------------------------------------------+
//| Custom indicator calculation function                            |
//+------------------------------------------------------------------+
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(Bars(_Symbol,_Period)<rates_total) return(-1);
   for(int i=(int)MathMax(prev_calculated-1,0); i<rates_total && !IsStopped(); i++)
     {
      double price = getPrice(inpPrice,open,close,high,low,i,rates_total);
      double _tr   = (i>0) ? MathMax(high[i],close[i-1])-MathMin(low[i],close[i-1]) : high[i]-low[i]; 
      double atr   = iSmooth(_tr,inpPeriods,0,i,rates_total);

      //
      //---
      //

      bufferMe[i] = iCustomMa(inpMaMethod,price,inpPeriods,i,rates_total);
      bufferUp[i] = bufferMe[i]+atr*inpMulti;
      bufferDn[i] = bufferMe[i]-atr*inpMulti;
      fupd[i]     = bufferMe[i]; fupu[i] = bufferUp[i];
      fdnu[i]     = bufferMe[i]; fdnd[i] = bufferDn[i];
      if(i>0)
        {
         bufferUpc[i] = bufferUpc[i-1];
         bufferDnc[i] = bufferDnc[i-1];

         //
         //---
         //

         if(bufferUp[i]>bufferUp[i-1]) bufferUpc[i] = 0;
         if(bufferUp[i]<bufferUp[i-1]) bufferUpc[i] = 1;
         if(bufferDn[i]>bufferDn[i-1]) bufferDnc[i] = 0;
         if(bufferDn[i]<bufferDn[i-1]) bufferDnc[i] = 1;
        }
     }
   return(rates_total);
  }

//+------------------------------------------------------------------+
//| Custom functions                                                 |
//+------------------------------------------------------------------+
#define _smoothInstances     1
#define _smoothInstancesSize 10
double m_wrk[][_smoothInstances*_smoothInstancesSize];
int    m_size=0;
//
//---
//
double iSmooth(double price,double length,double phase,int r,int bars,int instanceNo=0)
  {
   #define bsmax  5
   #define bsmin  6
   #define volty  7
   #define vsum   8
   #define avolty 9

   if(ArrayRange(m_wrk,0)!=bars) ArrayResize(m_wrk,bars); if(ArrayRange(m_wrk,0)!=bars) return(price); instanceNo*=_smoothInstancesSize;
   if(r==0 || length<=1) { int k=0; for(; k<7; k++) m_wrk[r][instanceNo+k]=price; for(; k<10; k++) m_wrk[r][instanceNo+k]=0; return(price); }

//
//---
//

   double len1   = MathMax(MathLog(MathSqrt(0.5*(length-1)))/MathLog(2.0)+2.0,0);
   double pow1   = MathMax(len1-2.0,0.5);
   double del1   = price - m_wrk[r-1][instanceNo+bsmax];
   double del2   = price - m_wrk[r-1][instanceNo+bsmin];
   int    forBar = MathMin(r,10);

   m_wrk[r][instanceNo+volty]=0;
   if(MathAbs(del1) > MathAbs(del2)) m_wrk[r][instanceNo+volty] = MathAbs(del1);
   if(MathAbs(del1) < MathAbs(del2)) m_wrk[r][instanceNo+volty] = MathAbs(del2);
   m_wrk[r][instanceNo+vsum]=m_wrk[r-1][instanceNo+vsum]+(m_wrk[r][instanceNo+volty]-m_wrk[r-forBar][instanceNo+volty])*0.1;

//
//---
//

   m_wrk[r][instanceNo+avolty]=m_wrk[r-1][instanceNo+avolty]+(2.0/(MathMax(4.0*length,30)+1.0))*(m_wrk[r][instanceNo+vsum]-m_wrk[r-1][instanceNo+avolty]);
   double dVolty=(m_wrk[r][instanceNo+avolty]>0) ? m_wrk[r][instanceNo+volty]/m_wrk[r][instanceNo+avolty]: 0;
   if(dVolty > MathPow(len1,1.0/pow1)) dVolty = MathPow(len1,1.0/pow1);
   if(dVolty < 1)                      dVolty = 1.0;

//
//---
//

   double pow2 = MathPow(dVolty, pow1);
   double len2 = MathSqrt(0.5*(length-1))*len1;
   double Kv   = MathPow(len2/(len2+1), MathSqrt(pow2));

   if(del1 > 0) m_wrk[r][instanceNo+bsmax] = price; else m_wrk[r][instanceNo+bsmax] = price - Kv*del1;
   if(del2 < 0) m_wrk[r][instanceNo+bsmin] = price; else m_wrk[r][instanceNo+bsmin] = price - Kv*del2;

//
//---
//

   double corr  = MathMax(MathMin(phase,100),-100)/100.0 + 1.5;
   double beta  = 0.45*(length-1)/(0.45*(length-1)+2);
   double alpha = MathPow(beta,pow2);

   m_wrk[r][instanceNo+0] = price + alpha*(m_wrk[r-1][instanceNo+0]-price);
   m_wrk[r][instanceNo+1] = (price - m_wrk[r][instanceNo+0])*(1-beta) + beta*m_wrk[r-1][instanceNo+1];
   m_wrk[r][instanceNo+2] = (m_wrk[r][instanceNo+0] + corr*m_wrk[r][instanceNo+1]);
   m_wrk[r][instanceNo+3] = (m_wrk[r][instanceNo+2] - m_wrk[r-1][instanceNo+4])*MathPow((1-alpha),2) + MathPow(alpha,2)*m_wrk[r-1][instanceNo+3];
   m_wrk[r][instanceNo+4] = (m_wrk[r-1][instanceNo+4] + m_wrk[r][instanceNo+3]);

//
//---
//

   return(m_wrk[r][instanceNo+4]);

   #undef bsmax
   #undef bsmin
   #undef volty
   #undef vsum
   #undef avolty
  }    
//
//---
///
#define _maInstances 1
#define _maWorkBufferx1 1*_maInstances
//
//---
//
double iCustomMa(int mode,double price,double length,int r,int bars,int instanceNo=0)
  {
   switch(mode)
     {
      case ma_sma   : return(iSma(price,(int)length,r,bars,instanceNo));
      case ma_ema   : return(iEma(price,length,r,bars,instanceNo));
      case ma_smma  : return(iSmma(price,(int)length,r,bars,instanceNo));
      case ma_lwma  : return(iLwma(price,(int)length,r,bars,instanceNo));
      default       : return(price);
     }
  }
//
//---
//
double workSma[][_maWorkBufferx1];
//
//---
//
double iSma(double price,int period,int r,int _bars,int instanceNo=0)
  {
   if(ArrayRange(workSma,0)!=_bars) ArrayResize(workSma,_bars);

   workSma[r][instanceNo]=price;
   double avg=price; int k=1; for(; k<period && (r-k)>=0; k++) avg+=workSma[r-k][instanceNo];
   return(avg/(double)k);
  }
//
//---
//
double workEma[][_maWorkBufferx1];
//
//---
//
double iEma(double price,double period,int r,int _bars,int instanceNo=0)
  {
   if(ArrayRange(workEma,0)!=_bars) ArrayResize(workEma,_bars);

   workEma[r][instanceNo]=price;
   if(r>0 && period>1)
      workEma[r][instanceNo]=workEma[r-1][instanceNo]+(2.0/(1.0+period))*(price-workEma[r-1][instanceNo]);
   return(workEma[r][instanceNo]);
  }
//
//---
//
double workSmma[][_maWorkBufferx1];
//
//---
//
double iSmma(double price,double period,int r,int _bars,int instanceNo=0)
  {
   if(ArrayRange(workSmma,0)!=_bars) ArrayResize(workSmma,_bars);

   workSmma[r][instanceNo]=price;
   if(r>1 && period>1)
      workSmma[r][instanceNo]=workSmma[r-1][instanceNo]+(price-workSmma[r-1][instanceNo])/period;
   return(workSmma[r][instanceNo]);
  }
//
//---
//
double workLwma[][_maWorkBufferx1];
//
//---
//
double iLwma(double price,double period,int r,int _bars,int instanceNo=0)
  {
   if(ArrayRange(workLwma,0)!=_bars) ArrayResize(workLwma,_bars);

   workLwma[r][instanceNo] = price; if(period<1) return(price);
   double sumw = period;
   double sum  = period*price;

   for(int k=1; k<period && (r-k)>=0; k++)
     {
      double weight=period-k;
      sumw  += weight;
      sum   += weight*workLwma[r-k][instanceNo];
     }
   return(sum/sumw);
  }
//
//---
//
double getPrice(ENUM_APPLIED_PRICE tprice,const double &open[],const double &close[],const double &high[],const double &low[],int i,int _bars)
  {
   switch(tprice)
     {
      case PRICE_CLOSE:     return(close[i]);
      case PRICE_OPEN:      return(open[i]);
      case PRICE_HIGH:      return(high[i]);
      case PRICE_LOW:       return(low[i]);
      case PRICE_MEDIAN:    return((high[i]+low[i])/2.0);
      case PRICE_TYPICAL:   return((high[i]+low[i]+close[i])/3.0);
      case PRICE_WEIGHTED:  return((high[i]+low[i]+close[i]+close[i])/4.0);
     }
   return(0);
  }
//+------------------------------------------------------------------+