//+------------------------------------------------------------------+
//|                                      L1VolatilityRegimeColor.mq5 |
//|                             Copyright 2000-2026, MetaQuotes Ltd. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2000-2026, MetaQuotes Ltd."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property indicator_separate_window
#property indicator_buffers 4
#property indicator_plots   4
//---
#property indicator_label1  "Range"
#property indicator_type1   DRAW_LINE
#property indicator_color1  clrDodgerBlue
#property indicator_width1  2
//---
#property indicator_label2  "Trend"
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrLime
#property indicator_width2  2
//---
#property indicator_label3  "Expansion"
#property indicator_type3   DRAW_LINE
#property indicator_color3  clrOrange
#property indicator_width3  2
//---
#property indicator_label4  "Panic"
#property indicator_type4   DRAW_LINE
#property indicator_color4  clrRed
#property indicator_width4  2
//--- input parameters
input int    BarsToShow    = 1000;  // Number of bars to calculate L1
input double CoefLambda    = 0.015; // Lambda in lambda_max units
input int    ATRPeriod     = 14;    // ATR period
input int    SmoothPeriod  = 10;    // Smooth period
input double L1MoveThresh  = 0.0;   // Move volatility  
input double LowVolThresh  = 0.5;   // Low volatility 
input double HighVolThresh = 1.5;   // High volatility 
input double PanicMult     = 2.0;   // Panic volatility
//--- buffers
double Regime[];
double BufRange[], BufTrend[], BufExpansion[], BufPanic[];
//+------------------------------------------------------------------+
//| Indicator initialization function                                |
//+------------------------------------------------------------------+
int OnInit()
{
   SetIndexBuffer(0,BufRange,INDICATOR_DATA);
   SetIndexBuffer(1,BufTrend,INDICATOR_DATA);
   SetIndexBuffer(2,BufExpansion,INDICATOR_DATA);
   SetIndexBuffer(3,BufPanic,INDICATOR_DATA);
//---
   PlotIndexSetDouble(0,PLOT_EMPTY_VALUE,EMPTY_VALUE);
   PlotIndexSetDouble(1,PLOT_EMPTY_VALUE,EMPTY_VALUE);
   PlotIndexSetDouble(2,PLOT_EMPTY_VALUE,EMPTY_VALUE);
   PlotIndexSetDouble(3,PLOT_EMPTY_VALUE,EMPTY_VALUE);
//---
   IndicatorSetInteger(INDICATOR_DIGITS,0);
   return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//| Indicator iteration 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(rates_total < BarsToShow+ATRPeriod)
   {
      ArrayInitialize(Regime, EMPTY_VALUE);
      ArrayInitialize(BufRange, EMPTY_VALUE);
      ArrayInitialize(BufTrend, EMPTY_VALUE);
      ArrayInitialize(BufExpansion, EMPTY_VALUE);
      ArrayInitialize(BufPanic, EMPTY_VALUE);
      return 0;
   }
   //--- new bars
   static datetime last_bar_time=0;
   bool new_bar=(time[0]!=last_bar_time);
   bool need_recalc=(prev_calculated==0) || new_bar || (rates_total!=prev_calculated);
   if(!need_recalc)
      return prev_calculated;
   last_bar_time=time[0];
//---
   int start = rates_total - BarsToShow;
   int count = BarsToShow;
//---
   ArrayResize(Regime,rates_total);
   for(int i=0;i<start;i++)
      Regime[i]=EMPTY_VALUE;
//---
   vector<double> DataClose(count), DataHigh(count), DataLow(count);
   for(int i=0;i<count;i++)
   {
      DataClose[i]=close[start+i];
      DataHigh[i]=high[start+i];
      DataLow[i]=low[start+i];
   }
//---
   vector<double> L1(count);
   if(!DataClose.L1TrendFilter(L1, CoefLambda, true))
      return prev_calculated;
//---
   vector<double> TR(count), ATR(count);
   for(int i=0;i<count;i++)
   {
      if(i==0) TR[i]=DataHigh[i]-DataLow[i];
      else
      {
         double h_l = DataHigh[i]-DataLow[i];
         double h_pc = MathAbs(DataHigh[i]-DataClose[i-1]);
         double l_pc = MathAbs(DataLow[i]-DataClose[i-1]);
         TR[i] = MathMax(h_l, MathMax(h_pc, l_pc));
      }
      int from=MathMax(0,i-ATRPeriod+1);
      double sumTR=0;
      int n=i-from+1;
      for(int j=from;j<=i;j++) sumTR+=TR[j];
      ATR[i]=sumTR/n;
   }
//---
   vector<double> NormVol(count), SmoothVol(count);
   for(int i=0;i<count;i++)
      NormVol[i] = (ATR[i]>0) ? MathAbs(DataClose[i]-L1[i])/ATR[i] : 0;
//---
   double alpha=2.0/(SmoothPeriod+1.0);
   SmoothVol[0]=NormVol[0];
   for(int i=1;i<count;i++)
      SmoothVol[i]=alpha*NormVol[i] + (1-alpha)*SmoothVol[i-1];
   //--- calc Regime[]
   for(int i=0;i<count;i++)
   {
      double vol = SmoothVol[i];
      double deltaL1 = (i>0) ? (L1[i]-L1[i-1]) : 0.0;
      if(vol < LowVolThresh)
         Regime[start+i]=0;
      else if(vol < HighVolThresh)
         Regime[start+i]= (MathAbs(deltaL1) > L1MoveThresh) ? 1 : 0;
      else if(vol < HighVolThresh*PanicMult)
         Regime[start+i]=2;
      else
         Regime[start+i]=3;
   }
   //--- buffers
   for(int i=0;i<rates_total;i++)
   {
      BufRange[i]     = (Regime[i]==0) ? Regime[i] : EMPTY_VALUE;
      BufTrend[i]     = (Regime[i]==1) ? Regime[i] : EMPTY_VALUE;
      BufExpansion[i] = (Regime[i]==2) ? Regime[i] : EMPTY_VALUE;
      BufPanic[i]     = (Regime[i]==3) ? Regime[i] : EMPTY_VALUE;
   }
//---
   return rates_total;
}