//+------------------------------------------------------------------+
//|                                         L1VolatilityAbsolute.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 1
#property indicator_plots   1
//---
#property indicator_label1  "L1VolatilityAbsolute"
#property indicator_type1   DRAW_LINE
#property indicator_color1  clrOrange
#property indicator_width1  2
//---
input int    BarsToShow = 1000;  // Number of bars to calculate L1
input double CoefLambda = 0.015; // Lambda in lambda_max units
//---
double Vol[];
//+------------------------------------------------------------------+
//| Indicator initialization function                                |
//+------------------------------------------------------------------+
int OnInit()
  {
   SetIndexBuffer(0,Vol,INDICATOR_DATA);
   ArrayInitialize(Vol,EMPTY_VALUE);
   PlotIndexSetDouble(0,PLOT_EMPTY_VALUE,EMPTY_VALUE);
   IndicatorSetInteger(INDICATOR_DIGITS,_Digits);
//---
   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[])
  {
//---
   static bool warned=false;
   if(rates_total < BarsToShow)
     {
      if(!warned)
        {
         Print("Waiting bars ",BarsToShow);
         warned=true;
        }
      ArrayInitialize(Vol,EMPTY_VALUE);
      return 0;
     }
   static datetime last_bar=0;
   bool new_bar=(time[0]!=last_bar);
//---
   if(!(prev_calculated==0 || new_bar || rates_total!=prev_calculated))
      return prev_calculated;
//---
   last_bar=time[0];
   int start=rates_total-BarsToShow;
   int N=BarsToShow;
   for(int i=0;i<start;i++)
      Vol[i]=EMPTY_VALUE;
//---
   vector<double> price;
   price.Resize(N);
   for(int i=0;i<N;i++)
      price[i]=close[start+i];
   vector<double> l1;
   l1.Resize(N);
   price.L1TrendFilter(l1,CoefLambda,true);
   for(int i=0;i<N;i++)
      Vol[start+i]=MathAbs(close[start+i]-l1[i]);
//---
   return rates_total;
  }
//+------------------------------------------------------------------+