//+------------------------------------------------------------------+
//|                                                 Holt_Channel.mq5 |
//|                                          Copyright 2025, xxxxxxxx|
//|                                                                  |
//+------------------------------------------------------------------+
#property copyright "Copyright 2025, xxxxxxxx"
#property version   "1.00"
#property description "Holt's Forecast Channel. Displays a channel based on"
#property description "the multi-period forecast of the Holt's Linear Trend model."

#property indicator_chart_window
#property indicator_buffers 3
#property indicator_plots   3

#include <MyIncludes\Holt_Calculator.mqh>

//--- Plot 1: Upper Band
#property indicator_label1  "Upper Channel"
#property indicator_type1   DRAW_LINE
#property indicator_color1  clrSilver
#property indicator_style1  STYLE_DOT
#property indicator_width1  1

//--- Plot 2: Lower Band
#property indicator_label2  "Lower Channel"
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrSilver
#property indicator_style2  STYLE_DOT
#property indicator_width2  1

//--- Plot 3: Center Line (Holt MA)
#property indicator_label3  "Center Line"
#property indicator_type3   DRAW_LINE
#property indicator_color3  clrMediumSeaGreen
#property indicator_style3  STYLE_SOLID
#property indicator_width3  2

//--- Input Parameters ---
input int              InpPeriod         = 20;
input double           InpAlpha          = 0.1;
input double           InpBeta           = 0.05;
input int              InpForecastPeriod = 5;     // Forecast period for the channel
input ENUM_APPLIED_PRICE InpSourcePrice    = PRICE_CLOSE;

//--- Indicator Buffers ---
double    BufferUpperBand[];
double    BufferLowerBand[];
double    BufferCenterLine[];

//--- Global calculator object ---
CHoltMACalculator *g_calculator;

//+------------------------------------------------------------------+
//| Custom indicator initialization function.                        |
//+------------------------------------------------------------------+
int OnInit()
  {
   SetIndexBuffer(0, BufferUpperBand,  INDICATOR_DATA);
   SetIndexBuffer(1, BufferLowerBand,  INDICATOR_DATA);
   SetIndexBuffer(2, BufferCenterLine, INDICATOR_DATA);

   ArraySetAsSeries(BufferUpperBand,  false);
   ArraySetAsSeries(BufferLowerBand,  false);
   ArraySetAsSeries(BufferCenterLine, false);

   PlotIndexSetInteger(0, PLOT_DRAW_BEGIN, 2);
   PlotIndexSetInteger(1, PLOT_DRAW_BEGIN, 2);
   PlotIndexSetInteger(2, PLOT_DRAW_BEGIN, 2);
   IndicatorSetString(INDICATOR_SHORTNAME, StringFormat("Holt Channel(%d, %d)", InpPeriod, InpForecastPeriod));

   g_calculator = new CHoltMACalculator();
   if(CheckPointer(g_calculator) == POINTER_INVALID || !g_calculator.Init(InpPeriod, InpAlpha, InpBeta))
     {
      Print("Failed to initialize Holt MA Calculator.");
      return(INIT_FAILED);
     }
   return(INIT_SUCCEEDED);
  }

//+------------------------------------------------------------------+
//| Custom indicator deinitialization function.                      |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   if(CheckPointer(g_calculator) != POINTER_INVALID)
      delete g_calculator;
  }

//+------------------------------------------------------------------+
//| Custom 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(CheckPointer(g_calculator) != POINTER_INVALID)
     {
      //--- Step 1: Run the main calculation to get the core components
      double trend_buffer[];
      g_calculator.Calculate(rates_total, InpSourcePrice, open, high, low, close, BufferCenterLine, trend_buffer);

      //--- Step 2: Calculate the channel bands based on the forecast and trend
      int forecast_period = (InpForecastPeriod < 1) ? 1 : InpForecastPeriod;

      for(int i = 2; i < rates_total; i++)
        {
         // Reconstruct the Level component: Level = Forecast - Trend
         double level = BufferCenterLine[i] - trend_buffer[i];

         // Calculate the multi-period forecast for the bands
         BufferUpperBand[i] = level + forecast_period * trend_buffer[i];
         BufferLowerBand[i] = level - forecast_period * trend_buffer[i];
        }
     }
   return(rates_total);
  }
//+------------------------------------------------------------------+
//+------------------------------------------------------------------+