//+------------------------------------------------------------------+
//|                                                      VPattern.mq5 |
//|                        Copyright 2023, MetaQuotes Software Corp. |
//|                                             https://www.metaquotes.net/ |
//+------------------------------------------------------------------+
#property copyright "Copyright 2023, MetaQuotes Software Corp."
#property link      "https://www.metaquotes.net/"
#property version   "1.00"
#property indicator_chart_window
#property indicator_buffers 4
#property indicator_plots   2
#property indicator_label1  "V Pattern Top"
#property indicator_type1   DRAW_ARROW
#property indicator_color1  clrGreen
#property indicator_width1  2
#property indicator_label2  "V Pattern Bottom"
#property indicator_type2   DRAW_ARROW
#property indicator_color2  clrRed
#property indicator_width2  2

//--- Input parameters
input int    LookbackPeriod=20;       // Bars to analyze for pattern
input double MinDeclinePercent=2.0;   // Minimum decline percentage
input double MinRisePercent=2.0;      // Minimum rise percentage
input bool   ShowAlerts=true;         // Show alert messages
input color  ArrowUpColor=clrGreen;   // Up arrow color
input color  ArrowDownColor=clrRed;   // Down arrow color

//--- Indicator buffers
double VTopBuffer[];
double VBottomBuffer[];
double TempHighBuffer[];
double TempLowBuffer[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexBuffer(0, VTopBuffer, INDICATOR_DATA);
   SetIndexBuffer(1, VBottomBuffer, INDICATOR_DATA);
   SetIndexBuffer(2, TempHighBuffer, INDICATOR_CALCULATIONS);
   SetIndexBuffer(3, TempLowBuffer, INDICATOR_CALCULATIONS);
   
//--- setting arrow codes
   PlotIndexSetInteger(0, PLOT_ARROW, 233);  // Up arrow
   PlotIndexSetInteger(1, PLOT_ARROW, 234);  // Down arrow
   
//--- setting arrow colors
   PlotIndexSetInteger(0, PLOT_LINE_COLOR, ArrowUpColor);
   PlotIndexSetInteger(1, PLOT_LINE_COLOR, ArrowDownColor);
   
//--- setting buffer values as EMPTY_VALUE
   ArrayInitialize(VTopBuffer, EMPTY_VALUE);
   ArrayInitialize(VBottomBuffer, EMPTY_VALUE);
   
//--- name for DataWindow and indicator subwindow label
   IndicatorSetString(INDICATOR_SHORTNAME, "V-Pattern Detector ("+string(LookbackPeriod)+")");
   
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| 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[])
  {
//--- check for minimum bars required
   if(rates_total < LookbackPeriod)
      return(0);
      
//--- start calculation from bar determined by prev_calculated
   int start;
   if(prev_calculated == 0)
      start = LookbackPeriod;
   else
      start = prev_calculated - 1;
   
//--- main calculation loop
   for(int i=start; i<rates_total && !IsStopped(); i++)
     {
      // Reset buffers
      VTopBuffer[i] = EMPTY_VALUE;
      VBottomBuffer[i] = EMPTY_VALUE;
      
      // Find the lowest low in the lookback period
      int lowestBar = iLowest(NULL, 0, MODE_LOW, LookbackPeriod, i-LookbackPeriod+1);
      double lowestLow = low[lowestBar];
      
      // Find the highest high before the lowest low
      int highBeforeLow = iHighest(NULL, 0, MODE_HIGH, lowestBar-(i-LookbackPeriod+1)+1, i-LookbackPeriod+1);
      double highestBefore = high[highBeforeLow];
      
      // Find the highest high after the lowest low
      int highAfterLow = iHighest(NULL, 0, MODE_HIGH, i-lowestBar, lowestBar+1);
      double highestAfter = high[highAfterLow];
      
      // Calculate percentage moves
      double declinePercent = (highestBefore - lowestLow) / highestBefore * 100;
      double risePercent = (highestAfter - lowestLow) / lowestLow * 100;
      
      // Check if we have a V pattern
      if(declinePercent >= MinDeclinePercent && risePercent >= MinRisePercent)
        {
         // Check if the low is in the middle third of the lookback period
         int lowPosition = lowestBar - (i-LookbackPeriod+1);
         if(lowPosition > LookbackPeriod/3 && lowPosition < 2*LookbackPeriod/3)
           {
            // Mark the pattern on chart
            VTopBuffer[highBeforeLow] = high[highBeforeLow];
            VBottomBuffer[lowestBar] = low[lowestBar];
            VTopBuffer[highAfterLow] = high[highAfterLow];
            
            // Show alert if enabled
            if(ShowAlerts && i == rates_total-1)
              {
               string alertText = StringFormat("V-Pattern detected! Decline: %.2f%%, Rise: %.2f%%",
                                              declinePercent, risePercent);
               Alert(alertText);
               Comment(alertText);
              }
           }
        }
     }
   
   return(rates_total);
  }
//+------------------------------------------------------------------+