//+------------------------------------------------------------------+
//|                                      ZigZag Indicator by ChatGPT |
//|                                      Copyright 2023, ChatGPT     |
//|                                      http://www.companyname.net  |
//+------------------------------------------------------------------+
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Red
#property indicator_color2 Blue
extern int ExtDepth = 12;
extern int ExtDeviation = 5;
extern int ExtBackstep = 3;
extern int nBars = 150;
double ExtMapBuffer[];
double ExtMapBuffer2[];
int init()
  {
   IndicatorBuffers(2);
   SetIndexStyle(0, DRAW_SECTION);
   SetIndexStyle(1, DRAW_SECTION);
   SetIndexBuffer(0, ExtMapBuffer);
   SetIndexBuffer(1, ExtMapBuffer2);
   SetIndexEmptyValue(0, 0.0);
   SetIndexEmptyValue(1, 0.0);
   ArraySetAsSeries(ExtMapBuffer, true);
   ArraySetAsSeries(ExtMapBuffer2, true);
   IndicatorShortName("ZigZag(" + ExtDepth + "," + ExtDeviation + "," + ExtBackstep + ")");
   return (0);
  }
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
int start()
  {
   int shift, back, lasthighpos, lastlowpos, LoopBegin, k;
   double val, res;
   double curlow, curhigh, lasthigh, lastlow;
   if(nBars == 0)
      LoopBegin = Bars - ExtDepth;
   else
      LoopBegin = nBars;
   LoopBegin = MathMin(Bars - ExtDepth, LoopBegin);
   for(shift = LoopBegin; shift >= 0; shift--)
     {
      val = Low[Lowest(NULL, 0, MODE_LOW, ExtDepth, shift)];
      if(val == lastlow)
         val = 0.0;
      else
        {
         lastlow = val;
         if((Low[shift] - val) > (ExtDeviation * Point))
            val = 0.0;
         else
           {
            for(back = 1; back <= ExtBackstep; back++)
              {
               res = ExtMapBuffer[shift + back];
               if((res != 0) && (res > val))
                  ExtMapBuffer[shift + back] = 0.0;
              }
           }
        }
      ExtMapBuffer[shift] = val;
      val = High[Highest(NULL, 0, MODE_HIGH, ExtDepth, shift)];
      if(val == lasthigh)
         val = 0.0;
      else
        {
         lasthigh = val;
         if((val - High[shift]) > (ExtDeviation * Point))
            val = 0.0;
         else
           {
            for(back = 1; back <= ExtBackstep; back++)
              {
               res = ExtMapBuffer2[shift + back];
               if((res != 0) && (res < val))
                  ExtMapBuffer2[shift + back] = 0.0;
              }
           }
        }
      ExtMapBuffer2[shift] = val;
     }
   lasthigh = -1;
   lasthighpos = -1;
   lastlow = -1;
   lastlowpos = -1;
   for(shift = Bars - ExtDepth; shift >= 0; shift--)
     {
      curlow = ExtMapBuffer[shift];
      curhigh = ExtMapBuffer2[shift];
      if((curlow == 0) && (curhigh == 0))
         continue;
      if(curhigh != 0)
        {
         if(lasthigh > 0)
           {
            if(lasthigh < curhigh)
               ExtMapBuffer2[lasthighpos] = 0;
            else
               ExtMapBuffer2[shift] = 0;
           }
         if(lasthigh < curhigh || lasthigh < 0)
           {
            lasthigh = curhigh;
            lasthighpos = shift;
           }
         lastlow = -1;
        }
      if(curlow != 0)
        {
         if(lastlow > 0)
           {
            if(lastlow > curlow)
               ExtMapBuffer[lastlowpos] = 0;
            else
               ExtMapBuffer[shift] = 0;
           }
         if((curlow < lastlow) || (lastlow < 0))
           {
            lastlow = curlow;
            lastlowpos = shift;
           }
         lasthigh = -1;
        }
     }
   for(shift = Bars - 1; shift >= 0; shift--)
     {
      if(shift >= Bars - ExtDepth)
        {
         ExtMapBuffer[shift] = 0.0;
         k = 0;
        }
      else
        {
         res = ExtMapBuffer2[shift];
         if(res != 0.0)
            ExtMapBuffer[shift] = res;
        }
     }
  }
//+------------------------------------------------------------------+