ta.pivothigh and ta.pivotlow in MQL5: confirmed swing points

//@version=6
indicator("Pivot highs and lows", overlay = true)

leftBars = input.int(5, "Bars on the left", minval = 1)
rightBars = input.int(5, "Bars on the right", minval = 1)

// The pivot's price, returned rightBars bars AFTER the pivot bar (na on every other bar)
ph = ta.pivothigh(high, leftBars, rightBars)
pl = ta.pivotlow(low, leftBars, rightBars)

// offset = -rightBars draws the shape back on the pivot bar itself
plotshape(not na(ph), "Pivot high", shape.triangledown, location.abovebar, color.red, offset = -rightBars, size = size.tiny)
plotshape(not na(pl), "Pivot low", shape.triangleup, location.belowbar, color.teal, offset = -rightBars, size = size.tiny)

//+------------------------------------------------------------------+
//| ta.pivothigh / ta.pivotlow in MQL5                               |
//| A pivot is confirmed InpRight closed bars later, then drawn on   |
//| the pivot bar itself (Pine's offset = -rightBars).               |
//| Custom indicator: save in MQL5/Indicators and compile (F7).      |
//+------------------------------------------------------------------+
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_plots   2

#property indicator_label1  "Pivot high"
#property indicator_type1   DRAW_ARROW
#property indicator_color1  clrRed
#property indicator_label2  "Pivot low"
#property indicator_type2   DRAW_ARROW
#property indicator_color2  clrTeal

input int InpLeft  = 5; // Bars on the left
input int InpRight = 5; // Bars on the right

double HighBuf[], LowBuf[];

int OnInit()
  {
   if(InpLeft < 1 || InpRight < 1)
      return INIT_PARAMETERS_INCORRECT;
   SetIndexBuffer(0, HighBuf, INDICATOR_DATA);
   SetIndexBuffer(1, LowBuf, INDICATOR_DATA);
   PlotIndexSetInteger(0, PLOT_ARROW, 234);        // down arrow above pivot highs
   PlotIndexSetInteger(1, PLOT_ARROW, 233);        // up arrow below pivot lows
   PlotIndexSetInteger(0, PLOT_ARROW_SHIFT, -12);
   PlotIndexSetInteger(1, PLOT_ARROW_SHIFT, 12);
   PlotIndexSetDouble(0, PLOT_EMPTY_VALUE, EMPTY_VALUE);
   PlotIndexSetDouble(1, PLOT_EMPTY_VALUE, EMPTY_VALUE);
   return INIT_SUCCEEDED;
  }

// Bar c is a pivot high if its high is strictly above the InpLeft highs before it and the InpRight highs after it
bool IsPivotHigh(const double &h[], const int c)
  {
   for(int j = 1; j <= InpLeft; j++)
      if(h[c - j] >= h[c])
         return false;
   for(int j = 1; j <= InpRight; j++)
      if(h[c + j] >= h[c])
         return false;
   return true;
  }

bool IsPivotLow(const double &l[], const int c)
  {
   for(int j = 1; j <= InpLeft; j++)
      if(l[c - j] <= l[c])
         return false;
   for(int j = 1; j <= InpRight; j++)
      if(l[c + j] <= l[c])
         return false;
   return true;
  }

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[])
  {
   int start = prev_calculated > 0 ? prev_calculated - 1 : 0;
   for(int i = start; i < rates_total; i++)
     {
      HighBuf[i] = EMPTY_VALUE;  // na until a later bar confirms a pivot here
      LowBuf[i]  = EMPTY_VALUE;
     }

   // Bar i confirms (or not) the candidate c = i - InpRight. Only closed bars confirm,
   // so the forming bar (rates_total - 1) never makes an arrow appear and then vanish
   for(int i = MathMax(start, InpLeft + InpRight); i < rates_total - 1; i++)
     {
      int c = i - InpRight;
      if(IsPivotHigh(high, c))
         HighBuf[c] = high[c];
      if(IsPivotLow(low, c))
         LowBuf[c] = low[c];
     }
   return rates_total;
  }
//+------------------------------------------------------------------+