function Initialize()
{
    IndicatorName = "HPIv2"; // Herrick Payoff Index (HPI)
    AddInput("Input", Inputs.Candle);
    PriceStudy = false;
    AddSeries("HPI", DrawAs.Line, Color.White, AxisType.ZeroBased);
    AddSeries("HPI_EMA1", DrawAs.Custom, Color.White, AxisType.ZeroBased);
    AddSeries("HPI_EMA2", DrawAs.Custom, Color.White, AxisType.ZeroBased);

	AddGlobalVariable("K1", Types.Double, 0.0);
	AddGlobalVariable("K2", Types.Double, 0.0);

    AddParameter("PointValue", 1);
   	AddParameter("EMA1_Period", 5);
    AddParameter("EMA2_Period", 21); 
}

function Evaluate()
{
	// 11/12/2024 dev by Maks
    // Herrick Payoff Index (HPI)
    if (CurrentIndex < 1) {
        HPI = 0.0;
   		HPI_EMA1[0] = HPI;
   		K1 = 2.0/(EMA1_Period + 1.0);
   		HPI_EMA2[0] = HPI;
   		K2 = 2.0/(EMA2_Period + 1.0);
    } else {
		double m =  (Input.High[ 0] + Input.Low[ 0]) / 2.0;
		double m1 = (Input.High[-1] + Input.Low[-1]) / 2.0;

   		double i = Math.Abs(Input.OpenInterest[0]- Input.OpenInterest[-1]);
		double g = Math.Min(Input.OpenInterest[0], Input.OpenInterest[-1]);

		if (g > 0) HPI = (m - m1) * PointValue * Input.Volume[0] * (1.0 + i / g);
		else HPI = HPI[1];
	//	HPI /= 100;
		
   		HPI_EMA1 = (1.0 - K1)*HPI_EMA1[-1] + K1*HPI[0];
    	HPI_EMA2 = (1.0 - K2)*HPI_EMA2[-1] + K2*HPI[0];
    	
    	if (HPI > HPI_EMA2)
			HPI_EMA1.DrawChannel(HPI_EMA2, Color.Green, 50);
        else
			HPI_EMA1.DrawChannel(HPI_EMA2, Color.Red, 50);
   }
}