Andrew's Pitchfork from Zigzag indicator

using cAlgo.API;
using cAlgo.API.Internals;
using cAlgo.API.Indicators;
 

namespace cAlgo.Indicators
{
    [Indicator(IsOverlay = true, AutoRescale = true, AccessRights = AccessRights.None)]
    public class AndrewsPitchforkZigZag : Indicator
    {

        #region Properties
         [Parameter("High", DefaultValue = "High")]
        public DataSeries High { get; set ; }

        [Parameter("Low", DefaultValue = "Low")]
        public DataSeries Low { get; set; }

        [Parameter("Period", DefaultValue = 16, MinValue = 1)]
        public int Period { get; set; }

        [Output("ZigZagSeries", Color = Colors.Green, Thickness = 1, PlotType = PlotType.Line)]
        public IndicatorDataSeries ZigZagSeries { get; set; }

        [Parameter("Show Andrews Pitchfork", DefaultValue = true)]
        public bool ShowAndrewsPitchfork { get; set; }

        [Parameter("AndrewsPitchfork Color" ,DefaultValue = Colors.Red )]
        public Colors AndrewsPitchforkColor{ get; set; }

        #endregion

        #region Variables
        double currentZigZagHigh, currentZigZagLow = 0;
        int lastSwingIndex = -1;
        double lastSwingPrice = 0.0;
        int trendDir, CurrentBar = 0;
        #endregion

        protected override void Initialize()
        {
            
        }

        public override void Calculate(int index)
        {
            CalculateZigZag(index) ;
       
            if (ShowAndrewsPitchfork)
                DrawAndrewsPitchfork(index);
        }

        public void CalculateZigZag(int index)
        {
            CurrentBar = High.Count;

            if (CurrentBar < 2)
                return;

            if (lastSwingPrice == 0.0)
                lastSwingPrice = Low[index] + (High[index] - Low[index]) / 2;

            bool isSwingHigh = High[index] == Functions.Maximum(High, Period);
            bool isSwingLow = Low[index] == Functions.Minimum(Low, Period);
            double saveValue = 0.0;
            bool addHigh= false;
            bool addLow= false;
            bool updateHigh= false;
            bool updateLow = false;

            if (trendDir == 1 && isSwingHigh && High[index] >= lastSwingPrice)
            {
                saveValue = High[index];
                updateHigh = true;
            }
            else if (trendDir == -1 && isSwingLow && Low[index] <= lastSwingPrice)
            {
                saveValue = Low[index];
                updateLow = true;
            }
            else if (trendDir <= 0 && isSwingHigh)
            {
                saveValue = High[index];
                addHigh = true;
                trendDir = 1;
            }
            else if (trendDir >= 0 && isSwingLow)
            {
                saveValue = Low[index];
                addLow = true;
                trendDir = -1;
            }

            if (addHigh || addLow || updateHigh || updateLow)
            {
                if (updateHigh && lastSwingIndex >= 0)
                {
                    ZigZagSeries[lastSwingIndex] = double.NaN;
                }
                else if (updateLow && lastSwingIndex >= 0)
                {
                    ZigZagSeries[lastSwingIndex] = double.NaN;
                }

                if (addHigh || updateHigh)
                {
                    currentZigZagHigh = saveValue;
                    ZigZagSeries[index] = currentZigZagHigh;
                }
                else if (addLow || updateLow)
                {
                    currentZigZagLow = saveValue;
                    ZigZagSeries[index] = currentZigZagLow;
                }

                lastSwingIndex = CurrentBar - 1;
                lastSwingPrice = saveValue;
            }
        }
        public void DrawAndrewsPitchfork(int index)
        {
            int barIndex1 = 0;
            int barIndex2 = 0;
            int barIndex3 = 0;
            int barIndex4 = 0;

            for (int i = index; i >= 0; i--)
            {
                if (ZigZagSeries[i] > 0)
                {
                    if (barIndex4 == 0)
                    {
                        barIndex4 = i;
                    }
                    else if (barIndex3 == 0)
                    {
                        barIndex3 = i;
                    }
                    else if (barIndex2 == 0)
                    {
                        barIndex2 = i;
                    }
                    else if (barIndex1 == 0)
                    {
                        barIndex1 = i;
                        break;
                    }
                }
            }

            var y1 = ZigZagSeries[barIndex1];
            var y2 = ZigZagSeries[barIndex2];
            var y3 = ZigZagSeries[barIndex3];

            Chart.DrawAndrewsPitchfork("AndrewsPitchFork", barIndex1, y1, barIndex2, y2, barIndex3, y3, Color.FromName(AndrewsPitchforkColor.ToString()) ); 
              
        }
    }
}