How to Use Heiken Ashi data calculated EMA cross-over and cross-under for cRobot scripts

I have tried the following but it didn't worked.

Can anyone help me out in this? It will be a great help. Thank You!!

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

namespace cAlgo.Robots
{
    [Robot(TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
    public class HeikenAshiEmaCrossOverBot : Robot
    {
        [Parameter("EMA Period", DefaultValue = 50)]
        public int EmaPeriod { get; set; }

        [Parameter("Volume", DefaultValue = 10000, MinValue = 0)]
        public int Volume { get; set; }

        private ExponentialMovingAverage _ema;
        private IndicatorDataSeries _haClose;
        private IndicatorDataSeries _haOpen;

        protected override void OnStart()
        {
            _haClose = CreateDataSeries();
            _haOpen = CreateDataSeries();
        }

        protected override void OnBar()
        {
            if (Bars.ClosePrices.Count < EmaPeriod)
            {
                return;
            }

            var index = Bars.ClosePrices.Count - 1;

            _haClose[index] = (MarketSeries.Open[index] + MarketSeries.High[index] + MarketSeries.Low[index] + MarketSeries.Close[index]) / 4;
            _haOpen[index] = index > 0 ? (_haOpen[index - 1] + _haClose[index - 1]) / 2 : (MarketSeries.Open[index] + MarketSeries.Close[index]) / 2;

            _ema = Indicators.ExponentialMovingAverage(_haClose, EmaPeriod);

            if (_haClose[index] > _ema.Result[index] && _haOpen[index - 1] < _ema.Result[index - 1])
            {
                ClosePreviousPositions();
                ExecuteMarketOrder(TradeType.Buy, SymbolName, Volume, "HeikenAshiEmaCrossOverBot");
            }
            else if (_haClose[index] < _ema.Result[index] && _haOpen[index - 1] > _ema.Result[index - 1])
            {
                ClosePreviousPositions();
                ExecuteMarketOrder(TradeType.Sell, SymbolName, Volume, "HeikenAshiEmaCrossOverBot");
            }
        }

        private void ClosePreviousPositions()
        {
            foreach (var position in Positions)
            {
                if (position.Label == "HeikenAshiEmaCrossOverBot")
                {
                    ClosePosition(position);
                }
            }
        }
    }
}