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Four Bar Momentum Reversal Strategy

The Four Bar Momentum Reversal strategy enters long when the close has been below the close from Lookback bars ago for at least BuyThreshold consecutive candles within the selected time window. The position is closed once price breaks above the previous candle high.

Details

  • Entry Criteria: BuyThreshold consecutive closes below the close from Lookback bars ago inside the time window.
  • Exit Criteria: Close price greater than the previous candle high.
  • Stops: None.
  • Default Values:
    • BuyThreshold = 4
    • Lookback = 4
    • StartTime = 2014-01-01
    • EndTime = 2099-01-01
namespace StockSharp.Samples.Strategies;

using System;
using System.Collections.Generic;

using Ecng.Common;

using StockSharp.Algo.Indicators;
using StockSharp.Algo.Strategies;
using StockSharp.BusinessEntities;
using StockSharp.Messages;

/// <summary>
/// Four Bar Momentum Reversal Strategy.
/// Enters long after consecutive closes below the close from N bars ago.
/// Exits on breakout above previous high.
/// Uses EMA as trend filter.
/// </summary>
public class FourBarMomentumReversalStrategy : Strategy
{
	private readonly StrategyParam<DataType> _candleType;
	private readonly StrategyParam<int> _buyThreshold;
	private readonly StrategyParam<int> _lookback;
	private readonly StrategyParam<int> _emaLength;
	private readonly StrategyParam<int> _cooldownBars;

	private ExponentialMovingAverage _ema;
	private readonly List<decimal> _closes = new();
	private int _belowCount;
	private decimal _prevHigh;
	private int _cooldownRemaining;

	public DataType CandleType { get => _candleType.Value; set => _candleType.Value = value; }
	public int BuyThreshold { get => _buyThreshold.Value; set => _buyThreshold.Value = value; }
	public int Lookback { get => _lookback.Value; set => _lookback.Value = value; }
	public int EmaLength { get => _emaLength.Value; set => _emaLength.Value = value; }
	public int CooldownBars { get => _cooldownBars.Value; set => _cooldownBars.Value = value; }

	public FourBarMomentumReversalStrategy()
	{
		_candleType = Param(nameof(CandleType), TimeSpan.FromMinutes(30).TimeFrame())
			.SetDisplay("Candle Type", "Type of candles to use", "General");

		_buyThreshold = Param(nameof(BuyThreshold), 3)
			.SetGreaterThanZero()
			.SetDisplay("Buy Threshold", "Consecutive closes below reference to trigger buy", "Strategy");

		_lookback = Param(nameof(Lookback), 4)
			.SetGreaterThanZero()
			.SetDisplay("Lookback", "Number of bars to compare", "Strategy");

		_emaLength = Param(nameof(EmaLength), 20)
			.SetGreaterThanZero()
			.SetDisplay("EMA Length", "EMA trend filter period", "Indicators");

		_cooldownBars = Param(nameof(CooldownBars), 15)
			.SetDisplay("Cooldown Bars", "Bars between trades", "Risk");
	}

	/// <inheritdoc />
	public override IEnumerable<(Security sec, DataType dt)> GetWorkingSecurities()
		=> [(Security, CandleType)];

	/// <inheritdoc />
	protected override void OnReseted()
	{
		base.OnReseted();

		_ema = null;
		_closes.Clear();
		_belowCount = 0;
		_prevHigh = 0;
		_cooldownRemaining = 0;
	}

	/// <inheritdoc />
	protected override void OnStarted2(DateTime time)
	{
		base.OnStarted2(time);

		_ema = new ExponentialMovingAverage { Length = EmaLength };

		var subscription = SubscribeCandles(CandleType);
		subscription
			.Bind(_ema, ProcessCandle)
			.Start();

		var area = CreateChartArea();
		if (area != null)
		{
			DrawCandles(area, subscription);
			DrawIndicator(area, _ema);
			DrawOwnTrades(area);
		}
	}

	private void ProcessCandle(ICandleMessage candle, decimal emaVal)
	{
		if (candle.State != CandleStates.Finished)
			return;

		if (!_ema.IsFormed)
		{
			_closes.Add(candle.ClosePrice);
			_prevHigh = candle.HighPrice;
			return;
		}

		var close = candle.ClosePrice;

		// Track past closes for lookback comparison
		if (_closes.Count >= Lookback)
		{
			var pastClose = _closes[_closes.Count - Lookback];

			if (close < pastClose)
				_belowCount++;
			else
				_belowCount = 0;
		}

		_closes.Add(close);

		// Keep list from growing too large
		if (_closes.Count > Lookback + 10)
			_closes.RemoveAt(0);

		if (!IsFormedAndOnlineAndAllowTrading())
		{
			_prevHigh = candle.HighPrice;
			return;
		}

		if (_cooldownRemaining > 0)
		{
			_cooldownRemaining--;
			_prevHigh = candle.HighPrice;
			return;
		}

		// Buy: consecutive closes below reference + price below EMA (reversal from weakness)
		if (_belowCount >= BuyThreshold && Position <= 0)
		{
			if (Position < 0)
				BuyMarket(Math.Abs(Position));
			BuyMarket(Volume);
			_cooldownRemaining = CooldownBars;
		}
		// Exit long: breakout above previous high
		else if (Position > 0 && close > _prevHigh)
		{
			SellMarket(Math.Abs(Position));
			_cooldownRemaining = CooldownBars;
		}
		// Short: consecutive closes above reference (overbought reversal)
		else if (_belowCount == 0 && _closes.Count > Lookback)
		{
			var pastClose = _closes[_closes.Count - 1 - Lookback];
			var aboveCount = 0;
			for (int i = _closes.Count - 1; i >= Math.Max(0, _closes.Count - BuyThreshold); i--)
			{
				if (_closes[i] > pastClose)
					aboveCount++;
				else
					break;
			}

			if (aboveCount >= BuyThreshold && Position >= 0 && close > emaVal)
			{
				if (Position > 0)
					SellMarket(Math.Abs(Position));
				SellMarket(Volume);
				_cooldownRemaining = CooldownBars;
			}
		}

		_prevHigh = candle.HighPrice;
	}
}