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Farhad Crab Strategy (C#)

Overview

The Farhad Crab strategy is a trend-following system that enters trades on pullbacks to an exponential moving average (EMA) and manages exits using fixed stops, take-profits, a Parabolic SAR-inspired trailing stop, and a higher time frame filter. The original MetaTrader 5 expert advisor relies on hourly candles for execution while referencing daily data to decide when to close open positions. This C# port keeps the same core logic by combining a working timeframe EMA filter with a daily EMA crossover exit rule.

Core Concepts

  • Trend filter: An EMA calculated on the working timeframe (default 15-period EMA on 1-hour candles). Only long signals are allowed when the previous candle's low remains above the EMA, and only short signals are allowed when the previous candle's high stays below the EMA.
  • Daily filter: A separate EMA computed on daily candles. When the daily EMA crosses above the daily close, all long positions are closed. When it crosses below, all short positions are closed. This mimics the original ClosePositions logic from the MQL5 code.
  • Risk controls: Fixed stop-loss and take-profit levels are derived from pip distances. A trailing stop moves the protective stop once the position gains enough profit, emulating the MT5 trailing function that combines TrailingStop and TrailingStep settings.
  • One-position management: The strategy trades a single net position. Entering a long position while holding a short (or vice versa) first closes the opposite exposure before opening the new trade, aligning with how MT5 hedging positions were aggregated in the conversion.

Trading Rules

  1. Signal detection (working timeframe):
    • Long entry when the previous candle's low is greater than the EMA value (after applying the configured shift).
    • Short entry when the previous candle's high is less than the EMA value.
  2. Position sizing: The Volume parameter sets the base order size. When reversing from a short to a long (or vice versa), the engine automatically sends the additional quantity required to flip the net position.
  3. Stop-loss & take-profit:
    • Distances are defined in pips. Pip size automatically adapts to the security's tick size, with five-digit and three-digit FX symbols using a 10x multiplier to match MT5 behaviour.
    • Stop-loss or take-profit can be disabled by setting the respective pip distance to zero.
  4. Trailing stop:
    • Activates only when TrailingStopPips is greater than zero.
    • The stop is moved to current_price - TrailingStopPips (for longs) or current_price + TrailingStopPips (for shorts) once the position profit exceeds TrailingStopPips + TrailingStepPips.
    • The additional trailing step prevents frequent modifications, matching the EA's use of TrailingStep.
  5. Daily exit filter:
    • Uses the last two completed daily candles.
    • Long positions are closed if the daily EMA was below the daily close two days ago and is above the daily close on the most recent day (bearish crossover).
    • Short positions are closed if the opposite crossover occurs.

Parameters

Name Type Default Description
CandleType DataType 1-hour time frame Working time frame used for the execution EMA and entry logic.
MaLength int 15 Period of the EMA on the working time frame.
MaShift int 0 Number of completed candles used to shift the EMA backwards.
DailyMaLength int 15 Period of the daily EMA that provides the crossover exit filter.
StopLossPips decimal 50 Stop-loss distance in pips. Set to 0 to disable.
TakeProfitPips decimal 50 Take-profit distance in pips. Set to 0 to disable.
TrailingStopPips decimal 10 Trailing stop distance in pips. Set to 0 to disable trailing.
TrailingStepPips decimal 5 Minimum additional gain in pips before the trailing stop is updated again.
Volume decimal 0.1 Base trade size in lots/contracts.

Notes & Differences from the MQL Version

  • This port always uses exponential moving averages, reflecting the original default (MODE_EMA). Other MT5 smoothing modes are not supported.
  • The MT5 expert advisor works with bid/ask quotes on every tick. This translation operates on finished candles, so stop-loss and take-profit checks are evaluated on candle highs/lows.
  • The Parabolic SAR indicator present in the original file did not influence trade decisions and is therefore omitted from the C# implementation.
  • Trailing logic adjusts the stored stop level but does not send broker stop orders. The exit occurs when the candle range touches the calculated stop or take-profit level.

Usage Tips

  • Choose a candle type that matches the desired trading horizon. The default one-hour candles replicate the behaviour of the source script.
  • Adjust MaLength and DailyMaLength together to tune responsiveness between intra-day entries and higher time frame trend filters.
  • For FX symbols quoted with five digits (e.g., EURUSD), pip distances will be automatically scaled so that 1 pip equals 0.0001.
  • When running in backtests, ensure the daily data stream is available so that the exit filter can function correctly.
using System;
using System.Linq;
using System.Collections.Generic;

using Ecng.Common;
using Ecng.Collections;
using Ecng.Serialization;

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

namespace StockSharp.Samples.Strategies;

/// <summary>
/// Trend-following strategy converted from the FarhadCrab1 MT5 expert advisor.
/// The strategy enters on pullbacks to an EMA, manages risk with pip-based levels,
/// and closes positions based on a daily EMA crossover filter.
/// </summary>
public class FarhadCrab1Strategy : Strategy
{
	private readonly StrategyParam<DataType> _candleType;
	private readonly StrategyParam<int> _maLength;
	private readonly StrategyParam<int> _maShift;
	private readonly StrategyParam<int> _dailyMaLength;
	private readonly StrategyParam<decimal> _stopLossPips;
	private readonly StrategyParam<decimal> _takeProfitPips;
	private readonly StrategyParam<decimal> _trailingStopPips;
	private readonly StrategyParam<decimal> _trailingStepPips;
	private readonly StrategyParam<decimal> _orderVolume;

	private readonly Queue<decimal> _maValues = new();

	private readonly DataType _dailyCandleType = TimeSpan.FromHours(1).TimeFrame();

	private decimal? _stopLossPrice;
	private decimal? _takeProfitPrice;

	private decimal? _prevDailyClose;
	private decimal? _prevDailyMa;
	private decimal? _prevPrevDailyClose;
	private decimal? _prevPrevDailyMa;

	private ICandleMessage _previousCandle;
	private decimal _entryPrice;

	/// <summary>
	/// Working candle type for the execution timeframe.
	/// </summary>
	public DataType CandleType
	{
		get => _candleType.Value;
		set => _candleType.Value = value;
	}

	/// <summary>
	/// Period of the EMA used on the working timeframe.
	/// </summary>
	public int MaLength
	{
		get => _maLength.Value;
		set => _maLength.Value = value;
	}

	/// <summary>
	/// Number of completed candles to shift the EMA backwards.
	/// </summary>
	public int MaShift
	{
		get => _maShift.Value;
		set => _maShift.Value = value;
	}

	/// <summary>
	/// Period of the daily EMA that closes positions on crossovers.
	/// </summary>
	public int DailyMaLength
	{
		get => _dailyMaLength.Value;
		set => _dailyMaLength.Value = value;
	}

	/// <summary>
	/// Stop-loss distance expressed in pips.
	/// </summary>
	public decimal StopLossPips
	{
		get => _stopLossPips.Value;
		set => _stopLossPips.Value = value;
	}

	/// <summary>
	/// Take-profit distance expressed in pips.
	/// </summary>
	public decimal TakeProfitPips
	{
		get => _takeProfitPips.Value;
		set => _takeProfitPips.Value = value;
	}

	/// <summary>
	/// Trailing stop distance in pips.
	/// </summary>
	public decimal TrailingStopPips
	{
		get => _trailingStopPips.Value;
		set => _trailingStopPips.Value = value;
	}

	/// <summary>
	/// Additional pip distance required before updating the trailing stop again.
	/// </summary>
	public decimal TrailingStepPips
	{
		get => _trailingStepPips.Value;
		set => _trailingStepPips.Value = value;
	}

	/// <summary>
	/// Base order volume in lots/contracts.
	/// </summary>
	public decimal OrderVolume
	{
		get => _orderVolume.Value;
		set => _orderVolume.Value = value;
	}

	/// <summary>
	/// Initializes a new instance of the <see cref="FarhadCrab1Strategy"/> class.
	/// </summary>
	public FarhadCrab1Strategy()
	{
		_candleType = Param(nameof(CandleType), TimeSpan.FromHours(4).TimeFrame())
			.SetDisplay("Candle Type", "Execution timeframe", "General");

		_maLength = Param(nameof(MaLength), 15)
			.SetGreaterThanZero()
			.SetDisplay("EMA Length", "EMA period on the working timeframe", "Indicators");

		_maShift = Param(nameof(MaShift), 0)
			.SetRange(0, 100)
			.SetDisplay("EMA Shift", "Shift EMA value backwards by N candles", "Indicators");

		_dailyMaLength = Param(nameof(DailyMaLength), 15)
			.SetGreaterThanZero()
			.SetDisplay("Daily EMA Length", "EMA period used on daily candles", "Indicators");

		_stopLossPips = Param(nameof(StopLossPips), 50m)
			.SetRange(0m, 500m)
			.SetDisplay("Stop Loss (pips)", "Stop-loss distance in pips", "Protection");

		_takeProfitPips = Param(nameof(TakeProfitPips), 50m)
			.SetRange(0m, 500m)
			.SetDisplay("Take Profit (pips)", "Take-profit distance in pips", "Protection");

		_trailingStopPips = Param(nameof(TrailingStopPips), 10m)
			.SetRange(0m, 500m)
			.SetDisplay("Trailing Stop (pips)", "Trailing stop distance in pips", "Protection");

		_trailingStepPips = Param(nameof(TrailingStepPips), 5m)
			.SetRange(0m, 500m)
			.SetDisplay("Trailing Step (pips)", "Extra gain in pips before updating the trailing stop", "Protection");

		_orderVolume = Param(nameof(OrderVolume), 0.1m)
			.SetGreaterThanZero()
			.SetDisplay("Volume", "Base order volume", "Trading");
	}

	/// <inheritdoc />
	public override IEnumerable<(Security sec, DataType dt)> GetWorkingSecurities()
	{
		return [(Security, CandleType), (Security, _dailyCandleType)];
	}

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

		_maValues.Clear();
		_stopLossPrice = null;
		_takeProfitPrice = null;
		_prevDailyClose = null;
		_prevDailyMa = null;
		_prevPrevDailyClose = null;
		_prevPrevDailyMa = null;
		_previousCandle = null;
		_entryPrice = 0m;
	}

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

		// Ensure the base strategy volume reflects the configured parameter.
		base.Volume = OrderVolume;

		// Subscribe to the working timeframe candles with an EMA for entry decisions.
		var ema = new ExponentialMovingAverage { Length = MaLength };
		var candleSubscription = SubscribeCandles(CandleType);
		candleSubscription
			.Bind(ema, ProcessWorkingCandle)
			.Start();

		// Subscribe to daily candles with another EMA for exit filtering.
		var dailyEma = new ExponentialMovingAverage { Length = DailyMaLength };
		var dailySubscription = SubscribeCandles(_dailyCandleType);
		dailySubscription
			.Bind(dailyEma, ProcessDailyCandle)
			.Start();

		// Draw candles, indicator, and trades on the chart if charting is available.
		var area = CreateChartArea();
		if (area != null)
		{
			DrawCandles(area, candleSubscription);
			DrawOwnTrades(area);
			DrawIndicator(area, ema);
		}
	}

	private void ProcessDailyCandle(ICandleMessage candle, decimal emaValue)
	{
		// Process only finished daily candles.
		if (candle.State != CandleStates.Finished)
			return;

		_prevPrevDailyClose = _prevDailyClose;
		_prevPrevDailyMa = _prevDailyMa;
		_prevDailyClose = candle.ClosePrice;
		_prevDailyMa = emaValue;
	}

	private void ProcessWorkingCandle(ICandleMessage candle, decimal emaValue)
	{
		// Use only completed candles for decision making.
		if (candle.State != CandleStates.Finished)
			return;

		// Store EMA values so we can apply the configured shift.
		UpdateMaBuffer(emaValue);
		var shiftedMa = GetShiftedMaValue();
		if (shiftedMa == null)
		{
			_previousCandle = candle;
			return;
		}

		// Require at least one previous candle to evaluate entry conditions.
		if (_previousCandle == null)
		{
			_previousCandle = candle;
			return;
		}

		// Close positions when the daily EMA filter signals a crossover against us.
		if (TryCloseByDailyFilter())
		{
			_previousCandle = candle;
			return;
		}

		var pipSize = GetPipSize();

		// Check for stop-loss or take-profit triggers before adjusting trailing stops.
		if (CheckStopsAndTargets(candle))
		{
			_previousCandle = candle;
			return;
		}

		// Update trailing stop levels if the position has moved far enough.
		ApplyTrailingStop(candle, pipSize);

		// Evaluate long entry condition: previous low above the EMA.
		if (Position <= 0 && _previousCandle.LowPrice > shiftedMa.Value)
		{
			var volume = OrderVolume + (Position < 0 ? -Position : 0m);
			if (volume > 0)
			{
				BuyMarket(volume);
				SetRiskLevels(candle.ClosePrice, pipSize, true);
			}
			_previousCandle = candle;
			return;
		}

		// Evaluate short entry condition: previous high below the EMA.
		if (Position >= 0 && _previousCandle.HighPrice < shiftedMa.Value)
		{
			var volume = OrderVolume + (Position > 0 ? Position : 0m);
			if (volume > 0)
			{
				SellMarket(volume);
				SetRiskLevels(candle.ClosePrice, pipSize, false);
			}
			_previousCandle = candle;
			return;
		}

		// Store the current candle for the next iteration.
		_previousCandle = candle;
	}

	private bool TryCloseByDailyFilter()
	{
		if (_prevDailyClose == null || _prevDailyMa == null || _prevPrevDailyClose == null || _prevPrevDailyMa == null)
			return false;

		var prevClose = _prevDailyClose.Value;
		var prevMa = _prevDailyMa.Value;
		var prev2Close = _prevPrevDailyClose.Value;
		var prev2Ma = _prevPrevDailyMa.Value;

		// Bearish crossover: EMA moved above the daily close -> exit long positions.
		if (Position > 0 && prevMa > prevClose && prev2Ma < prev2Close)
		{
			SellMarket(Position);
			ResetRiskLevels();
			return true;
		}

		// Bullish crossover: EMA moved below the daily close -> exit short positions.
		if (Position < 0 && prevMa < prevClose && prev2Ma > prev2Close)
		{
			BuyMarket(-Position);
			ResetRiskLevels();
			return true;
		}

		return false;
	}

	private bool CheckStopsAndTargets(ICandleMessage candle)
	{
		if (Position > 0)
		{
			if (_stopLossPrice.HasValue && candle.LowPrice <= _stopLossPrice.Value)
			{
				SellMarket(Position);
				ResetRiskLevels();
				return true;
			}

			if (_takeProfitPrice.HasValue && candle.HighPrice >= _takeProfitPrice.Value)
			{
				SellMarket(Position);
				ResetRiskLevels();
				return true;
			}
		}
		else if (Position < 0)
		{
			if (_stopLossPrice.HasValue && candle.HighPrice >= _stopLossPrice.Value)
			{
				BuyMarket(-Position);
				ResetRiskLevels();
				return true;
			}

			if (_takeProfitPrice.HasValue && candle.LowPrice <= _takeProfitPrice.Value)
			{
				BuyMarket(-Position);
				ResetRiskLevels();
				return true;
			}
		}
		else if (_stopLossPrice.HasValue || _takeProfitPrice.HasValue)
		{
			// Clear stored levels when the position is flat.
			ResetRiskLevels();
		}

		return false;
	}

	private void ApplyTrailingStop(ICandleMessage candle, decimal pipSize)
	{
		if (TrailingStopPips <= 0m)
			return;

		var entryPrice = _entryPrice;
		var threshold = (TrailingStopPips + TrailingStepPips) * pipSize;

		if (Position > 0)
		{
			var profit = candle.ClosePrice - entryPrice;
			if (profit > threshold)
			{
				var minStop = candle.ClosePrice - threshold;
				var candidate = candle.ClosePrice - TrailingStopPips * pipSize;
				if (!_stopLossPrice.HasValue || _stopLossPrice.Value < minStop)
					_stopLossPrice = candidate;
			}
		}
		else if (Position < 0)
		{
			var profit = entryPrice - candle.ClosePrice;
			if (profit > threshold)
			{
				var maxStop = candle.ClosePrice + threshold;
				var candidate = candle.ClosePrice + TrailingStopPips * pipSize;
				if (!_stopLossPrice.HasValue || _stopLossPrice.Value > maxStop)
					_stopLossPrice = candidate;
			}
		}
	}

	private void SetRiskLevels(decimal executionPrice, decimal pipSize, bool isLong)
	{
		_entryPrice = executionPrice;
		if (StopLossPips > 0m && pipSize > 0m)
			_stopLossPrice = isLong
				? executionPrice - StopLossPips * pipSize
				: executionPrice + StopLossPips * pipSize;
		else
			_stopLossPrice = null;

		if (TakeProfitPips > 0m && pipSize > 0m)
			_takeProfitPrice = isLong
				? executionPrice + TakeProfitPips * pipSize
				: executionPrice - TakeProfitPips * pipSize;
		else
			_takeProfitPrice = null;
	}

	private void ResetRiskLevels()
	{
		_stopLossPrice = null;
		_takeProfitPrice = null;
	}

	private decimal GetPipSize()
	{
		var security = Security;
		if (security == null)
			return 0.0001m;

		var step = security.PriceStep ?? 0.0001m;
		var decimals = security.Decimals;

		if (decimals == 3 || decimals == 5)
			return step * 10m;

		return step;
	}

	private void UpdateMaBuffer(decimal emaValue)
	{
		_maValues.Enqueue(emaValue);

		var maxCount = Math.Max(MaShift + 1, 1);
		while (_maValues.Count > maxCount)
			_maValues.Dequeue();
	}

	private decimal? GetShiftedMaValue()
	{
		var count = _maValues.Count;
		var targetIndex = count - MaShift - 1;
		if (targetIndex < 0)
			return null;

		var index = 0;
		foreach (var value in _maValues)
		{
			if (index == targetIndex)
				return value;
			index++;
		}

		return null;
	}
}