Pull Back Strategy

using System;
using System.Collections.Generic;

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

namespace StockSharp.Samples.Strategies;

public class PullBackStrategy : Strategy
{
	private readonly StrategyParam<DataType> _candleType;
	private readonly StrategyParam<int> _fastPeriod;
	private readonly StrategyParam<int> _slowPeriod;
	private decimal? _prevFast, _prevSlow;

	public DataType CandleType { get => _candleType.Value; set => _candleType.Value = value; }
	public int FastPeriod { get => _fastPeriod.Value; set => _fastPeriod.Value = value; }
	public int SlowPeriod { get => _slowPeriod.Value; set => _slowPeriod.Value = value; }

	public PullBackStrategy()
	{
		_candleType = Param(nameof(CandleType), TimeSpan.FromHours(1).TimeFrame()).SetDisplay("Candle Type", "Timeframe", "General");
		_fastPeriod = Param(nameof(FastPeriod), 5).SetGreaterThanZero().SetDisplay("Fast EMA", "Fast EMA period", "Indicators");
		_slowPeriod = Param(nameof(SlowPeriod), 15).SetGreaterThanZero().SetDisplay("Slow EMA", "Slow EMA period", "Indicators");
	}

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

	/// <inheritdoc />
	protected override void OnReseted()
	{
		base.OnReseted();
		_prevFast = null;
		_prevSlow = null;
	}

	protected override void OnStarted2(DateTime time)
	{
		base.OnStarted2(time);
		_prevFast = null; _prevSlow = null;
		var fast = new ExponentialMovingAverage { Length = FastPeriod };
		var slow = new ExponentialMovingAverage { Length = SlowPeriod };
		var subscription = SubscribeCandles(CandleType);
		subscription.Bind(fast, slow, ProcessCandle).Start();
		var area = CreateChartArea();
		if (area != null) { DrawCandles(area, subscription); DrawIndicator(area, fast); DrawIndicator(area, slow); DrawOwnTrades(area); }
	}

	private void ProcessCandle(ICandleMessage candle, decimal fast, decimal slow)
	{
		if (candle.State != CandleStates.Finished) return;
		if (!IsFormedAndOnlineAndAllowTrading()) { _prevFast = fast; _prevSlow = slow; return; }
		if (_prevFast == null || _prevSlow == null) { _prevFast = fast; _prevSlow = slow; return; }
		var prevAbove = _prevFast.Value > _prevSlow.Value;
		var currAbove = fast > slow;
		_prevFast = fast; _prevSlow = slow;
		if (!prevAbove && currAbove && Position <= 0) { if (Position < 0) BuyMarket(); BuyMarket(); }
		else if (prevAbove && !currAbove && Position >= 0) { if (Position > 0) SellMarket(); SellMarket(); }
	}
}

import clr

clr.AddReference("StockSharp.Messages")
clr.AddReference("StockSharp.Algo")
clr.AddReference("StockSharp.Algo.Indicators")
clr.AddReference("StockSharp.Algo.Strategies")

from System import TimeSpan
from StockSharp.Messages import DataType, CandleStates
from StockSharp.Algo.Indicators import ExponentialMovingAverage
from StockSharp.Algo.Strategies import Strategy


class pull_back_strategy(Strategy):
    def __init__(self):
        super(pull_back_strategy, self).__init__()

        self._candle_type = self.Param("CandleType", DataType.TimeFrame(TimeSpan.FromHours(1))) \
            .SetDisplay("Candle Type", "Timeframe", "General")
        self._fast_period = self.Param("FastPeriod", 5) \
            .SetDisplay("Fast EMA", "Fast EMA period", "Indicators")
        self._slow_period = self.Param("SlowPeriod", 15) \
            .SetDisplay("Slow EMA", "Slow EMA period", "Indicators")

        self._prev_fast = None
        self._prev_slow = None

    @property
    def CandleType(self):
        return self._candle_type.Value
    @property
    def FastPeriod(self):
        return self._fast_period.Value
    @property
    def SlowPeriod(self):
        return self._slow_period.Value

    def OnReseted(self):
        super(pull_back_strategy, self).OnReseted()
        self._prev_fast = None
        self._prev_slow = None

    def OnStarted2(self, time):
        super(pull_back_strategy, self).OnStarted2(time)
        self._prev_fast = None
        self._prev_slow = None
        fast = ExponentialMovingAverage()
        fast.Length = self.FastPeriod
        slow = ExponentialMovingAverage()
        slow.Length = self.SlowPeriod
        subscription = self.SubscribeCandles(self.CandleType)
        subscription.Bind(fast, slow, self._on_process).Start()
        area = self.CreateChartArea()
        if area is not None:
            self.DrawCandles(area, subscription)
            self.DrawIndicator(area, fast)
            self.DrawIndicator(area, slow)
            self.DrawOwnTrades(area)

    def _on_process(self, candle, fast_value, slow_value):
        if candle.State != CandleStates.Finished:
            return
        fv = float(fast_value)
        sv = float(slow_value)
        if self._prev_fast is None or self._prev_slow is None:
            self._prev_fast = fv
            self._prev_slow = sv
            return
        prev_above = self._prev_fast > self._prev_slow
        curr_above = fv > sv
        self._prev_fast = fv
        self._prev_slow = sv
        if not prev_above and curr_above and self.Position <= 0:
            if self.Position < 0:
                self.BuyMarket()
            self.BuyMarket()
        elif prev_above and not curr_above and self.Position >= 0:
            if self.Position > 0:
                self.SellMarket()
            self.SellMarket()

    def CreateClone(self):
        return pull_back_strategy()