//+------------------------------------------------------------------+
//|                                        trend-following-ea.mq5     |
//|  A simple trend-following EA: Moving Average crossover, filtered  |
//|  by ADX, with ATR-based Stop Loss/Take Profit and risk-based      |
//|  position sizing. One position at a time.                        |
//|  EDUCATIONAL — test on a demo account first. Past performance     |
//|  does not guarantee future results. This is not financial advice.|
//|  Source: web-forex (educational, free to use and modify)          |
//+------------------------------------------------------------------+
#property copyright "web-forex"
#include <Trade\Trade.mqh>

CTrade trade;

input string       ___Strategy___       = "--- Trend Following Strategy ---";
input int          FastMAPeriod         = 20;
input int          SlowMAPeriod         = 50;
input ENUM_MA_METHOD MAMethod           = MODE_EMA;
input int          ADXPeriod            = 14;
input double       ADXThreshold         = 25.0;

input string       ___RiskManagement___ = "--- Risk Management ---";
input int          ATRPeriod            = 14;
input double       ATRMultiplier        = 2.0;
input double       RiskRewardRatio      = 2.0;
input bool         UseFixedLot          = false;
input double       FixedLotSize         = 0.01;
input double       RiskPercent          = 1.0;

input string       ___Filters___        = "--- Filters ---";
input int          MaxSpreadPoints      = 30;

input string       ___General___        = "--- General ---";
input ulong        MagicNumber          = 20260717;
input bool         EnableTrading        = true;

int fastMAHandle = INVALID_HANDLE;
int slowMAHandle = INVALID_HANDLE;
int adxHandle    = INVALID_HANDLE;
int atrHandle    = INVALID_HANDLE;
datetime lastBarTime = 0;

int OnInit()
{
   trade.SetExpertMagicNumber(MagicNumber);

   fastMAHandle = iMA(_Symbol, _Period, FastMAPeriod, 0, MAMethod, PRICE_CLOSE);
   slowMAHandle = iMA(_Symbol, _Period, SlowMAPeriod, 0, MAMethod, PRICE_CLOSE);
   adxHandle    = iADX(_Symbol, _Period, ADXPeriod);
   atrHandle    = iATR(_Symbol, _Period, ATRPeriod);

   return(INIT_SUCCEEDED);
}

void OnDeinit(const int reason)
{
   IndicatorRelease(fastMAHandle);
   IndicatorRelease(slowMAHandle);
   IndicatorRelease(adxHandle);
   IndicatorRelease(atrHandle);
}

void OnTick()
{
   if (!EnableTrading)
      return;

   datetime currentBarTime = iTime(_Symbol, _Period, 0);
   if (currentBarTime == lastBarTime)
      return; // only evaluate once per new bar
   lastBarTime = currentBarTime;

   if (CountOpenPositions() > 0)
      return; // one position at a time

   long spreadPoints = SymbolInfoInteger(_Symbol, SYMBOL_SPREAD);
   if (spreadPoints > MaxSpreadPoints)
      return; // spread too wide right now, skip this bar

   double fastArr[], slowArr[], adxArr[], atrArr[];
   ArraySetAsSeries(fastArr, true);
   ArraySetAsSeries(slowArr, true);
   ArraySetAsSeries(adxArr, true);
   ArraySetAsSeries(atrArr, true);

   if (CopyBuffer(fastMAHandle, 0, 0, 3, fastArr) < 3) return;
   if (CopyBuffer(slowMAHandle, 0, 0, 3, slowArr) < 3) return;
   if (CopyBuffer(adxHandle, 0, 0, 2, adxArr) < 2) return;
   if (CopyBuffer(atrHandle, 0, 0, 2, atrArr) < 2) return;

   double fastPrev = fastArr[2];
   double slowPrev = slowArr[2];
   double fastLast = fastArr[1];
   double slowLast = slowArr[1];
   double adx       = adxArr[1];
   double atr       = atrArr[1];

   if (adx < ADXThreshold)
      return; // market not trending enough, skip this bar

   bool bullishCross = (fastPrev <= slowPrev && fastLast > slowLast);
   bool bearishCross = (fastPrev >= slowPrev && fastLast < slowLast);

   if (bullishCross)
      OpenTrade(ORDER_TYPE_BUY, atr);
   else if (bearishCross)
      OpenTrade(ORDER_TYPE_SELL, atr);
}

int CountOpenPositions()
{
   int count = 0;
   for (int i = 0; i < PositionsTotal(); i++)
   {
      ulong ticket = PositionGetTicket(i);
      if (ticket > 0 && PositionSelectByTicket(ticket))
      {
         if (PositionGetString(POSITION_SYMBOL) == _Symbol && PositionGetInteger(POSITION_MAGIC) == (long)MagicNumber)
            count++;
      }
   }
   return(count);
}

void OpenTrade(ENUM_ORDER_TYPE type, double atr)
{
   double slDistance = atr * ATRMultiplier;
   double tpDistance = slDistance * RiskRewardRatio;
   double lots       = CalculateLotSize(slDistance);
   double price, sl, tp;

   if (type == ORDER_TYPE_BUY)
   {
      price = SymbolInfoDouble(_Symbol, SYMBOL_ASK);
      sl = price - slDistance;
      tp = price + tpDistance;
      trade.Buy(lots, _Symbol, price, sl, tp, "Trend EA");
   }
   else
   {
      price = SymbolInfoDouble(_Symbol, SYMBOL_BID);
      sl = price + slDistance;
      tp = price - tpDistance;
      trade.Sell(lots, _Symbol, price, sl, tp, "Trend EA");
   }
}

double CalculateLotSize(double slDistance)
{
   if (UseFixedLot || slDistance <= 0)
      return(NormalizeLotSize(FixedLotSize));

   double riskAmount = AccountInfoDouble(ACCOUNT_BALANCE) * (RiskPercent / 100.0);
   double tickValue   = SymbolInfoDouble(_Symbol, SYMBOL_TRADE_TICK_VALUE);
   double tickSize    = SymbolInfoDouble(_Symbol, SYMBOL_TRADE_TICK_SIZE);
   if (tickSize <= 0 || tickValue <= 0)
      return(NormalizeLotSize(FixedLotSize));

   double slTicks = slDistance / tickSize;
   double lots    = riskAmount / (slTicks * tickValue);

   return(NormalizeLotSize(lots));
}

double NormalizeLotSize(double lots)
{
   double minLot  = SymbolInfoDouble(_Symbol, SYMBOL_VOLUME_MIN);
   double maxLot  = SymbolInfoDouble(_Symbol, SYMBOL_VOLUME_MAX);
   double lotStep = SymbolInfoDouble(_Symbol, SYMBOL_VOLUME_STEP);
   if (lotStep <= 0)
      return(minLot);

   lots = MathFloor(lots / lotStep) * lotStep;
   if (lots < minLot)
      lots = minLot;
   if (lots > maxLot)
      lots = maxLot;
   return(lots);
}