Placing and Managing Orders

//+------------------------------------------------------------------+
//| Lesson 11 - Raw OrderSend, filling modes, retcodes               |
//| WARNING: sends real market orders. Use a DEMO account.           |
//+------------------------------------------------------------------+
#property copyright "Strategist Academy"
#property version   "1.00"
#property strict

input double Lots        = 0.10;
input int    StopPoints  = 200;
input int    Deviation   = 10;
input ulong  MagicNumber = 11111111;

datetime lastBarTime = 0;

int OnInit()
{
   Print("Filling mode supported by ", _Symbol, ": ",
         EnumToString((ENUM_ORDER_TYPE_FILLING)SymbolInfoInteger(_Symbol, SYMBOL_FILLING_MODE)));
   return(INIT_SUCCEEDED);
}

void OnTick()
{
   datetime t = iTime(_Symbol, _Period, 0);
   if(t == lastBarTime) return;
   lastBarTime = t;

   if(PositionSelect(_Symbol))
   {
      Print("Position already open - skipping.");
      return;
   }

   OpenBuy(Lots, StopPoints);
}

//+------------------------------------------------------------------+
//| Market buy built by hand, with a filling-mode fallback chain     |
//+------------------------------------------------------------------+
void OpenBuy(const double lots, const double stopPoints)
{
   double ask = SymbolInfoDouble(_Symbol, SYMBOL_ASK);
   double sl  = NormalizeDouble(ask - stopPoints * _Point, _Digits);

   MqlTradeRequest req = {};
   MqlTradeResult  res = {};

   req.action    = TRADE_ACTION_DEAL;
   req.symbol    = _Symbol;
   req.volume    = NormalizeDouble(lots, 2);
   req.type      = ORDER_TYPE_BUY;
   req.price     = ask;
   req.sl        = sl;
   req.deviation = Deviation;
   req.magic     = MagicNumber;
   req.comment   = "lesson11";

   // Ask the symbol first; fall back through the rest if the server refuses.
   long supported = SymbolInfoInteger(_Symbol, SYMBOL_FILLING_MODE);

   ENUM_ORDER_TYPE_FILLING modes[3];
   if((supported & SYMBOL_FILLING_FOK) != 0)
      { modes[0] = ORDER_FILLING_FOK;    modes[1] = ORDER_FILLING_IOC;    modes[2] = ORDER_FILLING_RETURN; }
   else if((supported & SYMBOL_FILLING_IOC) != 0)
      { modes[0] = ORDER_FILLING_IOC;    modes[1] = ORDER_FILLING_RETURN; modes[2] = ORDER_FILLING_FOK;    }
   else
      { modes[0] = ORDER_FILLING_RETURN; modes[1] = ORDER_FILLING_FOK;    modes[2] = ORDER_FILLING_IOC;    }

   for(int i = 0; i < 3; i++)
   {
      req.type_filling = modes[i];
      ResetLastError();

      if(!OrderSend(req, res))
      {
         Print("OrderSend failed with ", EnumToString(modes[i]),
               ". GetLastError=", GetLastError());
         continue;
      }

      Print("Sent with ", EnumToString(modes[i]),
            " -> retcode=", res.retcode,
            "  deal=", res.deal,
            "  volume=", DoubleToString(res.volume, 2),
            "  price=", DoubleToString(res.price, _Digits));

      if(res.retcode == TRADE_RETCODE_DONE || res.retcode == TRADE_RETCODE_PLACED)
      {
         Print("SUCCESS: order accepted.");
         return;
      }

      // Retcode-specific hints - do not blindly retry these.
      if(res.retcode == TRADE_RETCODE_INVALID_STOPS)
      {
         Print("Invalid stops: your SL/TP is too close. Broker minimum is ",
               SymbolInfoInteger(_Symbol, SYMBOL_TRADE_STOPS_LEVEL), " points.");
         return;
      }
      if(res.retcode == TRADE_RETCODE_NO_MONEY)
      {
         Print("Not enough margin. Free margin: ",
               DoubleToString(AccountInfoDouble(ACCOUNT_MARGIN_FREE), 2));
         return;
      }
      Print("Rejected with retcode ", res.retcode, " - check the retcode table.");
      return;
   }
}