//+------------------------------------------------------------------+
//|                                                MoneyFixedLot.mqh |
//|                             Copyright 2000-2023, MetaQuotes Ltd. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#include "..\Expert\ExpertMoneyCustom.mqh"
// wizard description start
//+------------------------------------------------------------------+
//| Description of the class                                         |
//| Title=Trading with fixed trade volume                            |
//| Type=Money                                                       |
//| Name=FixLot                                                      |
//| Class=CMoneyFixedLot                                             |
//| Page=                                                            |
//| Parameter=Percent,double,10.0,Percent                            |
//| Parameter=Lots,double,0.1,Fixed volume                           |
//+------------------------------------------------------------------+
// wizard description end
//+------------------------------------------------------------------+
//| Class CMoneyFixedLot.                                            |
//| Purpose: Class of money management with fixed lot.               |
//|              Derives from class CExpertMoney.                    |
//+------------------------------------------------------------------+
class CMoneyFixedLot : public CExpertMoneyCustom
  {
protected:
   //--- input parameters
   double            m_lots;
   //--- declared ahead of the inline CheckOpenLong/Short bodies below that call it
   double            CheckedLot(ENUM_ORDER_TYPE type);

public:
   //---
   void              Lots(double lots)                      { m_lots=lots; }
   virtual bool      ValidationSettings(void);
   //--- The fixed lot from the input is a REQUEST, not a guarantee: it still has to clear the
   //--- broker's volume grid, the per-symbol SYMBOL_VOLUME_LIMIT and free margin before it can be
   //--- sent (article 2555 #2/#3/#5). Returning m_lots raw - as this class used to - meant a
   //--- Money_FixLot_Lots that a small/loaded account cannot margin was handed straight to
   //--- OrderSend() and rejected server-side with "not enough money" every single signal.
   virtual double    CheckOpenLong(double price,double sl)  { return(CheckedLot(ORDER_TYPE_BUY)); }
   virtual double    CheckOpenShort(double price,double sl) { return(CheckedLot(ORDER_TYPE_SELL)); }
  };
//+------------------------------------------------------------------+
//| Run the configured fixed lot through the shared pre-OrderSend     |
//| volume gate; 0.0 means "no legal volume right now", which         |
//| CExpert::OpenLong/OpenShort treat as "do not trade this tick".    |
//+------------------------------------------------------------------+
double CMoneyFixedLot::CheckedLot(ENUM_ORDER_TYPE type)
  {
   double lot = m_lots;
   string description;
   if(!ValidateLotForTrade(MoneySymbol(), lot, type, description))
      return(0.0);
   return(lot);
  }
//+------------------------------------------------------------------+
//| Validation settings protected data.                              |
//+------------------------------------------------------------------+
bool CMoneyFixedLot::ValidationSettings(void)
  {
   if(!CExpertMoney::ValidationSettings())
      return(false);
//--- initial data checks
   if(m_lots<m_symbol.LotsMin() || m_lots>m_symbol.LotsMax())
     {
      printf(__FUNCTION__+": lots amount must be in the range from %f to %f",m_symbol.LotsMin(),m_symbol.LotsMax());
      return(false);
     }
//--- article 2555 #10: LotsStep() is 0 until the broker syncs SYMBOL_VOLUME_STEP, and the
//--- multiple-of-step test below divides by it twice
   if(m_symbol.LotsStep()<=0.0)
     {
      printf(__FUNCTION__+": SYMBOL_VOLUME_STEP for %s is not available yet (%f)",m_symbol.Name(),m_symbol.LotsStep());
      return(false);
     }
   if(MathAbs(m_lots/m_symbol.LotsStep()-MathRound(m_lots/m_symbol.LotsStep()))>1.0E-10)
     {
      printf(__FUNCTION__+": lots amount is not corresponding with lot step %f",m_symbol.LotsStep());
      return(false);
     }
//--- ok
   return(true);
  }
//+------------------------------------------------------------------+