// @(#)root/vmc:$Id$
// Authors: Ivana Hrivnacova, Rene Brun , Federico Carminati 13/04/2002

/*************************************************************************
 * Copyright (C) 2006, Rene Brun and Fons Rademakers.                    *
 * Copyright (C) 2002, ALICE Experiment at CERN.                         *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/

#include "TVirtualMC.h"

//______________________________________________________________________________
//   Virtual MC provides a virtual interface to Monte Carlo.
//   It enables the user to build a virtual Monte Carlo application
//   independent of any actual underlying Monte Carlo implementation itself.
//
//   A user will have to implement a class derived from the abstract
//   Monte Carlo application class, and provide functions like
//   ConstructGeometry(), BeginEvent(), FinishEvent(), ... .
//   The concrete Monte Carlo (Geant3, Geant4) is selected at run time -
//   when processing a ROOT macro where the concrete Monte Carlo is instantiated.
//______________________________________________________________________________

ClassImp(TVirtualMC)

TMCThreadLocal TVirtualMC* TVirtualMC::fgMC=0;

////////////////////////////////////////////////////////////////////////////////
///
/// Standard constructor
///

TVirtualMC::TVirtualMC(const char *name, const char *title,
                       Bool_t /*isRootGeometrySupported*/)
  : TNamed(name,title),
    fApplication(0),
    fStack(0),
    fDecayer(0),
    fRandom(0),
    fMagField(0)
{
   if(fgMC) {
      Warning("TVirtualMC","Cannot initialise twice MonteCarlo class");
   } else {
      fgMC=this;

      fApplication = TVirtualMCApplication::Instance();

      if (!fApplication) {
         Error("TVirtualMC", "No user MC application is defined.");
      }

      fRandom = gRandom;
   }
}

////////////////////////////////////////////////////////////////////////////////
///
/// Default constructor
///

TVirtualMC::TVirtualMC()
  : TNamed(),
    fApplication(0),
    fStack(0),
    fDecayer(0),
    fRandom(0),
    fMagField(0)
{
}

////////////////////////////////////////////////////////////////////////////////
///
/// Destructor
///

TVirtualMC::~TVirtualMC()
{
   fgMC=0;
}

//
// methods
//

////////////////////////////////////////////////////////////////////////////////
///static: return virtual MC object

TVirtualMC *TVirtualMC::GetMC()
{
   return fgMC;
}

////////////////////////////////////////////////////////////////////////////////
///
/// Set particles stack.
///

void TVirtualMC::SetStack(TVirtualMCStack* stack)
{
   fStack = stack;
}

////////////////////////////////////////////////////////////////////////////////
///
/// Set external decayer.
///

void TVirtualMC::SetExternalDecayer(TVirtualMCDecayer* decayer)
{
   fDecayer = decayer;
}

////////////////////////////////////////////////////////////////////////////////
///
/// Set random number generator.
///

void TVirtualMC::SetRandom(TRandom* random)
{
   gRandom = random;
   fRandom = random;
}

////////////////////////////////////////////////////////////////////////////////
///
/// Set magnetic field.
///

void TVirtualMC::SetMagField(TVirtualMagField* field)
{
   fMagField = field;
}