/*//////////////////////////////////////////////////////////////////////////////
// CMT Cosmic Muon Tomography project //////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////

  Copyright (c) 2014, Universita' degli Studi di Padova, INFN sez. di Padova
  All rights reserved

  Authors: Andrea Rigoni Garola < andrea.rigoni@pd.infn.it >

  ------------------------------------------------------------------
  This library is free software;  you  can  redistribute  it  and/or
  modify it  under the  terms  of  the  GNU  Lesser  General  Public
  License as published  by  the  Free  Software  Foundation;  either
  version 3.0 of the License, or (at your option) any later version.

  This library is  distributed in  the hope that it will  be useful,
  but  WITHOUT ANY WARRANTY;  without  even  the implied warranty of
  MERCHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of  the GNU Lesser General  Public
  License along with this library.

//////////////////////////////////////////////////////////////////////////////*/

#ifndef U_GEANTEVENT_H
#define U_GEANTEVENT_H

#include "Core/Types.h"
#include "Core/Vector.h"
#include "Math/Dense.h"

#include <string>

namespace uLib {
namespace Geant {

// Forward declaration for friend access
class SteppingAction;

///////////////////////////////////////////////////////////////////////////////
/// GeantEvent — output of a Geant4 simulation run.
///
/// m_Momentum and m_GenVector are set from the EmitterPrimary at generation.
/// During simulation, each scattering interaction deposits a Delta in m_Path,
/// recording the change of momentum and direction at each step boundary.
///////////////////////////////////////////////////////////////////////////////

class GeantEvent {
  
public:

  /// A single interaction step along the muon path.
  struct Delta {
    Scalarf     m_Length;     ///< step length through the solid
    Scalarf     m_Momentum;  ///< momentum magnitude at this step
    HVector3f   m_Direction; ///< direction after scattering
    std::string m_SolidName; ///< name of the solid where interaction occurred

    uLibGetMacro(Length, Scalarf)
    uLibGetMacro(Momentum, Scalarf)
    uLibConstRefMacro(Direction, HVector3f)
    uLibConstRefMacro(SolidName, std::string)

    Delta() : m_Length(0), m_Momentum(0), m_Direction(HVector3f::Zero()) {}
  };

  // --- Read-only accessors (public) --- //
  uLibGetMacro(EventID, Id_t) 
  uLibGetMacro(Momentum, Scalarf)
  uLibConstRefMacro(GenVector, HLine3f)
  uLibConstRefMacro(Path, Vector<Delta>)

  void Print(const size_t size = 10) const;


private:
  Id_t m_EventID;
  Scalarf m_Momentum;
  HLine3f m_GenVector;
  Vector<Delta> m_Path;

public:
  GeantEvent() : m_EventID(0), m_Momentum(0), m_GenVector(HLine3f()), m_Path() {}

  // SteppingAction can populate the private fields during simulation
  friend class SteppingAction;
};

} // namespace Geant
} // namespace uLib

#endif // U_GEANTEVENT_H