#ifndef _TauolaHepMCParticle_h_included_
#define _TauolaHepMCParticle_h_included_

/**
 * @class TauolaHepMCParticle
 *
 * @brief Interface to HepMC::GenParticle objects
 *
 * This class implements the virtual methods of
 * TauolaParticle. In this way it provides an
 * interface between the generic TauolaParticle class
 * and a HepMC::GenParticle object.
 *
 * @author Nadia Davidson
 * @date 17 June 2008
 *
 * This code is licensed under GNU General Public Licence.
 * For more informations, see: http://www.gnu.org/licenses/
 */

#include <iostream>
#include <vector>

#include "HepMC/GenParticle.h"
#include "HepMC/SimpleVector.h"
#include "HepMC/GenEvent.h"

//#include "DecayList.h"
#include "TauolaParticle.h"
#include "f_Decay.h"

namespace Tauolapp
{

class TauolaHepMCParticle: public TauolaParticle{

 public:
  /** General constructor */
  TauolaHepMCParticle();

  ~TauolaHepMCParticle();

  /** Constructor which keeps a pointer to the HepMC::GenParticle*/
  TauolaHepMCParticle(HepMC::GenParticle * particle); 

  /** Constructor which creates a new HepMC::GenParticle and
       sets the properties pdg_id, statu and mass. */
  TauolaHepMCParticle(int pdg_id, int status, double mass);
  
  /** Returns the HepMC::GenParticle */
  HepMC::GenParticle * getHepMC();

  /** Remove the decay branch from the event record and reset the particle status code to stable. */
  void undecay();

  /** Set the mothers of this particle via a vector of TauolaParticle*/
  void setMothers(std::vector<TauolaParticle*> mothers);

  /** Set the daughters of this particle via a vector of TauolaParticle*/
  void setDaughters(std::vector<TauolaParticle*> daughters);

  /** Returns the mothers of this particle via a vector of TauolaParticle */
  std::vector<TauolaParticle*> getMothers();

  /** Returns the daughters of this particle via a vector of TauolaParticle */
  std::vector<TauolaParticle*> getDaughters();

  /** Set the PDG ID code of this particle */
  void setPdgID(int pdg_id);

  /** Set the status of this particle */
  void setStatus(int statu);

  /** Set the mass of this particle */
  void setMass(double mass);

  /** Get the PDG ID code of this particle */
  int getPdgID();

  /** Get the status of this particle */
  int getStatus();

  /** Get the barcode of this particle */
  int getBarcode();

  /** Check that the 4 momentum in conserved at the vertices producing
      and ending this particle */
  void checkMomentumConservation();

  /** Overriding of TauolaParticle decayEndgame method.
      Converts the momentum and length units
      and sets the vector (X,T) position */
  void decayEndgame();

  /** Create a new particle of type TauolaHepMCParticle, with the given
      properties. The new particle bares no relations to this
      particle, but it provides a way of creating a instance of
      this derived class. eg. createNewParticle() is used inside
      filhep_() so that a TauolaHepMCParticle can be created without
      the method having explicit knowledge of the TauolaHepMCParticle 
      class */
  TauolaHepMCParticle * createNewParticle(int pdg_id, int status, double mass,
                                          double px, double py,
                                          double pz, double e);

  /** Print some information about this particle to standard output */
  void print();

  /** Returns the px component of the four vector*/
  double getPx();

  /** Returns the py component of the four vector */
  double getPy();

  /** Returns the pz component of the four vector */
  double getPz();

  /** Returns the energy component of the four vector */
  double getE();

  /** Set the px component of the four vector */
  void setPx( double px );

  /** Set the px component of the four vector */
  void setPy( double py );

  /** Set the pz component of the four vector */
  void setPz( double pz );

  /** Set the energy component of the four vector */
  void setE( double e );


private:

  /** Sets the position for whole decay tree starting from given particle */
  void recursiveSetPosition(HepMC::GenParticle *p,HepMC::FourVector pos);

  /** A pointer to the HepMC::GenParticle particle */
  HepMC::GenParticle * m_particle;

  /** A list of mothers */
  std::vector<TauolaParticle*> m_mothers;

  /** A list of daughters */
  std::vector<TauolaParticle*> m_daughters;

  /** List to keep track of new particles which have been
      created from this one, so we can call their destructor later */
  std::vector<TauolaParticle*> m_created_particles;

};

} // namespace Tauolapp
#endif