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// G4AdjointPrimaryGeneratorAction
//
// Class description:
//
// This class represents the PrimaryGeneratorAction that is used during
// the entire adjoint simulation.
// It uses the class G4AdjointPrimaryGenerator to generate randomly
// adjoint primary particles on a user selected adjoint source
// (External surface of a volume or Sphere).
// The spectrum of the primary  adjoint particles is set as 1/E with
// user defined max and min energy.
// The weight of the primary is set according to ReverseMC theory as
// w=log(Emax/Emin)*E*adjoint_source_area*pi/n, with E the energy of
// the particle, n the number of adjoint primary particles of same type
// that will be generated during the simulation.
// Different types of adjoint particles are generated event after event
// in order to cover all the type of primaries and secondaries needed
// for the simulation. For example if reverse e- ionisation, brem,
// photo electric effect, and compton are considered both adjoint gamma
// and adjoint e- will be considered alternatively as adjoint primary.
// The user can decide to consider/neglect some type of particle by
// using the macro commands "/adjoint/ConsiderAsPrimary" and
// "/adjoint/NeglectAsPrimary". If  an adjoint primary or its secondary
// has reached the external surface, in the next event a fwd primary
// particle equivalent to the last generated adjoint primary is
// generated with the same position, energy but opposite direction
// and the forward tracking phase starts.

// --------------------------------------------------------------------
//   Class Name:     G4AdjointPrimaryGeneratorAction
//       Author:     L. Desorgher, 2007-2009
// Organisation:     SpaceIT GmbH
//     Contract:     ESA contract 21435/08/NL/AT
//     Customer:     ESA/ESTEC
// --------------------------------------------------------------------
#ifndef G4AdjointPrimaryGeneratorAction_hh
#define G4AdjointPrimaryGeneratorAction_hh 1

#include "G4ThreeVector.hh"
#include "G4VUserPrimaryGeneratorAction.hh"
#include "globals.hh"

#include <iterator>
#include <map>
#include <vector>

class G4AdjointPosOnPhysVolGenerator;
class G4ParticleGun;
class G4Event;
class G4AdjointPrimaryGenerator;
class G4ParticleDefinition;

// --------------------------------------------------------------------

class G4AdjointPrimaryGeneratorAction : public G4VUserPrimaryGeneratorAction
{
  public:
    G4AdjointPrimaryGeneratorAction();
    ~G4AdjointPrimaryGeneratorAction() override;

    G4AdjointPrimaryGeneratorAction(const G4AdjointPrimaryGeneratorAction&) = delete;
    G4AdjointPrimaryGeneratorAction& operator=(const G4AdjointPrimaryGeneratorAction&) = delete;

    void GeneratePrimaries(G4Event*) override;
    void SetEmin(G4double val);
    void SetEmax(G4double val);
    void SetEminIon(G4double val);
    void SetEmaxIon(G4double val);
    void SetSphericalAdjointPrimarySource(G4double radius, G4ThreeVector pos);
    void SetAdjointPrimarySourceOnAnExtSurfaceOfAVolume(const G4String& volume_name);
    void ConsiderParticleAsPrimary(const G4String& particle_name);
    void NeglectParticleAsPrimary(const G4String& particle_name);
    void SetPrimaryIon(G4ParticleDefinition* adjointIon, G4ParticleDefinition* fwdIon);
    void UpdateListOfPrimaryParticles();

    inline void SetRndmFlag(const G4String& val) { rndmFlag = val; }
    inline size_t GetNbOfAdjointPrimaryTypes() { return ListOfPrimaryAdjParticles.size(); }
    inline std::vector<G4ParticleDefinition*>* GetListOfPrimaryFwdParticles()
    {
      return &ListOfPrimaryFwdParticles;
    }
    inline const G4String& GetPrimaryIonName() { return ion_name; }
    inline void SetNbPrimaryFwdGammasPerEvent(G4int nb) { nb_fwd_gammas_per_event = nb; }
    inline void SetNbAdjointPrimaryGammasPerEvent(G4int nb)
    {
      nb_adj_primary_gammas_per_event = nb;
    }
    inline void SetNbAdjointPrimaryElectronsPerEvent(G4int nb)
    {
      nb_adj_primary_electrons_per_event = nb;
    }
    inline G4ParticleDefinition* GetLastGeneratedFwdPrimaryParticle()
    {
      return ListOfPrimaryFwdParticles[index_particle];
    }

  private:  // methods
    G4double ComputeEnergyDistWeight(G4double energy, G4double E1, G4double E2);

  private:  // attributes
    G4String rndmFlag;  // flag for a rndm impact point



    // Emin and Emax energies of the adjoint source
    //---------------------------------------------
    G4double Emin = 0.0;
    G4double Emax = 0.0;
    G4double EminIon = 0.0;
    G4double EmaxIon = 0.0;

    // List of type of primary adjoint and forward  particle used in the
    // simulation
    //------------------------------------------------------------------
    std::vector<G4ParticleDefinition*> ListOfPrimaryFwdParticles;
    std::vector<G4ParticleDefinition*> ListOfPrimaryAdjParticles;
    std::map<G4String, G4bool> PrimariesConsideredInAdjointSim;
    // if true considered if false not considered

    std::size_t index_particle = 100000;

    G4ThreeVector pos, direction, p;

    G4String type_of_adjoint_source;  // Spherical ExtSurfaceOfAVolume
    G4double radius_spherical_source = 0.0;
    G4ThreeVector center_spherical_source;
    G4int nb_fwd_gammas_per_event = 1;
    G4int nb_adj_primary_gammas_per_event = 1;
    G4int nb_adj_primary_electrons_per_event = 1;

    // For simulation with ions
    //--------------------------
    G4ParticleDefinition* fwd_ion = nullptr;
    G4ParticleDefinition* adj_ion = nullptr;
    G4String ion_name = "not_defined";
};

#endif