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//
// GEANT4 Class header file G4ChargeExchangeXS
//
// Author V.Ivanchenko 
//
// Modified: 09.08.2023 Tim Lok Chau, CERN summer student program 
//
 
// This is a class for charge exchange hadronic cross sections:
// pi- + N(Z, A) -> X + N(Z-1, A)
// pi+ + N(Z, A) -> X + N(Z+1, A)
//
// where X = pi0, eta, etaP, omega, f2
// V. Lyubovitsky, NA64 Collaboration (CERN)
//
// K- + N(Z, A) -> Y  + N(Z-1, A)
// K+ + N(Z, A) -> Y  + N(Z+1, A)
// KL + N(Z, A) -> K+ + N(Z-1, A)
// KL + N(Z, A) -> K- + N(Z+1, A)
//
// where Y = KS, KL
// 

#ifndef G4ChargeExchangeXS_h
#define G4ChargeExchangeXS_h 

#include "G4VCrossSectionDataSet.hh"
#include "globals.hh"
#include <vector>

class G4DynamicParticle;
class G4ParticleDefinition;
class G4Isotope;
class G4Element;
class G4Material;
class G4Pow;

class G4ChargeExchangeXS final : public G4VCrossSectionDataSet
{
public: 

  G4ChargeExchangeXS();

  ~G4ChargeExchangeXS() override = default;

  G4bool IsIsoApplicable(const G4DynamicParticle*, G4int Z, G4int A,
			 const G4Element*, const G4Material*) override;

  G4double GetIsoCrossSection(const G4DynamicParticle*, G4int Z, G4int A,
                              const G4Isotope* iso,
                              const G4Element* elm,
                              const G4Material* mat) override;

  void CrossSectionDescription(std::ostream&) const override;

  const G4ParticleDefinition*
  SampleSecondaryType(const G4ParticleDefinition*,
                      const G4int Z, const G4int A);

  void SetEnergyLimit(G4double val) { fEnergyLimit = val; };

  void SetCrossSectionFactor(G4double val) { fFactor = val; };

  G4ChargeExchangeXS & operator=(const G4ChargeExchangeXS &right) = delete;
  G4ChargeExchangeXS(const G4ChargeExchangeXS&) = delete;

private:

  G4Pow* g4calc;
  const G4ParticleDefinition* fPionSecPD[5];
  G4double fXSecPion[5] = {0.0, 0.0, 0.0, 0.0, 0.0};
  G4double fEnergyLimit{0.0};
  G4double fFactor{1.0};
};

#endif