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// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:    G4GammaNuclearXS
//
// Author  V.Ivantchenko, Geant4, 22 October 2020
//
 
// Class Description:
// This is a base class for gamma-nuclear cross section based on
// data files from G4PARTICLEXSDATA data set 
// Class Description - End

#ifndef G4GammaNuclearXS_h
#define G4GammaNuclearXS_h 1

#include "G4VCrossSectionDataSet.hh"
#include "globals.hh"
#include "G4PhysicsVector.hh"
#include "G4Threading.hh"
#include <vector>

class G4DynamicParticle;
class G4ParticleDefinition;
class G4Element;

class G4GammaNuclearXS final : public G4VCrossSectionDataSet
{
public: 

  explicit G4GammaNuclearXS();

  ~G4GammaNuclearXS() final;
    
  static const char* Default_Name() {return "G4GammaNuclearXS";}

  G4bool IsElementApplicable(const G4DynamicParticle*, 
			     G4int Z, const G4Material*) final;

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

  G4double GetElementCrossSection(const G4DynamicParticle*, 
			          G4int Z, const G4Material* mat) final; 

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

  const G4Isotope* SelectIsotope(const G4Element*, 
                                 G4double kinEnergy, G4double logE) final;

  void BuildPhysicsTable(const G4ParticleDefinition&) final;

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

  G4GammaNuclearXS & operator=(const G4GammaNuclearXS &right) = delete;
  G4GammaNuclearXS(const G4GammaNuclearXS&) = delete;
  
private: 

  void Initialise(G4int Z);

  void InitialiseOnFly(G4int Z);

  const G4String& FindDirectoryPath();

  inline G4PhysicsVector* GetPhysicsVector(G4int Z);

  G4VCrossSectionDataSet* ggXsection;
  const G4ParticleDefinition* gamma;

  static const G4int MAXZGAMMAN = 93;
  static G4PhysicsVector* data[MAXZGAMMAN];
  static G4double coeff[MAXZGAMMAN];
  static G4String gDataDirectory;

  G4bool  isMaster;

#ifdef G4MULTITHREADED
  static G4Mutex gNuclearXSMutex;
#endif
};

inline
G4PhysicsVector* G4GammaNuclearXS::GetPhysicsVector(G4int Z)
{
  if(nullptr == data[Z]) { InitialiseOnFly(Z); }
  return data[Z];
}

#endif