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//
// Class for description of  transition radiation generated
// by  charged particle crossed interface between material 1
// and material 2 (1 -> 2). Transition radiation could be of kind:
// - optical back
// - optical forward
// - X-ray   forward (for relativistic case Tkin/mass >= 10^2)
//
// GEANT 4 class header file --- Copyright CERN 1995
//
// History:
// 18.12.97, V. Grichine (Vladimir.Grichine@cern.ch)
// 02.02.00, V.Grichine, new data fEnergy and fVarAngle for double
//                       numerical integration in inherited classes
// 03.06.03, V.Ivanchenko fix compilation warnings
// 28.07.05, P.Gumplinger add G4ProcessType to constructor

#ifndef G4TransitionRadiation_h
#define G4TransitionRadiation_h

#include "globals.hh"
#include "G4ParticleDefinition.hh"
#include "G4Step.hh"
#include "G4Track.hh"
#include "G4VDiscreteProcess.hh"
#include "G4VParticleChange.hh"

class G4TransitionRadiation : public G4VDiscreteProcess
{
 public:
  explicit G4TransitionRadiation(const G4String& processName = "TR",
                                 G4ProcessType type = fElectromagnetic);

  virtual ~G4TransitionRadiation();

  G4TransitionRadiation(const G4TransitionRadiation& right) = delete;
  G4TransitionRadiation& operator=(const G4TransitionRadiation& right) = delete;

  // Methods

  G4bool IsApplicable(const G4ParticleDefinition& aParticleType) override;

  virtual G4double GetMeanFreePath(const G4Track&, G4double,
                                   G4ForceCondition* condition) override;

  virtual G4VParticleChange* PostStepDoIt(const G4Track&,
                                          const G4Step&) override;

  virtual void ProcessDescription(std::ostream&) const override;
  virtual void DumpInfo() const override { ProcessDescription(G4cout); };

  virtual G4double SpectralAngleTRdensity(G4double energy,
                                          G4double varAngle) const = 0;

  G4double IntegralOverEnergy(G4double energy1, G4double energy2,
                              G4double varAngle) const;

  G4double IntegralOverAngle(G4double energy, G4double varAngle1,
                             G4double varAngle2) const;

  G4double AngleIntegralDistribution(G4double varAngle1,
                                     G4double varAngle2) const;

  G4double EnergyIntegralDistribution(G4double energy1, G4double energy2) const;

 protected:
  // Local constants
  // Accuracy of Sympson integration
  static constexpr G4int fSympsonNumber = 100;
  static constexpr G4int fGammaNumber   = 15;
  static constexpr G4int fPointNumber   = 100;

  G4double fGamma;
  G4double fEnergy;
  G4double fVarAngle;

  G4double fMinEnergy;  //  min TR energy
  G4double fMaxEnergy;  //  max TR energy
  G4double fMaxTheta;   //  max theta of TR quanta

  G4double fSigma1;  // plasma energy Sq of matter1
  G4double fSigma2;  // plasma energy Sq of matter2

  G4int fMatIndex1;  // index of the 1st material
  G4int fMatIndex2;  // index of the 2nd material
};

#endif  // G4TransitionRadiation_h