//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
// $Id$
//
// Authors: G.Depaola & F.Longo
//

#ifndef G4LivermorePolarizedGammaConversionModel_h
#define G4LivermorePolarizedGammaConversionModel_h 1

#include "G4VEmModel.hh"
#include "G4Electron.hh"
#include "G4Positron.hh"
#include "G4ParticleChangeForGamma.hh"
#include "G4CrossSectionHandler.hh"
#include "G4LogLogInterpolation.hh"
#include "G4CompositeEMDataSet.hh"
#include "G4ProductionCutsTable.hh"
#include "G4ForceCondition.hh"


class G4LivermorePolarizedGammaConversionModel : public G4VEmModel
{

public:

  G4LivermorePolarizedGammaConversionModel(const G4ParticleDefinition* p = 0, 
		                   const G4String& nam = "LivermorePolarizedGammaConversion");

  virtual ~G4LivermorePolarizedGammaConversionModel();

  virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);

  virtual G4double ComputeCrossSectionPerAtom(
                                const G4ParticleDefinition*,
                                      G4double kinEnergy, 
                                      G4double Z, 
                                      G4double A=0, 
                                      G4double cut=0,
                                      G4double emax=DBL_MAX);

  virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*,
				 const G4MaterialCutsCouple*,
				 const G4DynamicParticle*,
				 G4double tmin,
				 G4double maxEnergy);

protected:

  G4ParticleChangeForGamma* fParticleChange;

  G4double GetMeanFreePath(const G4Track& aTrack, 
			   G4double previousStepSize, 
			   G4ForceCondition* condition);
private:

  G4double lowEnergyLimit;  
  G4double highEnergyLimit; 
  G4bool isInitialised;
  G4int verboseLevel;

  G4VEMDataSet* meanFreePathTable;
  G4VCrossSectionHandler* crossSectionHandler;


  // specific methods for polarization 
  
  G4ThreeVector GetRandomPolarization(G4ThreeVector& direction0); // Random Polarization
  G4ThreeVector GetPerpendicularPolarization(const G4ThreeVector& direction0, const G4ThreeVector& polarization0) const;
  G4ThreeVector SetPerpendicularVector(G4ThreeVector& a); // temporary
  void SystemOfRefChange(G4ThreeVector& direction0, G4ThreeVector& direction1, 
			 G4ThreeVector& polarization0);

  // Gamma Conversion methods 


  G4double SetPhi(G4double);
  G4double SetPsi(G4double, G4double); //

  G4double ScreenFunction1(G4double screenVariable);
  G4double ScreenFunction2(G4double screenVariable);
  void SetTheta(G4double*, G4double*, G4double);

  G4double Poli(G4double , G4double, G4double, G4double);
  G4double Fln(G4double, G4double, G4double);

  G4double Encu(G4double*, G4double*, G4double);

  G4double Flor(G4double*, G4double);
  G4double Glor(G4double*, G4double);

  G4double Fdlor(G4double*, G4double);
  G4double Fintlor(G4double*, G4double);
  G4double Finvlor(G4double*, G4double,G4double);

  G4double Ftan(G4double*, G4double);

  //G4double Gtan(G4double*, G4double);

  G4double Fdtan(G4double*, G4double);
  G4double Finttan(G4double*, G4double);
  G4double Finvtan(G4double*, G4double, G4double);

  G4double smallEnergy;
  G4double Psi, Phi;

  
  G4LivermorePolarizedGammaConversionModel & operator=(const  G4LivermorePolarizedGammaConversionModel &right);
  G4LivermorePolarizedGammaConversionModel(const  G4LivermorePolarizedGammaConversionModel&);

};

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....

#endif