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// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
// File name:     G4VEmAngularDistribution
//
// Author:        V. Ivanchenko using design of existing 
//                interface G4VBremAngularDistribution
// 
// Creation date: 13 October 2010
//
// Modifications: 
//
// Class Description: 
//
// Abstract base class for polar angle sampling
//
// Class Description: End 

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

#ifndef G4VEmAngularDistribution_h
#define G4VEmAngularDistribution_h 1

#include "globals.hh"
#include "Randomize.hh"
#include "G4ThreeVector.hh"
#include "G4DynamicParticle.hh"

class G4Material;

class G4VEmAngularDistribution
{
public:

  explicit G4VEmAngularDistribution(const G4String& name);

  virtual ~G4VEmAngularDistribution();

  // Sample direction in global coordinate system,
  // this means for zero scattering angle this direction is the same
  // as the direction of primary 
  virtual G4ThreeVector& SampleDirection(const G4DynamicParticle* dp,
					 G4double finalTotalEnergy,
					 G4int Z,
					 const G4Material*) = 0;

  // Sample direction in global coordinate system for given electronic shell,
  // this means for zero scattering angle this direction is the same
  // as the direction of primary 
  virtual G4ThreeVector& SampleDirectionForShell(
					 const G4DynamicParticle* dp,
					 G4double finalTotalEnergy,
					 G4int Z,
					 G4int shellID,
					 const G4Material*);

  virtual void SamplePairDirections(const G4DynamicParticle* dp,
				    G4double elecKinEnergy,
				    G4double posiKinEnergy,
				    G4ThreeVector& dirElectron,
				    G4ThreeVector& dirPositron,
				    G4int Z = 0,
				    const G4Material* mat = nullptr);

  inline const G4String& GetName() const;

protected:

  G4ThreeVector fLocalDirection;

private:

  // hide assignment operator
  G4VEmAngularDistribution & 
    operator=(const  G4VEmAngularDistribution &right) = delete;
  G4VEmAngularDistribution(const  G4VEmAngularDistribution&) = delete;

  G4String fName;
};

inline const G4String& G4VEmAngularDistribution::GetName() const
{
  return fName;
}

#endif

