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//
// Geant4 Class header file
//
// File name:     G4StokesVector
//
// Author:        Andreas Schaelicke
//
// Class Description:
//   Provides Stokesvector representation employed in implementation of
//   polarized processes.
//   - store three components of a stokesvector
//   - distinguish between boson or fermion state (different transformations)
//   - provide unique definition of reference frame (cf. G4PolarizationHelper)

#ifndef G4StokesVector_h
#define G4StokesVector_h 1

#include "G4ThreeVector.hh"
#include "G4RotationMatrix.hh"

class G4StokesVector : public G4ThreeVector
{
 public:
  G4StokesVector();
  explicit G4StokesVector(const G4ThreeVector& v);
  ~G4StokesVector() = default;

  G4bool IsZero() const;

  inline G4double p1() const { return x(); }
  inline G4double p2() const { return y(); }
  inline G4double p3() const { return z(); }

  inline G4double Transverse() const { return perp(); }

  inline G4ThreeVector PolSqr() const
  {
    return G4ThreeVector(x() * x(), y() * y(), z() * z());
  }
  inline G4ThreeVector PolSqrt() const
  {
    return G4ThreeVector(std::sqrt(x()), std::sqrt(y()), std::sqrt(z()));
  }
  G4ThreeVector PolError(const G4StokesVector& sum2, long n);

  // Ratio of 3-vectors.
  G4ThreeVector PolDiv(const G4StokesVector&);

  inline void SetPhoton() { fIsPhoton = true; }

  void RotateAz(G4ThreeVector nInteractionFrame,
                G4ThreeVector particleDirection);
  void InvRotateAz(G4ThreeVector nInteractionFrame,
                   G4ThreeVector particleDirection);
  void RotateAz(G4double cosphi, G4double sinphi);
  G4double GetBeta();

  void DiceUniform();
  void DiceP1();
  void DiceP2();
  void DiceP3();

  void FlipP3();

  // standard vectors:
  static const G4StokesVector ZERO;
  static const G4StokesVector P1;
  static const G4StokesVector P2;
  static const G4StokesVector P3;
  static const G4StokesVector M1;
  static const G4StokesVector M2;
  static const G4StokesVector M3;

 private:
  G4bool fIsPhoton;
};

#endif