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//
// INCL++ intra-nuclear cascade model
// Pekka Kaitaniemi, CEA and Helsinki Institute of Physics
// Davide Mancusi, CEA
// Alain Boudard, CEA
// Sylvie Leray, CEA
// Joseph Cugnon, University of Liege
//
#define INCLXX_IN_GEANT4_MODE 1

#include "globals.hh"

#ifndef G4INCLCrossSections_hh
#define G4INCLCrossSections_hh 1

#include "G4INCLParticle.hh"
#include "G4INCLIAvatar.hh"
#include "G4INCLIChannel.hh"

namespace G4INCL {
  class CrossSections {
  public:
    static G4double elastic(Particle const * const p1, Particle const * const p2);
    static G4double total(Particle const * const p1, Particle const * const p2);

    static G4double pionNucleon(Particle const * const p1, Particle const * const p2);

    static G4double recombination(Particle const * const p1, Particle const * const p2);
    static G4double deltaProduction(Particle const * const p1, Particle const * const p2);
    /** \brief Calculate the slope of the NN DDXS.
     *
     * \param energyCM energy in the CM frame, in MeV
     * \param iso total isospin of the system
     *
     * \return the slope of the angular distribution
     */
    static G4double calculateNNDiffCrossSection(G4double energyCM, G4int iso);

    /** \brief Compute the "interaction distance".
     *
     * Defined on the basis of the average value of the N-N cross sections at
     * the given kinetic energy.
     *
     * \return the interaction distance
     */
    static G4double interactionDistanceNN(const G4double projectileKineticEnergy);

    /** \brief Compute the "interaction distance".
     *
     * Defined on the basis of the average value of the pi-N cross sections at
     * the given kinetic energy.
     *
     * \return the interaction distance
     */
    static G4double interactionDistancePiN(const G4double projectileKineticEnergy);

    /** \brief The interaction distance for nucleons at 1 GeV.
     *
     * Used to determine the universe radius at any energy.
     */
    static G4double interactionDistanceNN1GeV() {
      static G4double answer = CrossSections::interactionDistanceNN(1000.);
      return answer;
    }

    /** \brief The interaction distance for pions at 1 GeV.
     *
     * Used to determine the universe radius at any energy.
     */
    static G4double interactionDistancePiN1GeV() {
      static G4double answer = CrossSections::interactionDistancePiN(1000.);
      return answer;
    }

  private:
    static G4double elasticNNHighEnergy(const G4double momentum);
    static G4double elasticProtonNeutron(const G4double momentum);
    static G4double elasticProtonProtonOrNeutronNeutron(const G4double momentum);
    static G4double elasticNN(Particle const * const p1, Particle const * const p2);
    static G4double elasticNNLegacy(Particle const * const p1, Particle const * const p2);

    static G4double deltaProduction(const G4int isospin, const G4double pCM);

    static G4double spnPiPlusPHE(const G4double x);
    static G4double spnPiMinusPHE(const G4double x);

  protected:
    CrossSections() {};
    ~CrossSections() {};
    
  };
}

#endif