///////////////////////////////////////////////////////////////////////////////
//
// Modification of the Cherenkov light emission process.
// More accurate physical model that is relevant for electrons up to 5 MeV.
// Use only for the water phase.
//
// Author: Dmytro Minchenko <minchenk@ualberta.ca>
//
// REVISION HISTORY:
//     08/16/2022 : D. Minchenko - New file
//
///////////////////////////////////////////////////////////////////////////////

#pragma once

/* include std lib */
#include <vector>

/* include RAT lib */
#include <RAT/Cerenkov.hh>

class CerenkovWaterSampling : public Cerenkov
{

public:
  typedef std::vector<std::pair<std::vector<double>, std::vector<double> > > scatteringAngleData;

  CerenkovWaterSampling(const G4String& processName = "Cerenkov",
                 G4ProcessType type = fElectromagnetic);
  virtual ~CerenkovWaterSampling() { }

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

private:
  // Parses the CDFs for sampling
  scatteringAngleData ParseData();

  // Get the mean free path for a given energy
  G4double GetLambda(G4double energy) const;

  // Samples the angles for Cherenkov light emission
  G4double SampleAngle(G4double energy) const;

  scatteringAngleData fSamplingHistograms;
  G4ThreeVector fp0Last;
  G4double fLambdaCorrection;
  std::vector<G4double> fLambdaFitParams;

};