///////////////////////////////////////////////////////////////////////////////
//
// Tracks and reflects the photons as necessary through the
// concentrator geometry.
//
// Author: Phil G Jones <p.jones22@physics.ox.ac.uk>
//
// REVISION HISTORY:
//     05/11/2010 : P G Jones - New file
//     2014-08-50 : P G Jones - Update doxygen.
//     05/04/2016 : R P F Stainforth - Add functionality for scaling the reflectivity
//                                     probabilities in constructor.
//
///////////////////////////////////////////////////////////////////////////////

#ifndef __RAT_ConcentratorOpticalModel_hh__
#define __RAT_ConcentratorOpticalModel_hh__

#include <G4VFastSimulationModel.hh>
#include <G4UImessenger.hh>

#include <RAT/OpticalModelBase.hh>

class G4Region;
class G4LogicalVolume;

namespace RAT
{

class ConcentratorOpticalModel : public G4VFastSimulationModel,
                                 public OpticalModelBase
{
public:
  // The constructor invoked with the model name and applicable region
  //
  // name: name of this model
  // region: region this model is applied in
  // params: parameters that control this models settings, index to RATDB
  // volume: volume this model applies to
  ConcentratorOpticalModel( const G4String name, G4Region* const region,
                            const std::string params, G4LogicalVolume* const volume );

  // Destructor
  ~ConcentratorOpticalModel();

  // Returns true if this model applies to the particle type
  //
  // type: type of particle this model applies to
  // Returns true if the type is an optical photon
  G4bool IsApplicable( const G4ParticleDefinition& type );

  // Returns true if this model should be invoked
  //
  // fastTrack: track to consider
  // Returns true if the fastTrack triggers this model
  G4bool ModelTrigger( const G4FastTrack & fastTrack );

  // The method that does the actual tracking
  //
  // fastTrack: track to track
  // fastStep: result of tracking
  virtual void DoIt( const G4FastTrack& fastTrack, G4FastStep& fastStep );

protected:
  // Enum of existing concentrator volumes, each one also acts as an index to fConcVolNames, so must ensure they match
  enum EConcVolumes{ eEnvelope, ePetal, ePlastic, eOut };

  // Track the photon through the concentrator geometry
  //
  // fastTrack: photon track information
  // position: position in local coordinates
  // direction: direction in local coordinates
  // polarisation: polarisation in local coordinates
  // time: time in global MC units
  // weight: weight of the track >0 to be alive
  void TrackPhoton( const G4FastTrack& fastTrack, G4ThreeVector& position,
                    G4ThreeVector& direction, G4ThreeVector& polarisation,
                    G4double& time, G4double& weight );

  // Reflect a photon at a boundary either normal, diffuse or absorbed
  //
  // position: position in local coordinates
  // energy: energy of the photon
  // direction: direction in local coordinates
  // polarisation: polarisation in local coordinates
  // weight: weight of the track >0 to be alive
  // Returns true if photon reflects
  bool Reflect( const G4ThreeVector& position, const G4double energy,
                G4ThreeVector& direction, G4ThreeVector& polarisation,
                G4double& weight );

  // Return the reflection probability for the angle and wavelength.
  //
  // Note DB table used is in 1nm blocks from 305nm to 800nm (inclusive) with
  // each block having 91 elements for 0-90 degrees
  //
  // position: position in local coordinates
  // theta: photon angle to the boundary, in radians
  // energy: energy of the photon
  // polarisation: polarisation in local coordinates
  // specularR: specular reflection probability
  // diffuseR: diffuse reflection probability
  virtual void GetReflectionProb( const G4ThreeVector& position,
                                  const G4double theta,  const G4double energy,
                                  const EPolarisation polarisation,
                                  G4double& specularR, G4double& diffuseR );

  std::vector<std::string> fConcVolNames; // The names of the Concentrator volumes, indexed by EConcVolumes

  std::vector<G4double> fReflectionSPol; // Reflection probability table for S polarised photons
  std::vector<G4double> fReflectionPPol; // Reflection probability table for P polarised photons

  G4MaterialPropertyVector* fGVelocityWater; // Water group velocity

  G4VSolid* fConcEnvelopeVolume; // Concentrator envelope volume
  G4VSolid* fPetalVolume; // Petal volume
  G4VSolid* fPlasticVolume; // Plastic volume

  G4double fDiffuseReflectionProb; // Probability of diffuse reflection
};

} //::RAT

#endif