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/// \file optical/wls/src/WLSPhotonDetSD.cc
/// \brief Implementation of the WLSPhotonDetSD class
//
//
#include "WLSPhotonDetSD.hh"

#include "WLSPhotonDetHit.hh"
#include "WLSUserTrackInformation.hh"

#include "G4OpticalPhoton.hh"
#include "G4SDManager.hh"
#include "G4Step.hh"
#include "G4ThreeVector.hh"
#include "G4TouchableHistory.hh"
#include "G4Track.hh"
#include "G4VTouchable.hh"

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

WLSPhotonDetSD::WLSPhotonDetSD(G4String name)
  : G4VSensitiveDetector(name)
{
  collectionName.insert("PhotonDetHitCollection");
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

void WLSPhotonDetSD::Initialize(G4HCofThisEvent* HCE)
{
  fPhotonDetHitCollection =
    new WLSPhotonDetHitsCollection(SensitiveDetectorName, collectionName[0]);

  if(fHCID < 0)
  {
    fHCID =
      G4SDManager::GetSDMpointer()->GetCollectionID(fPhotonDetHitCollection);
  }
  HCE->AddHitsCollection(fHCID, fPhotonDetHitCollection);
}

//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

G4bool WLSPhotonDetSD::ProcessHits(G4Step* aStep, G4TouchableHistory*)
{
  if(!aStep)
    return false;
  G4Track* theTrack = aStep->GetTrack();

  // Need to know if this is an optical photon
  if(theTrack->GetDefinition() != G4OpticalPhoton::OpticalPhotonDefinition())
  {
    return false;
  }

  // Find out information regarding the hit
  G4StepPoint* thePostPoint = aStep->GetPostStepPoint();

  auto trackInformation =
    (WLSUserTrackInformation*) theTrack->GetUserInformation();

  auto theTouchable = (G4TouchableHistory*) (thePostPoint->GetTouchable());

  G4ThreeVector photonExit   = trackInformation->GetExitPosition();
  G4ThreeVector photonArrive = thePostPoint->GetPosition();
  G4double arrivalTime       = theTrack->GetGlobalTime();
  G4double energy            = theTrack->GetTotalEnergy();

  // Convert the global coordinate for arriving photons into
  // the local coordinate of the detector
  photonArrive =
    theTouchable->GetHistory()->GetTopTransform().TransformPoint(photonArrive);

  // Creating the hit and add it to the collection
  fPhotonDetHitCollection->insert(
    new WLSPhotonDetHit(photonExit, photonArrive, arrivalTime, energy));

  return true;
}

void WLSPhotonDetSD::EndOfEvent(G4HCofThisEvent*)
{
  if ( verboseLevel>1 ) {
     G4int nofHits = fPhotonDetHitCollection->entries();
     G4cout << G4endl
            << "-------->Hits Collection: in this event there are " << nofHits
            << " hits in the photon detector: " << G4endl;
     for ( G4int i=0; i<nofHits; i++ ) (*fPhotonDetHitCollection)[i]->Print();
  }
}

