//
// ********************************************************************
// * License and Disclaimer                                           *
// *                                                                  *
// * The  Geant4 software  is  copyright of the Copyright Holders  of *
// * the Geant4 Collaboration.  It is provided  under  the terms  and *
// * conditions of the Geant4 Software License,  included in the file *
// * LICENSE and available at  http://cern.ch/geant4/license .  These *
// * include a list of copyright holders.                             *
// *                                                                  *
// * Neither the authors of this software system, nor their employing *
// * institutes,nor the agencies providing financial support for this *
// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
// * for the full disclaimer and the limitation of liability.         *
// *                                                                  *
// * This  code  implementation is the result of  the  scientific and *
// * technical work of the GEANT4 collaboration.                      *
// * By using,  copying,  modifying or  distributing the software (or *
// * any work based  on the software)  you  agree  to acknowledge its *
// * use  in  resulting  scientific  publications,  and indicate your *
// * acceptance of all terms of the Geant4 Software license.          *
// ********************************************************************
//
/// \file SteppingAction.cc
/// \brief Implementation of the SteppingAction class

#include "SteppingAction.hh"

#include "Run.hh"

#include "G4DecayProducts.hh"
#include "G4DecayTable.hh"
#include "G4LossTableManager.hh"
#include "G4ParticleDefinition.hh"
#include "G4ParticleTypes.hh"
#include "G4Step.hh"
#include "G4StepPoint.hh"
#include "G4SystemOfUnits.hh"
#include "G4TouchableHistory.hh"
#include "G4Track.hh"
#include "G4VDecayChannel.hh"
#include "G4VPhysicalVolume.hh"
#include "G4VTouchable.hh"

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

SteppingAction::SteppingAction() : G4UserSteppingAction()
{
  Initialize();
}

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

SteppingAction::~SteppingAction() {}

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

void SteppingAction::Initialize()
{
  // Initialization needed at the beginning of each Run
  fRunPtr = nullptr;
  fToleranceEPviolations = 1.0 * CLHEP::eV;  //***LOOKHERE***
  fPrimaryParticleId = 0;
  fPrimaryParticleInitialKineticEnergy = 0.0;
  fPrimaryParticleInitialTotalEnergy = 0.0;
  fPrimaryParticleInitialMomentum = 0.0;
  fPrimaryParticleInitialBeta = 1.0;
  fPrimaryParticleInitialGamma = 1.0;
  fPrimaryParticleInitial3Momentum = G4ThreeVector(0.0, 0.0, 0.0);
  fPrimaryParticleInitialPosition = G4ThreeVector(0.0, 0.0, 0.0);
  fMaxEkin_deltaMax = 0.0;
  fMaxEtot_deltaMax = 0.0;
  fMaxP_deltaMax = 0.0;
  fMaxPdir_deltaMax = 0.0;
  fMaxMass_deltaMax1 = 0.0;
  fMaxMass_deltaMax2 = 0.0;
  fMaxMass_deltaMax3 = 0.0;
  fMeanMass_deltaMax3 = 0.0;
  fMaxBeta_deltaMax1 = 0.0;
  fMaxBeta_deltaMax2 = 0.0;
  fMaxGamma_deltaMax1 = 0.0;
  fMaxGamma_deltaMax2 = 0.0;
  fMaxGamma_deltaMax3 = 0.0;
  fMaxT_proper_deltaMax = 0.0;
  fMaxT_lab_deltaMax = 0.0;
  fMaxMc_truth_rPos_deltaMax = 0.0;
  fMeanMc_truth_rPos_deltaMax = 0.0;
  fMeanDeltaR_primaryDecay = 0.0;
  fMinDeltaR_primaryDecay = 9999999.9;
  fMaxDeltaR_primaryDecay = -9999999.9;
  fMeanR_primaryDecay = 0.0;
  fMinR_primaryDecay = 9999999.9;
  fMaxR_primaryDecay = -9999999.9;
  fMeanX_primaryDecay = 0.0;
  fMinX_primaryDecay = 9999999.9;
  fMaxX_primaryDecay = -9999999.9;
  fMeanY_primaryDecay = 0.0;
  fMinY_primaryDecay = 9999999.9;
  fMaxY_primaryDecay = -9999999.9;
  fMeanZ_primaryDecay = 0.0;
  fMinZ_primaryDecay = 9999999.9;
  fMaxZ_primaryDecay = -9999999.9;
  fMeanDeltaAngle_primaryDecay = 0.0;
  fMinDeltaAngle_primaryDecay = 9999999.9;
  fMaxDeltaAngle_primaryDecay = -9999999.9;
  fMeanDeltaEkin_primaryDecay = 0.0;
  fMinDeltaEkin_primaryDecay = 9999999.9;
  fMaxDeltaEkin_primaryDecay = -9999999.9;
  fMeanEkin_primaryDecay = 0.0;
  fMinEkin_primaryDecay = 9999999.9;
  fMaxEkin_primaryDecay = -9999999.9;
  fMeanPx_primaryDecay = 0.0;
  fMinPx_primaryDecay = 9999999.9;
  fMaxPx_primaryDecay = -9999999.9;
  fMeanPy_primaryDecay = 0.0;
  fMinPy_primaryDecay = 9999999.9;
  fMaxPy_primaryDecay = -9999999.9;
  fMeanPz_primaryDecay = 0.0;
  fMinPz_primaryDecay = 9999999.9;
  fMaxPz_primaryDecay = -9999999.9;
  fMinUnderestimated_mc_truth_rPos_delta = 9999999.9;
  fMaxOverestimated_mc_truth_rPos_delta = -9999999.9;
  fMeanUnderestimated_mc_truth_rPos_delta = 0.0;
  fMeanOverestimated_mc_truth_rPos_delta = 0.0;
  fMinUnderestimated_rDeltaPos = 9999999.9;
  fMaxOverestimated_rDeltaPos = -9999999.9;
  fMeanUnderestimated_rDeltaPos = 0.0;
  fMeanOverestimated_rDeltaPos = 0.0;
  fMaxFloat_rDeltaPos_deltaMax = -9999999.9;
  fMeanViolationE_primaryDecay = 0.0;
  fMinViolationE_primaryDecay = 9999999.9;
  fMaxViolationE_primaryDecay = -9999999.9;
  fMeanViolationPx_primaryDecay = 0.0;
  fMinViolationPx_primaryDecay = 9999999.9;
  fMaxViolationPx_primaryDecay = -9999999.9;
  fMeanViolationPy_primaryDecay = 0.0;
  fMinViolationPy_primaryDecay = 9999999.9;
  fMaxViolationPy_primaryDecay = -9999999.9;
  fMeanViolationPz_primaryDecay = 0.0;
  fMinViolationPz_primaryDecay = 9999999.9;
  fMaxViolationPz_primaryDecay = -9999999.9;
}

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

void SteppingAction::UserSteppingAction(const G4Step* theStep)
{
  // Store the information about the ID and the kinetic energy of the primary particle,
  // at the first step of the first event.
  // Note that for the kinetic energy, we are considering the "pre-step" point of such first step.
  if (theStep->GetTrack()->GetParentID() == 0 && theStep->GetTrack()->GetCurrentStepNumber() == 1) {
    fPrimaryParticleId = theStep->GetTrack()->GetDefinition()->GetPDGEncoding();
    fPrimaryParticleInitialKineticEnergy = theStep->GetPreStepPoint()->GetKineticEnergy();
    fPrimaryParticleInitialTotalEnergy = theStep->GetPreStepPoint()->GetTotalEnergy();
    fPrimaryParticleInitial3Momentum = theStep->GetPreStepPoint()->GetMomentum();
    fPrimaryParticleInitialMomentum = fPrimaryParticleInitial3Momentum.mag();
    fPrimaryParticleInitialPosition = theStep->GetPreStepPoint()->GetPosition();
    fPrimaryParticleInitialBeta = theStep->GetPreStepPoint()->GetBeta();
    fPrimaryParticleInitialGamma = theStep->GetPreStepPoint()->GetGamma();
    // As tolerance for EP violations, consider the max value between the default value
    // and 1 billionth of the initial, primary particle kinetic energy.
    if (fToleranceEPviolations < fPrimaryParticleInitialKineticEnergy * 1.0e-9) {
      fToleranceEPviolations = fPrimaryParticleInitialKineticEnergy * 1.0e-9;
    }
    // Set the values of this run to the Run object
    if (fRunPtr) {
      fRunPtr->SetPrimaryParticleId(fPrimaryParticleId);
      fRunPtr->SetPrimaryParticleInitialKineticEnergy(fPrimaryParticleInitialKineticEnergy);
      fRunPtr->SetPrimaryParticleInitialTotalEnergy(fPrimaryParticleInitialTotalEnergy);
      fRunPtr->SetPrimaryParticleInitialMomentum(fPrimaryParticleInitialMomentum);
      fRunPtr->SetPrimaryParticleInitialBeta(fPrimaryParticleInitialBeta);
      fRunPtr->SetPrimaryParticleInitialGamma(fPrimaryParticleInitialGamma);
      fRunPtr->SetPrimaryParticleInitial3Momentum(fPrimaryParticleInitial3Momentum);
      fRunPtr->SetPrimaryParticleInitialPosition(fPrimaryParticleInitialPosition);
      fRunPtr->SetToleranceEPviolations(ToleranceEPviolations());
      fRunPtr->SetToleranceDeltaDecayRadius(ToleranceDeltaDecayRadius());
      fRunPtr->SetIsPreassignedDecayEnabled(IsPreassignedDecayEnabled());
      fRunPtr->SetIsBoostToLabEnabled(IsBoostToLabEnabled());
    }
    // Use the preassigned decay is enabled
    if (IsPreassignedDecayEnabled() && (!theStep->GetTrack()->GetDefinition()->GetPDGStable())) {
      G4DynamicParticle* dynamicParent =
        const_cast<G4DynamicParticle*>(theStep->GetTrack()->GetDynamicParticle());
      if (dynamicParent != nullptr) {
        G4DecayProducts* decayProducts =
          (G4DecayProducts*)(dynamicParent->GetPreAssignedDecayProducts());
        if (decayProducts == nullptr) {
          G4ParticleDefinition* parentDef = theStep->GetTrack()->GetDefinition();
          G4DecayTable* decayTable = (parentDef == nullptr ? nullptr : parentDef->GetDecayTable());
          if (decayTable != nullptr) {
            G4double parentMass = dynamicParent->GetMass();
            G4VDecayChannel* decayChannel = decayTable->SelectADecayChannel(parentMass);
            if (decayChannel != nullptr) {
              decayProducts = decayChannel->DecayIt(parentMass);
              if (!decayProducts->IsChecked()) decayProducts->DumpInfo();
              if (IsBoostToLabEnabled()) {
                // boost all decay products to laboratory frame
                decayProducts->Boost(dynamicParent->GetTotalEnergy(),
                                     dynamicParent->GetMomentumDirection());
              }
            }
            else {
              decayProducts = new G4DecayProducts(*dynamicParent);
            }
            dynamicParent->SetPreAssignedDecayProducts(decayProducts);
          }
        }
        else {
          G4cout << "WARNING : already present preassign decay !" << G4endl;
        }
      }
    }
  }

  // G4cout << theStep->GetPostStepPoint()->GetProcessDefinedStep()->GetProcessName() << G4endl;

  // If the primary decays somewhere inside the World volume, get the information about the decay
  if (theStep->GetTrack()->GetParentID() == 0
      && theStep->GetPostStepPoint()->GetProcessDefinedStep() != nullptr
      && theStep->GetPostStepPoint()->GetProcessDefinedStep()->GetProcessName().find("Decay")
           != std::string::npos)
  {
    // Get properties of the primary particle when it decays

    //--- Get values in different ways and check their consistency ---
    // Kinetic energy of the primary particle at the decay
    const G4double ekin_dynamicParticle =
      theStep->GetTrack()->GetDynamicParticle()->GetKineticEnergy();
    const G4double ekin_track = theStep->GetTrack()->GetKineticEnergy();
    const G4double ekin_postStepPoint = theStep->GetPostStepPoint()->GetKineticEnergy();
    const G4double ekin_deltaMax = std::max(std::abs(ekin_dynamicParticle - ekin_track),
                                            std::abs(ekin_dynamicParticle - ekin_postStepPoint));
    // G4cout << "\t ekin_deltaMax [eV] = " << ekin_deltaMax / CLHEP::eV << G4endl;
    const G4double ekin_val = ekin_dynamicParticle;  // To be used later
    // Total energy of the primary particle at the decay
    const G4double etot_dynamicParticle =
      theStep->GetTrack()->GetDynamicParticle()->GetTotalEnergy();
    const G4double etot_track = theStep->GetTrack()->GetTotalEnergy();
    const G4double etot_postStepPoint = theStep->GetPostStepPoint()->GetTotalEnergy();
    const G4double etot_deltaMax = std::max(std::abs(etot_dynamicParticle - etot_track),
                                            std::abs(etot_dynamicParticle - etot_postStepPoint));
    // G4cout << "\t etot_deltaMax [eV] = " << etot_deltaMax / CLHEP::eV << G4endl;
    const G4double etot_val = etot_dynamicParticle;  // To be used later
    // Module of the 3-momentum of the primary particle at the decay
    const G4double p_dynamicParticle =
      theStep->GetTrack()->GetDynamicParticle()->GetMomentum().mag();
    const G4double p_track = theStep->GetTrack()->GetMomentum().mag();
    const G4double p_postStepPoint = theStep->GetPostStepPoint()->GetMomentum().mag();
    const G4double p_deltaMax = std::max(std::abs(p_dynamicParticle - p_track),
                                         std::abs(p_dynamicParticle - p_postStepPoint));
    // G4cout << "\t p_deltaMax [eV] = " << p_deltaMax / CLHEP::eV << G4endl;
    const G4double p_val = p_dynamicParticle;  // To be used later
    // 3-momentum direction (adimensional) of the primary particle at the decay
    const G4ThreeVector pdir_dynamicParticle =
      theStep->GetTrack()->GetDynamicParticle()->GetMomentumDirection();
    const G4ThreeVector pdir_track = theStep->GetTrack()->GetMomentumDirection();
    const G4ThreeVector pdir_postStepPoint = theStep->GetPostStepPoint()->GetMomentumDirection();
    const G4double pdir_x_deltaMax =
      std::max(std::abs(pdir_dynamicParticle.x() - pdir_track.x()),
               std::abs(pdir_dynamicParticle.x() - pdir_postStepPoint.x()));
    const G4double pdir_y_deltaMax =
      std::max(std::abs(pdir_dynamicParticle.y() - pdir_track.y()),
               std::abs(pdir_dynamicParticle.y() - pdir_postStepPoint.y()));
    const G4double pdir_z_deltaMax =
      std::max(std::abs(pdir_dynamicParticle.z() - pdir_track.z()),
               std::abs(pdir_dynamicParticle.z() - pdir_postStepPoint.z()));
    const G4double pdir_deltaMax =
      std::max(std::max(pdir_x_deltaMax, pdir_y_deltaMax), pdir_z_deltaMax);
    // G4cout << "\t pdir_deltaMax = " << pdir_deltaMax << G4endl;
    //  Mass of the primary particle at the decay
    const G4double mass_dynamicParticle = theStep->GetTrack()->GetDynamicParticle()->GetMass();
    const G4double mass_preStepPoint = theStep->GetPreStepPoint()->GetMass();
    const G4double mass_postStepPoint = theStep->GetPostStepPoint()->GetMass();
    const G4double mass_from_etot_ekin = etot_val - ekin_val;
    const G4double mass_from4mom = std::sqrt(etot_val * etot_val - p_val * p_val);
    G4double mass_deltaMax1 = std::max(std::abs(mass_dynamicParticle - mass_preStepPoint),
                                       std::abs(mass_dynamicParticle - mass_postStepPoint));
    G4double mass_deltaMax2 = std::abs(mass_dynamicParticle - mass_from_etot_ekin);
    G4double mass_deltaMax3 = std::abs(mass_dynamicParticle - mass_from4mom);
    fMeanMass_deltaMax3 += mass_deltaMax3;
    // G4cout << "\t mass_deltaMax{1,2,3} [eV] = " << mass_deltaMax1 / CLHEP::eV << "\t"
    //        << mass_deltaMax2 / CLHEP::eV << "\t" << mass_deltaMax3 / CLHEP::eV << G4endl;
    const G4double mass_val = mass_dynamicParticle;  // To be used later
    // Lorentz beta of the primary particle at the decay
    // The following line works only for G4 versions >= 10.7
    const G4double beta_dynamicParticle = theStep->GetTrack()->GetDynamicParticle()->GetBeta();
    const G4double beta_postStepPoint = theStep->GetPostStepPoint()->GetBeta();
    // Before-10.7  const G4double beta_dynamicParticle = beta_postStepPoint;
    const G4double beta_velocity_track = theStep->GetTrack()->GetVelocity() / CLHEP::c_light;
    const G4double beta_velocity_postStepPoint =
      theStep->GetPostStepPoint()->GetVelocity() / CLHEP::c_light;
    const G4double beta_p_over_etot = p_val / etot_val;
    G4double beta_deltaMax1 = std::max(std::abs(beta_dynamicParticle - beta_postStepPoint),
                                       std::abs(beta_dynamicParticle - beta_velocity_track));
    beta_deltaMax1 =
      std::max(beta_deltaMax1, std::abs(beta_dynamicParticle - beta_velocity_postStepPoint));
    const G4double beta_deltaMax2 = std::abs(beta_dynamicParticle - beta_p_over_etot);
    // G4cout << "\t beta_deltaMax{1,2} = " << beta_deltaMax1 << " , " << beta_deltaMax2 << G4endl;
    const G4double beta_val = beta_dynamicParticle;  // To be used later
    // Lorentz gamma of the primary particle at the decay
    const G4double gamma_postStepPoint = theStep->GetPostStepPoint()->GetGamma();
    const G4double gamma_from_e_over_m = etot_val / mass_val;
    const G4double gamma_deltaMax1 = std::abs(gamma_postStepPoint - gamma_from_e_over_m);
    G4double gamma_from_beta = 0.0;
    G4double gamma_deltaMax2 = 0.0;
    G4double gamma_deltaMax3 = 0.0;
    if (beta_val < 1.0) {
      gamma_from_beta = 1.0 / std::sqrt(1.0 - beta_val * beta_val);
      gamma_deltaMax2 = std::abs(gamma_postStepPoint - gamma_from_beta);
      gamma_deltaMax3 = std::abs(gamma_from_e_over_m - gamma_from_beta);
    }
    const G4double gamma_val = gamma_postStepPoint;  // To be used later;
    // G4cout << "\t gamma_deltaMax{1,2,3} = " << gamma_deltaMax1 << " , " << gamma_deltaMax2
    //        << " , " << gamma_deltaMax3  << " ; gamma_postStepPoint = " << gamma_postStepPoint
    //        << " ; gamma_from_e_over_m = " << gamma_from_e_over_m << " ; gamma_from_beta = "
    //        << gamma_from_beta << G4endl;
    //  Proper time of the primary particle at the decay
    const G4double t_proper_track = theStep->GetTrack()->GetProperTime();
    const G4double t_proper_postStepPoint = theStep->GetPostStepPoint()->GetProperTime();
    const G4double t_proper_deltaMax = std::abs(t_proper_track - t_proper_postStepPoint);
    // G4cout << "\t t_proper_deltaMax [fs] = " << t_proper_deltaMax / femtosecond << G4endl;
    const G4double t_proper_val = t_proper_track;  // To be used later
    // Lab time of the primary particle at the decay
    // (Note: it would be wrong to trying to compute this lab time from the
    //        above proper time via the simple formula:
    //          const G4double t_lab_from_gamma = t_proper_val * gamma_val;
    //        because the gamma value of the primary particle has changed
    //        during its lifetime.)
    const G4double t_local_track = theStep->GetTrack()->GetLocalTime();
    const G4double t_local_postStepPoint = theStep->GetPostStepPoint()->GetLocalTime();
    const G4double t_global_track = theStep->GetTrack()->GetGlobalTime();
    const G4double t_global_postStepPoint = theStep->GetPostStepPoint()->GetGlobalTime();
    G4double t_lab_deltaMax = std::max(std::abs(t_local_track - t_local_postStepPoint),
                                       std::abs(t_local_track - t_global_track));
    t_lab_deltaMax = std::max(t_lab_deltaMax, std::abs(t_local_track - t_global_postStepPoint));
    // G4cout << "\t t_lab_deltaMax [fs] = " << t_lab_deltaMax / femtosecond << G4endl;
    const G4double t_lab_val = t_local_track;  // To be used later
    // "MC-truth" decay radius of the primary particle at the decay
    // (defined as the one that would happen if there are neither magnetic field effects
    // nor interactions with matter).
    const G4double primaryBeta =
      fPrimaryParticleInitialMomentum / fPrimaryParticleInitialTotalEnergy;
    const G4double mc_truth_rPos1 = t_lab_val * fPrimaryParticleInitialBeta * CLHEP::c_light;
    const G4double mc_truth_rPos2 = t_lab_val * primaryBeta * CLHEP::c_light;
    const G4double mc_truth_rPos_deltaMax = std::abs(mc_truth_rPos1 - mc_truth_rPos2);
    fMeanMc_truth_rPos_deltaMax += mc_truth_rPos_deltaMax;
    // G4cout << "\t mc_truth_rPos_deltaMax [mum] = "
    //        << mc_truth_rPos_deltaMax / CLHEP::micrometer << G4endl;
    if (mc_truth_rPos_deltaMax > ToleranceDeltaDecayRadius()) {
      // G4cout << std::setprecision(6)
      //        << " Large : mc_truth_rPos_deltaMax [mum]="
      //        << mc_truth_rPos_deltaMax / CLHEP::micrometer
      //        << " ; " << mc_truth_rPos1 << " , " << mc_truth_rPos2 << " mm" << G4endl;
      if (fRunPtr) fRunPtr->IncrementNumber_mc_truth_rPos_deltaMax_above();
    }
    const G4double mc_truth_rPos_val = mc_truth_rPos1;  // To be used later
    // Keep note of the biggest discrepancies
    fMaxEkin_deltaMax = std::max(fMaxEkin_deltaMax, ekin_deltaMax);
    fMaxEtot_deltaMax = std::max(fMaxEtot_deltaMax, etot_deltaMax);
    fMaxP_deltaMax = std::max(fMaxP_deltaMax, p_deltaMax);
    fMaxPdir_deltaMax = std::max(fMaxPdir_deltaMax, pdir_deltaMax);
    fMaxMass_deltaMax1 = std::max(fMaxMass_deltaMax1, mass_deltaMax1);
    fMaxMass_deltaMax2 = std::max(fMaxMass_deltaMax2, mass_deltaMax2);
    fMaxMass_deltaMax3 = std::max(fMaxMass_deltaMax3, mass_deltaMax3);
    fMaxBeta_deltaMax1 = std::max(fMaxBeta_deltaMax1, beta_deltaMax1);
    fMaxBeta_deltaMax2 = std::max(fMaxBeta_deltaMax2, beta_deltaMax2);
    fMaxGamma_deltaMax1 = std::max(fMaxGamma_deltaMax1, gamma_deltaMax1);
    fMaxGamma_deltaMax2 = std::max(fMaxGamma_deltaMax2, gamma_deltaMax2);
    fMaxGamma_deltaMax3 = std::max(fMaxGamma_deltaMax3, gamma_deltaMax3);
    fMaxT_lab_deltaMax = std::max(fMaxT_lab_deltaMax, t_lab_deltaMax);
    fMaxT_proper_deltaMax = std::max(fMaxT_proper_deltaMax, t_proper_deltaMax);
    fMaxMc_truth_rPos_deltaMax = std::max(fMaxMc_truth_rPos_deltaMax, mc_truth_rPos_deltaMax);
    //--- End consistency checks ---

    // Global position
    const G4double xPos = theStep->GetPostStepPoint()->GetPosition().x();
    const G4double yPos = theStep->GetPostStepPoint()->GetPosition().y();
    const G4double zPos = theStep->GetPostStepPoint()->GetPosition().z();
    const G4double rPos = std::sqrt(xPos * xPos + yPos * yPos + zPos * zPos);
    // I have verified that for this case in which only primaries are considered, the
    // "GetGlobalTime()" is the same as "GetLocalTime()" (the one we use).
    // Moreover, this value is also the same as "GetProperTime()"*gamma .
    G4double tPos = theStep->GetPostStepPoint()->GetLocalTime();
    // The "MC-truth" decay radius is defined as the one that would happen if there are
    // neither magnetic field effects nor interactions with matter.
    const G4double mc_truth_rPos = tPos * fPrimaryParticleInitialBeta * CLHEP::c_light;
    const G4double rDeltaPos = mc_truth_rPos - rPos;
    const G4double eKin = theStep->GetPostStepPoint()->GetKineticEnergy();
    const G4double xMom = theStep->GetPostStepPoint()->GetMomentum().x();
    const G4double yMom = theStep->GetPostStepPoint()->GetMomentum().y();
    const G4double zMom = theStep->GetPostStepPoint()->GetMomentum().z();
    // The compute here the angular deflection, in degrees, between the initial direction of
    // the primary particle - which is along the x-axis, and its direction when it decays.
    G4double xDirection = std::min(theStep->GetPostStepPoint()->GetMomentumDirection().x(), 1.0);
    if (xDirection < -1.0) xDirection = -1.0;
    const G4double deflection_angle_in_degrees = 57.29 * std::acos(xDirection);
    const G4double delta_ekin = fPrimaryParticleInitialKineticEnergy - eKin;
    // G4cout << std::setprecision(6)
    //        << " Decay: tPos[ns]=" << tPos << " ; rPos[mm]=" << rPos << " ; deltaR[mum]="
    //        << rDeltaPos /CLHEP::micrometer << " ; deltaEkin[MeV]=" << delta_ekin
    //        << " ; deltaAngle(deg)=" << deflection_angle_in_degrees << G4endl;
    //  If the absolute difference between the "MC-truth" decay radius and the real one is above a
    //  given threshold, then we notify this special situation in the output, with "LARGE_DELTA_R"
    //  for post-processing evaluation. Moreover, in this case, if the "MC-truth" decay radius is
    //  smaller than the real one, then we count this unexpected occurrence and we further notify
    //  this special situation in the output with "***UNEXPECTED***" for post-processing
    //  evaluation.
    if (std::abs(rDeltaPos) > ToleranceDeltaDecayRadius()) {
      // G4cout << "\t LARGE_DELTA_R : mc_truth_rPos[mm]=" << mc_truth_rPos
      //        << " ; rPos[mm]=" << rPos;
      if (rDeltaPos < 0.0) {
        // G4cout << "\t ***UNEXPECTED***";
        if (fRunPtr) fRunPtr->IncrementNumberUnexpectedDecays();
      }
      // G4cout << G4endl;
    }
    fMeanDeltaR_primaryDecay += rDeltaPos;
    fMinDeltaR_primaryDecay = std::min(fMinDeltaR_primaryDecay, rDeltaPos);
    fMaxDeltaR_primaryDecay = std::max(fMaxDeltaR_primaryDecay, rDeltaPos);
    fMeanR_primaryDecay += rPos;
    fMinR_primaryDecay = std::min(fMinR_primaryDecay, rPos);
    fMaxR_primaryDecay = std::max(fMaxR_primaryDecay, rPos);
    fMeanX_primaryDecay += xPos;
    fMinX_primaryDecay = std::min(fMinX_primaryDecay, xPos);
    fMaxX_primaryDecay = std::max(fMaxX_primaryDecay, xPos);
    fMeanY_primaryDecay += yPos;
    fMinY_primaryDecay = std::min(fMinY_primaryDecay, yPos);
    fMaxY_primaryDecay = std::max(fMaxY_primaryDecay, yPos);
    fMeanZ_primaryDecay += zPos;
    fMinZ_primaryDecay = std::min(fMinZ_primaryDecay, zPos);
    fMaxZ_primaryDecay = std::max(fMaxZ_primaryDecay, zPos);
    fMeanDeltaAngle_primaryDecay += deflection_angle_in_degrees;
    fMinDeltaAngle_primaryDecay =
      std::min(fMinDeltaAngle_primaryDecay, deflection_angle_in_degrees);
    fMaxDeltaAngle_primaryDecay =
      std::max(fMaxDeltaAngle_primaryDecay, deflection_angle_in_degrees);
    fMeanDeltaEkin_primaryDecay += delta_ekin;
    fMinDeltaEkin_primaryDecay = std::min(fMinDeltaEkin_primaryDecay, delta_ekin);
    fMaxDeltaEkin_primaryDecay = std::max(fMaxDeltaEkin_primaryDecay, delta_ekin);
    fMeanEkin_primaryDecay += eKin;
    fMinEkin_primaryDecay = std::min(fMinEkin_primaryDecay, eKin);
    fMaxEkin_primaryDecay = std::max(fMaxEkin_primaryDecay, eKin);
    fMeanPx_primaryDecay += xMom;
    fMinPx_primaryDecay = std::min(fMinPx_primaryDecay, xMom);
    fMaxPx_primaryDecay = std::max(fMaxPx_primaryDecay, xMom);
    fMeanPy_primaryDecay += yMom;
    fMinPy_primaryDecay = std::min(fMinPy_primaryDecay, yMom);
    fMaxPy_primaryDecay = std::max(fMaxPy_primaryDecay, yMom);
    fMeanPz_primaryDecay += zMom;
    fMinPz_primaryDecay = std::min(fMinPz_primaryDecay, zMom);
    fMaxPz_primaryDecay = std::max(fMaxPz_primaryDecay, zMom);

    //--- Extra checks ---
    // Compute the "MC-truth" decay radius using the proper time of the primary particle when
    // it decays.
    // To do this, we would need an "effective" or "average" Lorentz beta and gamma of the primary
    // particle during its lifetime, whereas in practice we have only the Lorentz beta and gamma
    // values at the beginning and at the end when it decays. So, we can get only either an
    // overestimate of the "MC-truth" decay radius - by using the initial Lorentz beta and gamma -
    // or an underestimate of it - by using the Lorentz beta and gamma at the decay.
    // We want to check the average values and the largest values of these wrong estimates.
    const G4double underestimated_mc_truth_rPos =
      t_proper_val * gamma_val * beta_val * CLHEP::c_light;
    const G4double overestimated_mc_truth_rPos =
      t_proper_val * fPrimaryParticleInitialGamma * fPrimaryParticleInitialBeta * CLHEP::c_light;
    const G4double underestimated_mc_truth_rPos_delta =
      underestimated_mc_truth_rPos - mc_truth_rPos_val;
    const G4double overestimated_mc_truth_rPos_delta =
      overestimated_mc_truth_rPos - mc_truth_rPos_val;
    fMeanUnderestimated_mc_truth_rPos_delta += underestimated_mc_truth_rPos_delta;
    fMeanOverestimated_mc_truth_rPos_delta += overestimated_mc_truth_rPos_delta;
    // G4cout << "\t underestimated_mc_truth_rPos_delta [mum] = "
    //        << underestimated_mc_truth_rPos_delta / CLHEP::micrometer
    //        << " ; overestimated_mc_truth_rPos_delta [mum] = "
    //        << overestimated_mc_truth_rPos_delta / CLHEP::micrometer << G4endl;
    if (-underestimated_mc_truth_rPos_delta > ToleranceDeltaDecayRadius()) {
      // G4cout << std::setprecision(6)
      //        << " Large : underestimated_mc_truth_rPos_delta [mum]="
      //        << underestimated_mc_truth_rPos_delta / CLHEP::micrometer
      //        << " ; " << underestimated_mc_truth_rPos << " , "
      //        << mc_truth_rPos_val << " mm" << G4endl;
      if (fRunPtr) fRunPtr->IncrementNumber_underestimated_mc_truth_rPos_delta_above();
    }
    if (overestimated_mc_truth_rPos_delta > ToleranceDeltaDecayRadius()) {
      // G4cout << std::setprecision(6)
      //        << " Large : overestimated_mc_truth_rPos_delta [mum]="
      //        << overestimated_mc_truth_rPos_delta / CLHEP::micrometer
      //        << " ; " << overestimated_mc_truth_rPos << " , "
      //        << mc_truth_rPos_val << " mm" << G4endl;
      if (fRunPtr) fRunPtr->IncrementNumber_overestimated_mc_truth_rPos_delta_above();
    }
    const G4double underestimated_rDeltaPos = underestimated_mc_truth_rPos - rPos;
    const G4double overestimated_rDeltaPos = overestimated_mc_truth_rPos - rPos;
    fMeanUnderestimated_rDeltaPos += underestimated_rDeltaPos;
    fMeanOverestimated_rDeltaPos += overestimated_rDeltaPos;
    // G4cout << std::setprecision(6)
    //        << "\t underestimated_rDeltaPos=" << underestimated_rDeltaPos/CLHEP::micrometer
    //        << " ; overestimated_rDeltaPos=" << overestimated_rDeltaPos/CLHEP::micrometer
    //        << " mum" << G4endl;
    if (-underestimated_rDeltaPos > ToleranceDeltaDecayRadius()) {
      if (fRunPtr) fRunPtr->IncrementNumberLargeUnderestimates();
    }
    if (overestimated_rDeltaPos > ToleranceDeltaDecayRadius()) {
      if (fRunPtr) fRunPtr->IncrementNumberLargeOverestimates();
    }
    // Keep note of the biggest discrepancies
    fMinUnderestimated_mc_truth_rPos_delta =
      std::min(fMinUnderestimated_mc_truth_rPos_delta, underestimated_mc_truth_rPos_delta);
    fMaxOverestimated_mc_truth_rPos_delta =
      std::max(fMaxOverestimated_mc_truth_rPos_delta, overestimated_mc_truth_rPos_delta);
    fMinUnderestimated_rDeltaPos = std::min(fMinUnderestimated_rDeltaPos, underestimated_rDeltaPos);
    fMaxOverestimated_rDeltaPos = std::max(fMaxOverestimated_rDeltaPos, overestimated_rDeltaPos);
    //--- End extra checks ---

    // Check numerical errors due to the use of  float  instead of  double : try out
    // several, equivalent computations, taking the one with the largest numerical error.
    const G4float float_xPos = static_cast<G4float>(theStep->GetPostStepPoint()->GetPosition().x());
    const G4float float_yPos = static_cast<G4float>(theStep->GetPostStepPoint()->GetPosition().y());
    const G4float float_zPos = static_cast<G4float>(theStep->GetPostStepPoint()->GetPosition().z());
    const G4float float_rPos =
      std::sqrt(float_xPos * float_xPos + float_yPos * float_yPos + float_zPos * float_zPos);
    const G4float float_tPos = static_cast<G4float>(theStep->GetPostStepPoint()->GetLocalTime());
    const G4float float_initialBeta1 = static_cast<G4float>(fPrimaryParticleInitialBeta);
    const G4float float_initialBeta2 = static_cast<G4float>(fPrimaryParticleInitialMomentum)
                                       / static_cast<G4float>(fPrimaryParticleInitialTotalEnergy);
    const G4float float_initialGamma = static_cast<G4float>(fPrimaryParticleInitialGamma);
    const G4float float_initialBeta3 =
      std::sqrt(float_initialGamma * float_initialGamma - 1.0) / float_initialGamma;
    const G4float float_c_light = static_cast<G4float>(CLHEP::c_light);
    const G4float float_mc_truth_rPos1 = float_tPos * float_initialBeta1 * float_c_light;
    const G4float float_mc_truth_rPos2 = float_tPos * float_initialBeta2 * float_c_light;
    const G4float float_mc_truth_rPos3 = float_tPos * float_initialBeta3 * float_c_light;
    const G4float float_rDeltaPos_0 = static_cast<G4float>(rDeltaPos);
    const G4float float_rDeltaPos_1 = float_mc_truth_rPos1 - float_rPos;
    const G4float float_rDeltaPos_2 = float_mc_truth_rPos2 - float_rPos;
    const G4float float_rDeltaPos_3 = float_mc_truth_rPos3 - float_rPos;
    const G4float float_rDeltaPos_4 = static_cast<G4float>(mc_truth_rPos) - float_rPos;
    const G4float float_rDeltaPos_5 = float_mc_truth_rPos1 - static_cast<G4float>(rPos);
    const G4float float_rDeltaPos_6 = float_mc_truth_rPos2 - static_cast<G4float>(rPos);
    const G4float float_rDeltaPos_7 = float_mc_truth_rPos3 - static_cast<G4float>(rPos);
    G4double rDeltaPos_deltaMax =
      std::max(std::abs(float_rDeltaPos_0 - rDeltaPos), std::abs(float_rDeltaPos_1 - rDeltaPos));
    rDeltaPos_deltaMax = std::max(rDeltaPos_deltaMax, std::abs(float_rDeltaPos_2 - rDeltaPos));
    rDeltaPos_deltaMax = std::max(rDeltaPos_deltaMax, std::abs(float_rDeltaPos_3 - rDeltaPos));
    rDeltaPos_deltaMax = std::max(rDeltaPos_deltaMax, std::abs(float_rDeltaPos_4 - rDeltaPos));
    rDeltaPos_deltaMax = std::max(rDeltaPos_deltaMax, std::abs(float_rDeltaPos_5 - rDeltaPos));
    rDeltaPos_deltaMax = std::max(rDeltaPos_deltaMax, std::abs(float_rDeltaPos_6 - rDeltaPos));
    rDeltaPos_deltaMax = std::max(rDeltaPos_deltaMax, std::abs(float_rDeltaPos_7 - rDeltaPos));
    // G4cout << std::setprecision(6) << " rDeltaPos_deltaMax[mum]="
    //        << rDeltaPos_deltaMax / CLHEP::micrometer << G4endl;
    fMaxFloat_rDeltaPos_deltaMax = std::max(fMaxFloat_rDeltaPos_deltaMax, rDeltaPos_deltaMax);

    // Get properties of the decay products and check the energy-momentum conservation of the
    // decay
    std::size_t nSec = theStep->GetNumberOfSecondariesInCurrentStep();
    const std::vector<const G4Track*>* ptrVecSecondaries = theStep->GetSecondaryInCurrentStep();
    G4double deltaE = 0.0, deltaPx = 0.0, deltaPy = 0.0, deltaPz = 0.0;
    if (nSec > 0 && ptrVecSecondaries != nullptr) {
      G4double sumEsecondaries = 0.0;
      G4ThreeVector sumPsecondaries(0.0, 0.0, 0.0);
      for (std::size_t i = 0; i < nSec; ++i) {
        if ((*ptrVecSecondaries)[i]) {
          sumEsecondaries += (*ptrVecSecondaries)[i]->GetTotalEnergy();
          sumPsecondaries += (*ptrVecSecondaries)[i]->GetMomentum();
        }
      }
      deltaE = sumEsecondaries - theStep->GetPostStepPoint()->GetTotalEnergy();
      fMeanViolationE_primaryDecay += deltaE;
      fMinViolationE_primaryDecay = std::min(fMinViolationE_primaryDecay, deltaE);
      fMaxViolationE_primaryDecay = std::max(fMaxViolationE_primaryDecay, deltaE);
      if (std::abs(deltaE) > ToleranceEPviolations()) {
        if (fRunPtr) fRunPtr->IncrementNumberEviolations();
      }
      deltaPx = sumPsecondaries.x() - xMom;
      fMeanViolationPx_primaryDecay += deltaPx;
      fMinViolationPx_primaryDecay = std::min(fMinViolationPx_primaryDecay, deltaPx);
      fMaxViolationPx_primaryDecay = std::max(fMaxViolationPx_primaryDecay, deltaPx);
      deltaPy = sumPsecondaries.y() - yMom;
      fMeanViolationPy_primaryDecay += deltaPy;
      fMinViolationPy_primaryDecay = std::min(fMinViolationPy_primaryDecay, deltaPy);
      fMaxViolationPy_primaryDecay = std::max(fMaxViolationPy_primaryDecay, deltaPy);
      deltaPz = sumPsecondaries.z() - zMom;
      fMeanViolationPz_primaryDecay += deltaPz;
      fMinViolationPz_primaryDecay = std::min(fMinViolationPz_primaryDecay, deltaPz);
      fMaxViolationPz_primaryDecay = std::max(fMaxViolationPz_primaryDecay, deltaPz);
      if (std::abs(deltaPx) > ToleranceEPviolations() || std::abs(deltaPy) > ToleranceEPviolations()
          || std::abs(deltaPz) > ToleranceEPviolations())
      {
        if (fRunPtr) fRunPtr->IncrementNumberPviolations();
      }
    }
    else {
      if (fRunPtr) fRunPtr->IncrementNumberBadPrimaryDecays();
    }

    if (fRunPtr) {
      fRunPtr->IncrementNumberDecays();
      fRunPtr->SetDecayT(tPos);
      fRunPtr->SetDecayR_mc_truth(mc_truth_rPos);
      fRunPtr->SetDecayR(rPos);
      fRunPtr->SetDecayX(xPos);
      fRunPtr->SetDecayY(yPos);
      fRunPtr->SetDecayZ(zPos);
      fRunPtr->SetDeltaDecayR(rDeltaPos);
      fRunPtr->SetDeflectionAngle(deflection_angle_in_degrees);
      fRunPtr->SetDeltaEkin(delta_ekin);
      fRunPtr->SetDecayEkin(eKin);
      fRunPtr->SetDecayPx(xMom);
      fRunPtr->SetDecayPy(yMom);
      fRunPtr->SetDecayPz(zMom);
      fRunPtr->SetDecayEtotViolation(deltaE);
      fRunPtr->SetDecayPxViolation(deltaPx);
      fRunPtr->SetDecayPyViolation(deltaPy);
      fRunPtr->SetDecayPzViolation(deltaPz);
      fRunPtr->SetMaxEkin_deltaMax(ekin_deltaMax);
      fRunPtr->SetMaxEtot_deltaMax(etot_deltaMax);
      fRunPtr->SetMaxP_deltaMax(p_deltaMax);
      fRunPtr->SetMaxPdir_deltaMax(pdir_deltaMax);
      fRunPtr->SetMaxMass_deltaMax1(mass_deltaMax1);
      fRunPtr->SetMaxMass_deltaMax2(mass_deltaMax2);
      fRunPtr->SetMaxMass_deltaMax3(mass_deltaMax3);
      fRunPtr->SetMaxBeta_deltaMax1(beta_deltaMax1);
      fRunPtr->SetMaxBeta_deltaMax2(beta_deltaMax2);
      fRunPtr->SetMaxGamma_deltaMax1(gamma_deltaMax1);
      fRunPtr->SetMaxGamma_deltaMax2(gamma_deltaMax2);
      fRunPtr->SetMaxGamma_deltaMax3(gamma_deltaMax3);
      fRunPtr->SetMaxT_proper_deltaMax(t_proper_deltaMax);
      fRunPtr->SetMaxT_lab_deltaMax(t_lab_deltaMax);
      fRunPtr->SetMaxMc_truth_rPos_deltaMax(mc_truth_rPos_deltaMax);
      fRunPtr->SetMinUnderestimated_mc_truth_rPos_delta(underestimated_mc_truth_rPos_delta);
      fRunPtr->SetMaxOverestimated_mc_truth_rPos_delta(overestimated_mc_truth_rPos_delta);
      fRunPtr->SetMinUnderestimated_rDeltaPos(underestimated_rDeltaPos);
      fRunPtr->SetMaxOverestimated_rDeltaPos(overestimated_rDeltaPos);
      fRunPtr->SetMaxFloat_rDeltaPos_deltaMax(fMaxFloat_rDeltaPos_deltaMax);
    }
  }
}

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