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/// \file PrimaryGeneratorAction.cc
/// \brief Implementation of the PrimaryGeneratorAction class

#include "PrimaryGeneratorAction.hh"

#include "DetectorConstruction.hh"

#include "G4Electron.hh"
#include "G4Event.hh"
#include "G4Gamma.hh"
#include "G4ParticleDefinition.hh"
#include "G4ParticleGun.hh"
#include "G4ParticleTable.hh"
#include "G4PhysicalConstants.hh"
#include "G4RandomDirection.hh"
#include "G4RunManager.hh"
#include "G4StateManager.hh"
#include "G4SystemOfUnits.hh"
#include "Randomize.hh"

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

PrimaryGeneratorAction::PrimaryGeneratorAction() {
  fDetector = dynamic_cast<const DetectorConstruction *>(
    G4RunManager::GetRunManager()->GetUserDetectorConstruction());
  fParticleGun = std::make_unique<G4ParticleGun>(1);
}

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

PrimaryGeneratorAction::~PrimaryGeneratorAction() {
  G4StateManager::GetStateManager()->DeregisterDependent(this);
}

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

void PrimaryGeneratorAction::GeneratePrimaries(G4Event *anEvent) {
  const G4double R = fDetector->GetNPRadius();
  G4double Ryz = 9999;

  // G4ParticleDefinition *particle = G4Electron::ElectronDefinition();
  // fParticleGun->SetParticleDefinition(particle);

  constexpr G4double scale = 1.;

  G4double xpos = 0, ypos = 0, zpos = 0;
  while (!(Ryz < R)) {
    ypos = (2. * G4UniformRand() - 1.) * R;
    zpos = (2. * G4UniformRand() - 1.) * R;
    Ryz = std::sqrt(ypos * ypos + zpos * zpos);
  }
  xpos = std::sqrt(R * R - (ypos * ypos + zpos * zpos));
  fParticleGun->SetParticlePosition(G4ThreeVector(-xpos * scale,
                                                  ypos * scale,
                                                  zpos * scale));
  fParticleGun->SetParticleMomentumDirection(G4ThreeVector(1, 0, 0));

  fParticleGun->GeneratePrimaryVertex(anEvent);
}

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

G4bool PrimaryGeneratorAction::Notify(G4ApplicationState requestedState) {
  if (requestedState == G4State_Idle) {
    if (fParticleGun != nullptr) return true;
    const G4double R = fDetector->GetNPRadius();
    G4double Ryz = 9999;

    // G4ParticleDefinition *particle = G4Electron::ElectronDefinition();
    // fParticleGun->SetParticleDefinition(particle);

    fParticleGun->SetParticleMomentumDirection(G4ThreeVector(-1, 0, 0));

    while (!(Ryz < R)) {
      const G4double ypos = (2. * G4UniformRand() - 1.) * R;
      const G4double zpos = (2. * G4UniformRand() - 1.) * R;
      Ryz = std::sqrt(ypos * ypos + zpos * zpos);
      const G4double xpos = std::sqrt(R * R - (ypos * ypos + zpos * zpos));
      fParticleGun->SetParticlePosition(G4ThreeVector(-xpos, ypos, zpos));
    }
    // fParticleGun->SetParticlePosition(G4ThreeVector(-Xposition,0,0));
    // fParticleGun->GeneratePrimaryVertex(anEvent);
  }

  return true;
}
