#include "FCALPrimaryGeneratorAction.hh"
#include "FCALPrimaryGeneratorMessenger.hh"

#include "G4Event.hh"
#include "G4ParticleGun.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"

FCALPrimaryGeneratorAction::FCALPrimaryGeneratorAction()
{
	generator_Messenger = new FCALPrimaryGeneratorMessenger(this);	

//	G4ThreeVector gun_Position(0.1*cm, 0.1*cm, -36.*cm);		// the position of the particle gun
	G4ThreeVector gun_Position(0.1*cm, 0.1*cm, -14.*cm);
	G4ThreeVector momentum_Direction(0, 0, 1);			// the momentum direction of incident particles
	G4ThreeVector particle_Polarization(0, 0, 0);			// set the particle polarization
	particle_Energy = 5.*GeV;					// set the particle energy
	G4int n_Incident_Particles = 1; 				// set the number of incident particles

	particle_Gun = new G4ParticleGun(n_Incident_Particles);		// generate an object of G4ParticleGun
	G4ParticleTable* particle_Table = G4ParticleTable::GetParticleTable();
	G4ParticleDefinition* particle = particle_Table->FindParticle("gamma");	
		particle_Gun->SetParticleDefinition(particle);		// This command should appear first.
		particle_Gun->SetParticleMomentumDirection(momentum_Direction);
		particle_Gun->SetParticleTime(0.*ns);	
		particle_Gun->SetParticleEnergy(particle_Energy);		
		particle_Gun->SetParticlePosition(gun_Position);
		particle_Gun->SetParticlePolarization(particle_Polarization); 
}

FCALPrimaryGeneratorAction::~FCALPrimaryGeneratorAction()
{
	delete generator_Messenger;
	delete particle_Gun;
}

void FCALPrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent) 
{
	particle_Gun->GeneratePrimaryVertex(anEvent);			// generate the particle
} 

void FCALPrimaryGeneratorAction::setParticleEnergy(G4double new_Value)
{
	particle_Energy = new_Value;
	particle_Gun->SetParticleEnergy(particle_Energy);
}

void FCALPrimaryGeneratorAction::setGunPosition(G4ThreeVector new_Value)
{
	G4ThreeVector gun_Position = new_Value;
	particle_Gun->SetParticlePosition(gun_Position);
}