//
// ********************************************************************
// * 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.          *
// ********************************************************************
//
// $Id: PrimaryGeneratorAction.cc,v 1.7 2006/06/29 16:53:00 gunter Exp $
// GEANT4 tag $Name: geant4-09-03-cand-01 $
//
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......

#include "PrimaryGeneratorAction.hh"

#include "PrimaryGeneratorMessenger.hh"
#include "DetectorConstruction.hh"
#include "HistoManager.hh"

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

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

PrimaryGeneratorAction::PrimaryGeneratorAction(DetectorConstruction* det,
                               HistoManager* hist)
:Detector(det),histoManager(hist) 
{
  G4int n_particle = 1;
  particleGun  = new G4ParticleGun(n_particle);
  SetDefaultKinematic();
  rndmBeam = 0.;
  
  //create a messenger for this class
  gunMessenger = new PrimaryGeneratorMessenger(this);
}

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

PrimaryGeneratorAction::~PrimaryGeneratorAction()
{
  delete particleGun;
  delete gunMessenger;
}

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

void PrimaryGeneratorAction::SetDefaultKinematic()
{
  G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
  G4String particleName;
  G4ParticleDefinition* particle
                    = particleTable->FindParticle(particleName="e-");
  particleGun->SetParticleDefinition(particle);
  particleGun->SetParticleMomentumDirection(G4ThreeVector(1.,0.,0.));
  particleGun->SetParticleEnergy(1.*GeV);
  G4double position = -0.5*(Detector->GetWorldSizeX());
  particleGun->SetParticlePosition(G4ThreeVector(position,0.*cm,0.*cm));
}

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

void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{
  //this function is called at the begining of event
  //
  //randomize the beam, if requested.
  if (rndmBeam > 0.) 
    {
      G4ThreeVector oldPosition = particleGun->GetParticlePosition();    
      G4double rbeam = 0.5*(Detector->GetCalorSizeYZ())*rndmBeam;
      G4double x0 = oldPosition.x();
      G4double y0 = oldPosition.y() + (2*G4UniformRand()-1.)*rbeam;
      G4double z0 = oldPosition.z() + (2*G4UniformRand()-1.)*rbeam;
      particleGun->SetParticlePosition(G4ThreeVector(x0,y0,z0));
      particleGun->GeneratePrimaryVertex(anEvent);
      particleGun->SetParticlePosition(oldPosition);      
    }
  else  particleGun->GeneratePrimaryVertex(anEvent);
}

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