//
// ********************************************************************
// * 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: G4RayShooter.cc,v 1.2 2006/06/29 18:10:00 gunter Exp $
// GEANT4 tag $Name: geant4-09-04-beta-01 $
//

#include "G4RayShooter.hh"
#include "G4PrimaryParticle.hh"
#include "G4Event.hh"
#include "G4ParticleTable.hh"
#include "G4ParticleDefinition.hh"
#include "globals.hh"


G4RayShooter::G4RayShooter()
{
  SetInitialValues();
}

void G4RayShooter::SetInitialValues()
{
  particle_definition = 0;
  G4ThreeVector zero;
  particle_momentum_direction = (G4ParticleMomentum)zero;
  particle_energy = 1.0*GeV;
  particle_position = zero;
  particle_time = 0.0;
  particle_polarization = zero;
}

G4RayShooter::~G4RayShooter()
{
}

void G4RayShooter::Shoot(G4Event* evt,G4ThreeVector vtx,G4ThreeVector direc)
{
  if(!particle_definition)
  {
    G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
    G4String particleName;
    particle_definition = particleTable->FindParticle(particleName="geantino");
    if(!particle_definition)
    {
      G4String msg;
      msg =  " G4RayTracer uses geantino to trace the ray, but your physics list does not\n";
      msg += "define G4Geantino. Please add G4Geantino in your physics list.";
      G4Exception("G4RayShooter::Shoot","RayTracer001",FatalException,msg);
    }
  }

  // create a new vertex
  G4PrimaryVertex* vertex = new G4PrimaryVertex(vtx,particle_time);

  // create new primaries and set them to the vertex
  G4double mass =  particle_definition->GetPDGMass();
  G4double energy = particle_energy + mass;
  G4double pmom = std::sqrt(energy*energy-mass*mass);
  G4double px = pmom*direc.x();
  G4double py = pmom*direc.y();
  G4double pz = pmom*direc.z();
  G4PrimaryParticle* particle =
      new G4PrimaryParticle(particle_definition,px,py,pz);
  particle->SetMass( mass );
  particle->SetPolarization(particle_polarization.x(),
                               particle_polarization.y(),
                               particle_polarization.z());
  vertex->SetPrimary( particle );

  evt->AddPrimaryVertex( vertex );
}