#include "AASteppingAction.hh"

#ifndef __CLING__
#include "G4PhysicalConstants.hh"
#include "G4PrimaryVertex.hh"
#include "G4Event.hh"
#include "G4RunManager.hh"
#include "G4Step.hh"
#endif


#include "Sim.hh"
#include "TrackSegment.hh"
#include "generate_photons.hh"

#include <iostream>
#include "stringutil.hh"
using namespace std;


AASteppingAction:: AASteppingAction()
{
  simulate_photons = true;
  total_length = 0;
}


void AASteppingAction::UserSteppingAction(const G4Step* step)
{
  TIMESCOPE

  G4Track* track = step->GetTrack();
  const double charge = track -> GetParticleDefinition ()-> GetPDGCharge () ;


  // -----------------------------------------------------------
  //  Do not process tracks that do not produce Cherenkov light
  // -----------------------------------------------------------
  if ( charge == 0 ) return;

  g_sim -> n_track_seg++;

  G4StepPoint* point1 = step->GetPreStepPoint();
  G4StepPoint* point2 = step->GetPostStepPoint();

  const double beta1  = point1 -> GetVelocity () / c_light;
  const double beta2  = point2 -> GetVelocity () / c_light;
  double beta = ( beta1 + beta2 ) / 2 ;

  // The following should be refined, somewhat.
  // it *may* be the case that a slow-heavy particle e.g. decays and
  // can still produce cherenkov.

  if ( beta < 0.7 )
  {
    step->GetTrack()->SetTrackStatus(fStopAndKill);
    return;
  }


  // ------------------------------------------------
  //  Make a TrackSegment
  // ------------------------------------------------

  static TrackSegment trkseg;

  G4ThreeVector pos1 = step->GetPreStepPoint()->GetPosition();
  G4ThreeVector pos2 = step->GetPostStepPoint()->GetPosition();

  trkseg.pos.set( pos1.x() / m , pos1.y() / m, pos1.z() / m );
  trkseg.dir.set( pos2.x() / m , pos2.y() / m, pos2.z() / m );
  trkseg.dir -= trkseg.pos;
  trkseg.len  = trkseg.dir.len();

  if ( trkseg.len > 0 ) trkseg.dir /= trkseg.len;

  trkseg.len_effective = step->GetStepLength() / m;
  trkseg.beta          = beta;
  trkseg.energy        = point1-> GetTotalEnergy() / GeV;
  trkseg.t             = step  -> GetPreStepPoint()->GetGlobalTime();
  trkseg.id            = track -> GetTrackID ();
  trkseg.type          = track -> GetParticleDefinition ()-> GetPDGEncoding ();
  //trkseg.nphot will be set in generate_photons.

  if ( trkseg.energy < 1e-4 )
  {
    dbg( beta1, beta2, beta );
    dbg( trkseg.type, charge );
    fatal("found a particle with too low energy");
  }


  // ------------------------------------------------
  //  simulate the photons
  // ------------------------------------------------

  if ( simulate_photons )
    generate_photons( *g_sim, trkseg );

  // if (g_sim -> verbose_tracks )
  // {
  //   get_track_pool().add_track_segment( trkseg.id, trkseg );
  // }

}