// HTrackGenerator.cpp

#include "HTrackGenerator.h"
#include "trfbase/VTrackGenerator.h"
#include "trfbase/HitGenerator.h"
#include <cassert>
#include "trfbase/ETrack.h"
#include "trffit/HTrack.h"
#include "trfbase/Hit.h"
#include "trfbase/PropStat.h"
#include "trfbase/Propagator.h"
#include "trfbase/Surface.h"

using trf::Surface;
using trf::TrackError;
using trf::VTrack;
using trf::PropStat;
using trf::Propagator;
using trf::HitList;
using trf::HTrack;
using trf::HTrackGenerator;

//**********************************************************************

// Constructor.

HTrackGenerator::HTrackGenerator( const HitGeneratorList& hgens,
                                  const Propagator& prop, 
                                  const Surface& srf,
                                  const TrackError& terr )
: _hgens(hgens), _terr(terr) {
  _pprop = prop.new_propagator();
  _psrf = srf.new_pure_surface();
}
 
//**********************************************************************

// Destructor.
// Members use reference-counting pointers so there is little to do
// here.

HTrackGenerator::~HTrackGenerator() { }

//**********************************************************************

// generate a new track
HTrack* HTrackGenerator::new_track(const VTrack& trv) {
  HTrack* ptrh = 0;
  VTrack newtrv(trv);
  // Create new list of hits.
  HitList track_hits;
  // Loop over hit surfaces.
  HitGeneratorList::iterator ihgen;
  for ( ihgen=_hgens.begin(); ihgen!=_hgens.end(); ++ihgen ) {
    HitGenerator& hgen = **ihgen;
    // Propagate to the surface.
    PropStat pstat = _pprop->vec_prop(newtrv,hgen.get_surface());
    if ( ! pstat.success() ) break;
    // Generate a cluster.
    ClusterPtr pclu = hgen.new_cluster(newtrv);
    if ( ! pclu ) break;
    // Generate a hit.
    HitList hits = pclu->predict( ETrack(newtrv,_terr) );
    if ( ! hits.size() ) break;
    track_hits.push_back( hits.front() );
  }
  // If the number of assigned does not equal the number of hit
  // generators, all hits were not found.  Exit with error.
  if ( track_hits.size() != _hgens.size() ) return ptrh;
  // Propagate to the surface.
  VTrack starttrv(trv);
  PropStat pstat = _pprop->vec_prop(starttrv,*_psrf);
  if ( ! pstat.success() ) return ptrh;
  const ETrack tre(starttrv,_terr);
  ptrh = new HTrack(tre);
  HitList::iterator ihit;
  for ( ihit=track_hits.begin(); ihit!=track_hits.end(); ++ihit )
    ptrh->add_hit(*ihit);
  return ptrh;
}

//**********************************************************************