// HTrackGenerator.h

#ifndef HTrackGenerator_H
#define HTrackGenerator_H

// Generates an HTrack from a VTrack using its track error matrix
// and a list of hit generators.  The VTrack is propagated to each 
// of the hit generator surfaces and used to generate a cluster which
// is in turn used to generate a hit.  This is repeated until a hit is
// succesfully produced at each surface.  The first hit from each
// surface is assigned to the HTrack.

#include <list>
#include "ptr/Ptr.h"
#include "ptr/SharedDeletePolicy.h"
#include "trfbase/SurfacePtr.h"
#include "trfbase/PropagatorPtr.h"
#include "trfutil/RandomGenerator.h"
#include "trfbase/TrackVector.h"
#include "trfbase/HitGenerator.h"

namespace trf {

class Surface;
class Propagator;
class VTrack;
class HTrack;

class HTrackGenerator : public RandomGenerator {

public:

  // typedef for the list of hit generators
  typedef Ptr<HitGenerator,SharedDeletePolicy> HitGeneratorPtr;
  typedef std::list<HitGeneratorPtr> HitGeneratorList;

private:

  // The Hit generators.
  HitGeneratorList _hgens;

  // The starting surface.
  SurfacePtr _psrf;

  // The track error matrix.
  TrackError _terr;

  // Propagator.
  PropagatorPtr _pprop;

public:

  // Constructor.
  HTrackGenerator(const HitGeneratorList& hgens, const Propagator& prop,
                  const Surface& srf, const TrackError& terr);

  // Destructor.
  virtual ~HTrackGenerator();

  // Return a new HTrack.
  // Return 0 for failure.
  HTrack* new_track(const VTrack& trv);

};

}  // end namespace trf

#endif