/** CbmLitTrackFinderNN.h
 * @author Andrey Lebedev <andrey.lebedev@gsi.de>
 * @since 2008
 * @version 1.0
 **
 ** Nearest neighbor tracking implementation. As input to tracking
 ** arrays with track seeds and hits from the detector are used.
 ** The track is prolongated from station to station and the
 ** nearest hit is attached to track. Flag fIsProcessSubstationsTogether
 ** defines which nearest hits should be attached to track.
 **/

#ifndef CBMLITTRACKFINDERNN_H_
#define CBMLITTRACKFINDERNN_H_

#include "base/CbmLitPtrTypes.h"
#include "base/CbmLitTypes.h"
#include "finder/CbmLitTrackFinderBase.h"

class CbmLitTrackFinderNN : public CbmLitTrackFinderBase
{
public:
   /* Constructor */
   CbmLitTrackFinderNN();

   /* Destructor */
   virtual ~CbmLitTrackFinderNN();

   /* Inherited from CbmLitTrackFinder */
   virtual LitStatus DoFind(
      HitPtrVector& hits,
      TrackPtrVector& trackSeeds,
      TrackPtrVector& tracks);

   /* Inherited from CbmLitTool */
   virtual LitStatus Initialize();

   /* Inherited from CbmLitTool */
   virtual LitStatus Finalize();

   /* Sets seed selection tool.
    * @param seedSelection Pointer to seed selection tool.
    */
   void SetSeedSelection(TrackSelectionPtr seedSelection) {
      fSeedSelection=seedSelection;
   }

   /* Sets track propagator tool.
    * @param propagator Pointer to track propagator tool.
    */
   void SetPropagator(TrackPropagatorPtr propagator) {
      fPropagator = propagator;
   }

   /* Sets final track selection tool.
    * @param finalSelection Pointer to final track selection tool.
    */
   void SetFinalSelection(TrackSelectionPtr finalSelection) {
      fFinalSelection = finalSelection;
   }

   /* Sets KF update tool.
    * @param filter Pointer to KF update tool.
    */
   void SetFilter(TrackUpdatePtr filter) {
      fFilter = filter;
   }

   /* Sets the flag which defines which nearest hits will be attached to track.
    * If true than only one nearest hit from all substations in station will be attached to track.
    * If false than the nearest hit from each substation in station will be attached to the track.
    * @param isProcessSubstationsTogether Flag value.
    */
   void IsProcessSubstationsTogether(bool isProcessSubstationsTogether) {
      fIsProcessSubstationsTogether = isProcessSubstationsTogether;
   }

protected:

   /* Inherited from CbmLitTrackFinderBase */
   void SetIterationParameters(
      int iter);

   /* Initialize the track seeds, i.e. selects with the track selection tool
    * proper ones and copies to local array.
    * @param itBegin Iterator to the first track seed.
    * @param itEnd iterator to the last track seed.
    */
   void InitTrackSeeds(
      TrackPtrIterator itBegin,
      TrackPtrIterator itEnd);

   /* Follows tracks through the detector
    * @param itBegin Iterator to the first track.
    * @param itEnd Iterator to the last track.
    */
   void FollowTracks(
      TrackPtrIterator itBegin,
      TrackPtrIterator itEnd);

   /* Follow one track through the detector.
    * @param track Pointer to the track.
    */
   void FollowTrack(
      CbmLitTrack* track);

   /* Processes the station group in order to attach hit(s) to track.
    * @param track Pointer to the track
    * @param stationGroup Index of the station group.
    * @return True if the track successfully passed through the station group.
    */
   bool ProcessStationGroup(
      CbmLitTrack* track,
      int stationGroup);

   /* Processes the station in station group in order to attach hit(s) to track.
    * @param track Pointer to the track.
    * @param stationGroup Index of the station group.
    * @param station Index of the station in the station group.
    * @return True if the hit was attached to track.
    */
   bool ProcessStation(
      CbmLitTrack* track,
      int stationGroup,
      int station);

   /* Adds the nearest hit to the track when fIsProcessSubstationsTogether == true.
    * @param track Pointer to the track.
    * @param hits Reference to hit vector from which the nearest hit will be attached.
    * @return True if the hit was attached to track.
    */
   bool AddNearestHit1(
      CbmLitTrack* track,
      HitPtrIteratorPair hits[],
      const CbmLitTrackParam par[],
      int nofSubstations);

   /* Adds the nearest hit to the track when fIsProcessSubstationsTogether == false.
    * @param track Pointer to the track.
    * @param hits Reference to hit vector from which the nearest hit will be attached.
    * @return True if the hit was attached to track.
    */
   bool AddNearestHit2(
      CbmLitTrack* track,
      HitPtrIteratorPair hits[],
      const CbmLitTrackParam par[],
      int nofSubstations);
private:
   TrackPtrVector fTracks; // local copy of tracks

   TrackUpdatePtr fFilter; // KF update tool
   TrackSelectionPtr fSeedSelection; // seed selection tool
   TrackSelectionPtr fFinalSelection; // final track selection tool
   TrackPropagatorPtr fPropagator; // track propagation tool

   // If true than only one nearest hit from all substations in station will be attached to track.
   // If false than the nearest hit from each substation in station will be attached to the track.
   bool fIsProcessSubstationsTogether;
};

#endif /* CBMLITTRACKFINDERNN_H_ */