//$Id$

#ifndef ALIHLTGLOBALTRACKMATCHER_H
#define ALIHLTGLOBALTRACKMATCHER_H


//* This file is property of and copyright by the ALICE HLT Project        * 
//* ALICE Experiment at CERN, All rights reserved.                         *
//* See cxx source for full Copyright notice                               *

/** @file   AliHLTGlobalTrackMatcher.h
    @author Svein Lindal (svein.lindal@fys.uio.no)
    @date   
    @brief  The HLT class matching TPC tracks to calorimeter clusters
*/



#include "AliHLTLogging.h"
#include "AliESDtrack.h"
#include "TObjArray.h"
#include "TArrayI.h"
#include "TVector3.h"

class AliHLTGlobalTrackMatcher : public AliHLTLogging{

public:
  AliHLTGlobalTrackMatcher();

  /** destructor */
  virtual ~AliHLTGlobalTrackMatcher();

  //Main function, loops over tracks and calls appropriate functions to establish matches
  template <class T>
  Int_t Match( TObjArray * trackArray, vector<T*>  &phosClustersVector, vector<T*>  &emcalClustersVector,  Double_t bz ); 
  
private:
  
  void DoInit();

  //Loops over clusters and decides if track is a good match to any of these
  template <class T>
  Int_t MatchTrackToClusters( AliExternalTrackParam * track, vector<T*>  &clustersVector, Int_t nClusters, Float_t * bestMatch, Double_t bz); 

  //Add track Id to cluster's list of matching tracks
  Int_t AddTrackToCluster(Int_t tId, Int_t* clustersArray, Bool_t bestMatch, Int_t nMatches);
  Int_t AddTrackToCluster(Int_t tId, TArrayI* clustersArray, Bool_t bestMatch, Int_t nMatches);

  //Projects track to detector volume and decides if it's anywhere near calorimeter volume
  Bool_t IsTrackCloseToDetector(AliExternalTrackParam * track, Double_t bz, Double_t fMaxX, Bool_t ySign, Double_t fMaxZ, Double_t dRadius);

  // Geometrical cut off values used to decide whether track is anywhere near calorimeter volumes
  Float_t fPhosMaxZ;              // max Z track    (cm)
  Float_t fPhosMaxX;              // max X track    (cm)
  Float_t fEmcalMaxZ;             // max Z track    (cm)
  Float_t fEmcalMaxX;             // max X track    (cm)

  Float_t fMatchDistance;        // Square of maximum distance where track is considered a match to cluster (cm^2)

  const Double_t fPhosRadius;          // Radial position of PHOS 
  const Double_t fEmcalRadius;         // Radial position of EMCAL

  AliHLTGlobalTrackMatcher(const AliHLTGlobalTrackMatcher & );
  AliHLTGlobalTrackMatcher & operator = (const AliHLTGlobalTrackMatcher &);

  ClassDef(AliHLTGlobalTrackMatcher,1) 
};


template <class T>
Int_t AliHLTGlobalTrackMatcher::Match( TObjArray * trackArray, vector<T*>  &phosClustersVector, vector<T*> &emcalClustersVector,  Double_t bz ) {
  //See above for documentation


  Int_t nTracks = trackArray->GetEntriesFast();
  Int_t nPhosClusters = phosClustersVector.size();
  Int_t nEmcalClusters = emcalClustersVector.size(); 
  

  //HLTError("tracks phos emcal %d %d %d", nTracks, nPhosClusters, nEmcalClusters);

  //See if there are tracks and clusters to match
  if ( nTracks <= 0 ) {
    return 0;
  } else if ( (nEmcalClusters <= 0) && (nPhosClusters <= 0))  {
    return 0;
  }


  Float_t bestMatchPhos[nPhosClusters];   
  for(int ic = 0; ic < nPhosClusters; ic++) {
    bestMatchPhos[ic] = 999999;
  }

  Float_t bestMatchEmcal[nEmcalClusters];   
  for(int ic = 0; ic < nEmcalClusters; ic++) {
    bestMatchEmcal[ic] = 999999;
  }

  //Loop over tracks
  for (int it = 0; it < nTracks; it++ ) {
    AliExternalTrackParam * track = static_cast<AliExternalTrackParam*>(trackArray->At(it));

    if ( IsTrackCloseToDetector(track, bz, fPhosMaxX, kFALSE, fPhosMaxZ, fPhosRadius ) ) {
      MatchTrackToClusters( track, phosClustersVector, nPhosClusters, bestMatchPhos, bz);

    } else if ( IsTrackCloseToDetector(track, bz, fEmcalMaxX, kTRUE, fEmcalMaxZ, fEmcalRadius ) ) {
      MatchTrackToClusters( track, emcalClustersVector, nEmcalClusters, bestMatchEmcal, bz);
    } 

  }   
    
  return 0;
} 



template <class T>
Int_t AliHLTGlobalTrackMatcher::MatchTrackToClusters( AliExternalTrackParam * track, vector<T*>  &clustersVector, Int_t nClusters, Float_t * bestMatch, Double_t bz) {
  
  //See header file for documentation
  Int_t iResult = 0;
 
  Float_t clusterPosition[3];
  Double_t trackPosition[3];
 
  
  for(int ic = 0; ic < nClusters; ic++) {
    
    T * cluster = clustersVector.at(ic);
    
    //Get cluster global coordinates
    cluster->GetPosition(clusterPosition);

    Double_t rCluster = TMath::Sqrt(clusterPosition[0]*clusterPosition[0] + clusterPosition[1]*clusterPosition[1]);      

    //Rotate tracking system to the angle of the cluster
    TVector3 cVec(clusterPosition);
    if (! (track->Rotate(cVec.Phi())) ) {
      continue;
    }
   
    if(! (track->GetXYZAt(rCluster, bz, trackPosition)) ) {
      continue;
    }

    //Calculate track - cluster residuals
    Double_t match = 0;
    for(int i = 0; i < 3; i++) {
      Double_t dd = trackPosition[i] - clusterPosition[i];
      match += dd*dd;
    }

    if( match > fMatchDistance  )  {     
      continue;
    }

    if (match < bestMatch[ic]) {
      
      bestMatch[ic] = match;
      cluster->SetEmcCpvDistance(TMath::Sqrt(match));
      
      Double_t dx = trackPosition[0] - clusterPosition[0];
      Double_t dy = trackPosition[1] - clusterPosition[1];
      Double_t dz = trackPosition[2] - clusterPosition[2];
      cluster->SetTrackDistance( ((dx > 0) ? 1 : -1 )*TMath::Sqrt(dx*dx + dy*dy), dz);
    }
    
    //Add track to cluster's array of matching tracks
    Int_t nTracksMatched = cluster->GetNTracksMatched();
    iResult = AddTrackToCluster(track->GetID(), cluster->GetTracksMatched(), match < bestMatch[ic], nTracksMatched);
  }
  
  return iResult;
}

#endif