#ifndef ALIV0READER_H
#define ALIV0READER_H
/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 * See cxx source for full Copyright notice     */


// --- ROOT system ---
#include "TObject.h" 
#include "TChain.h"
#include "AliESDv0.h"
#include "AliESDVertex.h"
#include "AliESDInputHandler.h"
#include "AliMCEventHandler.h"
#include "AliESDEvent.h"
#include "AliESDtrack.h"
#include "AliKFParticle.h"
#include "TParticle.h"
#include "AliStack.h"
#include "AliGammaConversionHistograms.h"
#include <vector>

class TClonesArray ; 
class TFormula ;
class TParticle ; 
class Riostream ;
class TChain;
//--- AliRoot system ---

class AliStack ;
class AliESDEvent ; 
class AliMCEventHandler;
class AliLog ;

class AliV0Reader : public TObject {

 public: 

  AliV0Reader();                                        //constructor
  AliV0Reader(const AliV0Reader & g);                   //copy constructor
  AliV0Reader & operator = (const AliV0Reader & g);     //assignment operator
  virtual ~AliV0Reader() {;}                            //virtual destructor
  /*
   *Initialize the reader
   */
  void Initialize();

  /*
   *Returns the number of v0s in the event, no cuts applied.
   */
  Int_t GetNumberOfV0s(){return fESDEvent->GetNumberOfV0s();}

  /*
   * Check if there are any more good v0s left in the v0 stack
   * if so, fCurrent v0 is set to this v0 and can be retrieved
   * by GetCurrentV0 function.
   * returns kFALSE if there is no more good v0s in the v0 stack
   */
  Bool_t NextV0();
  
  /*
   * Returns the v0 at the given index, no checks are done on the v0. 
   */
  AliESDv0* GetV0(Int_t index);

  /*
   * Returns the current v0
   */
  AliESDv0* GetCurrentV0(){return fCurrentV0;}

  /*
   * Returns the negative ESD track which belongs to fCurrentV0
   */
  AliESDtrack* GetNegativeESDTrack(){return fESDEvent->GetTrack(fCurrentV0->GetNindex());}

  /*
   * Returns the positive ESD track which belongs to fCurrentV0
   */
  AliESDtrack* GetPositiveESDTrack(){return fESDEvent->GetTrack(fCurrentV0->GetPindex());}

  /*
   * Returns the negative KF particle which belongs to fCurrentV0
   */
  AliKFParticle* GetNegativeKFParticle();

  /*
   * Returns the positive KF particle which belongs to fCurrentV0
   */
  AliKFParticle* GetPositiveKFParticle();
  /*
   * Returns the KFParticle object of the 2 tracks.
   */
  AliKFParticle* GetMotherCandidateKFCombination();
  /*
   * Checks the probablity that the PID of the particle is what we want it to be.
   */
  Bool_t CheckPIDProbability(Double_t negProbCut, Double_t posProbCut);

  /*
   *Get the negative MC TParticle from the stack 
   */
  TParticle * GetNegativeMCParticle(){return fNegativeMCParticle;}//fMCStack->Particle(TMath::Abs(fESDEvent->GetTrack(fCurrentV0->GetNindex())->GetLabel()));}

  /*
   *Get the positive MC TParticle from the stack 
   */
  TParticle * GetPositiveMCParticle(){return fPositiveMCParticle;}//{return fMCStack->Particle(TMath::Abs(fESDEvent->GetTrack(fCurrentV0->GetPindex())->GetLabel()));}

  /*
   *Get the mother MC TParticle from the stack 
   */
  TParticle * GetMotherMCParticle(){return fMotherMCParticle;}

  Bool_t HasSameMCMother();

  /*
   *Get the MC stack 
   */
  AliStack* GetMCStack(){return fMCStack;}

  /*
   *Get the magnetic field from the ESD event 
   */
  Double_t GetMagneticField(){return fESDEvent->GetMagneticField();}

  /*
   *Get the primary vertex from the esd event
   */
  const AliESDVertex *GetPrimaryVertex() const {return fESDEvent->GetPrimaryVertex();}

  /*
   * Set the PID of the negative track
   */
  void SetNegativeTrackPID(Int_t negTrackPID){fNegativeTrackPID=negTrackPID;}

  /*
   * Set the PID of the positive track
   */
  void SetPositiveTrackPID(Int_t posTrackPID){fPositiveTrackPID=posTrackPID;}

  /*
   * Set the flag to use the kfparticle class. Will also disable the use of esd tracks
   */
  void UseKFParticle(){fUseKFParticle = kTRUE; fUseESDTrack = kFALSE;}

  /*
   *  Set the flag to use the esd track class. Will also disable the use of kf particles
   */
  void UseESDTrack(){fUseESDTrack = kTRUE; fUseKFParticle = kFALSE;}

  /*
   *  Set the flag to use improved vertex or not
   */
  void SetUseImprovedVertex(Bool_t useImprovedVertex){fUseImprovedVertex=useImprovedVertex;}

  /*
   * Return the number in the species array belonging to the negative or positive track pid.
   */
  Int_t GetSpeciesIndex(Int_t chargeOfTrack);

  /*
   * Return the x coordinate of the v0
   */
  Double_t GetX(){return fCurrentXValue;}

  /*
   * Return the y coordinate of the v0
   */
  Double_t GetY(){return fCurrentYValue;}

  /*
   * Return the Z coordinate of the v0
   */
  Double_t GetZ(){return fCurrentZValue;}

  /*
   * Return the radius of the v0
   */
  Double_t GetXYRadius(){return sqrt((Double_t)(fCurrentXValue*fCurrentXValue + fCurrentYValue*fCurrentYValue));}

  /*
   * Get the opening angle between the two tracks
   */
  Double_t GetOpeningAngle(){return fNegativeTrackLorentzVector->Angle(fPositiveTrackLorentzVector->Vect());}

  Double_t GetNegativeTrackEnergy(){return fCurrentNegativeKFParticle->E();}
  Double_t GetPositiveTrackEnergy(){return fCurrentPositiveKFParticle->E();}
  Double_t GetMotherCandidateEnergy(){return fCurrentMotherKFCandidate->E();}

  Double_t GetNegativeTrackPt(){return fNegativeTrackLorentzVector->Pt();}
  Double_t GetPositiveTrackPt(){return fPositiveTrackLorentzVector->Pt();}
  Double_t GetMotherCandidatePt(){return fMotherCandidateLorentzVector->Pt();}

  Double_t GetNegativeTrackEta(){return fNegativeTrackLorentzVector->Eta();}
  Double_t GetPositiveTrackEta(){return fPositiveTrackLorentzVector->Eta();}
  Double_t GetMotherCandidateEta(){return fMotherCandidateLorentzVector->Eta();}

  Double_t GetMotherCandidateNDF(){return fCurrentMotherKFCandidate->GetNDF();}
  Double_t GetMotherCandidateChi2(){return fCurrentMotherKFCandidate->GetChi2();}
  Double_t GetMotherCandidateMass(){return fMotherCandidateKFMass;}
  Double_t GetMotherCandidateWidth(){return fMotherCandidateKFWidth;}

  Double_t GetNegativeTrackPhi();
  Double_t GetPositiveTrackPhi();
  Double_t GetMotherCandidatePhi();

  void UpdateEventByEventData();
  
  Double_t GetMaxRCut(){return fMaxR;}
  Double_t GetEtaCut(){return fEtaCut;}
  Double_t GetPtCut(){return fPtCut;}
  Double_t GetChi2Cut(){return fChi2Cut;}

  void SetMaxRCut(Double_t maxR){fMaxR=maxR;}
  void SetEtaCut(Double_t etaCut){fEtaCut=etaCut;}
  void SetPtCut(Double_t ptCut){fPtCut=ptCut;}
  void SetChi2Cut(Double_t chi2){fChi2Cut=chi2;}
  
  void SetXVertexCut(Double_t xVtx){fCurrentXValue=xVtx;}
  void SetYVertexCut(Double_t yVtx){fCurrentYValue=yVtx;}
  void SetZVertexCut(Double_t zVtx){fCurrentZValue=zVtx;}
  void SetPIDProbability(Double_t pidProb){fPIDProbabilityCutPositiveParticle=pidProb; fPIDProbabilityCutNegativeParticle=pidProb;}
  void SetPIDProbabilityNegativeParticle(Double_t pidProb){fPIDProbabilityCutNegativeParticle=pidProb;}
  void SetPIDProbabilityPositiveParticle(Double_t pidProb){fPIDProbabilityCutPositiveParticle=pidProb;}
  void SetSigmaMass(Double_t sigmaMass){fNSigmaMass=sigmaMass;}
  void UpdateV0Information();

  void SetHistograms(AliGammaConversionHistograms *histograms){fHistograms=histograms;}

  std::vector<AliKFParticle> fCurrentEventGoodV0s;
  std::vector<AliKFParticle> fPreviousEventGoodV0s;

 private:
  AliStack * fMCStack;           // pointer to MonteCarlo particle stack 
  AliMCEventHandler* fMCTruth;   // pointer to the MC event handler
  TChain * fChain;               // pointer to the TChain
  
  AliESDInputHandler* fESDHandler;      //! pointer to esd object
  AliESDEvent *fESDEvent;               //! pointer to esd object

  AliGammaConversionHistograms *fHistograms;
  
  Int_t fCurrentV0IndexNumber;
  AliESDv0 * fCurrentV0;                //! pointer to the current v0
  AliKFParticle * fCurrentNegativeKFParticle;  //! pointer to the negative KF particle
  AliKFParticle * fCurrentPositiveKFParticle;  //! pointer to the positive KF particle
  AliKFParticle * fCurrentMotherKFCandidate;   //! pointer to the positive KF particle

  AliESDtrack * fCurrentNegativeESDTrack;      //! pointer to the negative ESD track
  AliESDtrack * fCurrentPositiveESDTrack;      //! pointer to the positive ESD track
 
  TLorentzVector * fNegativeTrackLorentzVector; //! pointer to the negative Track Lorentz Vector
  TLorentzVector * fPositiveTrackLorentzVector; //! pointer to the positive Track Lorentz Vector
  TLorentzVector * fMotherCandidateLorentzVector;   //! pointer to the mother candidate Track Lorentz Vector

  Double_t fCurrentXValue;
  Double_t fCurrentYValue;
  Double_t fCurrentZValue;

  Int_t fPositiveTrackPID;
  Int_t fNegativeTrackPID;

  TParticle *fNegativeMCParticle;      //!
  TParticle *fPositiveMCParticle;      //!
  TParticle *fMotherMCParticle;        //!

  Double_t fMotherCandidateKFMass;
  Double_t fMotherCandidateKFWidth;

  Bool_t fUseKFParticle;
  Bool_t fUseESDTrack;
  Bool_t fDoMC;

  //cuts
  Double_t fMaxR;
  Double_t fEtaCut;
  Double_t fPtCut;
  Double_t fChi2Cut;
  Double_t fPIDProbabilityCutNegativeParticle;
  Double_t fPIDProbabilityCutPositiveParticle;
  Double_t fXVertexCut;
  Double_t fYVertexCut;
  Double_t fZVertexCut;
  
  Double_t fNSigmaMass;
  
  Bool_t fUseImprovedVertex;
  
  ClassDef(AliV0Reader,0)
};


#endif