#ifndef STNTUPLE_TStnVertex
#define STNTUPLE_TStnVertex

#ifdef __GNUG__
#pragma interface
#endif

class TMatrixRow;
class TMatrixColumn;
class TMatrixDiag;

#include "TLorentzVector.h"
#include "Stntuple/base/TMatrix33.hh"

class TStnTrack;
class StnVertexBlock_t;

class TStnVertex : public TObject {

  friend Int_t StnRun1InitVertex(TStnVertex*       Vert, 
				 StnVertexBlock_t* R1V , 
				 Int_t             I   );
public:
  enum { 
    kUNCLASSIFIED = -1,
    kEMPTY        =  0,  
    kBEAMGAS      =  1, 
    kPRIMARY      = 12
  };
//------------------------------------------------------------------------------
//  data members
//------------------------------------------------------------------------------
  Short_t        fNumber;		// sequential number of this vertex
  Short_t        fNTracks;		// N(tracks) assoc. with the vertex

  Int_t          fVClass;		// vertex class

  Float_t        fQ;			// total track charge in the vertex
  Float_t        fMassError;		// mass error
  Float_t        fChi2;			// chi2 of fit
  Float_t        fNdof;			// number of degrees of freedom of fit
  Float_t        fSumPt;		// scalar total pt of tracks in vertex
  Float_t        fT0 ;                  // T0 of the vertex , new in V3
  Float_t        fT0Error;              // uncertainty on T0, new in V3
  Float_t        fFloat[5];             // reserve          , new in V3

  TVector3       fVertex;		// position of the vertex
  TLorentzVector fMomentum;		// reconstructed momentum
  TMatrix33      fVtxCov;		// || vertex covariance 
  TMatrix33      fMomCov;		// || 3-momentum covariance
//-----------------------------------------------------------------------------
// transient-only data members
//-----------------------------------------------------------------------------
  Float_t        fSumW;			// !
  Float_t        fSumW2;		// !
  Float_t        fSumX;			// !
  Float_t        fSumX2;		// !
  Float_t        fSumY;			// !
  Float_t        fSumY2;		// !
  Float_t        fSumZ;			// !
  Float_t        fSumZ2;		// !
//------------------------------------------------------------------------------
//  functions
//------------------------------------------------------------------------------
					// ****** constructors and destructor
  TStnVertex(Int_t Number = -1);
  virtual ~TStnVertex();
					// ****** initialization methods
  int      Init(TStnTrack* track);
					// ****** accessors

  Int_t           VClass     () { return fVClass;    }
  Float_t         X          () { return fVertex[0]; }
  Float_t         Y          () { return fVertex[1]; }
  Float_t         Z          () { return fVertex[2]; }
  Float_t         T0         () { return fT0;        }
  Float_t         T0Error    () { return fT0Error;   }
  Float_t         SigmaX     () { return sqrt(fVtxCov(0,0)); }
  Float_t         SigmaY     () { return sqrt(fVtxCov(1,1)); }
  Float_t         SigmaZ     () { return sqrt(fVtxCov(2,2)); }
  TVector3*       Vertex     () { return &fVertex;}
  TLorentzVector* Momentum   () { return &fMomentum;}
  Float_t         Mass       () { return fMomentum.M();}
  Float_t         MassError  () { return fMassError;}
  TMatrix33*      VtxCov     () { return &fVtxCov; }
  TMatrix33*      MomCov     () { return &fMomCov; }
  Float_t         Q          () { return fQ;      }
  Float_t         Chi2       () { return fChi2;   }
  Float_t         Ndof       () { return fNdof;   }
  Int_t           NTracks    () { return fNTracks;}
  Int_t           Number     () { return fNumber; }
  Float_t         SumPt      () { return fSumPt;  }

					// ****** setters

  void     SetNumber(Int_t n) { fNumber = n; }

  void     SetXYZ   (Double_t X0, Double_t Y0, Double_t Z0) {
    fVertex.SetXYZ(X0,Y0,Z0);
  }
					// ****** non-trivial methods
					// add new track to the vertex
  int     Add(TStnTrack* track);
//-----------------------------------------------------------------------------
// overloaded functions of TObject
//-----------------------------------------------------------------------------
  virtual Bool_t  IsSortable() const { return kTRUE; }
  virtual Int_t   Compare(const TObject* vertex) const;
  virtual void    Print(Option_t* opt = "") const;
//-----------------------------------------------------------------------------
// schema evolution
//-----------------------------------------------------------------------------
  void     ReadV1 (TBuffer& R__b);
  void     ReadV2 (TBuffer& R__b);

  ClassDef(TStnVertex,3)
};

#endif