/** @file CbmVertex.h
 ** @author V.Friese <v.friese@gsi.de>
 **/

#ifndef CBMVERTEX_H
#define CBMVERTEX_H 1

#include <string>
#include "TMatrixFSym.h"
#include "TNamed.h"
#include "TVector3.h"

/** @class CbmVertex
 ** @brief Data class for a vertex in CBM.
 ** @author V. Friese <v.friese@gsi.de>
 ** @version 2.0
 **/
class CbmVertex : public TNamed
{

  public:

    /** Default constructor  **/
    CbmVertex();

    /** Constructor with name and title
     ** @param name  Vertex name
     ** @param title Vertex title
     **/
    CbmVertex(const char* name, const char* title);

    /** Constructor with all member variables
     ** @param name      Name of object
     ** @param title     Title of object
     ** @param x         x coordinate [cm]
     ** @param y         y coordinate [cm]
     ** @param z         z coordinate [cm]
     ** @param chi2      chi square of vertex fit
     ** @param ndf       Number of degrees of freedom of vertex fit
     ** @param nTracks   Number of tracks used for vertex fit
     ** @param covMat    Covariance Matrix (symmetric, 3x3)
     **/
    CbmVertex(const char* name, const char* title, Double_t x, Double_t y,
              Double_t z, Double_t chi2, Int_t ndf, Int_t nTracks,
              const TMatrixFSym& covMat);

    /** Destructor **/
    virtual ~CbmVertex();

    /** x coordinate
     ** value  x coordinate of vertex [cm]
     **/
    Double_t GetX() const {
      return fX;
    }

    /** y coordinate
     ** value  y coordinate of vertex [cm]
     **/
    Double_t GetY() const {
      return fY;
    }

    /** z coordinate
     ** value  z coordinate of vertex [cm]
     **/
    Double_t GetZ() const {
      return fZ;
    }

    /** chi square
     ** @value chi square of vertex fit
     **/
    Double_t GetChi2() const {
      return fChi2;
    }

    /** Degrees-of-freedom
     ** value  Number of degrees-of-freedom for vertex fit
     **/
    Int_t GetNDF() const {
      return fNDF;
    }

    /** Number of tracks used for the vertex fit
     ** @value  Number of tracks used for the vertex fit
     **/
    Int_t GetNTracks() const {
      return fNTracks;
    }
    ;

    /** Vertex position
     ** @param[out] Vertex position vector
     */
    void Position(TVector3& pos) const {
      pos.SetXYZ(fX, fY, fZ);
    }

    /** Covariance matrix
     ** @param[out] Covariance matrix
     **/
    void CovMatrix(TMatrixFSym& covMat) const {
      covMat = fCovMatrix;
    }

    /** Covariance matrix elements
     ** @param i  Matrix row index
     ** @param j  Matrix column index
     ** @value Covariance matrix element (i,j)
     **/
    Double_t GetCovariance(Int_t i, Int_t j) const {
      return fCovMatrix(i, j);
    }

    /** Reset the member variables **/
    void Reset();

    /** Set the member variables
     ** @param x         x coordinate [cm]
     ** @param y         y coordinate [cm]
     ** @param z         z coordinate [cm]
     ** @param chi2      chi square of vertex fit
     ** @param ndf       Number of degrees of freedom of vertex fit
     ** @param nTracks   Number of tracks used for vertex fit
     ** @param covMat    Covariance Matrix (symmetric, 3x3)
     **/
    void SetVertex(Double_t x, Double_t y, Double_t z, Double_t chi2,
                   Int_t ndf, Int_t nTracks, const TMatrixFSym& covMat);

    /** String output **/
    virtual std::string ToString() const;

  private:

    /** Position coordinates  [cm] **/
    Double32_t fX, fY, fZ;

    /** Chi2 of vertex fit **/
    Double32_t fChi2;

    /** Number of degrees of freedom of vertex fit **/
    Int_t fNDF;

    /** Number of tracks used for the vertex fit **/
    Int_t fNTracks;

    /** Covariance matrix for x, y, and z stored in an array. The
     ** sequence is a[0,0], a[0,1], a[0,2], a[1,1], a[1,2], a[2,2]
     **/
    TMatrixFSym fCovMatrix;


  ClassDef(CbmVertex,2);

};

#endif