// ************************************************************************
// 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                               *
//                                                                        *
//*************************************************************************


#ifndef ALIHLTTPCCATRACKLINEARISATION_H
#define ALIHLTTPCCATRACKLINEARISATION_H

#include "AliHLTTPCCATrackParam.h"


/**
 * @class AliHLTTPCCATrackLinearisation
 *
 * AliHLTTPCCATrackLinearisation class describes the parameters which are used
 * to linearise the transport equations for the track trajectory.
 *
 * The class is used during track (re)fit, when the AliHLTTPCTrackParam track is only
 * partially fitted, and there is some apriory knowledge about trajectory.
 * This apriory knowledge is used to linearise the transport equations.
 *
 * In case the track is fully fitted, the best linearisation point is
 * the track trajectory itself (AliHLTTPCCATrackLinearisation = AliHLTTPCTrackParam ).
 *
 */
class AliHLTTPCCATrackLinearisation
{

  public:

    AliHLTTPCCATrackLinearisation()
        : fSinPhi( 0 ), fCosPhi( 1 ), fDzDs( 0 ), fQPt( 0 ) {}

    AliHLTTPCCATrackLinearisation( float SinPhi1, float CosPhi1, float DzDs1, float QPt1 )
        : fSinPhi( SinPhi1 ), fCosPhi( CosPhi1 ), fDzDs( DzDs1 ), fQPt( QPt1 ) {}

    AliHLTTPCCATrackLinearisation( const AliHLTTPCCATrackParam &t );

    GPUd() void Set( float SinPhi1, float CosPhi1, float DzDs1, float QPt1 );


    GPUd() float SinPhi()const { return fSinPhi; }
    GPUd() float CosPhi()const { return fCosPhi; }
    GPUd() float DzDs()  const { return fDzDs; }
    GPUd() float QPt()   const { return fQPt; }

    GPUd() float GetSinPhi()const { return fSinPhi; }
    GPUd() float GetCosPhi()const { return fCosPhi; }
    GPUd() float GetDzDs()  const { return fDzDs; }
    GPUd() float GetQPt()   const { return fQPt; }

    GPUd() void SetSinPhi( float v ) {  fSinPhi = v; }
    GPUd() void SetCosPhi( float v ) {  fCosPhi = v; }
    GPUd() void SetDzDs( float v )  {  fDzDs   = v; }
    GPUd() void SetQPt( float v )   {  fQPt = v; }

  private:
    float fSinPhi; // SinPhi
    float fCosPhi; // CosPhi
    float fDzDs;   // DzDs
    float fQPt;    // QPt
};


GPUd() inline AliHLTTPCCATrackLinearisation::AliHLTTPCCATrackLinearisation( const AliHLTTPCCATrackParam &t )
    : fSinPhi( t.SinPhi() ), fCosPhi( 0 ), fDzDs( t.DzDs() ), fQPt( t.QPt() )
{
  if ( fSinPhi > .999 ) fSinPhi = .999;
  else if ( fSinPhi < -.999 ) fSinPhi = -.999;
  fCosPhi = CAMath::Sqrt( 1 - fSinPhi * fSinPhi );
  if ( t.SignCosPhi() < 0 ) fCosPhi = -fCosPhi;
}


GPUd() inline void AliHLTTPCCATrackLinearisation::Set( float SinPhi1, float CosPhi1,
    float DzDs1, float QPt1 )
{
  SetSinPhi( SinPhi1 );
  SetCosPhi( CosPhi1 );
  SetDzDs( DzDs1 );
  SetQPt( QPt1 );
}

#endif //ALIHLTTPCCATRACKLINEARISATION_H