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// Class G4VIntersectionLocator inline methods implementation
//
// Authors: John Apostolakis, Tatiana Nikitina (CERN), 27 October 2008
// --------------------------------------------------------------------

inline G4double G4VIntersectionLocator::GetDeltaIntersectionFor()
{
  return fiDeltaIntersection;
} 

inline G4double G4VIntersectionLocator::GetEpsilonStepFor()
{
  return fiEpsilonStep;
}

inline G4Navigator* G4VIntersectionLocator::GetNavigatorFor()
{
  return fiNavigator;
}

inline G4ChordFinder* G4VIntersectionLocator::GetChordFinderFor()
{
  return fiChordFinder;
}

inline G4int G4VIntersectionLocator::GetVerboseFor()
{
  return fVerboseLevel;
}

inline G4bool G4VIntersectionLocator::GetAdjustementOfFoundIntersection()
{
  return fUseNormalCorrection;
}

inline void G4VIntersectionLocator::
AddAdjustementOfFoundIntersection(G4bool UseCorrection )
{
  fUseNormalCorrection = UseCorrection;
}

inline void G4VIntersectionLocator::SetEpsilonStepFor( G4double EpsilonStep )
{
  fiEpsilonStep = EpsilonStep;
}

inline void G4VIntersectionLocator::
SetDeltaIntersectionFor( G4double deltaIntersection )
{
  fiDeltaIntersection = deltaIntersection;
}

inline void G4VIntersectionLocator::SetNavigatorFor( G4Navigator* fNavigator )
{
  fiNavigator = fNavigator;
}

inline void G4VIntersectionLocator::SetChordFinderFor(G4ChordFinder* fCFinder )
{
  fiChordFinder = fCFinder;
}

inline void G4VIntersectionLocator::SetSafetyParametersFor(G4bool UseSafety )
{
  fiUseSafety = UseSafety;
}

inline void G4VIntersectionLocator::SetVerboseFor(G4int fVerbose)
{
  fVerboseLevel = fVerbose;
}

inline G4bool
G4VIntersectionLocator::IntersectChord( const G4ThreeVector&  StartPointA,
                                        const G4ThreeVector&  EndPointB,
                                        G4double&      NewSafety,
                                        G4double&      PreviousSafety,
                                        G4ThreeVector& PreviousSftOrigin,
                                        G4double&      LinearStepLength,
                                        G4ThreeVector& IntersectionPoint,
                                        G4bool*        ptrCalledNavigator )
{
  G4bool CalledNavigator = false; 

  // Calculate the direction and length of the chord AB

  G4ThreeVector  ChordAB_Vector = EndPointB - StartPointA;
  G4double       ChordAB_Length = ChordAB_Vector.mag();  // Magnitude (norm)
  G4ThreeVector  ChordAB_Dir = ChordAB_Vector.unit();
  G4bool intersects;
  G4ThreeVector OriginShift = StartPointA - PreviousSftOrigin ;
  G4double MagSqShift  = OriginShift.mag2() ;
  G4double currentSafety;

  if( MagSqShift >= sqr(PreviousSafety) )
  {
    currentSafety = 0.0 ;
  }
  else
  {
    currentSafety = PreviousSafety - std::sqrt(MagSqShift) ;
  }

  if( fiUseSafety && (ChordAB_Length <= currentSafety) )
  {
    // The Step is guaranteed to be taken

    LinearStepLength = ChordAB_Length;
    intersects = false;
    NewSafety = currentSafety;
    CalledNavigator = false;
  }
  else
  {
    // Check whether any volumes are encountered by the chord AB

    LinearStepLength = GetNavigatorFor()->ComputeStep( StartPointA,
                                 ChordAB_Dir, ChordAB_Length, NewSafety );
    intersects = (LinearStepLength <= ChordAB_Length); 
       // G4Navigator contracts to return k_infinity if len==asked
       // and it did not find a surface boundary at that length
    
    LinearStepLength = std::min( LinearStepLength, ChordAB_Length);
    CalledNavigator = true; 

    // Save the last calculated safety!

    PreviousSftOrigin = StartPointA;
    PreviousSafety    = NewSafety;

    if( intersects )
    {
       // Intersection Point of chord AB and either volume A's surface 
       //                                or a daughter volume's surface ..
       IntersectionPoint = StartPointA + LinearStepLength * ChordAB_Dir;
    }
  }
  if( ptrCalledNavigator != nullptr )
  { 
    *ptrCalledNavigator = CalledNavigator; 
  }

  return intersects;
}