//////////////////////////////////////////////////////////////////////////////////////////
/// \class RAT::SphericalSubregion
///
/// \brief A pure virtual class that defines subregions.  A subregion is a feature on an otherwise
/// symmetric spherical shell.  If a subregion can be reached by a straight track from a point
/// within the shell, GEANT will check for intersections.
///
/// \author Aksel Hallin aksel.hallin@ualberta.ca
///
/// Revision History: \n
/// 2014-05-16  Aksel Hallin
///
///\detail This class is used to segment a G4VSolid that is built around a spherical shell into smaller units.  Only
/// features within a given segment need to be checked for intersection, interiorness, etc.
///
/////////////////////////////////////////////////////////////////////////////////////////



#ifndef RAT__SphericalSubregion__
#define RAT__SphericalSubregion__
#include "G4VSolid.hh"
#include <list>


class SphericalSubregion{
public:
    /// DistanceToIn Spherical subregion implementation to provide G4VSolid routine.
    virtual G4double DistanceToIn(const G4ThreeVector &p, const G4ThreeVector &n, const G4double dInner[2], const G4double dOuter[2])const= 0;
    /// DistanceToIn A spherical subregion needs to implement this to provide G4VSolid routines.
    virtual G4double DistanceToIn(const G4ThreeVector &p)const = 0;
    /// DistanceToOut A spherical subregion needs to implement this to provide G4VSolid routines.
    virtual G4double DistanceToOut(const G4ThreeVector &p)const = 0;
    /// Inside A spherical subregion needs to implement this to provide G4VSolid routines.
    virtual EInside Inside(const G4ThreeVector &p)const=0;
    /// SurfaceNormal A spherical subregion needs to implement this to provide G4VSolid routines.
    G4ThreeVector SurfaceNormal(const G4ThreeVector &p) { G4bool isValid; return SurfaceNormal(p, isValid); }
    /// SurfaceNormal A spherical subregion needs to implement this to provide G4VSolid routines.
    virtual G4ThreeVector SurfaceNormal(const G4ThreeVector &p, G4bool &isValid)const = 0;
    /// OverlapsRegion tests whether the spherical region bounded by the four corners overlaps with this specific
    /// spherical subregion.  This returns true if any event within the sector bounded by those four corners and the
    /// inner and outer spherical shell radii can intersect with a straight line path. Intersections that require
    /// passing through a spherical surface first return false.
    /// @param[in] corners[4] defines the spherical section.
    virtual G4bool OverlapsRegion(const G4ThreeVector [4])const {return true;}
};

#endif