////////////////////////////////////////////////////////////////////
/// \class RAT::PosGen_Paint
///
/// \brief  Generates events on the surface of set volume(s).
///
/// \author Phil G Jones <p.g.jones@qmul.ac.uk>
/// \author Matthew Mottram <m.mottram@qmul.ac.uk> -- contact person
///
/// REVISION HISTORY:\n
///     11 Jun  2012 : P.Jones - Refactor of GLG4PosGen.
///     17 July 2012 : D.Resnick - Use VolumeList to store volumes.
///
///  \details  Multiple volume paints can be added by calling the
///           /generator/pos/set command multiple times e.g:
///           /generator/pos/set 0 0 0
///           /generator/pos/set 1000 0 0
///           For events on the surface of the volumes located at the
///           centre and 1m on x axis.
///           The number of generated positions in each physical
///           volume is proportional to the surface area (size).
///
////////////////////////////////////////////////////////////////////
#ifndef __RAT_PosGen_Paint__
#define __RAT_PosGen_Paint__

#include <G4ThreeVector.hh>

#include <RAT/GLG4PosGen.hh>
#include <RAT/VolumeList.hh>

#include <vector>
#include <map>

class G4VPhysicalVolume;
class G4VSolid;

namespace RAT {
class PosGen_Paint : public GLG4PosGen
{
    public:
        /// Constructor sets the default db name
        PosGen_Paint(const std::string& dbname = std::string("paint")) :
            GLG4PosGen(dbname) { };
        /// Destructor
        virtual ~PosGen_Paint() { };
        /// Abstract interface for generating the position
        virtual void GeneratePosition(G4ThreeVector& argResult);
        /// Abstract interface for setting the state
        virtual void SetState(G4String newValues);
        /// Abstract interface for getting the state
        virtual G4String GetState() const;
    protected:
        VolumeList fVolumes; ///< List of volumes to generate events in
        std::vector<std::string> fStates; ///< List of states to build fVolumes
        /// List of thicknesses, per state
        std::vector<std::string> fStateThicknesses;
        std::vector<double> fThicknesses; ///< List of thicknesses, per volume
        /// The total surface area of all the physical volumes to paint, in mm^2
        double fTotalSurfaceArea;
        /// A flag marking whether the list of volumes needs to be regenerated
        bool fListValid;

        /// Memoized volume computation
        static double ComputeArea(const G4VPhysicalVolume* volume);
        /// A map of solid names to their cubic volumes, in mm^3
        static std::map<std::string, double> fSolidAreas;
};
} // namespace RAT

#endif