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// HadrontherapyRBEAccumulable.hh;
//
#ifndef HADRONTHERAPYRBEACCUMULABLE_HH
#define HADRONTHERAPYRBEACCUMULABLE_HH

#include <G4VAccumulable.hh>

#include <valarray>

/**
 * @brief Accumulable of RBE-related data (that must be thread-local).
 *
 * It keeps the sum of alpha and beta numerators/denominator, as well as energy deposits.
 * The class is closely tied with the singleton HadrontherapyRBE that is used both
 * to calculate alphas and betas, and also to store results.
 *
 * This is implemented as a customized G4VAccumulable with non-scalar data.
 *
 * @note There are two levels of merging (accumulation):
 *   1) From more threads in one run (G4VAccumulable merging is applied)
 *   2) (Optional) inter-run merging of data (implemented in HadrontherapyRBE).
 *
 * @note std::valarray is used (instead of C arrays or std::vectors)
 *    to accumulate data for its logical simplicity.
 */
class HadrontherapyRBEAccumulable : public G4VAccumulable
{
public:
    HadrontherapyRBEAccumulable();
    HadrontherapyRBEAccumulable(const HadrontherapyRBEAccumulable& other) = default;

    // G4VAccumulable virtual methods
    void Merge(const G4VAccumulable &rhs) override;
    void Reset() override;

    // Store information from a single step
    void Accumulate(G4double E, G4double energyDeposit, G4double dX, G4int Z, G4int i, G4int j, G4int k);

    // Type alias for numerical arrays
    using array_type = std::valarray<G4double>;

    // Access to stored data (to be called on the merged data)
    const array_type GetEnergyDeposit() const;
    const array_type GetAlphaNumerator() const { return fAlphaNumerator; }
    const array_type GetBetaNumerator() const { return fBetaNumerator; }
    const array_type GetDenominator() const { return fDenominator; }

    // Verbosity, shared with HadrontherapyRBE
    G4int GetVerboseLevel() const;

private:
    /** @brief Helper function to get the 1D index in the 3D array */
    inline G4int GetIndex(G4int i, G4int j, G4int k) const {return (i * fVoxelsAlongY + j) * fVoxelsAlongZ + k; }

    // Apply configuration from the HadrontherapyRBE class and prepare matrices
    void Initialize();
    G4bool fInitialized { false };

    array_type fAlphaNumerator;
    array_type fBetaNumerator;
    array_type fDenominator;
    array_type fEnergyDeposit;

    // How many voxels do we have?
    // ...along each axis
     G4int fVoxelsAlongX;
    G4int fVoxelsAlongY;
    G4int fVoxelsAlongZ;

    // ...and in total
    size_t fVoxels;

  


};

#endif // HADRONTHERAPYRBEACCUMULABLE_HH