module;

#include <mfem.hpp>
#include <vector>

export module mean_field:mapping.prepared_cache;
import :mapping.types;

export namespace mean_field::mapping {
    // Flat, owning storage for prepared volume contexts. Load into reusable
    // workspaces: no MFEM buffers or pointer aliases are owned per quadrature
    // point. The layout retains every public context field without recomputing
    // inverses or changing the mapper's numerical contract.
    class VolumeMappingCache {
    public:
        void SetSize(
            int point_count,
            int dimension
        );
        void Store(
            int point,
            const VolumeMappingContext &context
        );
        void Load(
            int point,
            VolumeMappingContext &context
        ) const;
        void LoadInverseJacobian(
            int point,
            mfem::DenseMatrix &inverse
        ) const;
        [[nodiscard]] int GetPointCount() const;
        [[nodiscard]] int GetDimension() const;

    private:
        [[nodiscard]] const double *GetPointData(int point) const;
        std::vector<double> m_data;
        int m_point_count{0};
        int m_dimension{0};
        int m_point_stride{0};
    };
} // namespace mean_field::mapping