module;
#include <cstdint>
#include <memory>
#include <mfem.hpp>

export module mean_field:operators.prepared_hdiv_mass;
export import :fem;
export import :mapping.domain_mapper;

export namespace mean_field::operators {
    class PreparedMappedHDivMassOperator final : public mfem::Operator {
    public:
        PreparedMappedHDivMassOperator(
            const fem::FEM &f,
            const mapping::DomainMapperStateless &domain_mapper
        );

        void Prepare(const mfem::Vector &displacement_true);
        void Mult(
            const mfem::Vector &gravity_gradient_true,
            mfem::Vector &action
        ) const override;

        [[nodiscard]] bool IsPrepared() const noexcept;
        [[nodiscard]] std::uint64_t GetPreparationCount() const noexcept;

    private:
        const fem::FEM &m_fem;
        const mapping::DomainMapperStateless &m_domain_mapper;

        mfem::Array<int> m_stellar_marker;
        mfem::Array<int> m_vacuum_marker;

        std::unique_ptr<mfem::MatrixCoefficient> m_stellar_mass_coefficient;
        std::unique_ptr<mfem::MatrixCoefficient> m_vacuum_mass_coefficient;
        std::unique_ptr<mfem::ParBilinearForm> m_mass_form;
        std::uint64_t m_preparation_count{0};
        bool m_is_prepared{false};
    };
} // namespace mean_field::operators