module;

#include <cstdint>
#include <string_view>

export module mean_field:deformation.descriptors;

export namespace mean_field::deformation {
    enum class SurfaceMotionKind : std::uint8_t { Radial, Normal, GeneralVector };

    enum class GeometricGaugeTreatment : std::uint8_t {
        Retained,
        ExcludedByParameterization,
        ConstrainedByPrescription
    };

    enum class InteriorCenterBehavior : std::uint8_t { Unspecified, FixedAtReferenceCenter, DeterminedBySurfaceMotion };

    enum class VacuumOuterBoundaryBehavior : std::uint8_t {
        Unspecified,
        FixedAtReferenceInfinity,
        DeterminedBySurfaceMotion
    };

    struct SurfaceDeformationDescriptor final {
        std::string_view name;
        int spatialDimension;
        SurfaceMotionKind motionKind;
        bool linearOnReferenceGeometry;
        bool requiresStarShapedReferenceSurface;
        bool hasExactDerivativeTranspose;
        bool hasExactPullbackDerivative;
        GeometricGaugeTreatment translationTreatment;
        GeometricGaugeTreatment orientationTreatment;

        [[nodiscard]] constexpr bool isValid() const noexcept {
            return !name.empty() && spatialDimension > 0;
        }

        [[nodiscard]] constexpr bool supportsExactNewtonLinearization() const noexcept {
            return hasExactDerivativeTranspose && hasExactPullbackDerivative;
        }

        constexpr bool operator==(const SurfaceDeformationDescriptor &) const = default;
    };

    struct InteriorDeformationExtensionDescriptor final {
        std::string_view name;
        int spatialDimension;
        bool linearOnReferenceGeometry;
        bool requiresRadialFoliation;
        bool requiresAuxiliarySolve;
        bool hasExactDerivativeTranspose;
        bool hasExactPullbackDerivative;
        InteriorCenterBehavior centerBehavior;

        [[nodiscard]] constexpr bool isValid() const noexcept {
            return !name.empty() && spatialDimension > 0 && centerBehavior != InteriorCenterBehavior::Unspecified;
        }

        [[nodiscard]] constexpr bool supportsExactNewtonLinearization() const noexcept {
            return hasExactDerivativeTranspose && hasExactPullbackDerivative;
        }

        constexpr bool operator==(const InteriorDeformationExtensionDescriptor &) const = default;
    };

    struct VacuumDeformationExtensionDescriptor final {
        std::string_view name;
        int spatialDimension;
        bool linearOnReferenceGeometry;
        bool requiresRadialFoliation;
        bool requiresAuxiliarySolve;
        bool hasExactDerivativeTranspose;
        bool hasExactPullbackDerivative;
        VacuumOuterBoundaryBehavior outerBoundaryBehavior;

        [[nodiscard]] constexpr bool isValid() const noexcept {
            return !name.empty() && spatialDimension > 0 &&
                   outerBoundaryBehavior != VacuumOuterBoundaryBehavior::Unspecified;
        }

        [[nodiscard]] constexpr bool supportsExactNewtonLinearization() const noexcept {
            return hasExactDerivativeTranspose && hasExactPullbackDerivative;
        }

        constexpr bool operator==(const VacuumDeformationExtensionDescriptor &) const = default;
    };

    struct DomainDeformationDescriptor final {
        SurfaceDeformationDescriptor surfaceDeformation;
        InteriorDeformationExtensionDescriptor stellarInteriorExtension;
        VacuumDeformationExtensionDescriptor vacuumExtension;
        bool linearOnReferenceGeometry;
        bool requiresAuxiliarySolve;
        bool hasExactDerivativeTranspose;
        bool hasExactPullbackDerivative;

        [[nodiscard]] constexpr bool isValid() const noexcept {
            return surfaceDeformation.isValid() && stellarInteriorExtension.isValid() && vacuumExtension.isValid() &&
                   surfaceDeformation.spatialDimension == stellarInteriorExtension.spatialDimension &&
                   surfaceDeformation.spatialDimension == vacuumExtension.spatialDimension;
        }

        [[nodiscard]] constexpr bool supportsExactNewtonLinearization() const noexcept {
            return hasExactDerivativeTranspose && hasExactPullbackDerivative;
        }

        constexpr bool operator==(const DomainDeformationDescriptor &) const = default;
    };
} // namespace mean_field::deformation