module;

#include <stdexcept>
#include <string>
#include <utility>

export module mean_field:eos.evaluation;
export import :eos.concepts;

export namespace mean_field::eos {
    enum class EvaluationErrorCode {
        unsupported_relation,
        unsupported_derivative,
        wrong_input_count,
        wrong_input_quantity,
        nonfinite_input,
        outside_domain,
        nonfinite_result
    };

    class EvaluationError final : public std::domain_error {
    public:
        explicit EvaluationError(
            const EvaluationErrorCode code,
            std::string message
        )
            : std::domain_error(std::move(message)),
              m_code(code) {
        }

        [[nodiscard]] EvaluationErrorCode code() const noexcept {
            return m_code;
        }

    private:
        EvaluationErrorCode m_code;
    };

    template <
        ThermodynamicQuantityType OutputQuantity,
        EquationOfStateModel EquationOfState,
        QuantityValueType... InputValues>
        requires SupportsRelation<
            EquationOfState,
            Relation<
                OutputQuantity,
                QuantityOfT<InputValues>...>>
    [[nodiscard]] constexpr QuantityValue<OutputQuantity> evaluate(
        const EquationOfState &equationOfState,
        const InputValues... inputValues
    ) noexcept(noexcept(equationOfState
                            .evaluate(
                                Relation<
                                    OutputQuantity,
                                    QuantityOfT<InputValues>...>{},
                                inputValues...
                            ))) {
        return equationOfState.evaluate(Relation<OutputQuantity, QuantityOfT<InputValues>...>{}, inputValues...);
    }

    template <
        ThermodynamicQuantityType OutputQuantity,
        ThermodynamicQuantityType InputQuantity,
        EquationOfStateModel EquationOfState,
        QuantityValueType... InputValues>
        requires SupportsPartialDerivative<
            EquationOfState,
            Relation<
                OutputQuantity,
                QuantityOfT<InputValues>...>,
            InputQuantity>
    [[nodiscard]] constexpr PartialDerivative<
        OutputQuantity,
        InputQuantity>
    partialDerivative(
        const EquationOfState &equationOfState,
        const InputValues... inputValues
    ) noexcept(noexcept(equationOfState
                            .partialDerivative(
                                Relation<
                                    OutputQuantity,
                                    QuantityOfT<InputValues>...>{},
                                WithRespectTo<InputQuantity>{},
                                inputValues...
                            ))) {
        return equationOfState.partialDerivative(
            Relation<OutputQuantity, QuantityOfT<InputValues>...>{}, WithRespectTo<InputQuantity>{}, inputValues...
        );
    }
} // namespace mean_field::eos