module;

#include <cmath>
#include <format>
#include <stdexcept>

export module mean_field:surface.isobaric;

export import :surface.base;

export namespace mean_field::surface {
    class Isobaric final : public SurfaceBase {
    public:
        explicit Isobaric(const double targetPressure = 0.0) : m_targetPressure(targetPressure) {
            validateTargetPressure();
        }

        [[nodiscard]] double targetPressure() const noexcept {
            return m_targetPressure;
        }

        [[nodiscard]] ResolvedSurfaceCondition
        resolve(const mean_field::eos::EquationOfState &equationOfState) const override {
            return ResolvedSurfaceCondition{resolveTargetEnthalpy(equationOfState)};
        }

        void validate(const mean_field::eos::EquationOfState &equationOfState) const override {
            static_cast<void>(resolveTargetEnthalpy(equationOfState));
        }

    private:
        [[nodiscard]] double resolveTargetEnthalpy(const mean_field::eos::EquationOfState &equationOfState) const {
            validateTargetPressure();

            const double targetEnthalpy = equationOfState.enthalpy_from_pressure(m_targetPressure);

            if (!std::isfinite(targetEnthalpy) || targetEnthalpy < 0.0) {
                throw std::domain_error(
                    std::format(
                        "The equation of state resolved the isobaric "
                        "target P = {} to the invalid enthalpy h = {}.",
                        m_targetPressure, targetEnthalpy
                    )
                );
            }

            return targetEnthalpy;
        }

        void validateTargetPressure() const {
            if (!std::isfinite(m_targetPressure) || m_targetPressure < 0.0) {
                throw std::invalid_argument(
                    std::format(
                        "The target surface pressure must be finite and "
                        "non-negative. Instead P = {} was provided.",
                        m_targetPressure
                    )
                );
            }
        }

        double m_targetPressure;
    };
} // namespace mean_field::surface