#include <cmath>
#include <limits>
#include <stdexcept>

#include <catch2/catch_test_macros.hpp>

import mean_field;
import test_helpers;

TEST_CASE(
    "Isobaric Surface Resolves Zero Pressure To Zero Enthalpy",
    tags::barotrope &tags::unit &tags::surface
) {
    const mean_field::eos::Polytrope equationOfState(3.0, 0.25);

    const mean_field::surface::Isobaric surface;

    const mean_field::surface::ResolvedSurfaceCondition resolved = surface.resolve(equationOfState);

    CHECK(surface.targetPressure() == 0.0);
    CHECK(resolved.targetEnthalpy == 0.0);
    CHECK(resolved.residual(0.0) == 0.0);
    CHECK(resolved.residual(0.37) == 0.37);
    CHECK(resolved.jacobianAction(-0.19) == -0.19);
}

TEST_CASE(
    "Isobaric Surface Resolves Positive Pressure Through The EOS",
    tags::barotrope &tags::unit &tags::surface
) {
    const mean_field::eos::Polytrope equationOfState(3.0, 0.25);

    constexpr double targetPressure = 0.03125;

    const mean_field::surface::Isobaric surface(targetPressure);

    const mean_field::surface::ResolvedSurfaceCondition resolved = surface.resolve(equationOfState);

    const double recoveredPressure = equationOfState.pressure_from_enthalpy(resolved.targetEnthalpy);

    INFO("Resolved surface enthalpy = " << resolved.targetEnthalpy);
    INFO("Recovered surface pressure = " << recoveredPressure);

    CHECK(resolved.targetEnthalpy > 0.0);
    CHECK(std::abs(recoveredPressure - targetPressure) < 64.0 * std::numeric_limits<double>::epsilon());
    CHECK(resolved.residual(resolved.targetEnthalpy) == 0.0);
}

TEST_CASE(
    "Isobaric Surface Rejects Invalid Pressure Targets",
    tags::barotrope &tags::unit &tags::surface
) {
    CHECK_THROWS_AS(mean_field::surface::Isobaric(-1.0), std::invalid_argument);

    CHECK_THROWS_AS(mean_field::surface::Isobaric(std::numeric_limits<double>::infinity()), std::invalid_argument);

    CHECK_THROWS_AS(mean_field::surface::Isobaric(std::numeric_limits<double>::quiet_NaN()), std::invalid_argument);
}

TEST_CASE(
    "Surface Base Dispatch Preserves The Isobaric Prescription",
    tags::barotrope &tags::unit &tags::surface
) {
    const mean_field::eos::Polytrope equationOfState(3.0, 0.25);

    const mean_field::surface::Isobaric isobaric(0.02);

    const mean_field::surface::SurfaceBase &surface = isobaric;

    surface.validate(equationOfState);

    const mean_field::surface::ResolvedSurfaceCondition resolved = surface.resolve(equationOfState);

    CHECK(resolved.targetEnthalpy > 0.0);
    CHECK(resolved.residual(resolved.targetEnthalpy) == 0.0);
}