#include <catch2/catch_test_macros.hpp>
#include <catch2/matchers/catch_matchers_floating_point.hpp>
#include "../src/physics.h"
#include "../src/simulation.h"
#include "../src/config_loader.h"
#include "../src/test_utilities.h"
#include <cmath>

using Catch::Matchers::WithinAbs;

SCENARIO("Orbital period measurement with analytical propagation",
         "[period][analytical]") {
    const double TIME_STEP = 60.0;
    const double SECONDS_PER_DAY = 86400.0;

    SimulationState* sim = create_simulation(10, 0, 0, TIME_STEP);
    REQUIRE(load_system_config(sim, "tests/test_orbital_period.toml"));

    auto propagate_and_check = [&](OrbitTracker* tracker, CelestialBody* body,
                                   CelestialBody* parent, double max_time,
                                   double expected_days) {
        while (sim->time < max_time && !tracker->orbit_completed) {
            update_simulation(sim);
            update_orbit_tracker(tracker, body, parent, sim->time);
        }
        REQUIRE(tracker->orbit_completed);

        const double measured_days = tracker->time_at_completion / SECONDS_PER_DAY;
        INFO("Measured period: " << measured_days << " days");
        REQUIRE_THAT(measured_days, WithinAbs(expected_days, 0.1));

        destroy_orbit_tracker(tracker);
    };

    SECTION("Earth completes one orbit in ~365 days") {
        CelestialBody* earth = &sim->bodies[1];
        CelestialBody* sun = &sim->bodies[0];
        OrbitTracker* tracker = create_orbit_tracker(1);

        const double max_time = 400.0 * SECONDS_PER_DAY;
        propagate_and_check(tracker, earth, sun, max_time, 365.2105);
    }

    SECTION("Mars completes one orbit in ~671 days") {
        CelestialBody* mars = &sim->bodies[2];
        CelestialBody* sun = &sim->bodies[0];
        OrbitTracker* tracker = create_orbit_tracker(2);

        const double max_time = 750.0 * SECONDS_PER_DAY;
        propagate_and_check(tracker, mars, sun, max_time, 670.9345);
    }
}