#include <catch2/catch_test_macros.hpp>
#include "../src/physics.h"
#include "../src/bodies.h"
#include "../src/test_utilities.h"
#include <cmath>

TEST_CASE("Orbital period - Earth (RK4)", "[period][rk4]") {
    const double TIME_STEP = 60.0;
    const double EXPECTED_PERIOD_DAYS = 365.0;
    const double SECONDS_PER_DAY = 86400.0;
    const double MAX_SIMULATION_DAYS = 400.0;

    SimulationState* sim = create_simulation(10, TIME_STEP);

    Vec3 sun_pos = {0, 0, 0};
    Vec3 sun_vel = {0, 0, 0};
    add_body(sim, "Sun", 1.989e30, 6.96e8, sun_pos, sun_vel, -1, 1.0, 1.0, 0.0, 0, 0);

    Vec3 earth_pos = {1.496e11, 0, 0};
    Vec3 earth_vel = {0, 29789, 0};
    add_body(sim, "Earth", 5.972e24, 6.371e6, earth_pos, earth_vel, 0, 0.0, 0.5, 1.0, 0, 1.496e11);

    OrbitTracker* tracker = create_orbit_tracker(1);

    double max_time = MAX_SIMULATION_DAYS * SECONDS_PER_DAY;
    while (sim->time < max_time && !tracker->orbit_completed) {
        update_simulation(sim);
        update_orbit_tracker(tracker, &sim->bodies[1], &sim->bodies[0], sim->time);
    }

    REQUIRE(tracker->orbit_completed);

    double measured_period_days = tracker->time_at_completion / SECONDS_PER_DAY;
    double period_error_days = fabs(measured_period_days - EXPECTED_PERIOD_DAYS);

    INFO("Expected period: " << EXPECTED_PERIOD_DAYS << " days");
    INFO("Measured period: " << measured_period_days << " days");
    INFO("Error: " << period_error_days << " days");

    REQUIRE(period_error_days < 5.0);

    destroy_orbit_tracker(tracker);
    destroy_simulation(sim);
}

TEST_CASE("Orbital period - Mars (RK4)", "[period][rk4]") {
    const double TIME_STEP = 60.0;
    const double EXPECTED_PERIOD_DAYS = 687.0;
    const double SECONDS_PER_DAY = 86400.0;
    const double MAX_SIMULATION_DAYS = 750.0;

    SimulationState* sim = create_simulation(10, TIME_STEP);

    Vec3 sun_pos = {0, 0, 0};
    Vec3 sun_vel = {0, 0, 0};
    add_body(sim, "Sun", 1.989e30, 6.96e8, sun_pos, sun_vel, -1, 1.0, 1.0, 0.0, 0, 0);

    Vec3 mars_pos = {2.244e11, 0, 0};
    Vec3 mars_vel = {0, 24323, 0};
    add_body(sim, "Mars", 6.39e23, 3.3895e6, mars_pos, mars_vel, 0, 0.8, 0.3, 0.1, 0, 2.244e11);

    OrbitTracker* tracker = create_orbit_tracker(1);

    double max_time = MAX_SIMULATION_DAYS * SECONDS_PER_DAY;
    while (sim->time < max_time && !tracker->orbit_completed) {
        update_simulation(sim);
        update_orbit_tracker(tracker, &sim->bodies[1], &sim->bodies[0], sim->time);
    }

    REQUIRE(tracker->orbit_completed);

    double measured_period_days = tracker->time_at_completion / SECONDS_PER_DAY;
    double period_error_days = fabs(measured_period_days - EXPECTED_PERIOD_DAYS);

    INFO("Expected period: " << EXPECTED_PERIOD_DAYS << " days");
    INFO("Measured period: " << measured_period_days << " days");
    INFO("Error: " << period_error_days << " days");

    REQUIRE(period_error_days < 25.0);

    destroy_orbit_tracker(tracker);
    destroy_simulation(sim);
}