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

TEST_CASE("Energy conservation - Earth circular orbit", "[energy][rk4]") {
    const double TIME_STEP = 60.0;
    const double DAYS_TO_SIMULATE = 10.0;
    const double SECONDS_PER_DAY = 86400.0;

    SimulationState* sim = create_simulation(10, 0, 0, TIME_STEP);

    REQUIRE(load_system_config(sim, "tests/test_energy.toml"));

    double initial_energy = calculate_system_total_energy(sim);

    double total_time = DAYS_TO_SIMULATE * SECONDS_PER_DAY;
    while (sim->time < total_time) {
        update_simulation(sim);
    }

    double final_energy = calculate_system_total_energy(sim);
    double energy_drift_percent = fabs((final_energy - initial_energy) / initial_energy) * 100.0;

    INFO("Initial energy: " << initial_energy << " J");
    INFO("Final energy: " << final_energy << " J");
    INFO("Energy drift: " << energy_drift_percent << "%");

    REQUIRE(energy_drift_percent < 5.0);

    destroy_simulation(sim);
}