#ifndef TEST_UTILITIES_H
#define TEST_UTILITIES_H

#include "simulation.h"
#include "physics.h"

// Test tolerance constants
// NOTE: Individual tests may use tighter or looser tolerances based on
// observed errors. See per-test comments for adjustments.
static const double A_TOL = 1e-6;           // semi-major axis (meters), |a| < 1e10
static const double E_TOL = 1e-12;          // eccentricity, round-trip conversion
static const double ANG_TOL = 1e-12;        // angles in radians (nu, inc, Ω, ω)
static const double ANG_TOL_COARSE = 1e-4;  // angles, degenerate cases (polar/retrograde)
static const double R_TOL = 1e-6;           // radius / distance magnitudes (meters)
static const double V_TOL = 1e-6;           // velocity magnitudes (m/s)
static const double M_TOL = 1e-6;           // time / period values (seconds)
static const double REL_TOL = 1e-8;         // relative / percentage errors (dimensionless)
static const double DRIFT_TOL = 1e-12;      // energy drift percent (parabolic orbit)

struct OrbitalMetrics {
    double kinetic_energy;
    double potential_energy;
    double total_energy;
    double orbital_radius;
    double velocity_magnitude;
};

struct OrbitTracker {
    double initial_angle;
    double previous_angle;
    double accumulated_rotation;
    bool initialized;
    bool orbit_completed;
    double time_at_completion;
    int body_index;
    double min_time_seconds;

    // Orbital elements for 3D angle calculation
    double inclination;
    double longitude_of_ascending_node;
    double argument_of_periapsis;
    bool has_orbital_elements;
};

double calculate_kinetic_energy(CelestialBody* body);
double calculate_potential_energy_pair(CelestialBody* body1, CelestialBody* body2);
double calculate_system_total_energy(SimulationState* sim);
OrbitalMetrics calculate_orbital_metrics(CelestialBody* body, CelestialBody* parent);

OrbitTracker* create_orbit_tracker(int body_index);
OrbitTracker* create_orbit_tracker_with_min_time(int body_index, double min_time_seconds);
OrbitTracker* create_orbit_tracker_3d(int body_index, double min_time_days,
                                       double inclination, double lon_ascending_node,
                                       double argument_of_periapsis);
void reset_orbit_tracker(OrbitTracker* tracker);
void update_orbit_tracker(OrbitTracker* tracker, CelestialBody* body, CelestialBody* parent, double current_time);
void destroy_orbit_tracker(OrbitTracker* tracker);

// Write simulation state to a caller-allocated buffer.
// Returns number of characters written (excluding null terminator).
// Caller must ensure buffer is large enough (recommended 4096 bytes).
int dump_simulation_state(SimulationState* sim, const char* label,
                          char* buffer, int buffer_size);

bool compare_vec3(Vec3 a, Vec3 b, double tolerance);

#endif