package zombie.vehicles;

import zombie.characters.IsoGameCharacter;

/**
 * Resolves the effective driver for constraint auth in chained towing.
 * For middle vehicles in a chain, prefer the front/lead driver's authority.
 */
public final class LandtrainConstraintAuthHelper {
    private LandtrainConstraintAuthHelper() {
    }

    public static IsoGameCharacter resolveConstraintDriver(BaseVehicle vehicle) {
        if (vehicle == null) {
            return null;
        }

        IsoGameCharacter driver = vehicle.getDriver();
        if (driver != null) {
            return driver;
        }

        BaseVehicle front = vehicle.getVehicleTowedBy();
        if (front != null) {
            driver = front.getDriver();
            if (driver != null) {
                return driver;
            }
        }

        BaseVehicle rear = vehicle.getVehicleTowing();
        if (rear != null) {
            return rear.getDriver();
        }

        return null;
    }
}