public class GameController : MonoBehaviour
{
    //this controller is persistent across the whole game
    private LevelController levelController;

    private GameState currentGameState;
    private GameState lastGameState;

    [SerializeField]
    PlayerController player;
    static PlayerController playerInstance;
    public static PlayerController Player { get { return playerInstance; } }

    void Start()
    {
        playerInstance = player;
        currentGameState = GameState.gameplayState;
        currentGameState.Enter();
    }

    public void ChangeGameState(GameState newState)
    {
        currentGameState.Exit();
        lastGameState = currentGameState;
        currentGameState = newState;
        currentGameState.Enter();
    }

    private void Update()
    {
        currentGameState.UpdateState();
    }

    private void FixedUpdate()
    {
        currentGameState.FixedUpdateState();
    }
}