using UnityEngine;

namespace State
{
    /// <summary>
    /// Simple state machine that provides OnEnter, OnExit, Update and FixedUpdate callbacks
    /// to the current state.
    /// </summary>
    public class Machine : MonoBehaviour
    {
        private GameState _currentState;
        
        public void Update()
        {
            _currentState?.OnUpdate(Time.deltaTime);
        }

        public void FixedUpdate()
        {
            _currentState?.OnFixedUpdate(Time.fixedDeltaTime);
        }

        // ChangeState calls the Exit callback on the currently loaded state if one is loaded, 
        // then loads up the new given state, and calls OnEnter on it.
        public void ChangeState(GameState newState)
        {
            _currentState?.OnExit();
            _currentState = newState;
            _currentState.OnEnter(this);
        }
    }
}