using Cysharp.Threading.Tasks;

namespace Framework
{
    // implement a finite state machine class

        public interface IState
        {
            bool exitFinished { get; }
            void OnEnter();
            void OnUpdate(float deltaTime);
            void OnExit();
        }

        public class StateMachine
        {
            private IState _currentState;
            private IState _previousState;

            public async UniTask ChangeState(IState newState)
            {
                if (_currentState != null)
                {
                    _currentState.OnExit();
                    while (!_currentState.exitFinished)
                    {
                        UniTask.NextFrame();
                    }
                }

                _previousState = _currentState;
                _currentState = newState;
                _currentState?.OnEnter();
            }

            public void Update(float deltaTime)
            {
                if (_currentState != null)
                {
                    _currentState.OnUpdate(deltaTime);
                }
            }

            public void RevertToPreviousState()
            {
                ChangeState(_previousState);
            }
            
            public IState GetCurrentState()
            {
                return _currentState;
            }
        }
    }