using Godot;
using System;
using System.Collections.Generic;
using System.Linq;

namespace BITKit.StateMachine
{
	public abstract partial class StateMachineNode<T> : Node ,IStateMachine<T> where T : class, IState
	{
		public bool Enabled { get; set; }
		public T CurrentState { get; set; }
		public event Action<T, T> OnStateChanged;
		public IDictionary<Type, T> StateDictionary { get; } = new Dictionary<Type, T>();
		public void Initialize()
		{
			foreach (var x in StateDictionary)
			{
				x.Value.Initialize();
			}
		}

		public void UpdateState(float deltaTime)
		{
			CurrentState?.OnStateUpdate(deltaTime);
		}

		public void DisposeState()
		{
			CurrentState?.OnStateExit(CurrentState,null);
			CurrentState = null;
		}

		public void TransitionState<State>() where State : T
		{
			TransitionState(StateDictionary[typeof(State)]);
		}

		public void TransitionState(T state)
		{
			CurrentState?.OnStateExit(CurrentState, state);
			var previousState = CurrentState;
			CurrentState = state;
			state.OnStateEntry(previousState);
			OnStateChanged?.Invoke(previousState, CurrentState);
			CurrentState = state;
		}

		public override void _Ready()
		{
			base._Ready();
			foreach (var x in MathNode.GetAllNode(this).OfType<T>())
			{
				StateDictionary.Add(x.GetType(), x);
			}

			Initialize();
			if (StateDictionary.Count > 0)
				TransitionState(StateDictionary.First().Value);
		}

		public override void _Process(double delta)
		{
			base._Process(delta);
			CurrentState?.OnStateUpdate((float)delta);
		}
	}
}