using System;

using Microsoft.Xna.Framework;

using Syntriax.Engine.Core.Abstract;
using Syntriax.Engine.Core.Exceptions;

namespace Syntriax.Engine.Core;

public class GameObject : IGameObject
{
    public Action<IAssignableStateEnable>? OnStateEnableAssigned { get; set; } = null;
    public Action<IAssignableTransform>? OnTransformAssigned { get; set; } = null;
    public Action<IAssignable>? OnUnassigned { get; set; } = null;
    public Action<IAssignableBehaviourController>? OnBehaviourControllerAssigned { get; set; } = null;

    public Action<IEntity>? OnNameChanged { get; set; } = null;

    public Action<IInitialize>? OnInitialized { get; set; } = null;
    public Action<IInitialize>? OnFinalized { get; set; } = null;

    public Action<IGameObject, GameTime>? OnUpdated { get; set; } = null;


    private ITransform _transform = null!;
    private IBehaviourController _behaviourController = null!;
    private IStateEnable _stateEnable = null!;

    private string _name = nameof(GameObject);
    private bool _initialized = false;

    public ITransform Transform => _transform;
    public IBehaviourController BehaviourController => _behaviourController;
    public IStateEnable StateEnable => _stateEnable;

    public bool Initialized
    {
        get => _initialized;
        private set
        {
            if (value == _initialized)
                return;

            _initialized = value;
            if (value)
                OnInitialized?.Invoke(this);
            else
                OnFinalized?.Invoke(this);
        }
    }

    public string Name
    {
        get => _name;
        set
        {
            if (value == _name) return;

            _name = value;
            OnNameChanged?.Invoke(this);
        }
    }

    public bool Initialize()
    {
        if (Initialized)
            return false;

        NotAssignedException.Check(this, _transform);
        NotAssignedException.Check(this, _behaviourController);
        NotAssignedException.Check(this, _stateEnable);

        Initialized = true;
        return true;
    }

    public void Update(GameTime time)
    {
        if (!_stateEnable.Enabled)
            return;

        OnUpdated?.Invoke(this, time);
    }

    public bool Finalize()
    {
        if (!Initialized)
            return false;


        System.Threading.Tasks.Parallel.ForEach(
            _behaviourController.GetBehaviours<IBehaviour>(),
            behaviour => behaviour.Finalize()
        );

        Initialized = false;
        return true;
    }

    public bool Assign(IStateEnable stateEnable)
    {
        if (Initialized)
            return false;

        _stateEnable = stateEnable;
        OnStateEnableAssigned?.Invoke(this);
        return true;
    }

    public bool Assign(ITransform transform)
    {
        if (Initialized)
            return false;

        _transform = transform;
        OnTransformAssigned?.Invoke(this);
        return true;
    }

    public bool Assign(IBehaviourController behaviourController)
    {
        if (Initialized)
            return false;

        _behaviourController = behaviourController;
        OnBehaviourControllerAssigned?.Invoke(this);
        return true;
    }

    public bool Unassign()
    {
        if (Initialized)
            return false;

        _stateEnable = null!;
        _transform = null!;
        _behaviourController = null!;

        OnUnassigned?.Invoke(this);
        return true;
    }

    public GameObject() { OnBehaviourControllerAssigned += ConnectBehaviourController; }
    private void ConnectBehaviourController(IAssignableBehaviourController controller)
    {
        controller.BehaviourController.OnBehaviourAdded += OnBehaviourAdded;
        controller.BehaviourController.OnBehaviourRemoved += OnBehaviourRemoved;
    }
    private void OnBehaviourRemoved(IBehaviourController _, IBehaviour behaviour) { if (Initialized) behaviour.Initialize(); }
    private void OnBehaviourAdded(IBehaviourController _, IBehaviour behaviour) { if (Initialized) behaviour.Finalize(); }
}