using Godot;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Threading;
using BITKit.Entities;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace  BITKit;
/// <summary>
/// 用于Godot的ECS.Entity实现
/// </summary>
public partial class Entity : Node,IEntity
{
	/// <summary>
	/// 类型组件的缓存
	/// </summary>
	private readonly Dictionary<Type,object> TypeComponents=new ();

	private Object[] Components = Array.Empty<Object>();
	/// <summary>
	/// IEntityService的缓存
	/// </summary>
	private  IEntitiesService _entitiesService;
	/// <summary>
	/// 所有EntityComponent
	/// </summary>
	IEntityComponent[] IEntity.Components => Components.OfType<IEntityComponent>().ToArray();
	/// <summary>
	/// IEntity.Id实现
	/// </summary>
	public ulong Id { get; private set; }

	public CancellationToken CancellationToken => _cancellationTokenSource.Token;
	private CancellationTokenSource _cancellationTokenSource;
	

	/// <summary>
	/// 服务提供者
	/// </summary>
	public IServiceProvider ServiceProvider { get; private set; }
	/// <summary>
	/// 服务集合
	/// </summary>
	public IServiceCollection ServiceCollection { get; private set; }
	

	public void Inject(object node)
	{
		foreach (var fieldInfo in node.GetType()
			         .GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
			         .Where(x=>x.GetCustomAttribute<InjectAttribute>() is not null)
		        )
		{
			var attribute = fieldInfo.GetCustomAttribute<InjectAttribute>();
			if(attribute is null)continue;
			fieldInfo.SetValue(node,
				attribute.CanBeNull
					? ServiceProvider.GetService(fieldInfo.FieldType)
					: ServiceProvider.GetRequiredService(fieldInfo.FieldType));
		}
	}
	
	public override void _EnterTree()
	{
		_cancellationTokenSource = new CancellationTokenSource();
	}

	public override void _ExitTree()
	{
		_cancellationTokenSource.Cancel();
		DI.Get<IEntitiesService>().UnRegister(this);
	}

	/// <summary>
	/// 加载所有EntityComponent的内部实现
	/// </summary>
	public override void _Ready()
	{
		Id = GetInstanceId();
		
		ServiceCollection = new ServiceCollection();
		
		DI.Get<IEntitiesService>().Register(this);
		
		Components = MathNode.GetAllNode(this).ToArray();
		List<IEntityComponent> entityComponents = new();
		
		_entitiesService = DI.Get<IEntitiesService>();

		foreach (var x in Components)
		{
			GetInstanceId();
			
			if (x is IEntityComponent entityComponent)
			{
				entityComponent.BuildService(ServiceCollection);
			}

			TypeComponents.TryAdd(x.GetType(), x);
			foreach (var customType in x.GetType().GetCustomAttributes<CustomTypeAttribute>())
			{
				TypeComponents.TryAdd(customType.Type, x);
				ServiceCollection.AddSingleton(customType.Type, x);
			}

			ServiceProvider = ServiceCollection.BuildServiceProvider();
			
			if (x is not IEntityComponent component) continue;
			component.Entity = this;
			entityComponents.Add(component);
		}

		foreach (var node in Components)
		{
			Inject(node);
		}
		foreach (var component in Components.OfType<IEntityBehavior>())
		{
			component.Initialize(this);
		}
		foreach (var component in Components.OfType<IEntityBehavior>())
		{
			component.OnAwake();
		}
		foreach (var component in Components.OfType<IEntityBehavior>())
		{
			component.OnStart();
		}
	}

	public override void _Process(double delta)
	{
		foreach (var component in Components.OfType<IEntityBehavior>())
		{
			component.OnUpdate((float)delta);
		}
		foreach (var component in Components.OfType<IEntityBehavior>())
		{
			component.OnLateUpdate((float)delta);
		}
	}

	public override void _PhysicsProcess(double delta)
	{
		foreach (var component in Components.OfType<IEntityBehavior>())
		{
			component.OnFixedUpdate((float)delta);
		}
	}

	public bool TryGetComponent<T>(out T component)
	{
		if (TypeComponents.TryGetValue(typeof(T), out var iComponent) && iComponent is T _component)
		{
			component = _component;
			return true;
		}
		component = default;
		return false;
	}
	
	public bool RegisterComponent<T>(T component)
	{
		return TypeComponents.TryAdd(typeof(T), component);
	}

	
}