using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Security.AccessControl;
using System.Threading;

namespace BITKit.Entities
{
    public class EntitiesService:IEntitiesService
    {
        private readonly ConcurrentDictionary<int, IEntity> _entities = new();
        private readonly ConcurrentDictionary<Type, IEntity[]> _queryCache = new();
        private readonly ConcurrentDictionary<(Type,Type), IEntity[]> _query2ComponentsCache = new();
        private readonly ConcurrentDictionary<(Type,Type,Type), IEntity[]> _query3ComponentsCache = new();
        public event Action<IEntity> OnAdd;
        public event Action<IEntity> OnRemove;
        public IEntity[] Entities => _entities.Values.ToArray();
        public bool Register(IEntity entity)
        {
            if (!_entities.TryAdd(entity.Id, entity)) return false;
            OnAdd?.Invoke(entity);
            return true;
        }

        public bool UnRegister(IEntity entity)
        {
            if (!_entities.TryRemove(entity.Id, out _)) return false;
            OnRemove?.Invoke(entity);
            return true;
        }
        public CancellationToken CancellationToken => _cancellationTokenSource.Token;
        private readonly CancellationTokenSource _cancellationTokenSource = new();
        public IEntity Get(int id)
        {
            return _entities[id];
        }

        public bool TryGetEntity(int id, out IEntity entity)
        {
            return _entities.TryGetValue(id, out entity);
        }

        public IEntity GetOrAdd(int id, Func<int, IEntity> factory)
        {
            return _entities.GetOrAdd(id, factory);
        }

        public IEntity[] Query<T>()
        {
            throw new NotImplementedException("Obsoleted");
        }

        public T[] QueryComponents<T>()
        {
            throw new NotImplementedException();
            // return _queryCache.GetOrAdd(typeof(T), type =>
            // {
            //     return _entities.Values.Where(entity => entity.TryGetComponent(out T component)).ToArray();
            // }).Cast<T>().ToArray();
        }
        public (T, T1)[] QueryComponents<T, T1>()
        {
            throw new NotImplementedException();
            // List<(T, T1)> list = new();
            // foreach (var entity in _entities.Values)
            // {
            //     if (entity.TryGetComponent(out T t) && entity.TryGetComponent(out T1 t1))
            //         list.Add((t, t1));
            // }
            // return list.ToArray();
        }
        public (T, T1, T2)[] QueryComponents<T, T1, T2>()
        {
            throw new NotImplementedException();
            // List<(T, T1, T2)> list = new();
            // foreach (var entity in _entities.Values)
            // {
            //     if (entity.TryGetComponent(out T t) && entity.TryGetComponent(out T1 t1) && entity.TryGetComponent(out T2 t2))
            //         list.Add((t, t1, t2));
            // }
            // return list.ToArray();
        }

        public (T, T1, T2, T3)[] QueryComponents<T, T1, T2, T3>()
        {
            throw new NotImplementedException();
            // List<(T, T1, T2, T3)> list = new();
            // foreach (var entity in _entities.Values)
            // {
            //     if (entity.TryGetComponent(out T t) && entity.TryGetComponent(out T1 t1) && entity.TryGetComponent(out T2 t2) && entity.TryGetComponent(out T3 t3))
            //         list.Add((t, t1, t2, t3));
            // }
            // return list.ToArray();
        }

        public (T, T1, T2, T3, T4)[] QueryComponents<T, T1, T2, T3, T4>()
        {
            throw new NotImplementedException();
            // List<(T, T1, T2, T3, T4)> list = new();
            // foreach (var entity in _entities.Values)
            // {
            //     if (entity.TryGetComponent(out T t) && entity.TryGetComponent(out T1 t1) && entity.TryGetComponent(out T2 t2) && entity.TryGetComponent(out T3 t3) && entity.TryGetComponent(out T4 t4))
            //         list.Add((t, t1, t2, t3, t4));
            // }
            // return list.ToArray();
        }

        public (T, T1, T2, T3, T4, T5)[] QueryComponents<T, T1, T2, T3, T4, T5>()
        {
            throw new NotImplementedException();
// List<(T, T1, T2, T3, T4, T5)> list = new();
//             foreach (var entity in _entities.Values)
//             {
//                 if (entity.TryGetComponent(out T t) && entity.TryGetComponent(out T1 t1) && entity.TryGetComponent(out T2 t2) && entity.TryGetComponent(out T3 t3) && entity.TryGetComponent(out T4 t4) && entity.TryGetComponent(out T5 t5))
//                     list.Add((t, t1, t2, t3, t4, t5));
//             }
//             return list.ToArray();
        }

        public (T, T1, T2, T3, T4, T5, T6)[] QueryComponents<T, T1, T2, T3, T4, T5, T6>()
        {
            throw new NotImplementedException();
            // List<(T, T1, T2, T3, T4, T5, T6)> list = new();
            // foreach (var entity in _entities.Values)
            // {
            //     if (entity.TryGetComponent(out T t) && entity.TryGetComponent(out T1 t1) && entity.TryGetComponent(out T2 t2) && entity.TryGetComponent(out T3 t3) && entity.TryGetComponent(out T4 t4) && entity.TryGetComponent(out T5 t5) && entity.TryGetComponent(out T6 t6))
            //         list.Add((t, t1, t2, t3, t4, t5, t6));
            // }
            // return list.ToArray();
        }

        public ValueTuple<T, T1, T2, T3, T4, T5, T6, TRest>[] QueryComponents<T, T1, T2, T3, T4, T5, T6, TRest>() where TRest : struct
        {
            throw new NotImplementedException();
            // throw new NotImplementedException();
        }
    }
}