#if DISABLE_DEBUG
#undef DEBUG
#endif
using DCFApixels.DragonECS.Core;
using DCFApixels.DragonECS.Internal;
using DCFApixels.DragonECS.PoolsCore;
using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.CompilerServices;
#if ENABLE_IL2CPP
using Unity.IL2CPP.CompilerServices;
#endif

namespace DCFApixels.DragonECS
{
    /// <summary>Standard component</summary>
    [MetaColor(MetaColor.DragonRose)]
    [MetaGroup(EcsConsts.PACK_GROUP, EcsConsts.POOLS_GROUP)]
    [MetaDescription(EcsConsts.AUTHOR, "Standard component.")]
    [MetaID("84D2537C9201D6F6B92FEC1C8883A07A")]
    public interface IEcsComponent : IEcsMember { }

    /// <summary>Pool for IEcsComponent components</summary>
#if ENABLE_IL2CPP
    [Il2CppSetOption(Option.NullChecks, false)]
#endif
    [MetaColor(MetaColor.DragonRose)]
    [MetaGroup(EcsConsts.PACK_GROUP, EcsConsts.POOLS_GROUP)]
    [MetaDescription(EcsConsts.AUTHOR, "Pool for IEcsComponent components.")]
    [MetaID("C501547C9201A4B03FC25632E4FAAFD7")]
    [DebuggerDisplay("Count: {Count} Type: {ComponentType}")]
    public sealed class EcsPool<T> : IEcsPoolImplementation<T>, IEcsStructPool<T>, IEntityStorage, IEnumerable<T> //IEnumerable<T> - IntelliSense hack
        where T : struct, IEcsComponent
    {
        private EcsWorld _source;
        private int _componentTypeID;
        private EcsMaskChunck _maskBit;

        private int[] _mapping;// index = entityID / value = itemIndex;/ value = 0 = no entityID
        private T[] _items; //dense
        private int _itemsCount = 0;
        private int _capacity = 0;

        private int[] _sparseEntities;
        private int[] _denseEntitiesDelayed;
        private int _denseEntitiesDelayedCount = 0;
        private bool _isDenseEntitiesDelayedValid = false;

        private readonly IEcsComponentLifecycle<T> _componentLifecycleHandler = EcsComponentResetHandler<T>.instance;
        private readonly bool _isHasComponentLifecycleHandler = EcsComponentResetHandler<T>.isHasHandler;
        private readonly IEcsComponentCopy<T> _componentCopyHandler = EcsComponentCopyHandler<T>.instance;
        private readonly bool _isHasComponentCopyHandler = EcsComponentCopyHandler<T>.isHasHandler;

#if !DISABLE_POOLS_EVENTS
        private readonly StructList<IEcsPoolEventListener> _listeners = new StructList<IEcsPoolEventListener>(2);
        private int _listenersCachedCount = 0;
#endif
        private bool _isLocked;

        private EcsWorld.PoolsMediator _mediator;

        #region Properites
        public int Count
        {
            get { return _itemsCount; }
        }
        public int Capacity
        {
            get { return _items.Length; }
        }
        public int ComponentTypeID
        {
            get { return _componentTypeID; }
        }
        public Type ComponentType
        {
            get { return typeof(T); }
        }
        public EcsWorld World
        {
            get { return _source; }
        }
        public bool IsReadOnly
        {
            get { return false; }
        }
        #endregion

        #region Methods
        public ref T Add(int entityID)
        {
            ref int itemIndex = ref _mapping[entityID];
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (itemIndex > 0) { EcsPoolThrowHelper.ThrowAlreadyHasComponent<T>(entityID); }
            if (_isLocked) { EcsPoolThrowHelper.ThrowPoolLocked(); }
#endif
            itemIndex = GetFreeItemIndex(entityID);
            _mediator.RegisterComponent(entityID, _componentTypeID, _maskBit);
            ref T result = ref _items[itemIndex];
            _sparseEntities[itemIndex] = entityID;
            EnableComponent(ref result);
#if !DISABLE_POOLS_EVENTS
            _listeners.InvokeOnAddAndGet(entityID, _listenersCachedCount);
#endif
            return ref result;
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public ref T Get(int entityID)
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (!Has(entityID)) { EcsPoolThrowHelper.ThrowNotHaveComponent<T>(entityID); }
#endif
#if !DISABLE_POOLS_EVENTS
            _listeners.InvokeOnGet(entityID, _listenersCachedCount);
#endif
            return ref _items[_mapping[entityID]];
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public ref readonly T Read(int entityID)
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (!Has(entityID)) { EcsPoolThrowHelper.ThrowNotHaveComponent<T>(entityID); }
#endif
            return ref _items[_mapping[entityID]];
        }
        public ref T TryAddOrGet(int entityID)
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (_isLocked) { EcsPoolThrowHelper.ThrowPoolLocked(); }
#endif
            ref int itemIndex = ref _mapping[entityID];
            if (itemIndex <= 0)
            { //Add block
                itemIndex = GetFreeItemIndex(entityID);
                _mediator.RegisterComponent(entityID, _componentTypeID, _maskBit);
                _sparseEntities[itemIndex] = entityID;
                EnableComponent(ref _items[itemIndex]);
#if !DISABLE_POOLS_EVENTS
                _listeners.InvokeOnAdd(entityID, _listenersCachedCount);
#endif
            } //Add block end
#if !DISABLE_POOLS_EVENTS
            _listeners.InvokeOnGet(entityID, _listenersCachedCount);
#endif
            return ref _items[itemIndex];
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public bool Has(int entityID)
        {
            return _mapping[entityID] != 0;
        }
        public void Del(int entityID)
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (_isLocked) { EcsPoolThrowHelper.ThrowPoolLocked(); }
#endif
            ref int itemIndex = ref _mapping[entityID];
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (itemIndex <= 0) { EcsPoolThrowHelper.ThrowNotHaveComponent<T>(entityID); }
#endif
            DisableComponent(ref _items[itemIndex]);
            _sparseEntities[itemIndex] = 0;
            itemIndex = 0;
            _itemsCount--;
            _mediator.UnregisterComponent(entityID, _componentTypeID, _maskBit);
            _isDenseEntitiesDelayedValid = false;
#if !DISABLE_POOLS_EVENTS
            _listeners.InvokeOnDel(entityID, _listenersCachedCount);
#endif
        }
        public void TryDel(int entityID)
        {
            if (Has(entityID))
            {
                Del(entityID);
            }
        }
        public void Copy(int fromEntityID, int toEntityID)
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (!Has(fromEntityID)) { EcsPoolThrowHelper.ThrowNotHaveComponent<T>(fromEntityID); }
#endif
            CopyComponent(ref Get(fromEntityID), ref TryAddOrGet(toEntityID));
        }
        public void Copy(int fromEntityID, EcsWorld toWorld, int toEntityID)
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (!Has(fromEntityID)) { EcsPoolThrowHelper.ThrowNotHaveComponent<T>(fromEntityID); }
#endif
            CopyComponent(ref Get(fromEntityID), ref toWorld.GetPool<T>().TryAddOrGet(toEntityID));
        }

        public void ClearAll()
        {
#if (DEBUG && !DISABLE_DEBUG) || ENABLE_DRAGONECS_ASSERT_CHEKS
            if (_isLocked) { EcsPoolThrowHelper.ThrowPoolLocked(); }
#endif
            if (_itemsCount <= 0) { return; }
            _itemsCount = 0;
            var span = _source.Where(out SingleAspect<T> _);
            foreach (var entityID in span)
            {
                ref int itemIndex = ref _mapping[entityID];
                DisableComponent(ref _items[itemIndex]);
                itemIndex = 0;
                _mediator.UnregisterComponent(entityID, _componentTypeID, _maskBit);
#if !DISABLE_POOLS_EVENTS
                _listeners.InvokeOnDel(entityID, _listenersCachedCount);
#endif
            }
        }
        #endregion

        #region Callbacks
        void IEcsPoolImplementation.OnInit(EcsWorld world, EcsWorld.PoolsMediator mediator, int componentTypeID)
        {
#if DEBUG
            AllowedInWorldsAttribute.CheckAllows<T>(world);
#endif

            _source = world;
            _mediator = mediator;
            _componentTypeID = componentTypeID;
            _maskBit = EcsMaskChunck.FromID(componentTypeID);

            _mapping = new int[world.Capacity];
            Resize(ArrayUtility.NormalizeSizeToPowerOfTwo(world.Configs.GetWorldConfigOrDefault().PoolComponentsCapacity));
            //_capacity = ArrayUtility.NormalizeSizeToPowerOfTwo(world.Configs.GetWorldConfigOrDefault().PoolComponentsCapacity);
            //_items = new T[_capacity];
            //_sparseEntities = new int[_capacity];
            //_denseEntitiesDelayed = new int[_capacity];
            //for (int i = 0; i < _capacity; i++)
            //{// можно оптимизировать тем чтобы вместо заполнения, в методе выдачи free index-а если _denseEntitiesDelayed возвращает 0, то free index определять через инкремент
            //    _denseEntitiesDelayed[i] = i;
            //}
        }
        void IEcsPoolImplementation.OnWorldResize(int newSize)
        {
            Array.Resize(ref _mapping, newSize);
        }
        void IEcsPoolImplementation.OnWorldDestroy() { }
        void IEcsPoolImplementation.OnReleaseDelEntityBuffer(ReadOnlySpan<int> buffer)
        {
            if (_itemsCount <= 0)
            {
                return;
            }
            foreach (var entityID in buffer)
            {
                TryDel(entityID);
            }
        }
        void IEcsPoolImplementation.OnLockedChanged_Debug(bool locked) { _isLocked = locked; }
        #endregion

        #region Other
        void IEcsPool.AddEmpty(int entityID) { Add(entityID); }
        void IEcsPool.AddRaw(int entityID, object dataRaw)
        {
            Add(entityID) = dataRaw == null ? default : (T)dataRaw;
        }
        object IEcsReadonlyPool.GetRaw(int entityID) { return Get(entityID); }
        void IEcsPool.SetRaw(int entityID, object dataRaw)
        {
            Get(entityID) = dataRaw == null ? default : (T)dataRaw;
        }


        public EcsSpan ToSpan()
        {
            UpdateDenseEntities();
            return new EcsSpan(_source.ID, _denseEntitiesDelayed, 1, _itemsCount);
        }
        private bool IsDenseEntitiesDelayedValid()
        {
            return _isDenseEntitiesDelayedValid;//_itemsCount == _denseEntitiesDelayedCount;
        }
        private void UpdateDenseEntities()
        {
            //if (IsDenseEntitiesDelayedValid()) { return; }
            _denseEntitiesDelayedCount = 0;
            for (int i = 0, jRight = _itemsCount + 1; i < _capacity; i++)
            {
                if (_sparseEntities[i] == 0 && i != 0)
                {
                    _denseEntitiesDelayed[jRight] = i;
                    jRight++;
                }
                else
                {
                    _denseEntitiesDelayed[_denseEntitiesDelayedCount++] = _sparseEntities[i];
                }
            }
            _isDenseEntitiesDelayedValid = true;
        }
        private int GetFreeItemIndex(int entityID)
        {
            //if (_denseEntitiesDelayedCount >= _capacity - 1)
            {
                UpdateDenseEntities();
            }

            if (_itemsCount >= _capacity - 1)
            {
                Resize(_items.Length << 1);
            }

            int result = _denseEntitiesDelayed[_denseEntitiesDelayedCount];
            _denseEntitiesDelayed[_denseEntitiesDelayedCount] = entityID;
            _itemsCount++;
            _denseEntitiesDelayedCount++;
            if(result == 0)
            {

            }
            return result;
        }
        private void CheckOrUpsize()
        {
            if (_itemsCount < _capacity) { return; }
            Resize(_items.Length << 1);
        }
        private void Resize(int newSize)
        {
            if (newSize <= _capacity) { return; }
            ArrayUtility.ResizeOrCreate(ref _sparseEntities, newSize);
            ArrayUtility.ResizeOrCreate(ref _items, newSize);
            _denseEntitiesDelayed = new int[newSize];
            _denseEntitiesDelayedCount = 0;
            _capacity = newSize;
            UpdateDenseEntities();
        }
        #endregion

        #region Listeners
#if !DISABLE_POOLS_EVENTS
        public void AddListener(IEcsPoolEventListener listener)
        {
            if (listener == null) { EcsPoolThrowHelper.ThrowNullListener(); }
            _listeners.Add(listener);
            _listenersCachedCount++;
        }
        public void RemoveListener(IEcsPoolEventListener listener)
        {
            if (listener == null) { EcsPoolThrowHelper.ThrowNullListener(); }
            if (_listeners.RemoveWithOrder(listener))
            {
                _listenersCachedCount--;
            }
        }
#endif
#endregion

        #region Enable/Disable/Copy
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void EnableComponent(ref T component)
        {
            if (_isHasComponentLifecycleHandler)
            {
                _componentLifecycleHandler.Enable(ref component);
            }
            else
            {
                component = default;
            }
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void DisableComponent(ref T component)
        {
            if (_isHasComponentLifecycleHandler)
            {
                _componentLifecycleHandler.Disable(ref component);
            }
            else
            {
                component = default;
            }
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void CopyComponent(ref T from, ref T to)
        {
            if (_isHasComponentCopyHandler)
            {
                _componentCopyHandler.Copy(ref from, ref to);
            }
            else
            {
                to = from;
            }
        }
        #endregion

        #region IEnumerator - IntelliSense hack
        IEnumerator<T> IEnumerable<T>.GetEnumerator() { throw new NotImplementedException(); }
        IEnumerator IEnumerable.GetEnumerator() { throw new NotImplementedException(); }
        #endregion

        #region MarkersConverter
        public static implicit operator EcsPool<T>(IncludeMarker a) { return a.GetInstance<EcsPool<T>>(); }
        public static implicit operator EcsPool<T>(ExcludeMarker a) { return a.GetInstance<EcsPool<T>>(); }
        public static implicit operator EcsPool<T>(OptionalMarker a) { return a.GetInstance<EcsPool<T>>(); }
        public static implicit operator EcsPool<T>(EcsWorld.GetPoolInstanceMarker a) { return a.GetInstance<EcsPool<T>>(); }
        #endregion
    }

    public static class EcsPoolExtensions
    {
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> GetPool<TComponent>(this EcsWorld self) where TComponent : struct, IEcsComponent
        {
            return self.GetPoolInstance<EcsPool<TComponent>>();
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> GetPoolUnchecked<TComponent>(this EcsWorld self) where TComponent : struct, IEcsComponent
        {
            return self.GetPoolInstanceUnchecked<EcsPool<TComponent>>();
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> Inc<TComponent>(this EcsAspect.Builder self) where TComponent : struct, IEcsComponent
        {
            return self.IncludePool<EcsPool<TComponent>>();
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> Exc<TComponent>(this EcsAspect.Builder self) where TComponent : struct, IEcsComponent
        {
            return self.ExcludePool<EcsPool<TComponent>>();
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> Opt<TComponent>(this EcsAspect.Builder self) where TComponent : struct, IEcsComponent
        {
            return self.OptionalPool<EcsPool<TComponent>>();
        }

        #region Obsolete
        [Obsolete("Use " + nameof(EcsAspect) + "." + nameof(EcsAspect.Builder) + "." + nameof(Inc) + "<T>()")]
        [EditorBrowsable(EditorBrowsableState.Never)]
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> Include<TComponent>(this EcsAspect.Builder self) where TComponent : struct, IEcsComponent
        {
            return self.IncludePool<EcsPool<TComponent>>();
        }
        [Obsolete("Use " + nameof(EcsAspect) + "." + nameof(EcsAspect.Builder) + "." + nameof(Exc) + "<T>()")]
        [EditorBrowsable(EditorBrowsableState.Never)]
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> Exclude<TComponent>(this EcsAspect.Builder self) where TComponent : struct, IEcsComponent
        {
            return self.ExcludePool<EcsPool<TComponent>>();
        }
        [Obsolete("Use " + nameof(EcsAspect) + "." + nameof(EcsAspect.Builder) + "." + nameof(Opt) + "<T>()")]
        [EditorBrowsable(EditorBrowsableState.Never)]
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static EcsPool<TComponent> Optional<TComponent>(this EcsAspect.Builder self) where TComponent : struct, IEcsComponent
        {
            return self.OptionalPool<EcsPool<TComponent>>();
        }
        #endregion
    }
}