using DCFApixels.DragonECS.Internal;
using DCFApixels.DragonECS.PoolsCore;
using System;
using System.Runtime.CompilerServices;

namespace DCFApixels.DragonECS.PoolsCore
{
    public interface IEcsComponentType { }
    /// <summary>Only used to implement a custom pool. In other contexts use IEcsPool or IEcsPool<T>.</summary>
    public interface IEcsPoolImplementation : IEcsPool
    {
        #region Methods
        void OnInit(EcsWorld world, EcsWorld.PoolsMediator mediator, int componentTypeID);
        void OnWorldResize(int newSize);
        void OnReleaseDelEntityBuffer(ReadOnlySpan<int> buffer);
        void OnWorldDestroy();
        #endregion
    }
    /// <summary>Only used to implement a custom pool. In other contexts use IEcsPool or IEcsPool<T>.</summary>
    /// <typeparam name="T">Component type</typeparam>
    public interface IEcsPoolImplementation<T> : IEcsPoolImplementation { }

    public static class EcsPoolThrowHalper
    {
        public static void ThrowAlreadyHasComponent<T>(int entityID)
        {
            throw new EcsFrameworkException($"Entity({entityID}) already has component {EcsDebugUtility.GetGenericTypeName<T>()}.");
        }
        public static void ThrowNotHaveComponent<T>(int entityID)
        {
            throw new EcsFrameworkException($"Entity({entityID}) has no component {EcsDebugUtility.GetGenericTypeName<T>()}.");
        }
        public static void ThrowAlreadyHasComponent(Type type, int entityID)
        {
            throw new EcsFrameworkException($"Entity({entityID}) already has component {EcsDebugUtility.GetGenericTypeName(type)}.");
        }
        public static void ThrowNotHaveComponent(Type type, int entityID)
        {
            throw new EcsFrameworkException($"Entity({entityID}) has no component {EcsDebugUtility.GetGenericTypeName(type)}.");
        }
        public static void ThrowNullListener()
        {
            throw new ArgumentNullException("listener is null");
        }
    }
}

namespace DCFApixels.DragonECS.Internal
{
    public struct NullComponent { }
    public sealed class EcsNullPool : IEcsPoolImplementation<NullComponent>
    {
        public static readonly EcsNullPool instance = new EcsNullPool();

        #region Properties
        int IEcsReadonlyPool.ComponentTypeID { get { return 0; } }//TODO Првоерить что NullComponent всегда имеет id 0 
        Type IEcsReadonlyPool.ComponentType { get { return typeof(NullComponent); } }
        EcsWorld IEcsReadonlyPool.World
        {
            get
            {
#if (DEBUG && !DISABLE_DEBUG)
                throw new NullInstanceException();
#else
                    return EcsWorld.GetWorld(0);
#endif
            }
        }
        public int Count { get { return 0; } }
        public bool IsReadOnly { get { return true; } }
        #endregion

        #region Methods
        bool IEcsReadonlyPool.Has(int index)
        {
            return false;
        }
        void IEcsPool.Del(int entityID)
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#endif
        }
        void IEcsPool.AddRaw(int entityID, object dataRaw)
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#endif
        }
        object IEcsReadonlyPool.GetRaw(int entityID)
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#else
                return null;
#endif
        }
        void IEcsPool.SetRaw(int entity, object dataRaw)
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#endif
        }
        void IEcsReadonlyPool.Copy(int fromEntityID, int toEntityID)
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#endif
        }
        void IEcsReadonlyPool.Copy(int fromEntityID, EcsWorld toWorld, int toEntityID)
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#endif
        }
        void IEcsPool.ClearAll()
        {
#if (DEBUG && !DISABLE_DEBUG)
            throw new NullInstanceException();
#endif
        }
        #endregion

        #region Callbacks
        void IEcsPoolImplementation.OnInit(EcsWorld world, EcsWorld.PoolsMediator mediator, int componentTypeID) { }
        void IEcsPoolImplementation.OnWorldDestroy() { }
        void IEcsPoolImplementation.OnWorldResize(int newSize) { }
        void IEcsPoolImplementation.OnReleaseDelEntityBuffer(ReadOnlySpan<int> buffer) { }
        #endregion

        #region Listeners
#if !DISABLE_POOLS_EVENTS
        void IEcsReadonlyPool.AddListener(IEcsPoolEventListener listener) { }
        void IEcsReadonlyPool.RemoveListener(IEcsPoolEventListener listener) { }
#endif
        #endregion
    }
}

namespace DCFApixels.DragonECS
{
    #region Interfaces
    public interface IEcsReadonlyPool
    {
        #region Properties
        int ComponentTypeID { get; }
        Type ComponentType { get; }
        EcsWorld World { get; }
        int Count { get; }
        bool IsReadOnly { get; }
        #endregion

        #region Methods
        bool Has(int entityID);
        object GetRaw(int entityID);
        void Copy(int fromEntityID, int toEntityID);
        void Copy(int fromEntityID, EcsWorld toWorld, int toEntityID);
        #endregion

#if !DISABLE_POOLS_EVENTS
        #region Add/Remove Listeners
        void AddListener(IEcsPoolEventListener listener);
        void RemoveListener(IEcsPoolEventListener listener);
        #endregion
#endif
    }
    public interface IEcsPool : IEcsReadonlyPool
    {
        #region Methods
        void AddRaw(int entityID, object dataRaw);
        void SetRaw(int entityID, object dataRaw);
        void Del(int entityID);
        void ClearAll();
        #endregion
    }
    /// <summary>A pool for struct components.</summary>
    public interface IEcsStructPool<T> : IEcsPool where T : struct
    {
        #region Methods
        ref T Add(int entityID);
        ref readonly T Read(int entityID);
        ref T Get(int entityID);
        #endregion
    }
    /// <summary>A pool for reference components of type T that instantiates components itself.</summary>
    public interface IEcsClassPool<T> : IEcsPool where T : class
    {
        #region Methods
        T Add(int entityID);
        T Get(int entityID);
        #endregion
    }
    /// <summary>A pool for reference components of type T, which does not instantiate components itself but receives components from external sources..</summary>
    public interface IEcsHybridPool<T> : IEcsPool where T : class
    {
        #region Methods
        void Add(int entityID, T component);
        T Get(int entityID);
        #endregion
    }
    #endregion

    #region Extensions
    public static class IEcsPoolImplementationExtensions
    {
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static bool IsNullOrDummy(this IEcsPool self)
        {
            return self == null || self == EcsNullPool.instance;
        }
    }
    #endregion

    #region Callbacks Interface
    public interface IEcsPoolEventListener
    {
        /// <summary>Called after adding an entity to the pool, but before changing values</summary>
        void OnAdd(int entityID);
        /// <summary>Is called when EcsPool.Get or EcsPool.Add is called, but before changing values</summary>
        void OnGet(int entityID);
        /// <summary>Called after deleting an entity from the pool</summary>
        void OnDel(int entityID);
    }
#if !DISABLE_POOLS_EVENTS
    public static class PoolEventListExtensions
    {
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnAdd(this List<IEcsPoolEventListener> self, int entityID)
        {
            self.InvokeOnAdd(entityID, self.Count);
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnAdd(this List<IEcsPoolEventListener> self, int entityID, int cachedCount)
        {
            for (int i = 0; i < cachedCount; i++) self[i].OnAdd(entityID);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnAddAndGet(this List<IEcsPoolEventListener> self, int entityID)
        {
            self.InvokeOnAddAndGet(entityID, self.Count);
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnAddAndGet(this List<IEcsPoolEventListener> self, int entityID, int cachedCount)
        {
            for (int i = 0; i < cachedCount; i++)
            {
                self[i].OnAdd(entityID);
                self[i].OnGet(entityID);
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnGet(this List<IEcsPoolEventListener> self, int entityID)
        {
            self.InvokeOnGet(entityID, self.Count);
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal static void InvokeOnGet(this List<IEcsPoolEventListener> self, int entityID, int cachedCount)
        {
            for (int i = 1; i < cachedCount; i++) self[i].OnGet(entityID);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnDel(this List<IEcsPoolEventListener> self, int entityID)
        {
            self.InvokeOnDel(entityID, self.Count);
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void InvokeOnDel(this List<IEcsPoolEventListener> self, int entityID, int cachedCount)
        {
            for (int i = 0; i < cachedCount; i++) self[i].OnDel(entityID);
        }
    }
#endif
    #endregion
}