using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Island.StandardLib.Storage
{
    public class PlayerPackage : IStorable
    {
        public static RunDevice Device { get; private set; }
        static Dictionary<int, AbstractItemBehavior> ItemBehaviors;
        static AbstractController Controller;

        public static void DefineItemBehaviors(AbstractController controller, RunDevice device, params AbstractItemBehavior[] behaviors)
        {
            Device = device;
            Controller = controller;
            if (ItemBehaviors != null)
                throw new Exception("ItemBehavior is already defined.");
            ItemBehaviors = new Dictionary<int, AbstractItemBehavior>();
            foreach (AbstractItemBehavior behavior in behaviors)
            {
                if (ItemBehaviors.ContainsKey(behavior.Id))
                    throw new Exception($"Redefined ItemBehavior, Id = {behavior.Id}");
                ItemBehaviors.Add(behavior.Id, behavior);
            }
        }

        public static AbstractItemBehavior GetItemBehavior(int id)
        {
            if (ItemBehaviors == null)
                throw new Exception("ItemBehavior is undefined. Use DefineItemBehaviors(...) to set behaviors first.");
            if (ItemBehaviors.TryGetValue(id, out AbstractItemBehavior behavior))
                return behavior;
            throw new Exception($"GetItemBehavior() Use undefined item behavior Id = {id}");
        }

        public class ItemData : IStorable
        {
            public int DataType;
            public byte[] Data;

            public MultData DataVisitor
            {
                get => new MultData(Data);
                set => Data = value.Data;
            }

            public ItemData()
            {
                DataType = 0;
                Data = new byte[0];
            }

            public ItemData(int dataType, MultData data)
            {
                DataType = dataType;
                Data = data.Data;
            }

            public ItemData(object data, int iStorageType = 10)
            {
                if (data is MultData)
                {
                    DataVisitor = (MultData)data;
                    DataType = 7;
                }
                else if (data is byte[])
                {
                    DataVisitor = new MultData((byte[])data);
                    DataType = 7;
                }
                else if (data is int)
                {
                    DataVisitor = new MultData((int)data);
                    DataType = 1;
                }
                else if (data is float)
                {
                    DataVisitor = new MultData((float)data);
                    DataType = 2;
                }
                else if (data is string)
                {
                    DataVisitor = new MultData((string)data);
                    DataType = 0;
                }
                else if (data is long)
                {
                    DataVisitor = new MultData((long)data);
                    DataType = 3;
                }
                else if (data is uint)
                {
                    DataVisitor = new MultData((uint)data);
                    DataType = 5;
                }
                else if (data is ulong)
                {
                    DataVisitor = new MultData((ulong)data);
                    DataType = 6;
                }
                else if (data is double)
                {
                    DataVisitor = new MultData((double)data);
                    DataType = 4;
                }
                else if (data is IStorable)
                {
                    DataVisitor = new MultData((IStorable)data);
                    DataType = iStorageType;
                }
                else throw new InvalidCastException();
            }

            public bool IsString => DataType == 0;
            public bool IsInt => DataType == 1;
            public bool IsFloat => DataType == 2;
            public bool IsLong => DataType == 3;
            public bool IsDouble => DataType == 4;
            public bool IsUInt => DataType == 5;
            public bool IsULong => DataType == 6;
            public bool IsByteArray => DataType == 7;
            public bool IsIStorable => DataType >= 10;

            public T As<T>() where T : IStorable, new()
            {
                DataStorage ds = new DataStorage(Data);
                T t = new T();
                t.ReadFromData(ds);
                return t;
            }

            public void SetData<T>(T data) where T : IStorable, new()
            {
                DataStorage ds = new DataStorage();
                data.WriteToData(ds);
                Data = ds.Bytes;
            }

            public void ReadFromData(DataStorage data)
            {
                data.ReadUncheck(out DataType);
                Data = data.Read();
            }

            public void WriteToData(DataStorage data)
            {
                data.WriteUncheck(DataType);
                data.Write(Data);
            }
        }

        public class Item : IStorable
        {
            public Item() : this(0, 0) { }

            public Item(int typeId, int instanceId, int stackCount = 1, StorableFixedArray<ItemData> data = null)
            {
                Data = data ?? new StorableFixedArray<ItemData>();
                TypeId = typeId;
                InstanceId = instanceId;
                StackCount = stackCount;
            }

            public int TypeId;
            public int InstanceId;
            public int StackCount;
            public StorableFixedArray<ItemData> Data;

            public ItemData this[int index] => Data[index];
            public int Length => Data.Length;

            public void ConsumeOne(ConnectionPlayerBase who, PlayerPackage package)
            {
                StackCount--;
                ServerSetModify(who, package);
            }

            public void ServerSetModify(ConnectionPlayerBase who, PlayerPackage package)
            {
                if (Device == RunDevice.Client) throw new Exception("SetModify only can use in Server mode.");
                if (StackCount <= 0)
                {
                    lock (package.objects) package.objects.Remove(InstanceId);
                    Controller.OnServerSendDeleteCommand(who, InstanceId);
                }
                else Controller.OnServerSendModifyCommand(who, this);
            }

            internal void ClientApplyChange(Item item)
            {
                TypeId = item.TypeId;
                StackCount = item.StackCount;
                Data = item.Data;
            }

            public bool CanUse => GetItemBehavior(TypeId).CanUse(this);

            public void ServerUse(ConnectionPlayerBase who)
            {
                if (!CanUse) return;
                GetItemBehavior(TypeId).ServerUse(who, this);
            }

            public void ClientUse()
            {
                if (!CanUse) return;
                GetItemBehavior(TypeId).ClientUse(this);
                Controller.OnClientSendUseCommand(InstanceId);
            }

            public void WriteToData(DataStorage data)
            {
                data.WriteUncheck(TypeId);
                data.WriteUncheck(InstanceId);
                data.WriteUncheck(StackCount);
                data.Write(Data);
            }

            public void ReadFromData(DataStorage data)
            {
                data.ReadUncheck(out TypeId);
                data.ReadUncheck(out InstanceId);
                data.ReadUncheck(out StackCount);
                data.Read(out Data);
            }
        }

        public void OnServerReceiveUseCommand(ConnectionPlayerBase who, int instanceId)
        {
            Item item = FindItem(instanceId);
            if (item == null)
                Logger.Log(LogLevel.Error, $"Player {who.Nick} trying to use a nonexists item. InstanceId {instanceId}");
            else item.ServerUse(who);
        }

        public abstract class AbstractItemBehavior
        {
            public abstract int Id { get; }
            public abstract void ServerUse(ConnectionPlayerBase who, Item item);
            public abstract void ClientUse(Item item);
            public abstract bool CanUse(Item item);
            public abstract int CanStack(Item root, Item append);
        }

        public abstract class AbstractUnstackableItemBehavior : AbstractItemBehavior
        {
            public override int CanStack(Item root, Item append) => 0;
        }

        public abstract class AbstractStackableItemBehavior : AbstractItemBehavior
        {
            public abstract int MaxStackSize { get; }

            protected virtual bool CompareStackCondition(Item root, Item append)
            {
                return root.Data.GetBytes().ByteEquals(append.Data.GetBytes());
            }

            public override int CanStack(Item root, Item append)
            {
                if (!CompareStackCondition(root, append)) return 0;
                return MaxStackSize - root.StackCount;
            }
        }

        public abstract class AbstractController
        {
            public abstract void OnServerSendModifyCommand(ConnectionPlayerBase who, Item changedItem);
            public abstract void OnServerSendDeleteCommand(ConnectionPlayerBase who, int itemInstanceId);
            public abstract void OnServerSendChangeMaxItemSizeCommand(ConnectionPlayerBase who, int newMaxItemSizeValue);
            public abstract void OnClientSendUseCommand(int itemInstanceId);
        }

        public PlayerPackage() : this(30) { }

        public PlayerPackage(int maxItemSize)
        {
            if (ItemBehaviors == null)
                throw new Exception("ItemBehavior is undefined. Use DefineItemBehaviors(...) to set behaviors first.");
            objects = new StorableDictionary<SInt, Item>();
            idAllocator = 0;
            this.maxItemSize = maxItemSize;
        }

        public StorableDictionary<SInt, Item> objects;
        int maxItemSize;
        int idAllocator;

        public void SetMaxItemSize(int newValue, ConnectionPlayerBase who = null)
        {
            if (Device == RunDevice.Server)
            {
                if (maxItemSize == newValue) return;
                if (maxItemSize > newValue) throw new ArgumentException("MaxItemSize: new value must be upper than current value.");
                maxItemSize = newValue;
                Controller.OnServerSendChangeMaxItemSizeCommand(who, newValue);
            }
            else
            {
                maxItemSize = newValue;
            }
        }

        public int MaxItemSize => maxItemSize;

        public int ItemSpace
        {
            get
            {
                lock (objects)
                    return objects.Count;
            }
        }

        public int EmptySpace => maxItemSize - ItemSpace;

        public int CreateItem(ConnectionPlayerBase who, int typeId, int stackCount = 1, StorableFixedArray<ItemData> data = null)
        {
            if (Device == RunDevice.Client) throw new Exception("CreateItem only can use in Server mode.");
            Item thisObject = new Item(typeId, -1, stackCount, data == null ? null : data.MemoryCopy());
            lock (objects)
            {
                foreach (var t in objects)
                {
                    if (t.Value.TypeId == thisObject.TypeId)
                    {
                        int canStackCount = GetItemBehavior(t.Value.TypeId).CanStack(t.Value, thisObject);
                        canStackCount = canStackCount <= thisObject.StackCount ? canStackCount : thisObject.StackCount;
                        if (canStackCount > 0)
                        {
                            t.Value.StackCount += canStackCount;
                            if (who != null)
                                t.Value.ServerSetModify(who, this);
                            thisObject.StackCount -= canStackCount;
                        }
                        if (thisObject.StackCount == 0)
                        {
                            thisObject = null;
                            break;
                        }
                    }
                }
                if (thisObject != null)
                {
                    int singleStk = GetItemBehavior(typeId).CanStack(new Item(typeId, 0, 0, data), new Item(typeId, 0, thisObject.StackCount, data));
                    do
                    {
                        if (objects.Count >= maxItemSize)
                            return thisObject.StackCount;
                        int curStack = thisObject.StackCount > singleStk ? singleStk : thisObject.StackCount;
                        Item curItem = new Item(typeId, idAllocator++, curStack, data);
                        objects.Add(curItem.InstanceId, curItem);
                        if (who != null)
                            curItem.ServerSetModify(who, this);
                        thisObject.StackCount -= curStack;
                    }
                    while (thisObject.StackCount > 0);
                }
            }
            return 0;
        }

        public Item FindItem(int instanceId)
        {
            if (objects.TryGetValue(instanceId, out Item item))
                return item;
            return null;
        }

        public int CreateItem(ConnectionPlayerBase who, Item copyItem)
        {
            return CreateItem(who, copyItem.TypeId, copyItem.StackCount, copyItem.Data);
        }

        public void DeleteItemWithInstance(ConnectionPlayerBase who, int itemInstanceId, int stackCount = 1)
        {
            if (Device == RunDevice.Client) throw new Exception("DeleteItem only can use in Server mode.");
            lock (objects)
            {
                if (objects.TryGetValue(itemInstanceId, out Item it))
                {
                    if (it.StackCount > stackCount)
                    {
                        it.StackCount -= stackCount;
                        it.ServerSetModify(who, this);
                    }
                    else if (it.StackCount == stackCount)
                    {
                        objects.Remove(itemInstanceId);
                        Controller.OnServerSendDeleteCommand(who, itemInstanceId);
                    }
                    else throw new Exception($"Trying delete InstanceId = {itemInstanceId} with StackCount = {stackCount}, no such stack count.");
                }
                else throw new Exception($"The InstanceId = {itemInstanceId} is not founded.");
            }
        }

        public void DeleteItemWithType(ConnectionPlayerBase who, int typeId, int stackCount = 1, Func<Item, bool> checker = null)
        {
            if (Device == RunDevice.Client) throw new Exception("DeleteItem only can use in Server mode.");
            lock (objects)
            {
                List<int> preDeletes = new List<int>();
                foreach (var obj in objects)
                {
                    if (obj.Value.TypeId == typeId)
                    {
                        if (checker != null)
                        {
                            if (!checker(obj.Value))
                                continue;
                        }
                        if (obj.Value.StackCount > stackCount)
                        {
                            obj.Value.StackCount -= stackCount;
                            stackCount = 0;
                            if (who != null)
                                obj.Value.ServerSetModify(who, this);
                            break;
                        }
                        else
                        {
                            stackCount -= obj.Value.StackCount;
                            preDeletes.Add(obj.Key);
                            if (who != null)
                                Controller.OnServerSendDeleteCommand(who, obj.Key);
                            if (stackCount == 0) break;
                        }
                    }
                }
                if (stackCount != 0)
                    throw new Exception("DeleteItem: FATAL ERROR: Count is not enough, but still maybe reduce some stack count, that already caught item lost.");
                for (int i = 0; i < preDeletes.Count; i++)
                    objects.Remove(preDeletes[i]);
            }
        }

        public bool CheckItems(int typeId, int stackCount = 1, Func<Item, bool> checker = null)
        {
            lock (objects)
            {
                foreach (var obj in objects)
                {
                    if (obj.Value.TypeId == typeId)
                    {
                        if (checker != null)
                        {
                            if (!checker(obj.Value))
                                continue;
                        }
                        if (obj.Value.StackCount > stackCount)
                        {
                            stackCount = 0;
                            break;
                        }
                        else
                        {
                            stackCount -= obj.Value.StackCount;
                            if (stackCount == 0) break;
                        }
                    }
                }
                return stackCount == 0;
            }
        }

        public class ItemRequest
        {
            public struct ItemQueryInfo
            {
                public ItemQueryInfo(int typeId, int stackCount = 1, Func<Item, bool> checker = null)
                {
                    TypeId = typeId;
                    StackCount = stackCount;
                    Checker = checker;
                }

                public int TypeId { get; private set; }
                public int StackCount { get; private set; }
                public Func<Item, bool> Checker { get; private set; }
            }

            ItemQueryInfo[] Requests;
            public ItemRequest(params ItemQueryInfo[] infos) => Requests = infos;

            public bool CheckIsEnough(PlayerPackage package)
            {
                bool isEnough = true;
                lock (package.objects)
                {
                    for (int i = 0; i < Requests.Length; i++)
                        isEnough &= package.CheckItems(Requests[i].TypeId, Requests[i].StackCount, Requests[i].Checker);
                }
                return isEnough;
            }

            public bool Consume(ConnectionPlayerBase who, PlayerPackage package)
            {
                lock (package.objects)
                {
                    if (CheckIsEnough(package))
                    {
                        for (int i = 0; i < Requests.Length; i++)
                            package.DeleteItemWithType(who, Requests[i].TypeId, Requests[i].StackCount, Requests[i].Checker);
                        return true;
                    }
                    return false;
                }
            }
        }

        public void OnClientReceivedModify(Item changedItem, out Item added)
        {
            lock (objects)
            {
                if (objects.TryGetValue(changedItem.InstanceId, out Item item))
                {
                    item.ClientApplyChange(changedItem);
                    added = null;
                }
                else
                {
                    objects.Add(changedItem.InstanceId, changedItem);
                    added = changedItem;
                }
            }
        }

        public void OnClientReceivedDelete(int itemInstanceId)
        {
            lock (objects)
            {
                if (objects.ContainsKey(itemInstanceId))
                    objects.Remove(itemInstanceId);
            }
        }

        public void ReadFromData(DataStorage data)
        {
            data.Read(out idAllocator);
            data.Read(out objects);
            data.ReadUncheck(out maxItemSize);
        }

        public void WriteToData(DataStorage data)
        {
            data.Write(idAllocator);
            data.Write(objects);
            data.WriteUncheck(maxItemSize);
        }
    }
}