using Barotrauma.Extensions;
using Barotrauma.Items.Components;
using Barotrauma.Networking;
using Microsoft.Xna.Framework;
using System.Collections.Generic;
using System.Linq;

namespace Barotrauma
{
    partial class Inventory : IClientSerializable
    {
        private readonly Dictionary<Client, List<ushort>[]> receivedItemIds = new Dictionary<Client, List<ushort>[]>();

        public void ServerEventRead(IReadMessage msg, Client c)
        {
            if (!receivedItemIds.TryGetValue(c, out List<ushort>[] receivedItemIdsFromClient))
            {
                receivedItemIdsFromClient = new List<ushort>[capacity];
                receivedItemIds.Add(c, receivedItemIdsFromClient);
            }

            SharedRead(msg, receivedItemIdsFromClient, out bool readyToApply);
            if (!readyToApply) { return; }

            if (c == null || c.Character == null) { return; }

            bool accessible = c.Character.CanAccessInventory(this);
            if (this is CharacterInventory characterInventory && accessible)
            {
                if (Owner == null || Owner is not Character ownerCharacter)
                {
                    accessible = false;
                }
                else if (!characterInventory.AccessibleWhenAlive && !ownerCharacter.IsDead && !characterInventory.AccessibleByOwner)
                {
                    accessible = false;
                }
            }

            if (!accessible)
            {
                //create a network event to correct the client's inventory state
                //otherwise they may have an item in their inventory they shouldn't have been able to pick up,
                //and receiving an event for that inventory later will cause the item to be dropped
                CreateNetworkEvent();
                for (int i = 0; i < capacity; i++)
                {
                    foreach (ushort id in receivedItemIdsFromClient[i])
                    {
                        if (Entity.FindEntityByID(id) is not Item item) { continue; }
                        item.PositionUpdateInterval = 0.0f;
                        if (item.ParentInventory != null && item.ParentInventory != this)
                        {
                            item.ParentInventory.CreateNetworkEvent();
                        }
                    }
                }
                return;
            }

            //we need to check which of the items the client can access at this point, before we start shuffling things around
            //otherwise if you're e.g. holding an item to access a cabinet, and picking up an item from the cabinet unequips the item you're holding,
            //you would fail to pick up the item because it gets unequipped before checking whether you can access the cabinet.
            Dictionary<Item, bool> canAccessItem = new Dictionary<Item, bool>();
            for (int i = 0; i < capacity; i++)
            {
                foreach (ushort id in receivedItemIdsFromClient[i])
                {
                    if (Entity.FindEntityByID(id) is not Item item) { continue; }
                    canAccessItem[item] = item.CanClientAccess(c);
                }
            }

            List<Item> prevItems = new List<Item>(AllItems.Distinct());
            List<Inventory> prevItemInventories = new List<Inventory>() { this };
            for (int i = 0; i < capacity; i++)
            {
                foreach (Item item in slots[i].Items.ToList())
                {
                    if (!receivedItemIdsFromClient[i].Contains(item.ID) && item.IsInteractable(c.Character))
                    {
                        Item droppedItem = item;
                        Entity prevOwner = Owner;
                        Inventory previousInventory = droppedItem.ParentInventory;
                        droppedItem.Drop(null);
                        droppedItem.PreviousParentInventory = previousInventory;

                        var previousCharacterInventory = prevOwner switch
                        {
                            Item itemInventory => itemInventory.FindParentInventory(inventory => inventory is CharacterInventory) as CharacterInventory,
                            Character character => character.Inventory,
                            _ => null
                        };

                        if (previousCharacterInventory != null && previousCharacterInventory != c.Character?.Inventory)
                        {
                            GameMain.Server?.KarmaManager.OnItemTakenFromPlayer(previousCharacterInventory, c, droppedItem);
                        }
                        
                        if (droppedItem.body != null && prevOwner != null)
                        {
                            droppedItem.body.SetTransform(prevOwner.SimPosition, 0.0f);
                        }
                    }
                }

                foreach (ushort id in receivedItemIdsFromClient[i])
                {
                    Item newItem = id == 0 ? null : Entity.FindEntityByID(id) as Item;
                    prevItemInventories.Add(newItem?.ParentInventory);
                }                
            }

            for (int i = 0; i < capacity; i++)
            {
                foreach (ushort id in receivedItemIdsFromClient[i])
                {
                    if (Entity.FindEntityByID(id) is not Item item || slots[i].Contains(item)) { continue; }

                    if (item.GetComponent<Pickable>() is not Pickable pickable ||
                        (pickable.IsAttached && !pickable.PickingDone) || item.AllowedSlots.None() || !item.IsInteractable(c.Character))
                    {
                        DebugConsole.AddWarning($"Client {c.Name} tried to pick up a non-pickable item \"{item}\" (parent inventory: {item.ParentInventory?.Owner.ToString() ?? "null"})",
                            item.Prefab.ContentPackage);
                        continue;
                    }

                    if (GameMain.Server != null)
                    {
                        var holdable = item.GetComponent<Holdable>();
                        if (holdable != null && !holdable.CanBeDeattached()) { continue; }

                        if (!prevItems.Contains(item) && !canAccessItem[item] && 
                            (c.Character == null || item.PreviousParentInventory == null || !c.Character.CanAccessInventory(item.PreviousParentInventory)))
                        {
    #if DEBUG || UNSTABLE
                            DebugConsole.NewMessage($"Client {c.Name} failed to pick up item \"{item}\" (parent inventory: {item.ParentInventory?.Owner.ToString() ?? "null"}). No access.", Color.Yellow);
    #endif
                            if (item.body != null && !c.PendingPositionUpdates.Contains(item))
                            {
                                c.PendingPositionUpdates.Enqueue(item);
                            }
                            item.PositionUpdateInterval = 0.0f;                            
                            continue;
                        }
                    }
                    TryPutItem(item, i, true, true, c.Character, false);
                    for (int j = 0; j < capacity; j++)
                    {
                        if (slots[j].Contains(item) && !receivedItemIdsFromClient[j].Contains(item.ID))
                        {
                            slots[j].RemoveItem(item);
                        }
                    }
                }
            }

            EnsureItemsInBothHands(c.Character);

            receivedItemIds.Remove(c);

            CreateNetworkEvent();
            foreach (Inventory prevInventory in prevItemInventories.Distinct())
            {
                if (prevInventory != this) { prevInventory?.CreateNetworkEvent(); }
            }

            foreach (Item item in AllItems.DistinctBy(it => it.Prefab))
            {
                if (item == null) { continue; }
                if (!prevItems.Contains(item))
                {
                    int amount = AllItems.Count(it => it.Prefab == item.Prefab && !prevItems.Contains(it));
                    string amountText = amount > 1 ? $"x{amount} " : string.Empty;
                    if (Owner == c.Character)
                    {
                        HumanAIController.ItemTaken(item, c.Character);
                        GameServer.Log($"{GameServer.CharacterLogName(c.Character)} picked up {amountText}{item.Name}", ServerLog.MessageType.Inventory);
                    }
                    else
                    {
                        GameServer.Log($"{GameServer.CharacterLogName(c.Character)} placed {amountText}{item.Name} in {Owner}", ServerLog.MessageType.Inventory);
                    }
                }
            }

            var droppedItems = prevItems.Where(it => it != null && !AllItems.Contains(it));
            foreach (Item item in droppedItems.DistinctBy(it => it.Prefab))
            {
                var matchingItems = prevItems.Where(it => it.Prefab == item.Prefab && !AllItems.Contains(it));
                int amount = matchingItems.Count();
                string amountText = amount > 1 ? $"x{amount} " : string.Empty;
                if (Owner == c.Character)
                {
                    GameServer.Log($"{GameServer.CharacterLogName(c.Character)} dropped {amountText}{item.Name}", ServerLog.MessageType.Inventory);
                }
                else
                {
                    GameServer.Log($"{GameServer.CharacterLogName(c.Character)} removed {amountText}{item.Name} from {Owner}", ServerLog.MessageType.Inventory);
                }
                item.CreateDroppedStack(matchingItems, allowClientExecute: true);                
            }
        }

        private void EnsureItemsInBothHands(Character character)
        {
            if (this is not CharacterInventory charInv) { return; }

            int leftHandSlot = charInv.FindLimbSlot(InvSlotType.LeftHand),
                rightHandSlot = charInv.FindLimbSlot(InvSlotType.RightHand);

            if (IsSlotIndexOutOfBound(leftHandSlot) || IsSlotIndexOutOfBound(rightHandSlot)) { return; }

            TryPutInOppositeHandSlot(rightHandSlot, leftHandSlot);
            TryPutInOppositeHandSlot(leftHandSlot, rightHandSlot);

            void TryPutInOppositeHandSlot(int originalSlot, int otherHandSlot)
            {
                const InvSlotType bothHandSlot = InvSlotType.LeftHand | InvSlotType.RightHand;

                foreach (Item it in slots[originalSlot].Items)
                {
                    if (it.AllowedSlots.None(static s => s.HasFlag(bothHandSlot)) || slots[otherHandSlot].Contains(it)) { continue; }

                    TryPutItem(it, otherHandSlot, true, true, character, false);
                }
            }

            bool IsSlotIndexOutOfBound(int index) => index < 0 || index >= slots.Length;
        }
    }
}