using System;
using System.Collections.Generic;
using RPGCore.BackpackEquipment.Data;
using RPGCore.BackpackEquipment.ObjectModules.Content.Events;
using RPGCore.BackpackEquipment.Objects;
using RPGCore.Core;
using RPGCore.Core.Objects;
using RPGCore.ObjectModules.EventObjectModule.Events;
using UnityEngine;

namespace RPGCore.BackpackEquipment.ObjectModules.Content
{
    [Serializable]
    [ObjectModule(
        name: "[Inventory] Content",
        description: "Simple content managing attached to any implementation of <b>BaseObject</b>. " +
        "By itself allows only: taking, dropping and deciding who manages items. " +
        "Attach implementation of <b>"+nameof(IContentOwner)+"</b> to manage content's items."
    )]
    public sealed class ContentModule : ObjectModule<BaseObject>
    {
        // RUNTIME
        private GameObject _contentGameObject;
        private Dictionary<ItemObject, IContentOwner> _items = new();

        private void Awake()
        {
            _contentGameObject = new GameObject("-- CONTENT --");
            _contentGameObject.transform.SetParent(transform);
            _contentGameObject.transform.SetLocalPositionAndRotation(Vector3.zero, Quaternion.identity);
        }

        public bool Take(ItemObject item)
        {
            if (item.data.Get<ItemObjectData>().carriedBy) return false;
            if (_items.ContainsKey(item)) return false;
            
            _items.TryAdd(item, null);
            item.data.Get<ItemObjectData>().carriedBy = parent;
            parent.events.Invoke(new ContentAddEvent{obj = parent, item = item});
            item.events.Register<RemoveEvent>(OnItemRemove);
            
            item.gameObject.SetActive(false);
            item.transform.SetParent(_contentGameObject.transform);
            item.transform.SetLocalPositionAndRotation(Vector3.zero, Quaternion.identity);

            return true;
        }

        public bool Drop(ItemObject item)
        {
            if (!_items.ContainsKey(item)) return false;
            
            _items[item]?.Remove_Internal(item);
            _items.Remove(item);
            item.data.Get<ItemObjectData>().carriedBy = null;
            parent.events.Invoke(new ContentRemoveEvent { obj = parent, item = item });
            item.events.Unregister<RemoveEvent>(OnItemRemove);
            
            item.gameObject.SetActive(true);
            item.transform.SetParent(null);

            return true;
        }

        public bool TransferTo(IContentOwner newOwner, ItemObject item, int index = -1)
        {
            if (item.data.Get<ItemObjectData>().carriedBy != parent) return false;

            if (!newOwner.CanAdd(item, index)) return false;
            
            _items.TryAdd(item, null);
            _items[item]?.Remove_Internal(item);
            _items[item] = newOwner;
            newOwner.Add_Internal(item, index);

            return true;
        }

        public bool TransferFrom(ItemObject item)
        {
            return _items[item]?.Remove_Internal(item) ?? false;
        }

        private void OnItemRemove(RemoveEvent removeEvent)
        {
            Drop(removeEvent.obj as ItemObject);
        }
    }
}