using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Xml.Linq;
using UnityEngine;
using UnityEngine.Pool;
using Object = UnityEngine.Object;

namespace BITKit
{
    [System.Serializable]
    public class UnityPool<T> where T : Component
    {
        public UnityPool()
        {
            pool = new ObjectPool<T>(Spawn, OnGet, OnReturn, OnDestroy, maxSize: 16);
        }
        [Header(Constant.Header.Settings)]
        [SerializeField] private int defaultCapacity = 16;
        [Header(Constant.Header.Prefabs)]
        [SerializeField] private T prefab;
        
        [Header(Constant.Header.Gameobjects)]
        [SerializeField] private Transform root;
        
        private ObjectPool<T> pool;
        
        private readonly List<T> _list=new();
        
        public int DefaultCapacity
        {
            get => defaultCapacity;
            set => defaultCapacity = value;
        }
        
        public T Get(T element = null, Transform _root = null)
        {
            if (_list.Count == defaultCapacity)
            {
                var next = _list[0];
                next.gameObject.SetActive(false);
                _list.RemoveAt(0);
                _list.Add(next);
                next.gameObject.SetActive(true);
                return next;
            }
            
            if (element is not null)
                prefab = element;
            if (_root is not null)
                root = _root;
            
            var instance = pool.Get();
            
            _list.Add(instance);
            
            return instance;
        }

        public void Return(T element)
        {
            pool.Release(element);
            _list.Remove(element);
        }
        private T Spawn() => Object.Instantiate(prefab, root);
        private void OnGet(T element) => element.gameObject.SetActive(true);
        private void OnReturn(T element) => element.gameObject.SetActive(false);
        private void OnDestroy(T element) => Object.Destroy(element.gameObject);

        #region 拓展

        private readonly ConcurrentDictionary<string, T> _dictionary=new();

        public T GetByKey(string key)
        {
            var instance = _dictionary.GetOrAdd(key, s => Get());
            return instance;
        }
        public void RemoveByKey(string key)
        {
            _dictionary.TryRemove(key);
        }

        #endregion
    }
}