using System;
using System.Collections.Generic;
using UnityEngine;
using Object = UnityEngine.Object;

namespace Roy.ObjectPool
{

    public class ObjectPool<T> where T : ObjectPoolItem
    {
        private readonly Queue<T> _pool; // 存储可重用对象的队列
        private readonly T _prefab; // 预制体
        private readonly string _poolName; // 预制体
        private readonly Transform _parent; // 对象的父级

        // 构造函数
        public ObjectPool(string objectName, T prefab, int initialSize, Transform parent = null)
        {
            _poolName = objectName;
            _prefab = prefab;
            _parent = parent;
            _pool = new Queue<T>();

            // 初始化对象池
            for (int i = 0; i < initialSize; i++)
            {
                T obj = CreateInstance();
                _pool.Enqueue(obj);
            }
        }

        // 创建对象的实例
        private T CreateInstance()
        {
            var gameObject = Object.Instantiate(_prefab.gameObject, _parent);
            gameObject.SetActive(false); // 初始化时设置为不激活
            var instance = gameObject.GetComponent<T>();
            instance.objectName = _poolName;
            return instance;
        }

        // 获取一个对象
        public T Get()
        {
            if (_pool.Count > 0)
            {
                T obj = _pool.Dequeue();
                obj.gameObject.SetActive(true); // 获取时激活对象
                return obj;
            }
            else
            {
                // 如果没有可用对象，创建一个新的
                var obj = CreateInstance();
                obj.gameObject.SetActive(true);// 激活对象
                return obj;
            }
        }

        // 归还对象
        public void ReturnToPool(T obj)
        {
            obj.OnRecycle();
            
            obj.gameObject.SetActive(false); // 归还时设置为不激活
            obj.transform.SetParent(_parent);
            obj.transform.localPosition = Vector3.zero;
            
            
            _pool.Enqueue(obj); // 将对象返回池中
        }

        // 清空对象池
        public void ClearPool()
        {
            while (_pool.Count > 0)
            {
                T obj = _pool.Dequeue();
                Object.Destroy(obj.gameObject); // 清除所有对象
            }
            
            Object.Destroy(_parent);
        }   
    }

}