using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace BaseGames.Core.Pool
{
    /// <summary>
    /// 可池化对象组件，挂在每个可池化 Prefab 的根节点上。
    /// 实现 <see cref="IPoolable"/> 的子类可覆盖 OnSpawn/OnDespawn。
    /// </summary>
    public class PooledObject : MonoBehaviour
    {
        public string AddressKey { get; private set; }
        private GlobalObjectPool _pool;

        // 组件缓存（避免反复 GetComponent）
        private readonly Dictionary<Type, Component> _componentCache = new();

        public void Setup(string key, GlobalObjectPool pool)
        {
            AddressKey = key;
            _pool      = pool;
        }

        public virtual void OnSpawn()  { }
        public virtual void OnDespawn(){ }

        // ── 归还 API ──────────────────────────────────────────────────────
        /// <summary>立即归还到对象池。</summary>
        public void ReturnToPool() => _pool?.Despawn(AddressKey, this);

        /// <summary>延迟 delay 秒后归还。</summary>
        public void ReturnToPoolDelayed(float delay) => StartCoroutine(DelayedReturn(delay));

        /// <summary>
        /// 由 GlobalObjectPool LRU 回收触发，不应由业务代码直接调用。
        /// </summary>
        internal void ForceReturnToPool()
        {
            OnDespawn();
            gameObject.SetActive(false);
        }

        // ── 组件缓存 ──────────────────────────────────────────────────────
        /// <summary>从缓存获取 Component，首次调用才执行 GetComponent。</summary>
        public T GetComponentCached<T>() where T : Component
        {
            if (!_componentCache.TryGetValue(typeof(T), out var cached))
                _componentCache[typeof(T)] = cached = GetComponent<T>();
            return (T)cached;
        }

        private IEnumerator DelayedReturn(float delay)
        {
            yield return new WaitForSeconds(delay);
            ReturnToPool();
        }
    }

    /// <summary>
    /// 可选接口：若池化对象需要在 Spawn/Despawn 时执行额外逻辑，
    /// 由 PooledObject 子类或同 GameObject 上的其他 MonoBehaviour 实现，
    /// 并在 PooledObject.OnSpawn/OnDespawn 中手动驱动。
    /// </summary>
    public interface IPoolable
    {
        void OnSpawn();
        void OnDespawn();
    }
}