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

public class Singel : MonoBehaviour
{

}


public class BaseSingleton<T> where T : new()
{
    private static T instance;
    //保护构造函数，保证单例只能在内部创建
    protected BaseSingleton() { }
    public static T Instance
    {
        get
        {
            if (instance == null)
            {
                instance = new T();
            }
            return instance;
        }
    }
}
public abstract class MonoSingleton<T> : MonoBehaviour where T : MonoSingleton<T>
{
    private static T instance;
    private readonly static object obj = new object();
    public static T Instance
    {
        get
        {
            if (instance != null) { return instance; }
            lock (obj)
            {
                Type type = typeof(T);

                // 改用 Resources.FindObjectsOfTypeAll 来查找所有的实例（包括禁用的对象）
                T[] instances = Resources.FindObjectsOfTypeAll<T>();
                // 如果场景中存在多个实例，抛出异常
                if (instances.Length > 1)
                {
                    Debug.Log(new Exception(string.Format("Singleton类型{0}存在多个实例", type.Name)));
                    instance = instances[0];  // 默认选择第一个实例
                    return instance;
                }

                // 如果场景中找到了唯一的实例，直接返回
                if (instances.Length == 1)
                {
                    instance = instances[0];
                    return instance;
                }

                // 如果没有找到实例，实例化一个空物体并添加T脚本
                instance = new GameObject("Singleton Of " + typeof(T).Name.ToString(), typeof(T)).GetComponent<T>();
                Debug.LogError("创建了新的");
                return instance;
            }
        }
    }

    virtual public void Awake()
    {
        // 如果 `instance` 已经被初始化（即通过 `Instance` 属性），销毁当前挂载的实例
        if (instance == null)
        {
            instance = this as T;
        }
    }
}