using UnityEngine;
internal interface I_Singleton
{
}
public abstract class Singleton_Mono<T> : MonoBehaviour, I_Singleton where T : Singleton_Mono<T>
{
    private static T singleton;
    private static object _lock = new object();
    public static T Singleton
    {
        get
        {
            if (singleton == null)
            {
                lock (_lock)
                {
                    T obj = SceneObjectLookupCache.FindFirst<T>();
                    if (obj != null)
                    {
                        obj.TryGetComponent(out Singleton_Mono<T> s);
                    }
                    if (obj == null)
                    {
                        var gameObj = new GameObject(typeof(T).Name);
                        obj = gameObj.AddComponent<T>();
                        if (!obj.Is_Singleton_Auto())
                        {
                            Destroy(obj.gameObject);
                            return null;
                        }
                    }
                    singleton = obj;
                }
            }
            return singleton;
        }
    }
    private void Awake()
    {
        var s = Singleton;
        if (s != null && singleton != this) Destroy(gameObject);
        if (s != this) return;
        Init();
    }
    public T Init()
    {
        if (singleton == this)
        {
            In_Init();
        }
        return singleton;
    }
    protected abstract bool Is_Singleton_Auto();
    protected abstract void In_Init();
    protected virtual void OnDestroy()
    {
        if (singleton == this)
        {
            singleton = null;
        }
    }
}
public class Singleton_Static<T> where T : new()
{
    protected static T singleton;
    private static object _lock = new object();
    public static T Singleton
    {
        get
        {
            if (singleton == null)
            {
                lock (_lock)
                {
                    singleton ??= new T();
                }
            }
            return singleton;
        }
    }
}