using System;
using UnityEngine;

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
    private static T _instance;

    public static T Instance
    {
        get
        {
            if (_instance == null)
            {
                _instance = FindObjectOfType<T>();

                if (_instance == null)
                {
                    GameObject obj = new GameObject();
                    obj.name = typeof(T).Name;
                    _instance = obj.AddComponent<T>();
                }
            }

            return _instance;
        }
    }

    protected virtual void Awake()
    {
        if (_instance == null)
        {
            _instance = this as T;
            OnLoad();
            DontDestroyOnLoad(gameObject);
        }
        else
        {
            Destroy(gameObject);
        }
    }

    private void Update()
    {
        OnUpdate();
    }


    #region 生命周期

    protected virtual void OnLoad()
    {
        
    }

    protected virtual void OnUpdate()
    {
        
    }

    #endregion
}