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


namespace Beyond
{
    public abstract class AutoSingleton<T> : MonoBehaviour where T : AutoSingleton<T>
    {
        private static T s_instance;
      
        public static T Instance
        {
            get
            {
                if (s_instance)
                {
                    return s_instance;
                }
                else
                {
                    var inst = FindObjectOfType<T>();
                    if (inst != null)
                    {
                        s_instance = inst;
                        return s_instance;
                    }
                    else
                    {
                        var go = new GameObject("_" + typeof (T).Name);
                        go.AddComponent<T>(); // _instance set by Awake() constructor
                    }
                }

                return s_instance;
            }
        }

        protected void OnDestroy()
        {
            if (s_instance == this)
                s_instance = null;
        }

        protected virtual void Awake()
        {
            if (s_instance == null)
            {
                s_instance = (T)this;
            }
            else
            {
                Debug.LogError("Multiple instances of singleton :"+gameObject.name);
            }
        }
    }
}