using System;
using UnityEngine;

/// <summary>
/// 单键类
/// </summary>
/// <typeparam name="T"></typeparam>
public abstract class MonoSingleton<T> : MonoBehaviour where T : MonoSingleton<T>
{
    /// <summary>
    /// 单键
    /// </summary>
    private static T m_Instance;

    /// <summary>
    /// 单键
    /// </summary>
    public static T Instance
    {
        get
        {
            if (object.ReferenceEquals(MonoSingleton<T>.m_Instance, null))
            {
                GameObject obj = new GameObject(typeof(T).ToString());
                obj.transform.parent = Container.transform;
                MonoSingleton<T>.m_Instance = obj.AddComponent<T>();
            }

            return MonoSingleton<T>.m_Instance;
        }
    }
    static GameObject _mC;
    static GameObject Container
    {
        get
        {
            if (null == _mC)
            {
                _mC = GameObject.Find("MonoSingleton");
            }
            if (null == _mC)
            {
                _mC = new GameObject("MonoSingleton");
                DontDestroyOnLoad(_mC);
            }
            return _mC;
        }
    }
    /// <summary>
    /// 单键是否有效
    /// </summary>
    public static bool IsInstanceValid
    {
        get
        {
            return !object.ReferenceEquals(MonoSingleton<T>.m_Instance, null);
        }
    }

    /// <summary>
    /// 初始化
    /// </summary>
    private void Awake()
    {
        if (object.ReferenceEquals(MonoSingleton<T>.m_Instance, null))
        {
            MonoSingleton<T>.m_Instance = (this as T);
            MonoSingleton<T>.m_Instance.OnAwake();
        }
    }



    /// <summary>
    /// 初始化
    /// </summary>
    protected virtual void OnAwake()
    {
    }

    /// <summary>
    /// 销毁
    /// </summary>
    protected virtual void DoOnDestroy()
    {
    }

    /// <summary>
    /// 销毁
    /// </summary>
    private void OnDestroy()
    {
        this.DoOnDestroy();
        if (object.ReferenceEquals(MonoSingleton<T>.m_Instance, this))
        {
            MonoSingleton<T>.m_Instance = (T)((object)null);
        }
    }
}