using UnityEngine;
using System;

public static class Single
{
    // 유틸
    public static DSPhysicsSGT              Physics         { get { return DSPhysicsSGT.Instance; } }
    public static DSEventSGT                Event           { get { return DSEventSGT.Instance; } }
    
}

public abstract class MonoSingleton<T> : MonoBehaviour where T : MonoSingleton<T>
{
    private static bool m_bApplicationQuit = false;
    private static object InstanceLocker = new object();

	public bool m_bInitialized = false;
	public T m_In;
	public static volatile T m_Instance;

    public static T Instance
    {
        get
        {
#if !UNITY_EDITOR
            if (true == m_bApplicationQuit)
                return null;
#endif

            lock (InstanceLocker)
            {
                // Instance requiered for the first time, we look for it
                if (null == m_Instance)
                {
					
					T instance = GameObject.FindObjectOfType(typeof(T)) as T;
				
                    // Object not found, we create a temporary one
					if (instance == null && IsCreatableSingleton(typeof(T)))
                    {
                        instance = new GameObject(typeof(T).ToString()).AddComponent<T>();

                        // Problem during the creation, this should not happen
                        if (instance == null)
                        {
                            Debug.LogError("Problem during the creation of " + typeof(T).ToString());
                        }
					}else if(instance==null && IsCreatableSingleton(typeof(T)) == false)	{		
#if UNITY_EDITOR
						throw new System.Exception();
#else
						Debug.LogError("Don't Create New singlton object : " + typeof(T).ToString());
#endif
						return null;
					}

                    if (instance != null)
                    {
                        Initialize(instance);
                    }
				}

                return m_Instance;
            }
        }
    }

    private static void Initialize(T instance)
    {
        if (m_Instance == null)
        {
            var startTime = System.DateTime.Now;
            m_Instance = instance;
			m_Instance.m_In = instance;
			bool act = m_Instance.transform.gameObject.activeSelf;

			m_Instance.transform.SetParent(GetParent("DSSingletons (Destroy)").transform);
            m_Instance.OnInitialize();
			m_Instance.m_bInitialized = true;

            var period = System.DateTime.Now - startTime;
            if (period.TotalSeconds > 1.0f)
            {
                var name = m_Instance.ToString();
                Debug.LogWarning("Profile Warnning. DSSingletion {" + name + "} too long init time : " 
                                 + period.TotalSeconds.ToString("F") + "Seconds");
            }
        }
        else if (m_Instance != instance)
        {
            DestroyImmediate(instance.gameObject);
        }
			
    }

    private static void Destroyed(T instance)
    {
		if (instance != null && m_Instance == instance)
        {
			m_Instance.OnFinalize();
			if(m_Instance.gameObject!=null)
				GameObject.Destroy(m_Instance.gameObject);
            m_Instance = null;
        }
    }

    public void CreateSingleton() { }
    public virtual void OnInitialize() { }
    public virtual void OnFinalize() { }
	public virtual void DoDestroy() { OnDestroy (); }

    // 인스턴스 널체크.
    public static bool IsNull()
    {
        return (null == m_Instance);
    }

	void Awake()
	{
		Instance.CleanDuplicate();
	}

    void OnDestroy()
    {
		Debug.Log("OnDestroy :: " + typeof(T).Name);
        Destroyed(this as T);
    }

    private void OnApplicationQuit()
    {
        m_bApplicationQuit = true;
        Destroyed(this as T);
    }

    static GameObject GetParent(string strName)
    {
        GameObject pDSRoot = GameObject.Find(strName) as GameObject;
        if (null == pDSRoot)
            pDSRoot = new GameObject(strName);

        return pDSRoot;
    }

    public void SetDontDestroy()
    {
        if (null == m_Instance)
            return;

		if (Application.isPlaying == false)
			return;

        GameObject pParent = GetParent("DSSingletons (DontDestroy)");
        DontDestroyOnLoad(pParent);

        m_Instance.transform.SetParent(pParent.transform);
    }


	public static void SafeInvoke( Action act )
	{
		if ( Instance != null )
		{
			act();
		}
	}

	public static bool IsCreatableSingleton(Type type)
	{		
		return true;
	}

	public void CleanDuplicate()
	{
		T[] lists = GameObject.FindObjectsOfType<T>();
		if(lists.Length>1)
		{
			T instance = null;
			foreach (var item in lists) {
				if(item.m_bInitialized == true)
					instance = item;
			}

			if(instance!=null)
			{
				foreach (var item in lists) {
					if(item.m_bInitialized==false)
					{
						GameObject.Destroy(item.gameObject);
					}
				}
			}
		}
	}

}