using System;
using UnityEngine;

namespace BitStrap
{
	public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
	{
		private static T instance;

		public static T Instance
		{
			get
			{
				return GetInstance(true);
			}
		}

		public static void RequireInstance(Action<T> callback)
		{
			T val = GetInstance(false);
			if (val != null && callback != null)
			{
				callback(val);
			}
		}

		public static T GetInstance(bool warnIfNotFound)
		{
			if (instance == null)
			{
				instance = UnityEngine.Object.FindObjectOfType<T>();
				if (instance == null && warnIfNotFound)
				{
					OnInstanceNotFound();
				}
			}
			return instance;
		}

		protected void ForceSingletonInstance()
		{
			instance = this as T;
		}

		protected virtual void OnDestroy()
		{
			instance = (T)null;
		}

		private static void OnInstanceNotFound()
		{
			Debug.LogWarningFormat("Didn't find a object of type {0}!", typeof(T).Name);
		}
	}
}