using UnityEngine;
using System.Collections;
using System;

//Based off http://forum.unity3d.com/threads/37896-Programming-architectures?p=847646&viewfull=1#post847646
//Changed it to static methods (less typing and less indirection)
//Added helper methods for posting notifications


public class GenericNotificationCenter<NT, N>
	where NT : struct, IConvertible, IComparable, IFormattable
	where N : GenericNotification<NT>, new()
{
	public delegate void OnNotificationDelegate(N note);
	private static OnNotificationDelegate[] _listeners = new OnNotificationDelegate[System.Enum.GetValues(typeof(NT)).Length];
	
	public static void AddListener(OnNotificationDelegate newListenerDelegate, NT type)
	{
		int typeInt = type.ToInt32(null);
		//Note that these checks will only be done when DEBUG is defined
		_listeners[typeInt] += newListenerDelegate;
	}

	static bool IsAlreadyRegistered(OnNotificationDelegate newListenerDelegate, int typeInt)
	{
		if (_listeners[typeInt] == null)
		{
			return false;
		}
		Delegate[] invocationList = _listeners[typeInt].GetInvocationList();
	    foreach (Delegate d in invocationList)
	    {
			if (d == newListenerDelegate)
			{
				return true;
			}
	    }
		return false;
	}

	public static void RemoveListener(OnNotificationDelegate listenerDelegate, NT type)
	{
		int typeInt = type.ToInt32(null);
		_listeners[typeInt] -= listenerDelegate;
	}

	public static void Post(NT type)
	{
		//AVDebug.Log("Firing "+type.ToString());
		N n = new N();
		n.type = type;
		Post(n);
	}

	public static void Post(NT type, object data)
	{
		N n = new N();
		n.type = type;
		n.data = data;
		Post(n);
	}
	
	public static void Post(N note)
	{
		int typeInt = note.type.ToInt32(null);

		if (_listeners[typeInt] != null)
		{
			_listeners[typeInt](note);
		}
	}

	#region For Testing/Debugging only
	/// <summary>
	/// Used for debugging to outputs the number of listeners to have an idea of how many listeners are currently registered.
	/// </summary>
	public static void OutputNumOfListeners()
	{
		for (int i = 0; i < _listeners.Length; i++)
		{
			NT notificationType = (NT)(object)i;
		}
	}

	public static int GetListenerCount(NT notificationType)
	{
		var typeListeners = _listeners[notificationType.ToInt32(null)];
		if (typeListeners != null)
		{
			return typeListeners.GetInvocationList().Length;
		} else
		{
			return 0;
		}
	}

	public static int GetTotalListenersCount()
	{
		int total = 0;
		for (int i = 0; i < _listeners.Length; i++)
		{
			total += GetListenerCount((NT)(object)i);
		}
		return total;
	}

	public static void Reset_USE_ONLY_FOR_UNIT_TESTS()
	{
		_listeners = new OnNotificationDelegate[System.Enum.GetValues(typeof(NT)).Length];
	}
	#endregion
}