// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// Copyright (c) 2007 Novell, Inc. (http://www.novell.com)
//
// Authors:
//	Chris Toshok (toshok@ximian.com)
//

using System;
using System.Windows;

namespace System.Collections.Specialized {

	public class CollectionChangedEventManager : WeakEventManager
	{
		internal CollectionChangedEventManager ()
		{
		}

		public static void AddListener (INotifyCollectionChanged source, IWeakEventListener listener)
		{
			CurrentManager.ProtectedAddListener (source, listener);
		}

		public static void RemoveListener (INotifyCollectionChanged source, IWeakEventListener listener)
		{
			CurrentManager.ProtectedAddListener (source, listener);
		}

		protected override void StartListening (object source)
		{
			INotifyCollectionChanged inotify = (INotifyCollectionChanged) source;
			inotify.CollectionChanged += OnCollectionChanged;
		}

		protected override void StopListening (object source)
		{
			INotifyCollectionChanged inotify = (INotifyCollectionChanged) source;
			inotify.CollectionChanged -= OnCollectionChanged;
		}

		private void OnCollectionChanged (object sender, NotifyCollectionChangedEventArgs e)
		{
			DeliverEvent (sender, e);
		}

		private static object CurrentManagerLock = new object ();

		private static CollectionChangedEventManager CurrentManager {
			get {
				lock (CurrentManagerLock) {
					CollectionChangedEventManager manager = (CollectionChangedEventManager)GetCurrentManager (typeof (CollectionChangedEventManager));
					if (manager == null) {
						manager = new CollectionChangedEventManager ();
						SetCurrentManager (typeof (CollectionChangedEventManager), manager);
					}
					return manager;
				}
			}
		}
	}
}