Unity Play Mode Detection

EditorPlayMode

//originally adopted from
//http://answers.unity3d.com/questions/447701/event-for-unity-editor-pause-and-playstop-events.html
//with a few modifications which makes the event firing nicer and cleaner
//Usage Example :
//
//using UnityEditor;
//using UnityEngine;
//
//[InitializeOnLoad]
//public class SingleEntryPoint
//{
//	static bool debugOp = false;
//	
//	static SingleEntryPoint()
//	{
//		Debug.Log("SingleEntryPoint. Up and running");
//		EditorPlayMode.PlayModeChanged += OnPlayModeChanged;
//	}
//	
//	private static void OnPlayModeChanged(PlayModeState currentMode, PlayModeState changedMode)
//	{
//		// DO your stuff here...
//		Debug.Log(currentMode.ToString() + " => " + changedMode.ToString());
//		
//		if (debugOp) {
//			Debug.Log(EditorApplication.isCompiling);
//			Debug.Log(EditorApplication.isPaused);
//			Debug.Log(EditorApplication.isPlaying);
//			Debug.Log(EditorApplication.isPlayingOrWillChangePlaymode);
//			Debug.Log(EditorApplication.isUpdating);
//			Debug.LogWarning("-------------------------------------");
//		}
//		
//		
//	}
//}

using UnityEditor;
using System;

namespace FFE {

	public enum PlayModeState
	{
		Stopped,
		Playing,
		Paused,
		AboutToStop,
		AboutToPlay
	}
	
	[InitializeOnLoad]
	public class EditorPlayMode
	{
		private static PlayModeState _currentState = PlayModeState.Stopped;
		
		static EditorPlayMode()
		{
			EditorApplication.playmodeStateChanged = OnUnityPlayModeChanged;
			if (EditorApplication.isPaused) 
				_currentState = PlayModeState.Paused;
		}
		
		static int Bool2Int(bool b) {if (b) return 1; else return 2;}
		
		static int GetEditorAppStateBoolComb() {
			int b1 = Bool2Int(EditorApplication.isUpdating);
			int b2 = Bool2Int(EditorApplication.isPlayingOrWillChangePlaymode);
			int b3 = Bool2Int(EditorApplication.isPlaying);
			int b4 = Bool2Int(EditorApplication.isPaused);
			int b5 = Bool2Int(EditorApplication.isCompiling);
			return b1 + b2 * 10 + b3 * 100 + b4 * 1000 + b5 * 10000;
		}
		public static event Action<PlayModeState, PlayModeState> PlayModeChanged;
		
		private static void OnPlayModeChanged(PlayModeState currentState, PlayModeState changedState)
		{
			if (PlayModeChanged != null)
				PlayModeChanged(currentState, changedState);
		}
		
		private static void OnUnityPlayModeChanged()
		{
			
			var changedState = PlayModeState.Stopped;
			
			//Stoped -> Playing : 22112
			//playing -> abouttostop : 22122
			//about2stop -> stopped : 22222
			//playing -> paused : 21112
			//paused -> playing : 22112
			//paused -> abouttostop : 21122
			//stoped -> paused in editor (stoped) : 21222
			//editor paused - > play(paused) : 21112
			//stoped -> abouttoplay in editor: 22212
			//editor paused -> play : 21212 //paused anyway
			
			int state = GetEditorAppStateBoolComb();
			switch (state) {
			case (22112):
				changedState = PlayModeState.Playing;
				break;
			case (21112):
				changedState = PlayModeState.Paused;
				break;
			case (22222):
				changedState = PlayModeState.Stopped;
				break;
			case (22122):
				changedState = PlayModeState.AboutToStop;
				break;
			case (21122):
				changedState = PlayModeState.AboutToStop;
				break;
			case (21222):
				changedState = PlayModeState.Stopped;
				break;
			case 22212:
				changedState = PlayModeState.Stopped;
				break;
			case 21212:
				changedState = PlayModeState.Paused;
				break;
			default:
				throw new SystemException("No such state combination defined: "+state);
			}
			
			// Fire PlayModeChanged event.
			if (_currentState!=changedState)
				OnPlayModeChanged(_currentState, changedState);
			
			// Set current state.
			_currentState = changedState;
			
			
		}
		
	}

}

I have not tried to add support for every possible editor state, if you find that I am missing some, please let me know ;D