import java.util.Deque;

import java.util.List;

	public final static int MSG_ADDTASK = 4;

	private DownloadHandler handler = new DownloadHandler();

	private final Messenger messenger = new Messenger(handler);

	private Deque<DownloadTask> downloadTasks = new LinkedList<DownloadTask>();

	public class DownloadHandler extends Handler{

			if(msg.obj != null){

				DownloadPackage pack = (DownloadPackage) msg.obj;

				DownloadTask task = null;

				Messenger replyToMessenger = msg.replyTo;

				for(DownloadTask _task : downloadTasks){

					if(_task.getPackage().equals(pack)){

						task = _task;

						break;

				switch(msg.what){

				case MSG_ADDTASK:

					if(task == null){

						task = new DownloadTask(pack);

						downloadTasks.add(task);

					}

					task.addClient(replyToMessenger);

					runNextTask();

					return;

				case MSG_CANCEL:

					if(task != null && task.getPackage().equals(pack) && task.getStatus() == TASK_STATE.RUNNING){

						asyncExecutor.cancel(false);

					}

					return;

				case MSG_UNREGISTER_CLIENT:

					if(task != null){

						task.removeClient(replyToMessenger);

					}

					return;

				}

	public void onCreate(){

		super.onCreate();

		nM = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

	}

	private void runNextTask(){

		if(asyncExecutor == null){//if (task isnt running right now) ...

			DownloadTask task = downloadTasks.pollFirst();

			if(task != null){

				asyncExecutor = new DownloadAsyncTask(task);

				asyncExecutor.execute(task.getPackage());

	class DownloadTask {

		private final DownloadPackage pack;

		private TASK_STATE status = TASK_STATE.PENDING;

		private Notification progressNotification, doneNotification;

		//I expect little to no removeClient calls that's why we go for a list rather than a map

		private final List<Messenger> clients;

		public DownloadTask(DownloadPackage _pack){

			pack = _pack;

			clients = new LinkedList<Messenger>();

		}

		public void addClient(Messenger messenger){

			clients.add(messenger);

		}

		public void removeClient(Messenger messenger){

			clients.remove(messenger);

		}

		public DownloadPackage getPackage(){

			return pack;

		}

		public TASK_STATE getStatus(){

			return status;

		}

		public void sendMessageToClients(Message msg){

			for(Messenger messenger : clients){

				try {

					messenger.send(msg);		

				} catch (RemoteException e) {

					e.printStackTrace();

				}

			}

		}

		/*

		 * Callbacks called from the async tasks

		 */

		//Thread safe method to let clients know the processing is starting and will process int max kbytes

		public void start(int max){

			progressNotification = new Notification(R.drawable.statusbar, getString(R.string.notification_title), System.currentTimeMillis());

			progressNotification.flags |= Notification.FLAG_ONGOING_EVENT;

			contentView = new RemoteViews(getPackageName(), R.layout.notification);

			contentView.setProgressBar(R.id.notification_progress, 100, 34, false);

			progressNotification.contentView = contentView;

			PendingIntent contentIntent = PendingIntent.getActivity(DownloadService.this, 0, new Intent(DownloadService.this, DownloadFragment.class), Intent.FLAG_ACTIVITY_NEW_TASK);

			progressNotification.contentIntent = contentIntent;

			startForeground(NOTIFICATION_PROCESSING, progressNotification);//TODO werkt het?

			Message msg = Message.obtain(null, DownloadFragment.MSG_START, max, 0);

			sendMessageToClients(msg);

		}

		//periodically gets called by the ASyncTask, we can't tell for sure when it's called

		public void update(int progress, int max, String fileName){

			progress = (progress/1024);

			contentView.setProgressBar(R.id.notification_progress, max, progress, false);

			contentView.setTextViewText(R.id.progressbar_sub, String.format("%dkb/%dkb (Compressed sizes)", progress, max));

			nM.notify(NOTIFICATION_PROCESSING, progressNotification);

			sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_UPDATE, progress, max, fileName));

		}

		//Call back from the ASync task when the task has either run into an error or finished otherwise

		public void done(boolean succesful){

			if(succesful){

				sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_DONE));

			}else sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_FAILED));

			stopForeground(true);

			nM.cancel(NOTIFICATION_PROCESSING);

			String title = getString(R.string.notification_title);

			doneNotification = new Notification(R.drawable.icon, title, System.currentTimeMillis());

			doneNotification.flags |= Notification.FLAG_AUTO_CANCEL;

			PendingIntent contentIntent = PendingIntent.getActivity(DownloadService.this, 0, new Intent(DownloadService.this, DownloadListActivity.class), Intent.FLAG_ACTIVITY_NEW_TASK);

			doneNotification.setLatestEventInfo(DownloadService.this, title, getString(R.string.notification_done) + pack, contentIntent);

			nM.notify(pack.getId(), doneNotification);

			asyncExecutor = null;

			runNextTask();//see if there are more tasks

		}

	enum TASK_STATE{

		RUNNING, FINISHED, PENDING;