/*
 * Hedgewars for Android. An Android port of Hedgewars, a free turn based strategy game
 * Copyright (c) 2011-2012 Richard Deurwaarder <xeli@xelification.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package org.hedgewars.hedgeroid.Downloader;

import java.util.LinkedList;
import java.util.List;

import org.hedgewars.hedgeroid.R;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.widget.RemoteViews;

public class DownloadService extends Service {
	public final static String INTENT_TASKID = "taskId";
	public final static String INTENT_TASK = "task";

	public static final String PREF_DOWNLOADED = "downloaded";
	public static final int MSG_CANCEL = 0;
	public static final int MSG_UNREGISTER_CLIENT = 2;
	public final static int MSG_ADDTASK = 4;

	public static final int NOTIFICATION_PROCESSING = 0;
	public static final int NOTIFICATION_DONE = 1;

	private DownloadAsyncTask asyncExecutor;

	private DownloadHandler handler = new DownloadHandler();
	private final Messenger messenger = new Messenger(handler);

	private NotificationManager nM;
	private RemoteViews contentView;

	private LinkedList<DownloadTask> downloadTasks = new LinkedList<DownloadTask>();
	private DownloadTask currentTask = null;

	public class DownloadHandler extends Handler{

		public void handleMessage(Message msg){
			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.PENDING){
						downloadTasks.remove(task);
					}
					if(currentTask != null && currentTask.getPackage().equals(pack)){//TODO synchronization problem?
						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);
	}
	public IBinder onBind(Intent intent) {
		return messenger.getBinder();
	}

	private void runNextTask(){
		if(asyncExecutor == null){//if (task isnt running right now) ...
			currentTask = downloadTasks.poll();
			if(currentTask != null){
				asyncExecutor = new DownloadAsyncTask(currentTask);
				asyncExecutor.execute(currentTask.getPackage());
			}
		}
	}

	public void onDestroy(){
		super.onDestroy();
		asyncExecutor.cancel(false);	
	}

	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, DownloadListActivity.class), Intent.FLAG_ACTIVITY_NEW_TASK);
			progressNotification.contentIntent = contentIntent;

			startForeground(NOTIFICATION_PROCESSING, progressNotification);

			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(int result){
			switch(result){
			case DownloadAsyncTask.EXIT_SUCCESS: 	sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_DONE)); break;
			case DownloadAsyncTask.EXIT_CONNERROR:  sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_FAILED, DownloadAsyncTask.EXIT_CONNERROR, 0)); break;
			case DownloadAsyncTask.EXIT_FNF:		sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_FAILED, DownloadAsyncTask.EXIT_FNF, 0)); break;
			case DownloadAsyncTask.EXIT_MD5:		sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_FAILED, DownloadAsyncTask.EXIT_MD5, 0)); break;
			case DownloadAsyncTask.EXIT_URLFAIL:	sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_FAILED, DownloadAsyncTask.EXIT_URLFAIL, 0)); break;
			case DownloadAsyncTask.EXIT_CANCELLED:	sendMessageToClients(Message.obtain(handler, DownloadFragment.MSG_DONE)); break;
			}
			
			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;
	}

}