/*
 * FrontlineSMS <http://www.frontlinesms.com>
 * Copyright 2007, 2008 kiwanja
 * 
 * This file is part of FrontlineSMS.
 * 
 * FrontlineSMS is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or (at
 * your option) any later version.
 * 
 * FrontlineSMS 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 Lesser
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with FrontlineSMS. If not, see <http://www.gnu.org/licenses/>.
 */
package net.frontlinesms.messaging.mms;

import java.util.Collection;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArraySet;

import net.frontlinesms.AppProperties;
import net.frontlinesms.FrontlineUtils;
import net.frontlinesms.data.DuplicateKeyException;
import net.frontlinesms.data.domain.EmailAccount;
import net.frontlinesms.data.domain.FrontlineMultimediaMessage;
import net.frontlinesms.data.repository.EmailAccountDao;
import net.frontlinesms.events.EventBus;
import net.frontlinesms.messaging.mms.email.MmsEmailService;
import net.frontlinesms.messaging.mms.email.MmsEmailServiceStatus;
import net.frontlinesms.messaging.mms.events.MmsReceivedNotification;
import net.frontlinesms.mms.MmsMessage;
import net.frontlinesms.mms.MmsReceiveException;

import org.apache.log4j.Logger;

/**
 * MmsServiceManager runs as a separate thread.
 * 
 * It handles the discovery of Multimedia Messages available on the e-mail accounts configures by the user, 
 * 
 * INCOMING MESSAGES
 * When a new MMS is filtered in the list of e-mails, an event is triggered through the {@link EventBus}
 * 
 * Incoming messages are immediately removed from accounts with a POP protocol
 * 
 * @author Morgan Belkadi <morgan@frontlinesms.com>
 */
public class MmsServiceManager extends Thread  {
	/** Set of {@link MmsEmailService} */
	private final Set<MmsService> mmsEmailServices = new CopyOnWriteArraySet<MmsService>();
	/** Flag indicating that the thread should continue running. */
	private boolean running;
	private EventBus eventBus;
	private EmailAccountDao emailAccountDao;

	private static Logger LOG = FrontlineUtils.getLogger(MmsServiceManager.class);

	public MmsServiceManager() {
		super("MmsServiceManager");
		
		// TODO Is there a cleaner way of doing this?  Email.receive() blocks in run().processMmsEmailReceiving()  
		this.setDaemon(true);
	}
	
	public void setEventBus(EventBus eventBus) {
		this.eventBus = eventBus;
	}
	
	/**
	 * Adds a new {@link EmailAccount} which will be used to receive Multimedia Messages
	 * @param emailAccount
	 */
	public synchronized void addMmsEmailReceiver(EmailAccount emailAccount) {
		MmsEmailService mmsEmailService = new MmsEmailService(emailAccount);
		
		mmsEmailServices.add(mmsEmailService);
	}
	
	/**
	 * Remove the {@link EmailAccount} from the list
	 * @param emailAccount
	 */
	public synchronized void removeMmsEmailReceiver(EmailAccount emailAccount) {
		for (MmsService mmsEmailService : this.mmsEmailServices) {
			if (((MmsEmailService)mmsEmailService).getEmailAccount().equals(emailAccount)) {
				this.mmsEmailServices.remove(mmsEmailService);
			}
		}
	}

	/**
	 * 
	 * @return All {@link MmsService}s
	 */
	public Set<MmsService> getAll () {
		return this.mmsEmailServices;
	}

	/**
	 * Starts the thread.
	 * Frequently fetches for new {@link FrontlineMultimediaMessage}
	 */
	public void run() {
		LOG.trace("ENTER");
		running = true;
		while (running) {
			processMmsEmailReceiving();

			FrontlineUtils.sleep_ignoreInterrupts(AppProperties.getInstance().getMmsPollingFrequency());
		}
		LOG.trace("EXIT");
	}

	/**
	 * Flags the internal thread to stop running.
	 */
	public void stopRunning() {
		this.running = false;
	}
	
	/**
	 * Processes the retrieving of e-mails.
	 * Automatically sets the status of the {@link MmsEmailService} depending on its state
	 */
	private void processMmsEmailReceiving() {
		for (MmsService mmsService : this.mmsEmailServices) {
			if (mmsService.isConnected()) {
				MmsEmailService mmsEmailService = (MmsEmailService)mmsService;
				try {
					mmsEmailService.setStatus(MmsEmailServiceStatus.FETCHING, this.eventBus);
					Collection<MmsMessage> mmsMessages = mmsEmailService.receive();
					
					for (MmsMessage mmsMessage : mmsMessages) {
						if (this.eventBus != null) {
							// Let's notify the observers that a new MMS has arrived
							this.eventBus.notifyObservers(new MmsReceivedNotification(mmsMessage));
						}
					}
					mmsEmailService.setStatus(MmsEmailServiceStatus.READY, this.eventBus);
					
					/** Last check update */
					// First, check if the service has not been removed
					if (this.mmsEmailServices.contains(mmsEmailService)) {
						mmsEmailService.updateLastCheck(this.emailAccountDao);
					}
				} catch (MmsReceiveException e) {
					mmsEmailService.setStatus(MmsEmailServiceStatus.FAILED_TO_CONNECT, this.eventBus);
				}
			}
		}
	}

	public void clearMmsEmailReceivers() {
		this.mmsEmailServices.clear();
	}

	public void setEmailAccountDao(EmailAccountDao emailAccountDao) {
		this.emailAccountDao = emailAccountDao;
	}

	/**
	 * Connect the {@link MmsEmailService}
	 * @param mmsEmailService
	 * @param connect
	 */
	public void connectMmsEmailService(MmsEmailService mmsEmailService, boolean connect) {
		mmsEmailService.setStatus((connect ? MmsEmailServiceStatus.READY : MmsEmailServiceStatus.DISCONNECTED), this.eventBus);
		EmailAccount emailAccount = mmsEmailService.getEmailAccount();
		emailAccount.setEnabled(connect);
		try {
			this.emailAccountDao.updateEmailAccount(mmsEmailService.getEmailAccount());
		} catch (DuplicateKeyException e) { }
	}

	/**
	 * Update the {@link MmsEmailService}s
	 */
	public synchronized void updateMmsEmailService(EmailAccount emailAccount) {
		for (MmsService mmsService : this.mmsEmailServices) {
			MmsEmailService mmsEmailService = (MmsEmailService) mmsService;
			if (mmsEmailService.getEmailAccount().isSameDatabaseEntity(emailAccount)) {
				mmsEmailService.populateReceiver(emailAccount);
				mmsEmailService.setEmailAccount(emailAccount);
				mmsEmailService.setStatus((emailAccount.isEnabled() ? MmsEmailServiceStatus.READY : MmsEmailServiceStatus.DISCONNECTED), this.eventBus);
			}
		}
	}

	/**
	 * @return The number of active MMS connections running
	 */
	public int getNumberOfActiveConnections() {
		int total = 0;

		for(MmsService modem : this.mmsEmailServices) {
			if (modem.isConnected()) {
				++total;
			}
		}

		return total;
	}
}