/**
 * $RCSfile: BridgedResolver.java,v $
 * $Revision: 1.1 $
 * $Date: 2007/07/02 17:41:07 $
 *
 * Copyright 2003-2005 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jivesoftware.smackx.jingle.nat;

import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Enumeration;
import java.util.Random;

import org.jivesoftware.smack.Connection;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smackx.jingle.JingleSession;

/**
 * Bridged Resolver use a RTPBridge Service to add a relayed candidate. A very
 * reliable solution for NAT Traversal.
 * <p/>
 * The resolver verify is the XMPP Server that the client is connected offer
 * this service. If the server supports, a candidate is requested from the
 * service. The resolver adds this candidate
 */
public class BridgedResolver extends TransportResolver {

	public static String getLocalHost() {
		Enumeration ifaces = null;

		try {
			ifaces = NetworkInterface.getNetworkInterfaces();
		} catch (final SocketException e) {
			e.printStackTrace();
		}

		while (ifaces.hasMoreElements()) {

			final NetworkInterface iface = (NetworkInterface) ifaces
					.nextElement();
			final Enumeration iaddresses = iface.getInetAddresses();

			while (iaddresses.hasMoreElements()) {
				final InetAddress iaddress = (InetAddress) iaddresses
						.nextElement();
				if (!iaddress.isLoopbackAddress()
						&& !iaddress.isLinkLocalAddress()
						&& !iaddress.isSiteLocalAddress()
						&& !(iaddress instanceof Inet6Address)) {
					return iaddress.getHostAddress();
				}
			}
		}

		try {
			return InetAddress.getLocalHost().getHostAddress();
		} catch (final Exception e) {
			e.printStackTrace();
		}

		return "127.0.0.1";

	}

	Connection connection;

	Random random = new Random();

	long sid;

	/**
	 * Constructor. A Bridged Resolver need a Connection to connect to a RTP
	 * Bridge.
	 */
	public BridgedResolver(Connection connection) {
		super();
		this.connection = connection;
	}

	@Override
	public void cancel() throws XMPPException {
		// Nothing to do here
	}

	@Override
	public void initialize() throws XMPPException {

		clearCandidates();

		if (!RTPBridge.serviceAvailable(connection)) {
			setInitialized();
			throw new XMPPException("No RTP Bridge service available");
		}
		setInitialized();

	}

	/**
	 * Resolve Bridged Candidate.
	 * <p/>
	 * The BridgedResolver takes the IP addresse and ports of a jmf proxy
	 * service.
	 */
	@Override
	public synchronized void resolve(JingleSession session)
			throws XMPPException {

		setResolveInit();

		clearCandidates();

		sid = Math.abs(random.nextLong());

		final RTPBridge rtpBridge = RTPBridge.getRTPBridge(connection,
				String.valueOf(sid));

		final String localIp = getLocalHost();

		final TransportCandidate localCandidate = new TransportCandidate.Fixed(
				rtpBridge.getIp(), rtpBridge.getPortA());
		localCandidate.setLocalIp(localIp);

		final TransportCandidate remoteCandidate = new TransportCandidate.Fixed(
				rtpBridge.getIp(), rtpBridge.getPortB());
		remoteCandidate.setLocalIp(localIp);

		localCandidate.setSymmetric(remoteCandidate);
		remoteCandidate.setSymmetric(localCandidate);

		localCandidate.setPassword(rtpBridge.getPass());
		remoteCandidate.setPassword(rtpBridge.getPass());

		localCandidate.setSessionId(rtpBridge.getSid());
		remoteCandidate.setSessionId(rtpBridge.getSid());

		localCandidate.setConnection(connection);
		remoteCandidate.setConnection(connection);

		addCandidate(localCandidate);

		setResolveEnd();
	}

}