/**
 * Copyright 2012-2013 Florian Schmaus
 *
 * 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.ping;

import org.jivesoftware.smack.Connection;
import org.jivesoftware.smack.SmackConfiguration;
import org.jivesoftware.smack.SmackError;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.ping.ServerPingManager;
import org.jivesoftware.smack.ping.packet.Ping;
import org.jivesoftware.smack.util.SyncPacketSend;
import org.jivesoftware.smackx.ServiceDiscoveryManager;
import org.jivesoftware.smackx.packet.DiscoverInfo;

/**
 * Implements the XMPP Ping as defined by XEP-0199.  The XMPP Ping protocol 
 * allows one entity to 'ping' any other entity by simply sending a ping to 
 * the appropriate JID.
 * <p>
 * NOTE: The {@link ServerPingManager} already provides a keepalive functionality 
 * for regularly pinging the server to keep the underlying transport connection
 * alive.  This class is specifically intended to do manual pings of other 
 * entities.  
 * 
 * @author Florian Schmaus
 * @see <a href="http://www.xmpp.org/extensions/xep-0199.html">XEP-0199:XMPP
 *      Ping</a>
 */
public class PingManager {
    private Connection connection;

    public PingManager(Connection connection) {
        ServiceDiscoveryManager sdm = ServiceDiscoveryManager.getInstanceFor(connection);
        sdm.addFeature(Ping.NAMESPACE);
        this.connection = connection;
    }

    /**
     * Pings the given jid. This method will return false if an error occurs.  The exception 
     * to this, is a server ping, which will always return true if the server is reachable, 
     * event if there is an error on the ping itself (i.e. ping not supported).
     * <p>
     * Use {@link #isPingSupported(String)} to determine if XMPP Ping is supported 
     * by the entity.
     * 
     * @param jid The id of the entity the ping is being sent to
     * @param pingTimeout The time to wait for a reply
     * @return true if a reply was received from the entity, false otherwise.
     */
    public boolean ping(String jid, long pingTimeout) {
        Ping ping = new Ping(jid);
        
        try {
            SyncPacketSend.getReply(connection, ping);
        }
        catch (XMPPException exc) {
            
            return (jid.equals(connection.getServiceName()) && (exc.getSmackError() != SmackError.NO_RESPONSE_FROM_SERVER));
        }
        return true;
    }
    
    /**
     * Same as calling {@link #ping(String, long)} with the defaultpacket reply 
     * timeout.
     * 
     * @param jid The id of the entity the ping is being sent to
     * @return true if a reply was received from the entity, false otherwise.
     */
    public boolean ping(String jid) {
        return ping(jid, SmackConfiguration.getPacketReplyTimeout());
    }
    
    /**
     * Query the specified entity to see if it supports the Ping protocol (XEP-0199)
     * 
     * @param jid The id of the entity the query is being sent to
     * @return true if it supports ping, false otherwise.
     * @throws XMPPException An XMPP related error occurred during the request 
     */
    public boolean isPingSupported(String jid) throws XMPPException {
        DiscoverInfo result = ServiceDiscoveryManager.getInstanceFor(connection).discoverInfo(jid);
        return result.containsFeature(Ping.NAMESPACE);
    }

    /**
     * Pings the server. This method will return true if the server is reachable.  It
     * is the equivalent of calling <code>ping</code> with the XMPP domain.
     * <p>
     * Unlike the {@link #ping(String)} case, this method will return true even if 
     * {@link #isPingSupported(String)} is false.
     * 
     * @return true if a reply was received from the server, false otherwise.
     */
    public boolean pingMyServer() {
        return ping(connection.getServiceName());
    }
}