/**
 *
 * Copyright 2016 Florian Schmaus
 *
 * 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.smack.roster;

import java.util.Collection;
import java.util.Date;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import org.jxmpp.jid.BareJid;
import org.jxmpp.jid.Jid;

public class RosterUtil {

    public static void waitUntilOtherEntityIsSubscribed(Roster roster, BareJid otherEntity, long timeoutMillis)
                    throws InterruptedException, TimeoutException {
        Date deadline = new Date(System.currentTimeMillis() + timeoutMillis);
        waitUntilOtherEntityIsSubscribed(roster, otherEntity, deadline);
    }

    public static void waitUntilOtherEntityIsSubscribed(Roster roster, final BareJid otherEntity, Date deadline)
                    throws InterruptedException, TimeoutException {
        final Lock lock = new ReentrantLock();
        final Condition maybeSubscribed = lock.newCondition();
        RosterListener rosterListener = new AbstractRosterListener() {
            private void signal() {
                lock.lock();
                try {
                    // No need to use signalAll() here.
                    maybeSubscribed.signal();
                }
                finally {
                    lock.unlock();
                }
            }

            @Override
            public void entriesAdded(Collection<Jid> addresses) {
                signal();
            }

            @Override
            public void entriesUpdated(Collection<Jid> addresses) {
                signal();
            }
        };

        roster.addRosterListener(rosterListener);

        boolean stillWaiting = true;
        // Using the example code pattern from Condition.awaitUntil(Date) javadoc.
        lock.lock();
        try {
            while (!roster.isSubscribedToMyPresence(otherEntity)) {
                if (!stillWaiting) {
                    throw new TimeoutException();
                }
                stillWaiting = maybeSubscribed.awaitUntil(deadline);
            }
        }
        finally {
            lock.unlock();
            // Make sure the listener is removed, so we don't leak it.
            roster.removeRosterListener(rosterListener);
        }
    }
}