/*
 * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Copyright @ 2015 Atlassian Pty Ltd
 *
 * 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 net.java.sip.communicator.impl.protocol.jabber.extensions.colibri;

import org.jivesoftware.smack.packet.*;

/**
 * The IQ used to trigger the graceful shutdown mode of the videobridge or force
 * shutdown the one which receives the stanza(given that source JID is
 * authorized to do so).
 *
 * @author Pawel Domas
 */
public class ShutdownIQ
    extends IQ
{
    /**
     * XML namespace name for shutdown IQs.
     */
    final static public String NAMESPACE = ColibriConferenceIQ.NAMESPACE;

    /**
     * Force shutdown IQ element name.
     */
    final static public String FORCE_ELEMENT_NAME = "force-shutdown";

    /**
     * Graceful shutdown IQ element name.
     */
    final static public String GRACEFUL_ELEMENT_NAME = "graceful-shutdown";

    /**
     * The element name of this IQ. Either {@link #FORCE_ELEMENT_NAME} or
     * {@link #GRACEFUL_ELEMENT_NAME}.
     */
    private final String elementName;

    /**
     * Checks if given element is a valid one for <tt>ShutdownIQ</tt>.
     *
     * @param elementName the name if XML element name inside of the IQ.
     *
     * @return <tt>true</tt> if given <tt>elementName</tt> is correct for
     *         <tt>ShutdownIQ</tt>.
     */
    public static boolean isValidElementName(String elementName)
    {
        return GRACEFUL_ELEMENT_NAME.equals(elementName)
            || FORCE_ELEMENT_NAME.equals(elementName);
    }

    /**
     * Creates shutdown IQ for given element name.
     *
     * @param elementName can be {@link #FORCE_ELEMENT_NAME} or
     *        {@link #GRACEFUL_ELEMENT_NAME}
     *
     * @return new <tt>ShutdownIQ</tt> instance for given element name.
     *
     * @throws IllegalArgumentException if given element name is neither
     *         {@link #FORCE_ELEMENT_NAME} nor {@link #GRACEFUL_ELEMENT_NAME}.
     */
    public static ShutdownIQ createShutdownIQ(String elementName)
    {
        if (!isValidElementName(elementName))
        {
            throw new IllegalArgumentException(
                "Invalid element name: " + elementName);
        }

        if (GRACEFUL_ELEMENT_NAME.equals(elementName))
        {
            return createGracefulShutdownIQ();
        }
        else
        {
            return createForceShutdownIQ();
        }
    }

    /**
     * Creates and returns new instance of graceful shutdown IQ.
     */
    public static ShutdownIQ createGracefulShutdownIQ()
    {
        return new ShutdownIQ(GRACEFUL_ELEMENT_NAME);
    }

    /**
     * Creates and returns new instance of force shutdown IQ.
     */
    public static ShutdownIQ createForceShutdownIQ()
    {
        return new ShutdownIQ(FORCE_ELEMENT_NAME);
    }

    private ShutdownIQ(String elementName)
    {
        this.elementName = elementName;
    }

    /**
     * Returns <tt>true</tt> if this IQ instance is a "graceful shutdown" one.
     * Otherwise it is a force shutdown IQ.
     */
    public boolean isGracefulShutdown()
    {
        return elementName.equals(GRACEFUL_ELEMENT_NAME);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getChildElementXML()
    {
        return "<" + elementName + " xmlns='" + NAMESPACE + "' />";
    }
}