/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 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.packet;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

import org.jivesoftware.smack.packet.PacketExtension;

/**
 * Represents timestamp information about data stored for later delivery. A DelayInformation will 
 * always includes the timestamp when the packet was originally sent and may include more 
 * information such as the JID of the entity that originally sent the packet as well as the reason
 * for the delay.<p>
 * 
 * For more information see <a href="http://xmpp.org/extensions/xep-0091.html">XEP-0091</a>
 * and <a href="http://xmpp.org/extensions/xep-0203.html">XEP-0203</a>.
 * 
 * @author Gaston Dombiak
 */
public class DelayInformation implements PacketExtension {

    /**
     * Date format according to the obsolete XEP-0091 specification.
     * XEP-0091 recommends to use this old format for date-time instead of
     * the one specified in XEP-0082.
     * <p>
     * Date formats are not synchronized. Since multiple threads access the format concurrently,
     * it must be synchronized externally. 
     */
    public static final DateFormat XEP_0091_UTC_FORMAT = new SimpleDateFormat(
            "yyyyMMdd'T'HH:mm:ss");
    static {
        XEP_0091_UTC_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
    }

    private Date stamp;
    private String from;
    private String reason;

    /**
     * Creates a new instance with the specified timestamp. 
     * @param stamp the timestamp
     */
    public DelayInformation(Date stamp) {
        super();
        this.stamp = stamp;
    }

    /**
     * Returns the JID of the entity that originally sent the packet or that delayed the 
     * delivery of the packet or <tt>null</tt> if this information is not available.
     * 
     * @return the JID of the entity that originally sent the packet or that delayed the 
     *         delivery of the packet.
     */
    public String getFrom() {
        return from;
    }

    /**
     * Sets the JID of the entity that originally sent the packet or that delayed the 
     * delivery of the packet or <tt>null</tt> if this information is not available.
     * 
     * @param from the JID of the entity that originally sent the packet.
     */
    public void setFrom(String from) {
        this.from = from;
    }

    /**
     * Returns the timestamp when the packet was originally sent. The returned Date is 
     * be understood as UTC.
     * 
     * @return the timestamp when the packet was originally sent.
     */
    public Date getStamp() {
        return stamp;
    }

    /**
     * Returns a natural-language description of the reason for the delay or <tt>null</tt> if 
     * this information is not available.
     * 
     * @return a natural-language description of the reason for the delay or <tt>null</tt>.
     */
    public String getReason() {
        return reason;
    }

    /**
     * Sets a natural-language description of the reason for the delay or <tt>null</tt> if 
     * this information is not available.
     * 
     * @param reason a natural-language description of the reason for the delay or <tt>null</tt>.
     */
    public void setReason(String reason) {
        this.reason = reason;
    }

    public String getElementName() {
        return "x";
    }

    public String getNamespace() {
        return "jabber:x:delay";
    }

    public String toXML() {
        StringBuilder buf = new StringBuilder();
        buf.append("<").append(getElementName()).append(" xmlns=\"").append(getNamespace()).append(
                "\"");
        buf.append(" stamp=\"");
        synchronized (XEP_0091_UTC_FORMAT) {
            buf.append(XEP_0091_UTC_FORMAT.format(stamp));
        }
        buf.append("\"");
        if (from != null && from.length() > 0) {
            buf.append(" from=\"").append(from).append("\"");
        }
        buf.append(">");
        if (reason != null && reason.length() > 0) {
            buf.append(reason);
        }
        buf.append("</").append(getElementName()).append(">");
        return buf.toString();
    }

}