/*
* LumaQQ - Java QQ Client
*
* Copyright (C) 2004 luma <stubma@163.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.tsinghua.lumaqq.qq.packets.in;

import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import edu.tsinghua.lumaqq.qq.PacketParseException;
import edu.tsinghua.lumaqq.qq.QQ;
import edu.tsinghua.lumaqq.qq.Utils;
import edu.tsinghua.lumaqq.qq.packets.InPacket;


/**
 * <pre>
 * 系統(tǒng)消息包，系統(tǒng)消息和ReceiveIMPacket里面的系統(tǒng)通知有什么區(qū)別呢？
 * 系統(tǒng)消息是表示你被別人加為好友了之類的消息，所以有源有目的，其他人
 * 收不到的，系統(tǒng)通知是系統(tǒng)發(fā)給大家的消息。好了，廢話這么多，系統(tǒng)消息的
 * 格式是:
 * 1. 頭部，頭部說明了系統(tǒng)消息的類型，目前已知的有四種
 * 2. 以0x1F相隔的多個字段，對于已知的類型，分別是消息類型，源，目的，消息正文，對于未知的
 *    消息類型，前面三個是一樣的，后面的就未知了
 * 3. 尾部
 * </pre>
 *
 * @author 馬若劼
 */
public class SystemNotificationPacket extends InPacket {   
    // 分隔符
    public static final String DIVIDER = Character.toString((char)0x1F);
    // 消息類型
    public char type;
    // 從哪里來，是源的QQ號
    public int from;
    // 到哪里去，目的的QQ號
    public int to;
    // 附加的消息，比如如果別人拒絕了你加他為好友，并說了理由，那就在這里了
    public String message;
    
    /**
     * 構(gòu)造函數(shù)
     * @param buf 緩沖區(qū)
     * @param length 包長度
     * @throws PacketParseException 解析錯誤
     */
    public SystemNotificationPacket(ByteBuffer buf, int length) throws PacketParseException {
        super(buf, length);
    }   

    /* (non-Javadoc)
     * @see edu.tsinghua.lumaqq.qq.packets.InPacket#parseBody(java.nio.ByteBuffer)
     */
    protected void parseBody(ByteBuffer buf) throws PacketParseException {
        byte[] b = buf.array();
        String s = null;
        try {
            s = new String(b, QQ.QQ_CHARSET_DEFAULT);
        } catch (UnsupportedEncodingException e) {
            s = new String(b);
        }
        String[] fields = s.split(DIVIDER);
        type = Utils.getChar(fields[0], 0);
        from = Utils.getInt(fields[1], 0);
        to = Utils.getInt(fields[2], 0);
        if(fields.length > 3)
            message = fields[3];
        else
            message = "";
        if(from == 0 || to == 0)
            throw new PacketParseException("系統(tǒng)通知字段解析出錯");
    }
}