/*
 * Copyright (c) 2013, OpenCloudDB/MyCAT and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software;Designed and Developed mainly by many Chinese 
 * opensource volunteers. you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License version 2 only, as published by the
 * Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * Any questions about this component can be directed to it's project Web address 
 * https://code.google.com/p/opencloudb/.
 *
 */
package org.opencloudb.server.response;

import java.nio.ByteBuffer;

import org.opencloudb.config.Fields;
import org.opencloudb.mysql.PacketUtil;
import org.opencloudb.net.mysql.EOFPacket;
import org.opencloudb.net.mysql.FieldPacket;
import org.opencloudb.net.mysql.ResultSetHeaderPacket;
import org.opencloudb.net.mysql.RowDataPacket;
import org.opencloudb.parser.util.ParseUtil;
import org.opencloudb.server.ServerConnection;
import org.opencloudb.util.LongUtil;

/**
 * @author mycat
 */
public class SelectLastInsertId {

    private static final String ORG_NAME = "LAST_INSERT_ID()";
    private static final int FIELD_COUNT = 1;
    private static final ResultSetHeaderPacket header = PacketUtil.getHeader(FIELD_COUNT);
    static {
        byte packetId = 0;
        header.packetId = ++packetId;
    }

    public static void response(ServerConnection c, String stmt, int aliasIndex) {
        String alias = ParseUtil.parseAlias(stmt, aliasIndex);
        if (alias == null) {
            alias = ORG_NAME;
        }

        ByteBuffer buffer = c.allocate();

        // write header
        buffer = header.write(buffer, c,true);

        // write fields
        byte packetId = header.packetId;
        FieldPacket field = PacketUtil.getField(alias, ORG_NAME, Fields.FIELD_TYPE_LONGLONG);
        field.packetId = ++packetId;
        buffer = field.write(buffer, c,true);

        // write eof
        EOFPacket eof = new EOFPacket();
        eof.packetId = ++packetId;
        buffer = eof.write(buffer, c,true);

        // write rows
        RowDataPacket row = new RowDataPacket(FIELD_COUNT);
        row.add(LongUtil.toBytes(c.getLastInsertId()));
        row.packetId = ++packetId;
        buffer = row.write(buffer, c,true);

        // write last eof
        EOFPacket lastEof = new EOFPacket();
        lastEof.packetId = ++packetId;
        buffer = lastEof.write(buffer, c,true);

        // post write
        c.write(buffer);
    }

}