/*
 * 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 static org.opencloudb.server.parser.ServerParseSet.CHARACTER_SET_CLIENT;
import static org.opencloudb.server.parser.ServerParseSet.CHARACTER_SET_CONNECTION;
import static org.opencloudb.server.parser.ServerParseSet.CHARACTER_SET_RESULTS;

import org.apache.log4j.Logger;
import org.opencloudb.config.ErrorCode;
import org.opencloudb.net.mysql.OkPacket;
import org.opencloudb.server.ServerConnection;
import org.opencloudb.server.parser.ServerParseSet;
import org.opencloudb.util.SplitUtil;

/**
 * 字符集属性设置
 */
/**
 * @author mycat
 */
public class CharacterSet {

    private static final Logger logger = Logger.getLogger(CharacterSet.class);

    public static void response(String stmt, ServerConnection c, int rs) {
        if (-1 == stmt.indexOf(',')) {
            /* 单个属性 */
            oneSetResponse(stmt, c, rs);
        } else {
            /* 多个属性 ,但是只关注CHARACTER_SET_RESULTS，CHARACTER_SET_CONNECTION */
            multiSetResponse(stmt, c, rs);
        }
    }

    private static void oneSetResponse(String stmt, ServerConnection c, int rs) {
        if ((rs & 0xff) == CHARACTER_SET_CLIENT) {
            /* 忽略client属性设置 */
            c.write(c.writeToBuffer(OkPacket.OK, c.allocate()));
        } else {
            String charset = stmt.substring(rs >>> 8).trim();
            if (charset.endsWith(";")) {
                /* 结尾为 ; 标识符 */
                charset = charset.substring(0, charset.length() - 1);
            }

            if (charset.startsWith("'") || charset.startsWith("`")) {
                /* 与mysql保持一致，引号里的字符集不做trim操作 */
                charset = charset.substring(1, charset.length() - 1);
            }

            // 设置字符集
            setCharset(charset, c);
        }
    }

    private static void multiSetResponse(String stmt, ServerConnection c, int rs) {
        String charResult = "null";
        String charConnection = "null";
        String[] sqlList = SplitUtil.split(stmt, ',', false);

        // check first
        switch (rs & 0xff) {
        case CHARACTER_SET_RESULTS:
            charResult = sqlList[0].substring(rs >>> 8).trim();
            break;
        case CHARACTER_SET_CONNECTION:
            charConnection = sqlList[0].substring(rs >>> 8).trim();
            break;
        }

        // check remaining
        for (int i = 1; i < sqlList.length; i++) {
            String sql = new StringBuilder("set ").append(sqlList[i]).toString();
            if ((i + 1 == sqlList.length) && sql.endsWith(";")) {
                /* 去掉末尾的 ‘;’ */
                sql = sql.substring(0, sql.length() - 1);
            }
            int rs2 = ServerParseSet.parse(sql, "set".length());
            switch (rs2 & 0xff) {
            case CHARACTER_SET_RESULTS:
                charResult = sql.substring(rs2 >>> 8).trim();
                break;
            case CHARACTER_SET_CONNECTION:
                charConnection = sql.substring(rs2 >>> 8).trim();
                break;
            case CHARACTER_SET_CLIENT:
                break;
            default:
                StringBuilder s = new StringBuilder();
                logger.warn(s.append(c).append(sql).append(" is not executed").toString());
            }
        }

        if (charResult.startsWith("'") || charResult.startsWith("`")) {
            charResult = charResult.substring(1, charResult.length() - 1);
        }
        if (charConnection.startsWith("'") || charConnection.startsWith("`")) {
            charConnection = charConnection.substring(1, charConnection.length() - 1);
        }

        // 如果其中一个为null，则以另一个为准。
        if ("null".equalsIgnoreCase(charResult)) {
            setCharset(charConnection, c);
            return;
        }
        if ("null".equalsIgnoreCase(charConnection)) {
            setCharset(charResult, c);
            return;
        }
        if (charConnection.equalsIgnoreCase(charResult)) {
            setCharset(charConnection, c);
        } else {
            StringBuilder sb = new StringBuilder();
            sb.append("charset is not consistent:[connection=").append(charConnection);
            sb.append(",results=").append(charResult).append(']');
            c.writeErrMessage(ErrorCode.ER_UNKNOWN_CHARACTER_SET, sb.toString());
        }
    }

    private static void setCharset(String charset, ServerConnection c) {
        if ("null".equalsIgnoreCase(charset)) {
            /* 忽略字符集为null的属性设置 */
            c.write(c.writeToBuffer(OkPacket.OK, c.allocate()));
        } else if (c.setCharset(charset)) {
            c.write(c.writeToBuffer(OkPacket.OK, c.allocate()));
        } else {
            try {
                if (c.setCharsetIndex(Integer.parseInt(charset))) {
                    c.write(c.writeToBuffer(OkPacket.OK, c.allocate()));
                } else {
                    c.writeErrMessage(ErrorCode.ER_UNKNOWN_CHARACTER_SET, "Unknown charset :" + charset);
                }
            } catch (RuntimeException e) {
                c.writeErrMessage(ErrorCode.ER_UNKNOWN_CHARACTER_SET, "Unknown charset :" + charset);
            }
        }
    }

}