/*
 * Copyright (C) 2016-2022 ActionTech.
 * License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
 */

package com.actiontech.dble.services.manager.response;

import com.actiontech.dble.backend.mysql.PacketUtil;
import com.actiontech.dble.config.Fields;
import com.actiontech.dble.config.model.ParamInfo;
import com.actiontech.dble.net.mysql.*;
import com.actiontech.dble.services.manager.ManagerService;
import com.actiontech.dble.singleton.SystemParams;
import com.actiontech.dble.util.StringUtil;

import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;

/**
 * show Sysconfig param detail info
 *
 * @author rainbow
 */
public final class ShowSysParam {
    private ShowSysParam() {
    }

    private static final int FIELD_COUNT = 3;
    private static final ResultSetHeaderPacket HEADER = PacketUtil.getHeader(FIELD_COUNT);
    private static final FieldPacket[] FIELDS = new FieldPacket[FIELD_COUNT];
    private static final EOFPacket EOF = new EOFPacket();

    static {
        int i = 0;
        byte packetId = 0;
        HEADER.setPacketId(++packetId);

        FIELDS[i] = PacketUtil.getField("PARAM_NAME", Fields.FIELD_TYPE_VARCHAR);
        FIELDS[i++].setPacketId(++packetId);

        FIELDS[i] = PacketUtil.getField("PARAM_VALUE", Fields.FIELD_TYPE_VARCHAR);
        FIELDS[i++].setPacketId(++packetId);

        FIELDS[i] = PacketUtil.getField("PARAM_DESCR", Fields.FIELD_TYPE_VARCHAR);
        FIELDS[i].setPacketId(++packetId);

        EOF.setPacketId(++packetId);
    }

    public static void execute(ManagerService service) {
        ByteBuffer buffer = service.allocate();

        // write header
        buffer = HEADER.write(buffer, service, true);

        // write fields
        for (FieldPacket field : FIELDS) {
            buffer = field.write(buffer, service, true);
        }

        // write eof
        buffer = EOF.write(buffer, service, true);

        // write rows
        byte packetId = EOF.getPacketId();
        List<ParamInfo> params = new ArrayList<>();
        params.addAll(SystemParams.getInstance().getReadOnlyParams());
        params.addAll(SystemParams.getInstance().getVolatileParams());
        for (ParamInfo info : params) {
            RowDataPacket row = new RowDataPacket(FIELD_COUNT);
            row.add(StringUtil.encode(info.getName(), service.getCharset().getResults()));
            row.add(StringUtil.encode(info.getValue(), service.getCharset().getResults()));
            row.add(StringUtil.encode(info.getComment(), service.getCharset().getResults()));
            row.setPacketId(++packetId);
            buffer = row.write(buffer, service, true);
        }

        // write last eof
        EOFRowPacket lastEof = new EOFRowPacket();
        lastEof.setPacketId(++packetId);


        lastEof.write(buffer, service);
    }
}
