content: /*
   * Copyright (C) 2016-2023 ActionTech.
   * based on code by MyCATCopyrightHolder Copyright (c) 2013, OpenCloudDB/MyCAT.
   * License: http://www.gnu.org/licenses/gpl.html GPL version 2 or higher.
   */
  package com.actiontech.dble.server.response;
  
  import com.actiontech.dble.DbleServer;
  import com.actiontech.dble.backend.mysql.PacketUtil;
  import com.actiontech.dble.config.Fields;
  import com.actiontech.dble.net.mysql.*;
  import com.actiontech.dble.services.mysqlsharding.ShardingService;
  import com.actiontech.dble.util.StringUtil;
  
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * @author mycat
   */
  public final class SelectUser implements InnerFuncResponse {
  
      private static final int FIELD_COUNT = 1;
      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();
      private static final ErrorPacket ERROR = PacketUtil.getShutdown();
  
      public static void response(ShardingService service) {
          if (DbleServer.getInstance().isOnline()) {
              HEADER.setPacketId(service.nextPacketId());
              FIELDS[0] = PacketUtil.getField("USER()", Fields.FIELD_TYPE_VAR_STRING);
              FIELDS[0].setPacketId(service.nextPacketId());
              EOF.setPacketId(service.nextPacketId());
  
              ByteBuffer buffer = service.allocate();
              buffer = HEADER.write(buffer, service, true);
              for (FieldPacket field : FIELDS) {
                  buffer = field.write(buffer, service, true);
              }
              buffer = EOF.write(buffer, service, true);
  
              RowDataPacket row = new RowDataPacket(FIELD_COUNT);
              row.add(getUser(service));
              row.setPacketId(service.nextPacketId());
              buffer = row.write(buffer, service, true);
              EOFRowPacket lastEof = new EOFRowPacket();
              lastEof.setPacketId(service.nextPacketId());
              lastEof.write(buffer, service);
          } else {
              ERROR.write(service.getConnection());
          }
      }
  
      private static byte[] getUser(ShardingService service) {
          return StringUtil.encode(service.getUser().getFullName() + '@' + service.getConnection().getHost(), service.getCharset().getResults());
      }
  
  
      public List<FieldPacket> getField() {
          List<FieldPacket> result = new ArrayList<>();
          result.add(PacketUtil.getField("USER()", Fields.FIELD_TYPE_VAR_STRING));
          return result;
      }
  
      public List<RowDataPacket> getRows(ShardingService service) {
          List<RowDataPacket> result = new ArrayList<>();
          RowDataPacket row = new RowDataPacket(FIELD_COUNT);
          row.add(getUser(service));
          result.add(row);
          return result;
      }
  }
  