content: /*
   * Copyright (C) 2016-2023 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.DbleServer;
  import com.actiontech.dble.backend.mysql.PacketUtil;
  import com.actiontech.dble.config.Fields;
  import com.actiontech.dble.net.IOProcessor;
  import com.actiontech.dble.net.connection.BackendConnection;
  import com.actiontech.dble.net.connection.FrontendConnection;
  import com.actiontech.dble.net.mysql.*;
  import com.actiontech.dble.net.service.AbstractService;
  import com.actiontech.dble.rwsplit.RWSplitNonBlockingSession;
  import com.actiontech.dble.server.NonBlockingSession;
  import com.actiontech.dble.services.manager.ManagerService;
  import com.actiontech.dble.services.mysqlsharding.ShardingService;
  import com.actiontech.dble.services.rwsplit.RWSplitService;
  import com.actiontech.dble.util.StringUtil;
  
  import java.nio.ByteBuffer;
  import java.util.Collection;
  import java.util.Objects;
  
  /**
   * show front session detail info
   *
   * @author wuzhih
   */
  public final class ShowSession {
      private ShowSession() {
      }
  
      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("FRONT_ID", Fields.FIELD_TYPE_VARCHAR);
          FIELDS[i++].setPacketId(++packetId);
  
          FIELDS[i] = PacketUtil.getField("DN_COUNT", Fields.FIELD_TYPE_VARCHAR);
          FIELDS[i++].setPacketId(++packetId);
  
          FIELDS[i] = PacketUtil.getField("DN_LIST", 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();
          for (IOProcessor process : DbleServer.getInstance().getFrontProcessors()) {
              for (FrontendConnection front : process.getFrontends().values()) {
                  if (front.isManager()) {
                      continue;
                  }
                  RowDataPacket row = getRow(front.getService(), service.getCharset().getResults());
                  if (row != null) {
                      row.setPacketId(++packetId);
                      buffer = row.write(buffer, service, true);
                  }
              }
          }
  
          // write last eof
          EOFRowPacket lastEof = new EOFRowPacket();
          lastEof.setPacketId(++packetId);
  
  
          lastEof.write(buffer, service);
      }
  
      private static RowDataPacket getRow(AbstractService sc, String charset) {
          if (sc instanceof ShardingService) {
              return getRow((ShardingService) sc, charset);
          } else if (sc instanceof RWSplitService) {
              return getRow((RWSplitService) sc, charset);
          } else {
              return null;
          }
      }
  
      private static RowDataPacket getRow(ShardingService sc, String charset) {
          StringBuilder sb = new StringBuilder();
          NonBlockingSession session = sc.getSession2();
          Collection<BackendConnection> backConnections = session.getTargetMap().values();
          int cnCount = backConnections.size();
          if (cnCount == 0) {
              return null;
          }
          for (BackendConnection backCon : backConnections) {
              sb.append(backCon.toString2()).append("\r\n");
          }
          return createRowDataPacket(FIELD_COUNT, sc.getConnection().getId(), cnCount, sb.toString(), charset);
      }
  
      private static RowDataPacket getRow(RWSplitService sc, String charset) {
          StringBuilder sb = new StringBuilder();
          RWSplitNonBlockingSession session = sc.getSession2();
          BackendConnection backendConnection = session.getConn();
          if (Objects.isNull(backendConnection)) {
              return null;
          }
          sb.append(backendConnection);
          return createRowDataPacket(FIELD_COUNT, sc.getConnection().getId(), 1, sb.toString(), charset);
      }
  
      private static RowDataPacket createRowDataPacket(int fieldCount, long id, int cnCount, String sb, String charset) {
          RowDataPacket row = new RowDataPacket(fieldCount);
          row.add(StringUtil.encode(String.valueOf(id), charset));
          row.add(StringUtil.encode(String.valueOf(cnCount), charset));
          row.add(StringUtil.encode(sb, charset));
          return row;
      }
  }
  