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.ErrorCode;
  import com.actiontech.dble.config.Fields;
  import com.actiontech.dble.config.model.sharding.SchemaConfig;
  import com.actiontech.dble.config.model.sharding.table.BaseTableConfig;
  import com.actiontech.dble.config.model.sharding.table.SingleTableConfig;
  import com.actiontech.dble.net.mysql.*;
  import com.actiontech.dble.services.manager.ManagerService;
  import com.actiontech.dble.sqlengine.OneRawSQLQueryResultHandler;
  import com.actiontech.dble.sqlengine.SQLJob;
  import com.actiontech.dble.sqlengine.SQLQueryResult;
  import com.actiontech.dble.sqlengine.SQLQueryResultListener;
  import com.actiontech.dble.util.IntegerUtil;
  import com.actiontech.dble.util.StringUtil;
  import com.google.common.base.Strings;
  
  import java.nio.ByteBuffer;
  import java.util.Map;
  import java.util.TreeMap;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.locks.Condition;
  import java.util.concurrent.locks.ReentrantLock;
  
  public final class ShowDataDistribution {
      private ShowDataDistribution() {
      }
  
      private static final int FIELD_COUNT = 2;
      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("SHARDING_NODE", Fields.FIELD_TYPE_VAR_STRING);
          FIELDS[i++].setPacketId(++packetId);
          FIELDS[i] = PacketUtil.getField("COUNT", Fields.FIELD_TYPE_LONG);
          FIELDS[i].setPacketId(++packetId);
  
          EOF.setPacketId(++packetId);
      }
  
      public static void execute(ManagerService service, String name) {
          if (!name.startsWith("'") || !name.endsWith("'")) {
              service.writeErrMessage(ErrorCode.ER_YES, "The query should be show @@data_distribution where table ='schema.table'");
              return;
          }
          if (DbleServer.getInstance().getSystemVariables().isLowerCaseTableNames()) {
              name = name.toLowerCase();
          }
          String[] schemaInfo = name.substring(1, name.length() - 1).split("\\.");
          if (schemaInfo.length != 2) {
              service.writeErrMessage(ErrorCode.ER_YES, "The query should be show @@data_distribution where table ='schema.table'");
              return;
          }
          SchemaConfig schemaConfig = DbleServer.getInstance().getConfig().getSchemas().get(schemaInfo[0]);
          if (schemaConfig == null) {
              service.writeErrMessage(ErrorCode.ER_YES, "The schema " + schemaInfo[0] + " doesn't exist");
              return;
          } else if (schemaConfig.isNoSharding()) {
              service.writeErrMessage(ErrorCode.ER_YES, "The schema " + schemaInfo[0] + " is no sharding schema");
              return;
          }
          BaseTableConfig tableConfig = schemaConfig.getTables().get(schemaInfo[1]);
          if (tableConfig == null) {
              final String defaultSingleShardingNode = getDefaultSingleShardingNode(schemaConfig);
              if (defaultSingleShardingNode == null) {
                  service.writeErrMessage(ErrorCode.ER_YES, "The table " + name + " doesn't exist");
              } else {
                  parserAndExecuteShowTables(service, defaultSingleShardingNode, schemaInfo[1], name);
              }
              return;
          } else if (tableConfig instanceof SingleTableConfig) {
              service.writeErrMessage(ErrorCode.ER_YES, "The table " + name + " is Single table");
              return;
          }
          ReentrantLock lock = new ReentrantLock();
          Condition cond = lock.newCondition();
          Map<String, Integer> results = new ConcurrentHashMap<>();
          AtomicBoolean succeed = new AtomicBoolean(true);
          for (String shardingNode : tableConfig.getShardingNodes()) {
              OneRawSQLQueryResultHandler resultHandler = new OneRawSQLQueryResultHandler(new String[]{"COUNT"}, new ShowDataDistributionListener(shardingNode, lock, cond, results, succeed));
              SQLJob sqlJob = new SQLJob("SELECT COUNT(*) AS COUNT FROM " + schemaInfo[1], shardingNode, resultHandler, true);
              sqlJob.run();
          }
          lock.lock();
          try {
              while (results.size() != tableConfig.getShardingNodes().size()) {
                  cond.await();
              }
          } catch (InterruptedException e) {
              service.writeErrMessage(ErrorCode.ER_YES, "occur InterruptedException, so try again later ");
              return;
          } finally {
              lock.unlock();
          }
  
          if (!succeed.get()) {
              service.writeErrMessage(ErrorCode.ER_YES, "occur Exception, so see dble.log to check reason");
              return;
          }
          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();
          Map<String, Integer> orderResults = new TreeMap<>(results);
  
          for (Map.Entry<String, Integer> entry : orderResults.entrySet()) {
              RowDataPacket row = new RowDataPacket(FIELD_COUNT);
              row.add(StringUtil.encode(entry.getKey(), service.getCharset().getResults()));
              row.add(IntegerUtil.toBytes(entry.getValue()));
              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 String getDefaultSingleShardingNode(SchemaConfig schema) {
          String node = schema.getDefaultSingleNode();
          return Strings.isNullOrEmpty(node) ? null : node;
      }
  
      private static void parserAndExecuteShowTables(ManagerService service, String shardingNode, String tableName, String fullName) {
          OneRawSQLQueryResultHandler resultHandler = new OneRawSQLQueryResultHandler(new String[0], new CheckNoShardingTableExistListener(service, fullName));
          SQLJob sqlJob = new SQLJob("show tables like  '" + tableName + "'", shardingNode, resultHandler, false);
          sqlJob.run();
      }
  
      private static final class CheckNoShardingTableExistListener implements SQLQueryResultListener<SQLQueryResult<Map<String, String>>> {
          ManagerService service;
          String fullName;
  
          private CheckNoShardingTableExistListener(ManagerService service, String fullName) {
              this.service = service;
              this.fullName = fullName;
          }
  
          @Override
          public void onResult(SQLQueryResult<Map<String, String>> result) {
              if (!result.isSuccess()) {
                  service.writeErrMessage(ErrorCode.ER_UNKNOWN_ERROR, "check NoSharding query failed.");
              } else {
                  if (result.isZeroRow()) {
                      service.writeErrMessage(ErrorCode.ER_YES, "The table " + fullName + " doesn't exist");
                  } else {
                      service.writeErrMessage(ErrorCode.ER_YES, "The table " + fullName + " is NoSharding table");
                  }
              }
          }
      }
  
  
      private static class ShowDataDistributionListener implements SQLQueryResultListener<SQLQueryResult<Map<String, String>>> {
          private ReentrantLock lock;
          private Condition cond;
          private Map<String, Integer> results;
          private AtomicBoolean succeed;
          private String shardingNode;
  
          ShowDataDistributionListener(String shardingNode, ReentrantLock lock, Condition cond, Map<String, Integer> results, AtomicBoolean succeed) {
              this.shardingNode = shardingNode;
              this.lock = lock;
              this.cond = cond;
              this.results = results;
              this.succeed = succeed;
  
          }
  
          @Override
          public void onResult(SQLQueryResult<Map<String, String>> result) {
              if (!result.isSuccess()) {
                  succeed.set(false);
                  results.put(shardingNode, 0);
              } else {
                  String count = result.getResult().get("COUNT");
                  results.put(shardingNode, Integer.valueOf(count));
              }
              lock.lock();
              try {
                  cond.signal();
              } finally {
                  lock.unlock();
              }
          }
      }
  }
  