/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.shardingsphere.proxy.backend.session;
  
  import io.netty.util.AttributeMap;
  import lombok.AccessLevel;
  import lombok.Getter;
  import lombok.Setter;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.executor.sql.prepare.driver.ExecutorStatementManager;
  import org.apache.shardingsphere.infra.metadata.user.Grantee;
  import org.apache.shardingsphere.infra.session.connection.ConnectionContext;
  import org.apache.shardingsphere.infra.session.query.QueryContext;
  import org.apache.shardingsphere.proxy.backend.connector.ProxyDatabaseConnectionManager;
  import org.apache.shardingsphere.proxy.backend.connector.jdbc.statement.JDBCBackendStatement;
  import org.apache.shardingsphere.proxy.backend.session.transaction.TransactionStatus;
  import org.apache.shardingsphere.sql.parser.statement.core.enums.TransactionIsolationLevel;
  
  import java.util.Optional;
  import java.util.concurrent.atomic.AtomicReference;
  
  /**
   * Connection session.
   */
  @Getter
  @Setter
  public final class ConnectionSession {
      
      private final DatabaseType protocolType;
      
      @Setter(AccessLevel.NONE)
      private volatile String currentDatabaseName;
      
      private volatile int connectionId;
      
      private final TransactionStatus transactionStatus;
      
      private final AttributeMap attributeMap;
      
      private volatile boolean autoCommit = true;
      
      private volatile boolean readOnly;
      
      private TransactionIsolationLevel defaultIsolationLevel;
      
      private TransactionIsolationLevel isolationLevel;
      
      private final ProxyDatabaseConnectionManager databaseConnectionManager;
      
      @SuppressWarnings("rawtypes")
      private final ExecutorStatementManager statementManager;
      
      private final ServerPreparedStatementRegistry serverPreparedStatementRegistry = new ServerPreparedStatementRegistry();
      
      private final AtomicReference<ConnectionContext> connectionContext = new AtomicReference<>();
      
      private final RequiredSessionVariableRecorder requiredSessionVariableRecorder = new RequiredSessionVariableRecorder();
      
      private volatile String processId;
      
      private QueryContext queryContext;
      
      public ConnectionSession(final DatabaseType protocolType, final AttributeMap attributeMap) {
          this.protocolType = protocolType;
          transactionStatus = new TransactionStatus();
          this.attributeMap = attributeMap;
          databaseConnectionManager = new ProxyDatabaseConnectionManager(this);
          statementManager = new JDBCBackendStatement();
      }
      
      /**
       * Set grantee.
       *
       * @param grantee grantee
       */
      public void setGrantee(final Grantee grantee) {
          connectionContext.set(new ConnectionContext(databaseConnectionManager::getUsedDataSourceNames, grantee));
      }
      
      /**
       * Change database of current channel.
       *
       * @param currentDatabaseName current database name
       */
     public void setCurrentDatabaseName(final String currentDatabaseName) {
         if (null == currentDatabaseName || !currentDatabaseName.equals(this.currentDatabaseName)) {
             this.currentDatabaseName = currentDatabaseName;
             connectionContext.get().setCurrentDatabaseName(currentDatabaseName);
         }
     }
     
     /**
      * Get connection context.
      *
      * @return connection context
      */
     public ConnectionContext getConnectionContext() {
         return connectionContext.get();
     }
     
     /**
      * Get used database name.
      *
      * @return used database name
      */
     public String getUsedDatabaseName() {
         return null == queryContext || queryContext.getUsedDatabaseNames().isEmpty() ? currentDatabaseName : queryContext.getUsedDatabaseNames().iterator().next();
     }
     
     /**
      * Get isolation level.
      *
      * @return isolation level
      */
     public Optional<TransactionIsolationLevel> getIsolationLevel() {
         return Optional.ofNullable(isolationLevel);
     }
     
     /**
      * Clear query context.
      */
     public void clearQueryContext() {
         queryContext = null;
     }
 }