/*
    * 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.connector.jdbc.statement;
  
  import org.apache.shardingsphere.db.protocol.parameter.TypeUnspecifiedSQLParameter;
  import org.apache.shardingsphere.infra.database.core.spi.DatabaseTypedSPILoader;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.executor.sql.context.ExecutionUnit;
  import org.apache.shardingsphere.infra.executor.sql.execute.engine.ConnectionMode;
  import org.apache.shardingsphere.infra.executor.sql.prepare.driver.jdbc.ExecutorJDBCStatementManager;
  import org.apache.shardingsphere.infra.executor.sql.prepare.driver.jdbc.StatementOption;
  
  import java.sql.Connection;
  import java.sql.PreparedStatement;
  import java.sql.SQLException;
  import java.sql.Statement;
  import java.sql.Types;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Optional;
  
  /**
   * JDBC backend statement.
   */
  public final class JDBCBackendStatement implements ExecutorJDBCStatementManager {
      
      @Override
      public Statement createStorageResource(final Connection connection, final ConnectionMode connectionMode, final StatementOption option, final DatabaseType databaseType) throws SQLException {
          Statement result = connection.createStatement();
          if (ConnectionMode.MEMORY_STRICTLY == connectionMode) {
              setFetchSize(result, databaseType);
          }
          return result;
      }
      
      @Override
      public Statement createStorageResource(final ExecutionUnit executionUnit, final Connection connection, final ConnectionMode connectionMode, final StatementOption option,
                                             final DatabaseType databaseType) throws SQLException {
          String sql = executionUnit.getSqlUnit().getSql();
          List<Object> params = executionUnit.getSqlUnit().getParameters();
          PreparedStatement result = option.isReturnGeneratedKeys()
                  ? connection.prepareStatement(executionUnit.getSqlUnit().getSql(), Statement.RETURN_GENERATED_KEYS)
                  : connection.prepareStatement(sql);
          Iterator<Object> paramIterator = params.iterator();
          int index = 0;
          while (paramIterator.hasNext()) {
              Object param = paramIterator.next();
              if (param instanceof TypeUnspecifiedSQLParameter) {
                  result.setObject(index + 1, param, Types.OTHER);
              } else {
                  result.setObject(index + 1, param);
              }
              index++;
          }
          if (ConnectionMode.MEMORY_STRICTLY == connectionMode) {
              setFetchSize(result, databaseType);
          }
          return result;
      }
      
      private void setFetchSize(final Statement statement, final DatabaseType databaseType) throws SQLException {
          Optional<StatementMemoryStrictlyFetchSizeSetter> fetchSizeSetter = DatabaseTypedSPILoader.findService(StatementMemoryStrictlyFetchSizeSetter.class, databaseType);
          if (fetchSizeSetter.isPresent()) {
              fetchSizeSetter.get().setFetchSize(statement);
          }
      }
  }