/*
    * 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.driver.jdbc.core.statement;
  
  import lombok.EqualsAndHashCode;
  import lombok.RequiredArgsConstructor;
  import org.apache.shardingsphere.driver.jdbc.adapter.executor.ForceExecuteTemplate;
  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.SQLFeatureNotSupportedException;
  import java.sql.Statement;
  import java.util.Map;
  import java.util.Optional;
  import java.util.concurrent.ConcurrentHashMap;
  
  /**
   * Statement manager.
   */
  public final class StatementManager implements ExecutorJDBCStatementManager, AutoCloseable {
      
      private final Map<CacheKey, Statement> cachedStatements = new ConcurrentHashMap<>();
      
      private final ForceExecuteTemplate<Statement> forceExecuteTemplate = new ForceExecuteTemplate<>();
      
      @Override
      public Statement createStorageResource(final Connection connection, final ConnectionMode connectionMode, final StatementOption option, final DatabaseType databaseType) throws SQLException {
          return createStatement(connection, option);
      }
      
      @Override
      public Statement createStorageResource(final ExecutionUnit executionUnit, final Connection connection, final int connectionOffset,
                                             final ConnectionMode connectionMode, final StatementOption option, final DatabaseType databaseType) throws SQLException {
          CacheKey cacheKey = new CacheKey(executionUnit, connectionMode, connectionOffset);
          Statement result = cachedStatements.get(cacheKey);
          if (null == result || result.getConnection().isClosed() || result.isClosed()) {
              Optional.ofNullable(result).ifPresent(optional -> cachedStatements.remove(cacheKey));
              result = prepareStatement(executionUnit, connection, option);
              cachedStatements.put(cacheKey, result);
          }
          return result;
      }
      
      @SuppressWarnings("MagicConstant")
      private Statement createStatement(final Connection connection, final StatementOption option) throws SQLException {
          Statement result;
          try {
              result = connection.createStatement(option.getResultSetType(), option.getResultSetConcurrency(), option.getResultSetHoldability());
          } catch (final SQLFeatureNotSupportedException ignore) {
              result = connection.createStatement();
          }
          return result;
      }
      
      private PreparedStatement prepareStatement(final ExecutionUnit executionUnit, final Connection connection, final StatementOption option) throws SQLException {
          PreparedStatement result;
          String sql = executionUnit.getSqlUnit().getSql();
          if (option.isReturnGeneratedKeys()) {
              result = null == option.getColumns() || 0 == option.getColumns().length
                      ? connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)
                      : connection.prepareStatement(sql, option.getColumns());
          } else {
              result = prepareStatement(connection, sql, option.getResultSetType(), option.getResultSetConcurrency(), option.getResultSetHoldability());
          }
          return result;
      }
      
      private PreparedStatement prepareStatement(final Connection connection, final String sql, final int resultSetType, final int resultSetConcurrency,
                                                 final int resultSetHoldability) throws SQLException {
          PreparedStatement result;
          try {
              result = connection.prepareStatement(sql, resultSetType, resultSetConcurrency, resultSetHoldability);
          } catch (final SQLFeatureNotSupportedException ignore) {
              result = connection.prepareStatement(sql);
          }
          return result;
      }
      
     @Override
     public void close() throws SQLException {
         try {
             forceExecuteTemplate.execute(cachedStatements.values(), Statement::close);
         } finally {
             cachedStatements.clear();
         }
     }
     
     @RequiredArgsConstructor
     @EqualsAndHashCode
     private static final class CacheKey {
         
         private final ExecutionUnit executionUnit;
         
         private final ConnectionMode connectionMode;
         
         private final int connectionOffset;
     }
 }