/*
    * 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.encrypt.merge.dql;
  
  import lombok.RequiredArgsConstructor;
  import org.apache.shardingsphere.encrypt.exception.data.DecryptFailedException;
  import org.apache.shardingsphere.encrypt.rule.EncryptRule;
  import org.apache.shardingsphere.encrypt.rule.column.EncryptColumn;
  import org.apache.shardingsphere.infra.binder.context.segment.select.projection.impl.ColumnProjection;
  import org.apache.shardingsphere.infra.binder.context.statement.dml.SelectStatementContext;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseTypeRegistry;
  import org.apache.shardingsphere.infra.exception.core.external.sql.identifier.SQLExceptionIdentifier;
  import org.apache.shardingsphere.infra.merge.result.MergedResult;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  
  import java.io.InputStream;
  import java.io.Reader;
  import java.sql.SQLException;
  import java.util.Calendar;
  import java.util.Optional;
  
  /**
   * Merged result for encrypt.
   */
  @RequiredArgsConstructor
  public final class EncryptMergedResult implements MergedResult {
      
      private final ShardingSphereDatabase database;
      
      private final EncryptRule encryptRule;
      
      private final SelectStatementContext selectStatementContext;
      
      private final MergedResult mergedResult;
      
      @Override
      public boolean next() throws SQLException {
          return mergedResult.next();
      }
      
      @Override
      public Object getValue(final int columnIndex, final Class<?> type) throws SQLException {
          Optional<ColumnProjection> columnProjection = selectStatementContext.findColumnProjection(columnIndex);
          if (!columnProjection.isPresent()) {
              return mergedResult.getValue(columnIndex, type);
          }
          String originalTableName = columnProjection.get().getOriginalTable().getValue();
          String originalColumnName = columnProjection.get().getOriginalColumn().getValue();
          if (!encryptRule.findEncryptTable(originalTableName).map(optional -> optional.isEncryptColumn(originalColumnName)).orElse(false)) {
              return mergedResult.getValue(columnIndex, type);
          }
          Object cipherValue = mergedResult.getValue(columnIndex, Object.class);
          EncryptColumn encryptColumn = encryptRule.getEncryptTable(originalTableName).getEncryptColumn(originalColumnName);
          String schemaName =
                  selectStatementContext.getTablesContext().getSchemaName().orElseGet(() -> new DatabaseTypeRegistry(selectStatementContext.getDatabaseType()).getDefaultSchemaName(database.getName()));
          try {
              return encryptColumn.getCipher().decrypt(database.getName(), schemaName, originalTableName, originalColumnName, cipherValue);
              // CHECKSTYLE:OFF
          } catch (final Exception ex) {
              // CHECKSTYLE:ON
              throw new DecryptFailedException(String.valueOf(cipherValue), new SQLExceptionIdentifier(database.getName(), originalTableName, originalColumnName), ex);
          }
      }
      
      @Override
      public Object getCalendarValue(final int columnIndex, final Class<?> type, final Calendar calendar) throws SQLException {
          return mergedResult.getCalendarValue(columnIndex, type, calendar);
      }
      
      @Override
      public InputStream getInputStream(final int columnIndex, final String type) throws SQLException {
          return mergedResult.getInputStream(columnIndex, type);
      }
      
      @Override
      public Reader getCharacterStream(final int columnIndex) throws SQLException {
          return mergedResult.getCharacterStream(columnIndex);
      }
      
      @Override
      public boolean wasNull() throws SQLException {
          return mergedResult.wasNull();
      }
  }