/*
    * 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.distsql.handler.update;
  
  import lombok.Setter;
  import org.apache.shardingsphere.distsql.handler.engine.update.rdl.rule.spi.database.DatabaseRuleAlterExecutor;
  import org.apache.shardingsphere.distsql.handler.required.DistSQLExecutorCurrentRuleRequired;
  import org.apache.shardingsphere.distsql.segment.AlgorithmSegment;
  import org.apache.shardingsphere.encrypt.config.EncryptRuleConfiguration;
  import org.apache.shardingsphere.encrypt.distsql.handler.converter.EncryptRuleStatementConverter;
  import org.apache.shardingsphere.encrypt.distsql.segment.EncryptRuleSegment;
  import org.apache.shardingsphere.encrypt.distsql.statement.AlterEncryptRuleStatement;
  import org.apache.shardingsphere.encrypt.rule.EncryptRule;
  import org.apache.shardingsphere.encrypt.spi.EncryptAlgorithm;
  import org.apache.shardingsphere.infra.algorithm.core.config.AlgorithmConfiguration;
  import org.apache.shardingsphere.infra.exception.core.ShardingSpherePreconditions;
  import org.apache.shardingsphere.infra.exception.kernel.metadata.rule.InvalidRuleConfigurationException;
  import org.apache.shardingsphere.infra.exception.kernel.metadata.rule.MissingRequiredRuleException;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  import org.apache.shardingsphere.infra.spi.type.typed.TypedSPILoader;
  
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.LinkedHashSet;
  import java.util.Map;
  import java.util.Objects;
  import java.util.stream.Collectors;
  
  /**
   * Alter encrypt rule executor.
   */
  @DistSQLExecutorCurrentRuleRequired(EncryptRule.class)
  @Setter
  public final class AlterEncryptRuleExecutor implements DatabaseRuleAlterExecutor<AlterEncryptRuleStatement, EncryptRule, EncryptRuleConfiguration> {
      
      private ShardingSphereDatabase database;
      
      private EncryptRule rule;
      
      @Override
      public void checkBeforeUpdate(final AlterEncryptRuleStatement sqlStatement) {
          checkToBeAlteredRules(sqlStatement);
          checkColumnNames(sqlStatement);
          checkToBeAlteredEncryptors(sqlStatement);
      }
      
      private void checkToBeAlteredRules(final AlterEncryptRuleStatement sqlStatement) {
          Collection<String> notExistEncryptTableNames = getToBeAlteredEncryptTableNames(sqlStatement).stream().filter(each -> !rule.getAllTableNames().contains(each)).collect(Collectors.toList());
          ShardingSpherePreconditions.checkMustEmpty(notExistEncryptTableNames, () -> new MissingRequiredRuleException("Encrypt", database.getName(), notExistEncryptTableNames));
      }
      
      private Collection<String> getToBeAlteredEncryptTableNames(final AlterEncryptRuleStatement sqlStatement) {
          return sqlStatement.getRules().stream().map(EncryptRuleSegment::getTableName).collect(Collectors.toList());
      }
      
      private void checkColumnNames(final AlterEncryptRuleStatement sqlStatement) {
          for (EncryptRuleSegment each : sqlStatement.getRules()) {
              ShardingSpherePreconditions.checkState(isColumnNameNotConflicts(each),
                      () -> new InvalidRuleConfigurationException("encrypt", "assisted query column or like query column conflicts with logic column"));
          }
      }
      
      private boolean isColumnNameNotConflicts(final EncryptRuleSegment rule) {
          return rule.getColumns().stream().noneMatch(each -> null != each.getLikeQuery() && each.getName().equals(each.getLikeQuery().getName())
                  || null != each.getAssistedQuery() && each.getName().equals(each.getAssistedQuery().getName()));
      }
      
      private void checkToBeAlteredEncryptors(final AlterEncryptRuleStatement sqlStatement) {
          Collection<AlgorithmSegment> encryptors = new LinkedHashSet<>();
          sqlStatement.getRules().forEach(each -> each.getColumns().forEach(column -> {
              encryptors.add(column.getCipher().getEncryptor());
              if (null != column.getAssistedQuery()) {
                  encryptors.add(column.getAssistedQuery().getEncryptor());
              }
              if (null != column.getLikeQuery()) {
                  encryptors.add(column.getLikeQuery().getEncryptor());
              }
          }));
          encryptors.stream().filter(Objects::nonNull).forEach(each -> TypedSPILoader.checkService(EncryptAlgorithm.class, each.getName(), each.getProps()));
      }
      
      @Override
      public EncryptRuleConfiguration buildToBeAlteredRuleConfiguration(final AlterEncryptRuleStatement sqlStatement) {
         return EncryptRuleStatementConverter.convert(sqlStatement.getRules());
     }
     
     @Override
     public EncryptRuleConfiguration buildToBeDroppedRuleConfiguration(final EncryptRuleConfiguration toBeAlteredRuleConfig) {
         Collection<String> unusedEncryptor = UnusedAlgorithmFinder.findUnusedEncryptor(rule.getConfiguration());
         Map<String, AlgorithmConfiguration> toBeDroppedEncryptors = new HashMap<>(unusedEncryptor.size(), 1F);
         unusedEncryptor.forEach(each -> toBeDroppedEncryptors.put(each, rule.getConfiguration().getEncryptors().get(each)));
         return new EncryptRuleConfiguration(Collections.emptyList(), toBeDroppedEncryptors);
     }
     
     @Override
     public Class<EncryptRule> getRuleClass() {
         return EncryptRule.class;
     }
     
     @Override
     public Class<AlterEncryptRuleStatement> getType() {
         return AlterEncryptRuleStatement.class;
     }
 }