/*
    * 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.sharding.distsql.handler.update;
  
  import com.cedarsoftware.util.CaseInsensitiveSet;
  import lombok.Setter;
  import org.apache.shardingsphere.distsql.handler.engine.update.rdl.rule.spi.database.DatabaseRuleAlterExecutor;
  import org.apache.shardingsphere.infra.exception.kernel.metadata.rule.DuplicateRuleException;
  import org.apache.shardingsphere.infra.exception.kernel.metadata.rule.InvalidRuleConfigurationException;
  import org.apache.shardingsphere.infra.exception.kernel.metadata.rule.MissingRequiredRuleException;
  import org.apache.shardingsphere.distsql.handler.required.DistSQLExecutorCurrentRuleRequired;
  import org.apache.shardingsphere.infra.exception.core.ShardingSpherePreconditions;
  import org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase;
  import org.apache.shardingsphere.sharding.api.config.ShardingRuleConfiguration;
  import org.apache.shardingsphere.sharding.api.config.rule.ShardingAutoTableRuleConfiguration;
  import org.apache.shardingsphere.sharding.api.config.rule.ShardingTableReferenceRuleConfiguration;
  import org.apache.shardingsphere.sharding.api.config.rule.ShardingTableRuleConfiguration;
  import org.apache.shardingsphere.sharding.distsql.handler.checker.ShardingTableRuleStatementChecker;
  import org.apache.shardingsphere.sharding.distsql.segment.table.TableReferenceRuleSegment;
  import org.apache.shardingsphere.sharding.distsql.statement.AlterShardingTableReferenceRuleStatement;
  import org.apache.shardingsphere.sharding.rule.ShardingRule;
  
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.stream.Collectors;
  
  /**
   * Alter sharding table reference rule executor.
   */
  @DistSQLExecutorCurrentRuleRequired(ShardingRule.class)
  @Setter
  public final class AlterShardingTableReferenceRuleExecutor implements DatabaseRuleAlterExecutor<AlterShardingTableReferenceRuleStatement, ShardingRule, ShardingRuleConfiguration> {
      
      private ShardingSphereDatabase database;
      
      private ShardingRule rule;
      
      @Override
      public void checkBeforeUpdate(final AlterShardingTableReferenceRuleStatement sqlStatement) {
          checkToBeAlteredRulesExisted(sqlStatement);
          checkDuplicatedTablesInShardingTableReferenceRules(sqlStatement);
          checkToBeReferencedShardingTablesExisted(sqlStatement);
          checkShardingTableReferenceRulesValid(sqlStatement);
      }
      
      private void checkToBeAlteredRulesExisted(final AlterShardingTableReferenceRuleStatement sqlStatement) {
          Collection<String> currentRuleNames = rule.getConfiguration().getBindingTableGroups().stream().map(ShardingTableReferenceRuleConfiguration::getName).collect(Collectors.toSet());
          Collection<String> notExistedRuleNames = sqlStatement.getRules().stream().map(TableReferenceRuleSegment::getName).filter(each -> !currentRuleNames.contains(each)).collect(Collectors.toSet());
          ShardingSpherePreconditions.checkMustEmpty(notExistedRuleNames, () -> new MissingRequiredRuleException("Sharding table reference", database.getName(), notExistedRuleNames));
      }
      
      private void checkDuplicatedTablesInShardingTableReferenceRules(final AlterShardingTableReferenceRuleStatement sqlStatement) {
          Collection<String> currentReferencedTableNames = getReferencedTableNames(getToBeAlteredRuleNames(sqlStatement));
          Collection<String> duplicatedTableNames = sqlStatement.getTableNames().stream().filter(currentReferencedTableNames::contains).collect(Collectors.toSet());
          ShardingSpherePreconditions.checkMustEmpty(duplicatedTableNames, () -> new DuplicateRuleException("sharding table reference", database.getName(), duplicatedTableNames));
      }
      
      private Collection<String> getReferencedTableNames(final Collection<String> getToBeAlteredRuleNames) {
          Collection<String> result = new HashSet<>();
          rule.getConfiguration().getBindingTableGroups().forEach(each -> {
              if (!getToBeAlteredRuleNames.contains(each.getName())) {
                  result.addAll(Arrays.stream(each.getReference().split(",")).map(String::trim).collect(Collectors.toSet()));
              }
          });
          return result;
      }
      
      private Collection<String> getToBeAlteredRuleNames(final AlterShardingTableReferenceRuleStatement sqlStatement) {
          return sqlStatement.getRules().stream().map(TableReferenceRuleSegment::getName).collect(Collectors.toSet());
      }
      
      private void checkToBeReferencedShardingTablesExisted(final AlterShardingTableReferenceRuleStatement sqlStatement) {
          Collection<String> currentShardingTableNames = getCurrentShardingTableNames();
          Collection<String> notExistedTableNames = sqlStatement.getTableNames().stream().filter(each -> !currentShardingTableNames.contains(each)).collect(Collectors.toSet());
          ShardingSpherePreconditions.checkMustEmpty(notExistedTableNames, () -> new MissingRequiredRuleException("Sharding", database.getName(), notExistedTableNames));
      }
      
      private Collection<String> getCurrentShardingTableNames() {
          Collection<String> result = new CaseInsensitiveSet<>();
          result.addAll(rule.getConfiguration().getTables().stream().map(ShardingTableRuleConfiguration::getLogicTable).collect(Collectors.toSet()));
          result.addAll(rule.getConfiguration().getAutoTables().stream().map(ShardingAutoTableRuleConfiguration::getLogicTable).collect(Collectors.toSet()));
          return result;
     }
     
     private void checkShardingTableReferenceRulesValid(final AlterShardingTableReferenceRuleStatement sqlStatement) {
         Collection<ShardingTableReferenceRuleConfiguration> toBeAlteredShardingTableReferenceRules = buildToBeAlteredRuleConfiguration(sqlStatement).getBindingTableGroups();
         Collection<String> ruleNames = toBeAlteredShardingTableReferenceRules.stream().map(ShardingTableReferenceRuleConfiguration::getName).collect(Collectors.toList());
         ShardingSpherePreconditions.checkState(ShardingTableRuleStatementChecker.isValidBindingTableGroups(toBeAlteredShardingTableReferenceRules, rule.getConfiguration()),
                 () -> new InvalidRuleConfigurationException("sharding table", ruleNames, Collections.singleton("invalid sharding table reference.")));
     }
     
     @Override
     public ShardingRuleConfiguration buildToBeAlteredRuleConfiguration(final AlterShardingTableReferenceRuleStatement sqlStatement) {
         ShardingRuleConfiguration result = new ShardingRuleConfiguration();
         sqlStatement.getRules().forEach(each -> result.getBindingTableGroups().add(new ShardingTableReferenceRuleConfiguration(each.getName(), each.getReference())));
         return result;
     }
     
     @Override
     public ShardingRuleConfiguration buildToBeDroppedRuleConfiguration(final ShardingRuleConfiguration toBeAlteredRuleConfig) {
         return null;
     }
     
     @Override
     public Class<ShardingRule> getRuleClass() {
         return ShardingRule.class;
     }
     
     @Override
     public Class<AlterShardingTableReferenceRuleStatement> getType() {
         return AlterShardingTableReferenceRuleStatement.class;
     }
 }