/*
    * 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.mode.metadata.builder;
  
  import com.google.common.base.Strings;
  import org.apache.shardingsphere.mode.path.rule.RuleNodePath;
  import org.apache.shardingsphere.mode.path.rule.item.NamedRuleItemNodePath;
  import org.apache.shardingsphere.mode.path.rule.item.UniqueRuleItemNodePath;
  import org.apache.shardingsphere.infra.rule.event.GovernanceEvent;
  import org.apache.shardingsphere.infra.spi.ShardingSphereServiceLoader;
  import org.apache.shardingsphere.mode.event.DataChangedEvent;
  import org.apache.shardingsphere.mode.event.NamedRuleItemChangedEventCreator;
  import org.apache.shardingsphere.mode.event.UniqueRuleItemChangedEventCreator;
  import org.apache.shardingsphere.mode.spi.RuleNodePathProvider;
  
  import java.util.Map.Entry;
  import java.util.Optional;
  
  /**
   * Rule configuration event builder.
   */
  public final class RuleConfigurationEventBuilder {
      
      /**
       * Build rule changed event.
       *
       * @param databaseName database name
       * @param event data changed event
       * @return rule changed event
       */
      public Optional<GovernanceEvent> build(final String databaseName, final DataChangedEvent event) {
          for (RuleNodePathProvider each : ShardingSphereServiceLoader.getServiceInstances(RuleNodePathProvider.class)) {
              Optional<GovernanceEvent> result = build(each.getRuleNodePath(), databaseName, event);
              if (result.isPresent()) {
                  return result;
              }
          }
          return Optional.empty();
      }
      
      private Optional<GovernanceEvent> build(final RuleNodePath ruleNodePath, final String databaseName, final DataChangedEvent event) {
          if (!ruleNodePath.getRoot().isValidatedPath(event.getKey()) || Strings.isNullOrEmpty(event.getValue())) {
              return Optional.empty();
          }
          for (Entry<String, NamedRuleItemNodePath> entry : ruleNodePath.getNamedItems().entrySet()) {
              Optional<String> itemName = entry.getValue().getNameByActiveVersion(event.getKey());
              if (itemName.isPresent()) {
                  return Optional.of(new NamedRuleItemChangedEventCreator().create(databaseName, itemName.get(), event, ruleNodePath.getRoot().getRuleType() + "." + entry.getKey()));
              }
          }
          for (Entry<String, UniqueRuleItemNodePath> entry : ruleNodePath.getUniqueItems().entrySet()) {
              if (entry.getValue().isActiveVersionPath(event.getKey())) {
                  return Optional.of(new UniqueRuleItemChangedEventCreator().create(databaseName, event, ruleNodePath.getRoot().getRuleType() + "." + entry.getKey()));
              }
          }
          return Optional.empty();
      }
  }