/*
    * 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;
  
  import lombok.Getter;
  import lombok.SneakyThrows;
  import org.apache.shardingsphere.infra.database.core.metadata.database.DialectDatabaseMetaData;
  import org.apache.shardingsphere.infra.database.core.spi.DatabaseTypedSPILoader;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseType;
  import org.apache.shardingsphere.infra.database.core.type.DatabaseTypeRegistry;
  import org.apache.shardingsphere.infra.metadata.ShardingSphereMetaData;
  import org.apache.shardingsphere.infra.metadata.statistics.ShardingSphereDatabaseData;
  import org.apache.shardingsphere.infra.metadata.statistics.ShardingSphereSchemaData;
  import org.apache.shardingsphere.infra.metadata.statistics.ShardingSphereStatistics;
  import org.apache.shardingsphere.infra.metadata.statistics.ShardingSphereTableData;
  import org.apache.shardingsphere.infra.metadata.statistics.builder.ShardingSphereStatisticsBuilder;
  import org.apache.shardingsphere.infra.rule.ShardingSphereRule;
  import org.apache.shardingsphere.infra.spi.type.typed.TypedSPILoader;
  import org.apache.shardingsphere.metadata.persist.MetaDataBasedPersistService;
  
  import java.util.Collection;
  import java.util.LinkedList;
  import java.util.Map.Entry;
  import java.util.Optional;
  
  /**
   * Meta data contexts.
   */
  @Getter
  public final class MetaDataContexts implements AutoCloseable {
      
      private final MetaDataBasedPersistService persistService;
      
      private final ShardingSphereMetaData metaData;
      
      private final ShardingSphereStatistics statistics;
      
      public MetaDataContexts(final MetaDataBasedPersistService persistService, final ShardingSphereMetaData metaData) {
          this.persistService = persistService;
          this.metaData = metaData;
          this.statistics = initStatistics(metaData);
      }
      
      private ShardingSphereStatistics initStatistics(final ShardingSphereMetaData metaData) {
          if (metaData.getDatabases().isEmpty()) {
              return new ShardingSphereStatistics();
          }
          DatabaseType protocolType = metaData.getDatabases().values().iterator().next().getProtocolType();
          DialectDatabaseMetaData dialectDatabaseMetaData = new DatabaseTypeRegistry(protocolType).getDialectDatabaseMetaData();
          // TODO can `protocolType instanceof SchemaSupportedDatabaseType ? "PostgreSQL" : protocolType.getType()` replace to trunk database type?
          DatabaseType databaseType = dialectDatabaseMetaData.getDefaultSchema().isPresent() ? TypedSPILoader.getService(DatabaseType.class, "PostgreSQL") : protocolType;
          Optional<ShardingSphereStatisticsBuilder> statisticsBuilder = DatabaseTypedSPILoader.findService(ShardingSphereStatisticsBuilder.class, databaseType);
          if (!statisticsBuilder.isPresent()) {
              return new ShardingSphereStatistics();
          }
          ShardingSphereStatistics result = statisticsBuilder.get().build(metaData);
          Optional<ShardingSphereStatistics> loadedStatistics = persistService.getShardingSphereDataPersistService().load(metaData);
          loadedStatistics.ifPresent(optional -> useLoadedToReplaceInit(result, optional));
          return result;
      }
      
      private void useLoadedToReplaceInit(final ShardingSphereStatistics initStatistics, final ShardingSphereStatistics loadedStatistics) {
          for (Entry<String, ShardingSphereDatabaseData> entry : initStatistics.getDatabaseData().entrySet()) {
              if (loadedStatistics.getDatabaseData().containsKey(entry.getKey())) {
                  useLoadedToReplaceInitByDatabaseData(entry.getValue(), loadedStatistics.getDatabaseData().get(entry.getKey()));
              }
          }
      }
      
      private void useLoadedToReplaceInitByDatabaseData(final ShardingSphereDatabaseData initDatabaseData, final ShardingSphereDatabaseData loadedDatabaseData) {
          for (Entry<String, ShardingSphereSchemaData> entry : initDatabaseData.getSchemaData().entrySet()) {
              if (loadedDatabaseData.getSchemaData().containsKey(entry.getKey())) {
                  useLoadedToReplaceInitBySchemaData(entry.getValue(), loadedDatabaseData.getSchemaData().get(entry.getKey()));
              }
          }
      }
      
      private void useLoadedToReplaceInitBySchemaData(final ShardingSphereSchemaData initSchemaData, final ShardingSphereSchemaData loadedSchemaData) {
          for (Entry<String, ShardingSphereTableData> entry : initSchemaData.getTableData().entrySet()) {
              if (loadedSchemaData.getTableData().containsKey(entry.getKey())) {
                  entry.setValue(loadedSchemaData.getTableData().get(entry.getKey()));
              }
          }
      }
     
     @SneakyThrows(Exception.class)
     @Override
     public void close() {
         persistService.getRepository().close();
         for (ShardingSphereRule each : getAllRules()) {
             if (each instanceof AutoCloseable) {
                 ((AutoCloseable) each).close();
             }
         }
     }
     
     private Collection<ShardingSphereRule> getAllRules() {
         Collection<ShardingSphereRule> result = new LinkedList<>(metaData.getGlobalRuleMetaData().getRules());
         metaData.getDatabases().values().stream().map(each -> each.getRuleMetaData().getRules()).forEach(result::addAll);
         return result;
     }
 }