content: /*
   *  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.causeway.core.config.datasources;
  
  import java.sql.DatabaseMetaData;
  import java.sql.SQLException;
  import java.util.List;
  import java.util.Optional;
  import java.util.stream.Stream;
  
  import javax.sql.DataSource;
  
  import jakarta.annotation.Priority;
  import jakarta.inject.Named;
  
  import org.jspecify.annotations.NonNull;
  
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.stereotype.Service;
  
  import org.apache.causeway.applib.annotation.PriorityPrecedence;
  import org.apache.causeway.commons.collections.Can;
  import org.apache.causeway.commons.internal.base._Lazy;
  import org.apache.causeway.core.config.CausewayModuleCoreConfig;
  
  import lombok.SneakyThrows;
  import lombok.extern.log4j.Log4j2;
  
  /**
   * For a given <i>Spring</i> context, makes information about configured data-sources available.
   *
   * @apiNote The {@link DataSourceInfo} value type can be extended as needed.
   *
   * @since 2.0 {@index}
   * @see <a href="https://stackoverflow.com/questions/44446597/where-does-the-default-datasource-url-for-h2-come-from-on-spring-boot">stackoverflow.com</a>
   */
  @Service
  @Named(CausewayModuleCoreConfig.NAMESPACE + "..DataSourceIntrospectionService")
  @Priority(PriorityPrecedence.MIDPOINT)
  @Qualifier("Default")
  @Log4j2
  public class DataSourceIntrospectionService {
  
      @Autowired(required = false)
      private List<DataSource> dataSources;
  
      public record DataSourceInfo(String jdbcUrl) {
  
          @SneakyThrows
          private static DataSourceInfo fromMetaData(final @NonNull DatabaseMetaData databaseMetaData) {
              return new DataSourceInfo(databaseMetaData.getURL());
          }
      }
  
      public Can<DataSourceInfo> getDataSourceInfos() {
          return dataSourceInfos.get();
      }
  
      // -- HELPER
  
      private final _Lazy<Can<DataSourceInfo>> dataSourceInfos =
              _Lazy.threadSafe(()->Can.ofStream(streamDataSourceInfos()));
  
      private Stream<DataSourceInfo> streamDataSourceInfos() {
  
          var registeredDataSources = Can.ofCollection(dataSources);
  
          log.debug("about to introspect data-sources: {}",
                  ()->registeredDataSources.map(ds->ds.getClass().getName()));
  
          return registeredDataSources
                  .stream()
                  .map(this::dsInfoForDataSource)
                  .filter(Optional::isPresent)
                  .map(Optional::get);
      }
  
      private Optional<DataSourceInfo> dsInfoForDataSource(
              final @NonNull DataSource dataSource) {
  
          // make sure we close any connection after having consumed the meta-data
          try(var connection = dataSource.getConnection()){
              return Optional.ofNullable(connection.getMetaData())
                      .map(DataSourceInfo::fromMetaData);
          } catch (SQLException e) {
              log.warn("failed to get metadata from SQL connection using datasource of type {}",
                      dataSource.getClass());
          }
          return Optional.empty();
      }
  
  }
  