/*
    * 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.syncope.core.persistence.jpa.dao;
  
  import java.util.Map;
  import java.util.Optional;
  import java.util.concurrent.ConcurrentHashMap;
  import javax.persistence.EntityManager;
  import javax.persistence.EntityManagerFactory;
  import org.apache.openjpa.jdbc.meta.MappingRepository;
  import org.apache.openjpa.jdbc.sql.OracleDictionary;
  import org.apache.openjpa.persistence.OpenJPAEntityManagerFactory;
  import org.apache.openjpa.persistence.OpenJPAEntityManagerFactorySPI;
  import org.apache.openjpa.persistence.OpenJPAPersistence;
  import org.apache.syncope.core.persistence.api.dao.DAO;
  import org.apache.syncope.core.persistence.api.entity.Entity;
  import org.apache.syncope.core.spring.ApplicationContextProvider;
  import org.apache.syncope.core.spring.security.AuthContextUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.orm.jpa.EntityManagerFactoryUtils;
  
  public abstract class AbstractDAO<E extends Entity> implements DAO<E> {
  
      protected static final Logger LOG = LoggerFactory.getLogger(DAO.class);
  
      private static final Map<String, Boolean> IS_ORACLE = new ConcurrentHashMap<>();
  
      protected EntityManagerFactory entityManagerFactory() {
          return EntityManagerFactoryUtils.findEntityManagerFactory(
                  ApplicationContextProvider.getBeanFactory(), AuthContextUtils.getDomain());
      }
  
      protected EntityManager entityManager() {
          return Optional.ofNullable(EntityManagerFactoryUtils.getTransactionalEntityManager(entityManagerFactory())).
                  orElseThrow(() -> new IllegalStateException(
                  "Could not find EntityManager for domain " + AuthContextUtils.getDomain()));
      }
  
      @Override
      public void refresh(final E entity) {
          entityManager().refresh(entity);
      }
  
      @Override
      public void detach(final E entity) {
          entityManager().detach(entity);
      }
  
      protected boolean isOracle() {
          Boolean isOracle = IS_ORACLE.get(AuthContextUtils.getDomain());
          if (isOracle == null) {
              OpenJPAEntityManagerFactory emf = OpenJPAPersistence.cast(entityManagerFactory());
              OpenJPAEntityManagerFactorySPI emfspi = (OpenJPAEntityManagerFactorySPI) OpenJPAPersistence.cast(emf);
              isOracle = ((MappingRepository) emfspi.getConfiguration()
                      .getMetaDataRepositoryInstance()).getDBDictionary() instanceof OracleDictionary;
              IS_ORACLE.put(AuthContextUtils.getDomain(), isOracle);
          }
          return isOracle;
      }
  }