/**
 * Licensed to Apereo under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright ownership. Apereo
 * 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 the
 * following location:
 *
 * <p>http://www.apache.org/licenses/LICENSE-2.0
 *
 * <p>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.apereo.portal.hibernate;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.ServiceLoader;
import java.util.Set;
import org.hibernate.cfg.Configuration;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.integrator.spi.Integrator;
import org.hibernate.metamodel.source.MetadataImplementor;
import org.hibernate.service.spi.SessionFactoryServiceRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Works with {@link HibernateConfigurationAware} beans to provide configuration information from
 * hibernate to other beans.
 *
 * <p>Configured via the {@link ServiceLoader} mechanism.
 *
 */
public class DelegatingHibernateIntegrator implements Integrator {
    private static final Set<HibernateConfigurationAwareInjector> configurationAwareBeans =
            new HashSet<HibernateConfigurationAwareInjector>();
    private static final Map<String, HibernateConfiguration> hibernateInfoMap =
            new HashMap<String, DelegatingHibernateIntegrator.HibernateConfiguration>();

    protected final Logger logger = LoggerFactory.getLogger(getClass());

    public static void registerConfigurationAwareBeans(
            HibernateConfigurationAwareInjector configurationAwareBean) {
        synchronized (configurationAwareBeans) {
            //make sure any hibernate configs already loaded get injected
            for (final Map.Entry<String, HibernateConfiguration> configEntry :
                    hibernateInfoMap.entrySet()) {
                configurationAwareBean.setConfiguration(
                        configEntry.getKey(), configEntry.getValue());
            }

            configurationAwareBeans.add(configurationAwareBean);
        }
    }

    public static void unregisterConfigurationAwareBeans(
            HibernateConfigurationAwareInjector configurationAwareBean) {
        configurationAwareBeans.remove(configurationAwareBean);
    }

    @Override
    public void integrate(
            Configuration configuration,
            SessionFactoryImplementor sessionFactory,
            SessionFactoryServiceRegistry serviceRegistry) {

        final String persistenceUnitName = configuration.getProperty("persistenceUnitName");
        if (persistenceUnitName == null) {
            logger.warn(
                    "Hibernate Configuration does not have '"
                            + persistenceUnitName
                            + "' set. It will not be considered for injecting into HibernateConfigurationAware beans: "
                            + configuration);
            return;
        }

        final HibernateConfiguration hibernateConfiguration =
                new HibernateConfiguration(configuration, sessionFactory, serviceRegistry);

        synchronized (configurationAwareBeans) {
            hibernateInfoMap.put(persistenceUnitName, hibernateConfiguration);

            for (final HibernateConfigurationAwareInjector configurationAwareBean :
                    configurationAwareBeans) {
                configurationAwareBean.setConfiguration(
                        persistenceUnitName, hibernateConfiguration);
            }
        }
    }

    @Override
    public void integrate(
            MetadataImplementor metadata,
            SessionFactoryImplementor sessionFactory,
            SessionFactoryServiceRegistry serviceRegistry) {
        throw new UnsupportedOperationException(
                "TODO REWRITE CODE AFTER HIBERNATE SWITCHES TO METAMODEL");
    }

    @Override
    public void disintegrate(
            SessionFactoryImplementor sessionFactory,
            SessionFactoryServiceRegistry serviceRegistry) {
        //ignore
    }

    public static final class HibernateConfiguration {
        private final Configuration configuration;
        private final SessionFactoryImplementor sessionFactory;
        private final SessionFactoryServiceRegistry serviceRegistry;

        public HibernateConfiguration(
                Configuration configuration,
                SessionFactoryImplementor sessionFactory,
                SessionFactoryServiceRegistry serviceRegistry) {
            this.configuration = configuration;
            this.sessionFactory = sessionFactory;
            this.serviceRegistry = serviceRegistry;
        }

        public Configuration getConfiguration() {
            return configuration;
        }

        public SessionFactoryImplementor getSessionFactory() {
            return sessionFactory;
        }

        public SessionFactoryServiceRegistry getServiceRegistry() {
            return serviceRegistry;
        }
    }
}