/*
 * Copyright 2008,  Unitils.org
 *
 * Licensed 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.unitils.orm.jpa.util.provider.hibernate;

import static org.apache.commons.lang.StringUtils.isEmpty;
import org.hibernate.Session;
import org.hibernate.dialect.Dialect;
import org.hibernate.ejb.Ejb3Configuration;
import org.springframework.instrument.classloading.LoadTimeWeaver;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.unitils.core.UnitilsException;
import org.unitils.orm.hibernate.util.HibernateAssert;
import org.unitils.orm.jpa.util.JpaProviderSupport;

import javax.persistence.EntityManager;
import javax.persistence.spi.PersistenceProvider;

/**
 * Implementation of {@link JpaProviderSupport} for hibernate JPA
 *
 * @author Filip Neven
 * @author Tim Ducheyne
 */
public class HibernateJpaProviderSupport implements JpaProviderSupport {


    /**
     * Checks if the mapping of the JPA entities with the database is still correct.
     */
    public void assertMappingWithDatabaseConsistent(EntityManager entityManager, Object configurationObject) {
        Ejb3Configuration configuration = (Ejb3Configuration) configurationObject;
        Dialect databaseDialect = getHibernateDatabaseDialect(configuration);

        HibernateAssert.assertMappingWithDatabaseConsistent(configuration.getHibernateConfiguration(), (Session) entityManager.getDelegate(), databaseDialect);
    }


    /**
     * Gets the database dialect from the Hibernate <code>Ejb3Configuration</code.
     *
     * @param configuration The hibernate config, not null
     * @return the database Dialect, not null
     */
    protected Dialect getHibernateDatabaseDialect(Ejb3Configuration configuration) {
        String dialectClassName = configuration.getProperties().getProperty("hibernate.dialect");
        if (isEmpty(dialectClassName)) {
            throw new UnitilsException("Property hibernate.dialect not specified");
        }
        try {
            return (Dialect) Class.forName(dialectClassName).newInstance();
        } catch (Exception e) {
            throw new UnitilsException("Could not instantiate dialect class " + dialectClassName, e);
        }
    }


    public JpaVendorAdapter getSpringJpaVendorAdaptor() {
        return new UnitilsHibernateJpaVendorAdapter();
    }


    public Object getProviderSpecificConfigurationObject(
            PersistenceProvider persistenceProvider) {
        if (!(persistenceProvider instanceof UnitilsHibernatePersistenceProvider)) {
            throw new UnitilsException("Make sure that the persistence provider that is used is an instance of " + UnitilsHibernatePersistenceProvider.class.getSimpleName());
        }
        UnitilsHibernatePersistenceProvider hibernatePersistenceProvider = (UnitilsHibernatePersistenceProvider) persistenceProvider;
        return hibernatePersistenceProvider.getHibernateConfiguration();
    }


    public LoadTimeWeaver getLoadTimeWeaver() {
        return null;
    }

}