/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.service.jdbc.connections.internal;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Map;
import javax.sql.DataSource;
import org.hibernate.HibernateException;
import org.hibernate.cfg.Environment;
import org.hibernate.service.UnknownUnwrapTypeException;
import org.hibernate.service.jdbc.connections.spi.ConnectionProvider;
import org.hibernate.service.jndi.spi.JndiService;
import org.hibernate.service.spi.Configurable;
import org.hibernate.service.spi.InjectService;
import org.hibernate.service.spi.Stoppable;

/**
 * A {@link ConnectionProvider} that manages connections from an underlying {@link DataSource}.
 * <p/>
 * The {@link DataSource} to use may be specified by either:<ul>
 * <li>injection via {@link #setDataSource}</li>
 * <li>decaring the {@link DataSource} instance using the {@link Environment#DATASOURCE} config property</li>
 * <li>decaring the JNDI name under which the {@link DataSource} can be found via {@link Environment#DATASOURCE} config property</li>
 * </ul>
 *
 * @author Gavin King
 * @author Steve Ebersole
 */
public class DatasourceConnectionProviderImpl implements ConnectionProvider, Configurable, Stoppable {

	private DataSource dataSource;
	private String user;
	private String pass;
	private boolean useCredentials;
	private JndiService jndiService;

	private boolean available;

	public DataSource getDataSource() {
		return dataSource;
	}

	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
	}

	@InjectService( required = false )
	public void setJndiService(JndiService jndiService) {
		this.jndiService = jndiService;
	}

	@Override
	public boolean isUnwrappableAs(Class unwrapType) {
		return ConnectionProvider.class.equals( unwrapType ) ||
				DatasourceConnectionProviderImpl.class.isAssignableFrom( unwrapType ) ||
				DataSource.class.isAssignableFrom( unwrapType );
	}

	@Override
	@SuppressWarnings( {"unchecked"})
	public <T> T unwrap(Class<T> unwrapType) {
		if ( ConnectionProvider.class.equals( unwrapType ) ||
				DatasourceConnectionProviderImpl.class.isAssignableFrom( unwrapType ) ) {
			return (T) this;
		}
		else if ( DataSource.class.isAssignableFrom( unwrapType ) ) {
			return (T) getDataSource();
		}
		else {
			throw new UnknownUnwrapTypeException( unwrapType );
		}
	}

	/**
	 * {@inheritDoc}
	 */
	public void configure(Map configValues) {
		if ( this.dataSource == null ) {
			final Object dataSource = configValues.get( Environment.DATASOURCE );
			if ( DataSource.class.isInstance( dataSource ) ) {
				this.dataSource = (DataSource) dataSource;
			}
			else {
				final String dataSourceJndiName = (String) dataSource;
				if ( dataSourceJndiName == null ) {
					throw new HibernateException(
							"DataSource to use was not injected nor specified by [" + Environment.DATASOURCE
									+ "] configuration property"
					);
				}
				if ( jndiService == null ) {
					throw new HibernateException( "Unable to locate JndiService to lookup Datasource" );
				}
				this.dataSource = (DataSource) jndiService.locate( dataSourceJndiName );
			}
		}
		if ( this.dataSource == null ) {
			throw new HibernateException( "Unable to determine appropriate DataSource to use" );
		}

		user = (String) configValues.get( Environment.USER );
		pass = (String) configValues.get( Environment.PASS );
		useCredentials = user != null || pass != null;
		available = true;
	}

	public void stop() {
		available = false;
		dataSource = null;
	}

	/**
	 * {@inheritDoc}
	 */
	public Connection getConnection() throws SQLException {
		if ( !available ) {
			throw new HibernateException( "Provider is closed!" );
		}
		return useCredentials ? dataSource.getConnection( user, pass ) : dataSource.getConnection();
	}

	/**
	 * {@inheritDoc}
	 */
	public void closeConnection(Connection connection) throws SQLException {
		connection.close();
	}

	/**
	 * {@inheritDoc}
	 */
	public boolean supportsAggressiveRelease() {
		return true;
	}
}