/**

  * SQL-DK

  * Copyright © 2015 František Kučera (frantovo.cz)

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License, or

  * (at your option) any later version.

  *

  * 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 General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. If not, see <http://www.gnu.org/licenses/>.

  */

 package info.globalcode.sql.dk.jdbc;

 import info.globalcode.sql.dk.Constants;

 import info.globalcode.sql.dk.configuration.Configuration;

 import info.globalcode.sql.dk.configuration.ConfigurationException;

 import info.globalcode.sql.dk.configuration.DatabaseDefinition;

 import info.globalcode.sql.dk.configuration.Loader;

 import info.globalcode.sql.dk.configuration.Properties;

 import info.globalcode.sql.dk.configuration.Property;

 import java.sql.Connection;

 import java.sql.DriverManager;

 import java.sql.DriverPropertyInfo;

 import java.sql.SQLException;

 import java.sql.SQLFeatureNotSupportedException;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 /**

  * <p>

  * Meta JDBC driver that works as redirector/router. It loads SQL-DK's configuration file and

  * instantiates a real JDBC connection (PostgreSQL, MariDB etc.) of given name.

  * </p>

  *

  * <p>

  * Raison d'être: user can define his/her database connections just once (in SQL-DK's configuration)

  * and use them in many other programs – there is no need to define the connection (hostname,

  * username, password, properties…) in each application again and again. User will simply connect to

  * e.g. <code>jdbc:sql-dk://my-connection</code> and this driver reads parameters of

  * <code>my-connection</code> from SQL-DK's configuration and returns real driver implementation.

  * </p>

  *

  * <p>

  * Of course, the real JDBC driver for given database is still needed on the class path.

  * </p>

  *

  * <p>

  * TODO: current version is quite heavy-weight, because it includes whole SQL-DK source tree. Some

  * refactoring and separation is desired to provide more light-weight JDBC driver. However the

  * public interface and behavior of this driver should remain unchanged.

  * </p>

  *

  * @author Ing. František Kučera (frantovo.cz)

  */

 public class Driver implements java.sql.Driver {

 	private static final Logger log = Logger.getLogger(Driver.class.getName());

 	private final Loader loader = new Loader();

 	static {

 		try {

 			DriverManager.registerDriver(new Driver());

 		} catch (SQLException e) {

 			log.log(Level.SEVERE, "Unable to register JDBC driver", e);

 		}

 	}

 	@Override

 	public Connection connect(String url, java.util.Properties info) throws SQLException {

 		if (acceptsURL(url)) {

 			log.log(Level.FINER, "Loading SQL-DK configuration for URL: {0}", url);

 			String name = extractDatabaseName(url);

 			log.log(Level.FINE, "Loading SQL-DK configuration for name: {0}", name);

 			try {

 				return getConnection(name, info);

 			} catch (ConfigurationException e) {

 				log.log(Level.SEVERE, "Unable to load SQL-DK configuration for name: {0}. Is it defined in {1}?", new Object[]{name, Constants.CONFIG_FILE});

 				throw new SQLException("Unable to load SQL-DK configuration for name: " + name, e);

 			}

 		} else {

 			// The driver should return "null" if it realizes it is the wrong kind of driver to connect to the given URL.

 			return null;

 		}

 	}

 	private Connection getConnection(String connectionName, java.util.Properties info) throws SQLException, ConfigurationException {

 		Configuration c = loader.loadConfiguration();

 		DatabaseDefinition dd = c.getDatabase(connectionName);

 		if (acceptsURL(dd.getUrl())) {

 			log.log(Level.SEVERE, "SQL-DK meta JDBC driver loops to itself: {0} → {1} Please check {2}", new Object[]{connectionName, dd.getUrl(), Constants.CONFIG_FILE});

 			throw new ConfigurationException("SQL-DK meta JDBC driver loops to itself.");

 		} else {

 			return Loader.jdbcConnect(dd, translate(info));

 		}

 	}

 	private String extractDatabaseName(String url) {

 		return url.split("//", 2)[1];

 	}

 	/**

 	 * TODO: refactor/move, reuse

 	 *

 	 * @param info

 	 * @return

 	 */

 	private Properties translate(java.util.Properties info) {

 		Properties properties = new Properties();

 		for (String name : info.stringPropertyNames()) {

 			String value = info.getProperty(name);

 			properties.add(new Property(name, value));

 		}

 		return properties;

 	}

 	@Override

 	public boolean acceptsURL(String url) throws SQLException {

 		return url != null && url.startsWith("jdbc:sql-dk://");

 	}

 	@Override

 	public DriverPropertyInfo[] getPropertyInfo(String url, java.util.Properties info) throws SQLException {

 		return new DriverPropertyInfo[0];

 	}

 	@Override

 	public int getMajorVersion() {

 		return 0;

 	}

 	@Override

 	public int getMinorVersion() {

 		return 1;

 	}

 	@Override

 	public boolean jdbcCompliant() {

 		return false;

 	}

 	@Override

 	public Logger getParentLogger() throws SQLFeatureNotSupportedException {

 		throw new SQLFeatureNotSupportedException("Not supported yet.");

 	}

 }