/**

 * 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.");

	}

}