/*
 * Copyright 2004-2013 H2 Group. Multiple-Licensed under the H2 License,
 * Version 1.0, and under the Eclipse Public License, Version 1.0
 * (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import javax.naming.Context;
import javax.sql.DataSource;
import org.h2.message.DbException;

/**
 * This is a utility class with JDBC helper functions.
 */
public class JdbcUtils {

    private static final String[] DRIVERS = {
        "h2:", "org.h2.Driver",
        "Cache:", "com.intersys.jdbc.CacheDriver",
        "daffodilDB://", "in.co.daffodil.db.rmi.RmiDaffodilDBDriver",
        "daffodil", "in.co.daffodil.db.jdbc.DaffodilDBDriver",
        "db2:", "COM.ibm.db2.jdbc.net.DB2Driver",
        "derby:net:", "org.apache.derby.jdbc.ClientDriver",
        "derby://", "org.apache.derby.jdbc.ClientDriver",
        "derby:", "org.apache.derby.jdbc.EmbeddedDriver",
        "FrontBase:", "com.frontbase.jdbc.FBJDriver",
        "firebirdsql:", "org.firebirdsql.jdbc.FBDriver",
        "hsqldb:", "org.hsqldb.jdbcDriver",
        "informix-sqli:", "com.informix.jdbc.IfxDriver",
        "jtds:", "net.sourceforge.jtds.jdbc.Driver",
        "microsoft:", "com.microsoft.jdbc.sqlserver.SQLServerDriver",
        "mimer:", "com.mimer.jdbc.Driver",
        "mysql:", "com.mysql.jdbc.Driver",
        "odbc:", "sun.jdbc.odbc.JdbcOdbcDriver",
        "oracle:", "oracle.jdbc.driver.OracleDriver",
        "pervasive:", "com.pervasive.jdbc.v2.Driver",
        "pointbase:micro:", "com.pointbase.me.jdbc.jdbcDriver",
        "pointbase:", "com.pointbase.jdbc.jdbcUniversalDriver",
        "postgresql:", "org.postgresql.Driver",
        "sybase:", "com.sybase.jdbc3.jdbc.SybDriver",
        "sqlserver:", "com.microsoft.sqlserver.jdbc.SQLServerDriver",
        "teradata:", "com.ncr.teradata.TeraDriver",
    };

    private JdbcUtils() {
        // utility class
    }

    /**
     * Close a statement without throwing an exception.
     *
     * @param stat the statement or null
     */
    public static void closeSilently(Statement stat) {
        if (stat != null) {
            try {
                stat.close();
            } catch (SQLException e) {
                // ignore
            }
        }
    }

    /**
     * Close a connection without throwing an exception.
     *
     * @param conn the connection or null
     */
    public static void closeSilently(Connection conn) {
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                // ignore
            }
        }
    }

    /**
     * Close a result set without throwing an exception.
     *
     * @param rs the result set or null
     */
    public static void closeSilently(ResultSet rs) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                // ignore
            }
        }
    }

    /**
     * Open a new database connection with the given settings.
     *
     * @param driver the driver class name
     * @param url the database URL
     * @param user the user name
     * @param password the password
     * @return the database connection
     */
    public static Connection getConnection(String driver, String url, String user, String password) throws SQLException {
        Properties prop = new Properties();
        if (user != null) {
            prop.setProperty("user", user);
        }
        if (password != null) {
            prop.setProperty("password", password);
        }
        return getConnection(driver, url, prop);
    }

    /**
     * Open a new database connection with the given settings.
     *
     * @param driver the driver class name
     * @param url the database URL
     * @param prop the properties containing at least the user name and password
     * @return the database connection
     */
    public static Connection getConnection(String driver, String url, Properties prop) throws SQLException {
        if (StringUtils.isNullOrEmpty(driver)) {
            JdbcUtils.load(url);
        } else {
            Class<?> d = Utils.loadUserClass(driver);
            if (java.sql.Driver.class.isAssignableFrom(d)) {
                return DriverManager.getConnection(url, prop);
            } else if (javax.naming.Context.class.isAssignableFrom(d)) {
                // JNDI context
                try {
                    Context context = (Context) d.newInstance();
                    DataSource ds = (DataSource) context.lookup(url);
                    String user = prop.getProperty("user");
                    String password = prop.getProperty("password");
                    if (StringUtils.isNullOrEmpty(user) && StringUtils.isNullOrEmpty(password)) {
                        return ds.getConnection();
                    }
                    return ds.getConnection(user, password);
                } catch (Exception e) {
                    throw DbException.toSQLException(e);
                }
            } else {
                // don't know, but maybe it loaded a JDBC Driver
                return DriverManager.getConnection(url, prop);
            }
        }
        return DriverManager.getConnection(url, prop);
    }

    /**
     * Get the driver class name for the given URL, or null if the URL is
     * unknown.
     *
     * @param url the database URL
     * @return the driver class name
     */
    public static String getDriver(String url) {
        if (url.startsWith("jdbc:")) {
            url = url.substring("jdbc:".length());
            for (int i = 0; i < DRIVERS.length; i += 2) {
                String prefix = DRIVERS[i];
                if (url.startsWith(prefix)) {
                    return DRIVERS[i + 1];
                }
            }
        }
        return null;
    }

    /**
     * Load the driver class for the given URL, if the database URL is known.
     *
     * @param url the database URL
     */
    public static void load(String url) {
        String driver = getDriver(url);
        if (driver != null) {
            Utils.loadUserClass(driver);
        }
    }

}
