/**
 * HSQLDBserver.java
 * jCOLIBRI2 framework. 
 * @author Juan A. Recio-Garc�a.
 * GAIA - Group for Artificial Intelligence Applications
 * http://gaia.fdi.ucm.es
 * 04/07/2007
 */
package es.ucm.fdi.gaia.jcolibri.test.database;

import java.io.File;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.util.HashMap;

import org.apache.log4j.LogManager;
import org.hsqldb.Server;

import es.ucm.fdi.gaia.jcolibri.util.FileIO;

/**
 * Creates a data base server.<br>
 * Server can be persistent (saved into the file system) or not (just in memory).<br>
 * User can load several sql files to import the data.
 * @author Juan A. Recio-Garcia
 * @version 1.0
 */
public class ConfigurableHSQLDBserver
{
    static boolean initialized = false;

    private static Server server;
    
    private static PrintStream outStream = new PrintStream(System.out);
    private static PrintWriter out = new PrintWriter(outStream);
    private static String dataBaseName;

    /**
     * Initialize the server using a non persistent data base in memory 
     * @param databaseName is the name of the data base
     * @param showLog indicates if log comments must be shown
     */
    public static void initInMemory(String databaseName, boolean showLog)
    {
        if (initialized)
            return;
        
        LogManager.getLogger(ConfigurableHSQLDBserver.class).info("Creating data base ...");

        dataBaseName = databaseName;
        
        server = new Server();
        server.setDatabaseName(0, databaseName);
        server.setDatabasePath(0, "mem:"+databaseName+";sql.enforce_strict_size=true");

        if(showLog)
        {
            server.setLogWriter(out);
            server.setErrWriter(out);
        }
        else
        {
            server.setLogWriter(null);
            server.setErrWriter(null);
        }
        server.setSilent(!showLog);
        server.setTrace(showLog);
        
        server.start();
        
        initialized = true;
    }
    
    /**
     * Initialize the server using a persistent data base in the file system <p>
     * This persistent data base contains HSQLDB MEMORY tables.
     * Memory tables are the default type when the CREATE TABLE command is used. 
     * Their data is held entirely in memory but any change to their structure or contents is written to the <dbname>.script file. 
     * The script file is read the next time the database is opened, and the MEMORY tables are recreated with all their contents. 
     * So MEMORY tables are persistent.
     * <p>
     * More info: <a href="http://hsqldb.org/doc/guide/ch01.html">http://hsqldb.org/doc/guide/ch01.html</a>
     * 
     * @param databaseName is the name of the data base
     * @param showLog indicates if log comments must be shown
     * @param directory where the data base must be created or loaded from. This directory must exist.
     */
    public static void initInFileSystem(String databaseName, boolean showLog, String directory)
    {
        if (initialized)
            return;
        
        LogManager.getLogger(ConfigurableHSQLDBserver.class).info("Creating data base in file system...");

        dataBaseName = databaseName;
        
        server = new Server();
        
        server.setDatabaseName(0, databaseName);
        server.setDatabasePath(0, "file:"+directory+File.separator+databaseName+";sql.enforce_strict_size=true");

        if(showLog)
        {
            server.setLogWriter(out);
            server.setErrWriter(out);
        }
        else
        {
            server.setLogWriter(null);
            server.setErrWriter(null);
        }
        server.setSilent(!showLog);
        server.setTrace(showLog);
        
        server.start();
        
        initialized = true;
    }
    
    /**
     * Loads the given sql file.
     * @param sqlfile to be loaded
     */
    public static void loadSQLFile(String sqlfile)
    {
        if (!initialized)
        {
            LogManager.getLogger(ConfigurableHSQLDBserver.class).warn("Server must be initialized before loading SQL files.");
            return;
        }

        try
        {
            Class.forName("org.hsqldb.jdbcDriver");

            Connection conn = DriverManager.getConnection("jdbc:hsqldb:hsql://localhost/"+dataBaseName, "sa", "");
            File f = new File( FileIO.findFile(sqlfile).getFile() );
            SqlFile file = new SqlFile(f,false,new HashMap<Object,Object>());
            file.execute(conn,outStream,outStream, true);

            LogManager.getLogger(ConfigurableHSQLDBserver.class).info("SQL file: "+sqlfile+" loaded");
            
        } catch (Exception e)
        {
            LogManager.getLogger(ConfigurableHSQLDBserver.class).error(e);
        }

    }

    /**
     * Shutdown the server
     */
    public static void shutDown()
    {
        if (!initialized)
            return;
        
        try
        {
            Connection conn = DriverManager.getConnection("jdbc:hsqldb:hsql://localhost/"+dataBaseName, "sa", "");
            Statement st = conn.createStatement();
            st.execute("SHUTDOWN");
            server.stop();
            initialized = false;
        } catch (Exception e)
        {
            LogManager.getLogger(ConfigurableHSQLDBserver.class).error(e);
            
        }

        
    }

    /**
     * Testing method
     */
    public static void main(String[] args)
    {
        ConfigurableHSQLDBserver.initInMemory("travel", true);
        ConfigurableHSQLDBserver.loadSQLFile("es/ucm/fdi/gaia/jcolibri/test/database/travel.sql");
        ConfigurableHSQLDBserver.shutDown();
        System.exit(0);
        
    }

}