package de.intevation.flys.backend;

import de.intevation.artifacts.common.utils.Config;

import java.util.Properties;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;

import de.intevation.flys.model.Annotation;
import de.intevation.flys.model.Attribute;
import de.intevation.flys.model.DischargeTable;
import de.intevation.flys.model.DischargeTableValue;
import de.intevation.flys.model.Gauge;
import de.intevation.flys.model.MainValueType;
import de.intevation.flys.model.NamedMainValues;
import de.intevation.flys.model.Position;
import de.intevation.flys.model.Range;
import de.intevation.flys.model.River;
import de.intevation.flys.model.TimeInterval;
import de.intevation.flys.model.WstColumn;
import de.intevation.flys.model.WstColumnQRange;
import de.intevation.flys.model.WstColumnValue;
import de.intevation.flys.model.Wst;
import de.intevation.flys.model.WstQRange;

import org.apache.log4j.Logger;

public final class SessionFactoryProvider
{
    private static Logger log = Logger.getLogger(SessionFactoryProvider.class);

    public static final String XPATH_USER =
        "/artifact-database/backend-database/user/text()";

    public static final String XPATH_PASSWORD =
        "/artifact-database/backend-database/password/text()";

    public static final String XPATH_DIALECT =
        "/artifact-database/backend-database/dialect/text()";

    public static final String XPATH_DRIVER =
        "/artifact-database/backend-database/driver/text()";

    public static final String XPATH_URL =
        "/artifact-database/backend-database/url/text()";

    public static final String DEFAULT_USER     = "flys";
    public static final String DEFAULT_PASSWORD = "flys";
    public static final String DEFAULT_DIALECT  =
        "org.hibernate.dialect.PostgreSQLDialect";

    public static final String DEFAULT_DRIVER =
        "org.postgresql.Driver";

    public static final String DEFAULT_URL =
        "jdbc:postgresql://localhost:5432/flys";

    private static SessionFactory sessionFactory;

    private SessionFactoryProvider() {
    }

    public static synchronized SessionFactory getSessionFactory() {
        if (sessionFactory == null) {
            sessionFactory = createSessionFactory();
        }
        return sessionFactory;
    }

    private static SessionFactory createSessionFactory() {

        Configuration cfg = new Configuration();

        // TODO: Use package reflection here.
        cfg.addAnnotatedClass(Annotation.class);
        cfg.addAnnotatedClass(Attribute.class);
        cfg.addAnnotatedClass(DischargeTable.class);
        cfg.addAnnotatedClass(DischargeTableValue.class);
        cfg.addAnnotatedClass(Gauge.class);
        cfg.addAnnotatedClass(MainValueType.class);
        cfg.addAnnotatedClass(NamedMainValues.class);
        cfg.addAnnotatedClass(Position.class);
        cfg.addAnnotatedClass(Range.class);
        cfg.addAnnotatedClass(River.class);
        cfg.addAnnotatedClass(TimeInterval.class);
        cfg.addAnnotatedClass(WstColumn.class);
        cfg.addAnnotatedClass(WstColumnQRange.class);
        cfg.addAnnotatedClass(WstColumnValue.class);
        cfg.addAnnotatedClass(Wst.class);
        cfg.addAnnotatedClass(WstQRange.class);

        String user =
            Config.getStringXPath(XPATH_USER, DEFAULT_USER);
        String password =
            Config.getStringXPath(XPATH_PASSWORD, DEFAULT_PASSWORD);
        String dialect =
            Config.getStringXPath(XPATH_DIALECT, DEFAULT_DIALECT);
        String driver = 
            Config.getStringXPath(XPATH_DRIVER, DEFAULT_DRIVER);
        String url =
            Config.getStringXPath(XPATH_URL, DEFAULT_URL);

        if (log.isDebugEnabled()) {
            log.debug("user: "    + user);
            log.debug("dialect: " + dialect);
            log.debug("driver: "  + driver);
            log.debug("url: "     + url);
        }

        Properties props = new Properties();

        // We rely on our own connection pool
        props.setProperty(
            "hibernate.connection.provider_class",
            "org.hibernate.connection.DBCPConnectionProvider");

        props.setProperty(Environment.DIALECT, dialect);
        props.setProperty(Environment.USER,    user);
        props.setProperty(Environment.PASS,    password);
        props.setProperty(Environment.DRIVER,  driver);
        props.setProperty(Environment.URL,     url);

        cfg.mergeProperties(props);

        return cfg.buildSessionFactory();
    }
}
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