package org.pentaho.pac.server.common;

import java.util.HashMap;
import java.util.Map;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;


/**
 * Configures and provides access to Hibernate sessions, tied to the
 * current thread of execution.  Follows the Thread Local Session
 * pattern, see {@link http://hibernate.org/42.html }.
 */
public class HibernateSessionFactory {

	public static final String DEFAULT_CONFIG_NAME = "$$DEFAULT_CONFIG";
    public static String DEFAULT_CONFIG_FILE_LOCATION = "hsql.hibernate.cfg.xml"; //$NON-NLS-1$
	/** 
     * Location of hibernate.cfg.xml file.
     * Location should be on the classpath as Hibernate uses  
     * #resourceAsStream style lookup for its configuration file. 
     * The default classpath location of the hibernate config file is 
     * in the default package. Use #setConfigFile() to update 
     * the location of the configuration file for the current session.   
     */
   // private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
   // private  static org.hibernate.cfg.AnnotationConfiguration configuration = new AnnotationConfiguration();
    //private static org.hibernate.SessionFactory sessionFactory;
     
    private static Map<String,HibConfig> configs = new HashMap<String,HibConfig>();
    private static String defaultConfigFile = null;

    private HibernateSessionFactory() {
    }
    
    public static void addDefaultConfiguration() {
      defaultConfigFile = AppConfigProperties.getInstance().getHibernateConfigPath();
      if(defaultConfigFile != null && defaultConfigFile.length() > 0) {
        addConfiguration(DEFAULT_CONFIG_NAME,defaultConfigFile);
      } else {
        defaultConfigFile = DEFAULT_CONFIG_FILE_LOCATION;
        addConfiguration(DEFAULT_CONFIG_NAME,defaultConfigFile);
      }
      
    }
    public static void addConfiguration(String name,String configFile)
    {
    	if (!configs.containsKey(name))
    	addOrUpdateConfiguration(name,configFile);
    }
    
    
    
    public static void addOrUpdateConfiguration(String name,String configFile)
    {
    	Configuration configuration = new AnnotationConfiguration();
    	
    	try {
			configuration.configure(configFile);
			SessionFactory sessionFactory = configuration.buildSessionFactory();
			configs.put(name,new HibConfig(sessionFactory,configuration,configFile));
		} catch (Exception e) {
			System.err
					.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
    }
	
	/**
     * Returns the ThreadLocal Session instance.  Lazy initialize
     * the <code>SessionFactory</code> if needed.
     *
     *  @return Session
     *  @throws HibernateException
     */
    public static Session getSession() throws HibernateException {
       return getSession(DEFAULT_CONFIG_NAME);
    }
    
    /**
     * Returns the ThreadLocal Session instance.  Lazy initialize
     * the <code>SessionFactory</code> if needed.
     *
     *  @return Session
     *  @throws HibernateException
     */
    public static Session getSession(String configName) throws HibernateException {
    	HibConfig cfg = configs.get(configName);
    	if (cfg==null)
    		throw new HibernateException("Unknown configuration: " + configName);
    	
        Session session = cfg.threadLocal.get();

		if (session == null || !session.isOpen()) {
			if (cfg.sessionFactory == null) {
				rebuildSessionFactory(cfg);
			}
			session = (cfg.sessionFactory != null) ? cfg.sessionFactory.openSession()
					: null;
			cfg.threadLocal.set(session);
		}

        return session;
    }
    
    

	/**
     *  Rebuild hibernate session factory
     *
     */
	public static void rebuildSessionFactory(HibConfig cfg) {
		try {
			cfg.configuration.configure(cfg.configFile);
			cfg.sessionFactory = cfg.configuration.buildSessionFactory();
		} catch (Exception e) {
			System.err
					.println("%%%% Error Creating SessionFactory %%%%"); //$NON-NLS-1$
			e.printStackTrace();
		}
	}

	/**
     *  Close the single hibernate session instance.
     *
     *  @throws HibernateException
     */
    public static void closeSession() throws HibernateException {
       closeSession(DEFAULT_CONFIG_NAME);
    }
    
    public static void closeSession(String configName)
    {
    	HibConfig cfg = configs.get(configName);
    	if (cfg==null)
    		throw new HibernateException("Unknown configuration: " + configName);
    	
    	 Session session = (Session) cfg.threadLocal.get();
         cfg.threadLocal.set(null);

         if (session != null) {
             session.close();
         }
    }

	/**
     *  return session factory
     *
     */
	public static org.hibernate.SessionFactory getSessionFactory() {
		return getSessionFactory(defaultConfigFile);
	}
	
	public static org.hibernate.SessionFactory getSessionFactory(String configName) {
		HibConfig cfg = configs.get(configName);
    	if (cfg==null)
    		throw new HibernateException("Unknown configuration: " + configName);
    	
    	return cfg.sessionFactory;
	}

	/**
     *  return hibernate configuration
     *
     */
	public static Configuration getConfiguration() {
		return getConfiguration(defaultConfigFile);
	}


	/**
     *  return hibernate configuration
     *
     */
	public static Configuration getConfiguration(String configName) {
		HibConfig cfg = configs.get(configName);
    	if (cfg==null)
    		throw new HibernateException("Unknown configuration: " + configName);
    	
    	return cfg.configuration;
	}
	
	private static class HibConfig
	{
		HibConfig(SessionFactory sessionFactory,Configuration configuration,String configFile)
		{
			this.sessionFactory = sessionFactory;
			this.configuration = configuration;
			this.configFile = configFile;
		}
		SessionFactory sessionFactory;
		Configuration configuration;
		ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
		String configFile;
		
	}

}