package gov.bnl.gums.db;
   
   import java.text.DateFormat;
   import java.util.ArrayList;
   import java.util.Collection;
   import java.util.Date;
   import java.util.Iterator;
   
   import gov.bnl.gums.persistence.HibernatePersistenceFactory;
  
  import org.hibernate.Query;
  import org.hibernate.Session;
  import org.hibernate.Transaction;
  
  import org.apache.log4j.Logger;
  
  public class HibernateConfigurationDB implements ConfigurationDB {
  	private Logger log = Logger.getLogger(LDAPUserGroupDB.class);
  	private HibernatePersistenceFactory persistenceFactory;
  
  	public HibernateConfigurationDB(HibernatePersistenceFactory persistenceFactory) {
  		this.persistenceFactory = persistenceFactory;
  		log.trace("LDAPConfigurationDB object create: factory " + persistenceFactory);
  	}
  
  	public boolean deleteBackupConfiguration(String name) {
  		Session session = null;
  		Transaction tx = null;
  		try {
  			session = persistenceFactory.retrieveSessionFactory().openSession();
  			tx = session.beginTransaction();		
  			Query q = session.createQuery("FROM HibernateConfig c where c.name = ?");
  			q.setString(0, name);
  			if (q.list().size() == 1) {
  				HibernateConfig config = (HibernateConfig)q.list().get(0);
  				session.delete(config);
  				tx.commit();
  				return true;
  			}
  			else {
  				log.error("None or more than one configuration is stored for name " + name);
  				throw new RuntimeException("None or more than one configuration is stored name " + name);
  			}        	
  			// Handles when transaction goes wrong...
  		} catch (Exception e) {
  			log.error("Couldn't retrieve backup configuration", e);
  			if (tx != null) {
  				try {
  					tx.rollback();
  				} catch (Exception e1) {
  					log.error("Hibernate error: rollback failed", e1);
  					throw new RuntimeException("Database errors: " + e.getMessage() + " - " + e1.getMessage(), e);
  				}
  			}
  			throw new RuntimeException("Database error: " + e.getMessage(), e);
  		} finally {
  			if (session != null) {
  				try {
  					session.close();
  				} catch (Exception e1) {
  					log.error("Hibernate error: couldn't close session", e1);
  					throw new RuntimeException("Database error: " + e1.getMessage(), e1);
  				}
  			}
  		}		
  	}
  
  	public Collection getBackupNames(DateFormat format) {
  		Session session = null;
  		Transaction tx = null;
  		ArrayList list = new ArrayList();
  		try {
  			// Checks whether the value is present in the database
  			session = persistenceFactory.retrieveSessionFactory().openSession();
  			tx = session.beginTransaction();			
  			Query q;
  			q = session.createQuery("FROM HibernateConfig c WHERE c.current = FALSE AND c.name != null");
  			Iterator it = q.list().iterator();
  			if (q.list().size() > 0) {
  				while (it.hasNext()) {
  					HibernateConfig config = (HibernateConfig)it.next();
  					if (config.getName() != null)
  						list.add(config.getName());
  				}
  			}
  			tx.commit();
  			return list;
  			// Handles when transaction goes wrong...
  		} catch (Exception e) {
  			log.error("Couldn't retrive backup configuration dates", e);
  			if (tx != null) {
  				try {
  					tx.rollback();
  				} catch (Exception e1) {
  					log.error("Hibernate error: rollback failed", e1);
  					throw new RuntimeException("Database errors: " + e.getMessage() + " - " + e1.getMessage(), e);
  				}
  			}
  			throw new RuntimeException("Database error: " + e.getMessage(), e);
 		} finally {
 			if (session != null) {
 				try {
 					session.close();
 				} catch (Exception e1) {
 					log.error("Hibernate error: couldn't close session", e1);
 					throw new RuntimeException("Database error: " + e1.getMessage(), e1);
 				}
 			}
 		}
 	}
 
 	public Date getLastModification() {
 		Session session = null;
 		Transaction tx = null;
 		try {
 			// Checks whether the value is present in the database
 			session = persistenceFactory.retrieveSessionFactory().openSession();
 			tx = session.beginTransaction();			
 			Query q;
 			q = session.createQuery("select c.timestamp from HibernateConfig c where c.current = TRUE");
 			if (q.list().size() == 0)
 				return new Date(0);
 			else {
 				Date date = (Date)((Date)q.list().get(0)).clone();
 				return date;
 			}
 			// Handles when transaction goes wrong...
 		} catch (Exception e) {
 			log.error("Couldn't retrieve current configuration", e);
 			if (tx != null) {
 				try {
 					tx.rollback();
 				} catch (Exception e1) {
 					log.error("Hibernate error: rollback failed", e1);
 					throw new RuntimeException("Database errors: " + e.getMessage() + " - " + e1.getMessage(), e);
 				}
 			}
 			throw new RuntimeException("Database error: " + e.getMessage(), e);
 		} finally {
 			if (tx != null)
 				tx.commit();
 			if (session != null)
 				session.close();
 		}
 	}
 
 	public boolean isActive() {
 		return true;
 	}
 
 	public String restoreConfiguration(String name) {
 		Session session = null;
 		Transaction tx = null;
 		try {
 			// Checks whether the value is present in the database
 			session = persistenceFactory.retrieveSessionFactory().openSession();
 			tx = session.beginTransaction();			
 			Query q;
 			q = session.createQuery("FROM HibernateConfig c WHERE c.name = ?");
 			q.setString(0, name);
 			if (q.list().size() == 1) {
 				String xml = ((HibernateConfig)q.list().get(0)).getXml();
 				tx.commit();
 				return xml;
 			}
 			else {
 				throw new RuntimeException("None or more than one configuration is stored name " + name);
 			}
 			// Handles when transaction goes wrong...
 		} catch (Exception e) {
 			log.error("Couldn't restore configuration", e);
 			if (tx != null) {
 				try {
 					tx.rollback();
 				} catch (Exception e1) {
 					log.error("Hibernate error: rollback failed", e1);
 					throw new RuntimeException("Database errors: " + e.getMessage() + " - " + e1.getMessage(), e);
 				}
 			}
 			throw new RuntimeException("Database error: " + e.getMessage(), e);
 		} finally {
 			if (session != null) {
 				try {
 					session.close();
 				} catch (Exception e1) {
 					log.error("Hibernate error: couldn't close session", e1);
 					throw new RuntimeException("Database error: " + e1.getMessage(), e1);
 				}
 			}
 		}		
 	}
 
 	public String retrieveCurrentConfiguration() {
 		Session session = null;
 		Transaction tx = null;
 		try {
 			// Checks whether the value is present in the database
 			session = persistenceFactory.retrieveSessionFactory().openSession();
 			tx = session.beginTransaction();			
 			Query q;
 			q = session.createQuery("FROM HibernateConfig c WHERE c.current = TRUE");
 			if (q.list().size() != 1) {
 				log.error("None or more than one configuration is set to current in the database");
 				throw new RuntimeException("None or more than one configuration is set to current in the database");
 			}
 			tx.commit();
 			return new String(((HibernateConfig)q.list().get(0)).getXml());
 			// Handles when transaction goes wrong...
 		} catch (Exception e) {
 			log.error("Couldn't retrive current configuration", e);
 			if (tx != null) {
 				try {
 					tx.rollback();
 				} catch (Exception e1) {
 					log.error("Hibernate error: rollback failed", e1);
 					throw new RuntimeException("Database errors: " + e.getMessage() + " - " + e1.getMessage(), e);
 				}
 			}
 			throw new RuntimeException("Database error: " + e.getMessage(), e);
 		} finally {
 			if (session != null) {
 				try {
 					session.close();
 				} catch (Exception e1) {
 					log.error("Hibernate error: couldn't close session", e1);
 					throw new RuntimeException("Database error: " + e1.getMessage(), e1);
 				}
 			}
 		}		
 	}
 
 	public void setConfiguration(String text, boolean backupCopy, String name, Date date) {
 		Session session = null;
 		Transaction tx = null;
 		
 		try {
 			// Checks whether the value is present in the database
 			session = persistenceFactory.retrieveSessionFactory().openSession();
 			tx = session.beginTransaction();
 
 			if (backupCopy) {
 				// delete any configurations with the same name
 				Query q = session.createQuery("FROM HibernateConfig c WHERE c.name = ?");
 				q.setString(0, name);
 				Iterator it = q.list().iterator();
 				while (it.hasNext()) {
 					HibernateConfig hibernateConfig = (HibernateConfig)it.next();
 					if (hibernateConfig.getTimestamp().compareTo(date)==0)
 						session.delete(hibernateConfig);
 				}
 			}
 			else
 			{
 				// delete current configuration
 				Query q = session.createQuery("DELETE FROM HibernateConfig WHERE current = TRUE");
 				q.executeUpdate();
 			}
 
 			// add new configuration
 			HibernateConfig config = new HibernateConfig();
 			config.setXml(text);
 			config.setTimestamp(date);
 			config.setCurrent(new Boolean(!backupCopy));
 			config.setName(name);
 			session.save(config);
 
 			tx.commit();
 			// Handles when transaction goes wrong...
 		} catch (Exception e) {
 			log.error("Couldn't set configuration", e);
 			if (tx != null) {
 				try {
 					tx.rollback();
 				} catch (Exception e1) {
 					log.error("Hibernate error: rollback failed", e1);
 					throw new RuntimeException("Database errors: " + e.getMessage() + " - " + e1.getMessage(), e);
 				}
 			}
 			throw new RuntimeException("Database error: " + e.getMessage(), e);
 		} finally {
 			if (session != null) {
 				try {
 					session.close();
 				} catch (Exception e1) {
 					log.error("Hibernate error: couldn't close session", e1);
 					throw new RuntimeException("Database error: " + e1.getMessage(), e1);
 				}
 			}
 		}			
 	}    
 
 }