package com.trentris.tracaranda.persistence;

import javax.servlet.ServletContext;

import org.apache.cocoon.environment.ObjectModelHelper;
import org.apache.cocoon.sitemap.EnterSitemapEvent;
import org.apache.cocoon.sitemap.EnterSitemapEventListener;
import org.apache.cocoon.sitemap.LeaveSitemapEvent;
import org.apache.cocoon.sitemap.LeaveSitemapEventListener;
import org.apache.cocoon.util.AbstractLogEnabled;
import org.hibernate.FlushMode;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.orm.hibernate3.SessionFactoryUtils;
import org.springframework.orm.hibernate3.SessionHolder;
import org.springframework.transaction.support.TransactionSynchronizationManager;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

public class HibernateSessionSitemapListener extends AbstractLogEnabled implements
		EnterSitemapEventListener, LeaveSitemapEventListener{

	public static final String DEFAULT_SESSION_FACTORY_BEAN_NAME = "sessionFactory";

	private String sessionFactoryBeanName = DEFAULT_SESSION_FACTORY_BEAN_NAME;

	private boolean singleSession = true;

	private FlushMode flushMode = FlushMode.NEVER;

	public void enteredSitemap(EnterSitemapEvent event) {
		System.out.println("HIBERNATE LISTENER: " + event.getEnvironment().getURI());
		ServletContext context = ObjectModelHelper.getContext(event.getEnvironment().getObjectModel());
		SessionFactory sessionFactory = lookupSessionFactory(context);
		Boolean participate = false;
		if (isSingleSession()) {
			// single session mode
			if (TransactionSynchronizationManager.hasResource(sessionFactory)) {
				// Do not modify the Session: just set the participate flag.
				participate = true;
			} else {
				getLogger()
						.debug(
								"Opening single Hibernate Session in HibernateSessionSitemapListener");
				Session session = getSession(sessionFactory);
				TransactionSynchronizationManager.bindResource(sessionFactory,
						new SessionHolder(session));
			}
		} else {
			// deferred close mode
			if (SessionFactoryUtils.isDeferredCloseActive(sessionFactory)) {
				// Do not modify deferred close: just set the participate flag.
				participate = true;
			} else {
				SessionFactoryUtils.initDeferredClose(sessionFactory);
			}
		}
		context.setAttribute("hibernateParticipate", participate);
		//return participate;
	}

	public void leftSitemap(LeaveSitemapEvent event) {
		ServletContext context = ObjectModelHelper.getContext(event.getEnvironment().getObjectModel());
		SessionFactory sessionFactory = lookupSessionFactory(context);
		Boolean participate = (Boolean) context.getAttribute("hibernateParticipate");
		if (participate != null && !participate.booleanValue()) {
			if (isSingleSession()) {
				// single session mode
				SessionHolder sessionHolder = (SessionHolder) TransactionSynchronizationManager
						.unbindResource(sessionFactory);
				getLogger()
						.debug(
								"Closing single Hibernate Session in HibernateSessionSitemapListener");
				closeSession(sessionHolder.getSession(), sessionFactory);
			} else {
				// deferred close mode
				SessionFactoryUtils.processDeferredClose(sessionFactory);
			}
			context.removeAttribute("hibernateParticipate");
		}
		

	}

	/**
	 * Set the bean name of the SessionFactory to fetch from Spring's root
	 * application context. Default is "sessionFactory".
	 * 
	 * @see #DEFAULT_SESSION_FACTORY_BEAN_NAME
	 */
	public void setSessionFactoryBeanName(String sessionFactoryBeanName) {
		this.sessionFactoryBeanName = sessionFactoryBeanName;
	}

	/**
	 * Return the bean name of the SessionFactory to fetch from Spring's root
	 * application context.
	 */
	protected String getSessionFactoryBeanName() {
		return this.sessionFactoryBeanName;
	}

	/**
	 * Set whether to use a single session for each request. Default is "true".
	 * <p>
	 * If set to "false", each data access operation or transaction will use its
	 * own session (like without Open Session in View). Each of those sessions
	 * will be registered for deferred close, though, actually processed at
	 * request completion.
	 * 
	 * @see SessionFactoryUtils#initDeferredClose
	 * @see SessionFactoryUtils#processDeferredClose
	 */
	public void setSingleSession(boolean singleSession) {
		this.singleSession = singleSession;
	}

	/**
	 * Return whether to use a single session for each request.
	 */
	protected boolean isSingleSession() {
		return this.singleSession;
	}

	/**
	 * Specify the Hibernate FlushMode to apply to this filter's
	 * {@link org.hibernate.Session}. Only applied in single session mode.
	 * <p>
	 * Can be populated with the corresponding constant name in XML bean
	 * definitions: e.g. "AUTO".
	 * <p>
	 * The default is "NEVER". Specify "AUTO" if you intend to use this filter
	 * without service layer transactions.
	 * 
	 * @see org.hibernate.Session#setFlushMode
	 * @see org.hibernate.FlushMode#NEVER
	 * @see org.hibernate.FlushMode#AUTO
	 */
	public void setFlushMode(FlushMode flushMode) {
		this.flushMode = flushMode;
	}

	/**
	 * Return the Hibernate FlushMode that this filter applies to its
	 * {@link org.hibernate.Session} (in single session mode).
	 */
	protected FlushMode getFlushMode() {
		return this.flushMode;
	}

	/**
	 * Look up the SessionFactory that this filter should use, taking the
	 * current HTTP request as argument.
	 * <p>
	 * The default implementation delegates to the
	 * {@link #lookupSessionFactory()} variant without arguments.
	 * 
	 * @param request
	 *            the current request
	 * @return the SessionFactory to use
	 */
	// protected SessionFactory lookupSessionFactory(HttpServletRequest request)
	// {
	// return lookupSessionFactory();
	// }
	/**
	 * Look up the SessionFactory that this filter should use.
	 * <p>
	 * The default implementation looks for a bean with the specified name in
	 * Spring's root application context.
	 * 
	 * @return the SessionFactory to use
	 * @see #getSessionFactoryBeanName
	 */
	protected SessionFactory lookupSessionFactory(ServletContext context) {
		getLogger().debug(
				"Using SessionFactory '" + getSessionFactoryBeanName()
						+ "' for HibernateSessionSitemapListener");
		WebApplicationContext wac = WebApplicationContextUtils
				.getRequiredWebApplicationContext(context);

		return (SessionFactory) wac.getBean(getSessionFactoryBeanName(),
				SessionFactory.class);
	}

	/**
	 * Get a Session for the SessionFactory that this filter uses. Note that
	 * this just applies in single session mode!
	 * <p>
	 * The default implementation delegates to the
	 * <code>SessionFactoryUtils.getSession</code> method and sets the
	 * <code>Session</code>'s flush mode to "NEVER".
	 * <p>
	 * Can be overridden in subclasses for creating a Session with a custom
	 * entity interceptor or JDBC exception translator.
	 * 
	 * @param sessionFactory
	 *            the SessionFactory that this filter uses
	 * @return the Session to use
	 * @throws DataAccessResourceFailureException
	 *             if the Session could not be created
	 * @see org.springframework.orm.hibernate3.SessionFactoryUtils#getSession(SessionFactory,
	 *      boolean)
	 * @see org.hibernate.FlushMode#NEVER
	 */
	protected Session getSession(SessionFactory sessionFactory)
			throws DataAccessResourceFailureException {
		Session session = SessionFactoryUtils.getSession(sessionFactory, true);
		FlushMode flushMode = getFlushMode();
		if (flushMode != null) {
			session.setFlushMode(flushMode);
		}
		return session;
	}

	/**
	 * Close the given Session. Note that this just applies in single session
	 * mode!
	 * <p>
	 * Can be overridden in subclasses, e.g. for flushing the Session before
	 * closing it. See class-level javadoc for a discussion of flush handling.
	 * Note that you should also override getSession accordingly, to set the
	 * flush mode to something else than NEVER.
	 * 
	 * @param session
	 *            the Session used for filtering
	 * @param sessionFactory
	 *            the SessionFactory that this filter uses
	 */
	protected void closeSession(Session session, SessionFactory sessionFactory) {
		SessionFactoryUtils.closeSession(session);
	}

}