/*
 * JBoss, Home of Professional Open Source
 * Copyright 2008, Red Hat Middleware LLC, and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.jboss.weld.environment.servlet;

import javax.enterprise.inject.spi.BeanManager;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.Reference;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import org.jboss.weld.environment.servlet.logging.WeldServletLogger;

/**
 * Emulates the behavior of the naming resource binding that is typically done
 * using configuration files in Tomcat and Jetty. This listener provides the ability
 * to bind the BeanManager to JNDI without the need for configuration.
 *
 * @author Dan Allen
 * @author Christian Sadilek <csadilek@redhat.com>
 */
public class BeanManagerResourceBindingListener implements ServletContextListener {
    private static final String RESOURCES_CONTEXT = "java:comp/env";
    private static final String BEAN_MANAGER_JNDI_NAME = "BeanManager";
    private static final String QUALIFIED_BEAN_MANAGER_JNDI_NAME = RESOURCES_CONTEXT + "/" + BEAN_MANAGER_JNDI_NAME;
    private static final String BEAN_MANAGER_OBJECT_FACTORY = "org.jboss.weld.resources.ManagerObjectFactory";

    private boolean bound = false;

    public void contextInitialized(ServletContextEvent sce) {
        try {
            InitialContext ctx = new InitialContext();
            boolean present = false;
            try {
                NamingEnumeration<NameClassPair> entries = ctx.list(RESOURCES_CONTEXT);
                while (entries.hasMoreElements()) {
                    try {
                        NameClassPair e = entries.next();
                        if (e.getName().equals(BEAN_MANAGER_JNDI_NAME) && e.getClassName().equals(BeanManager.class)) {
                            present = true;
                            break;
                        }
                    } catch (Exception e) {
                        WeldServletLogger.LOG.problemWhenInterating(RESOURCES_CONTEXT, e);
                    }
                }
            } catch (NamingException e) {
                WeldServletLogger.LOG.couldNotReadContext(RESOURCES_CONTEXT);
                try {
                    Context compCtx = (Context) ctx.lookup("java:comp");
                    compCtx.createSubcontext("env");
                } catch (Exception ex) {
                    WeldServletLogger.LOG.couldntCreateContext(RESOURCES_CONTEXT);
                }
            }

            if (!present) {
                try {
                    // we rebind just in case it really is there and we just couldn't read it
                    ctx.rebind(QUALIFIED_BEAN_MANAGER_JNDI_NAME,
                            new Reference(BeanManager.class.getName(), BEAN_MANAGER_OBJECT_FACTORY, null));
                    bound = true;
                    WeldServletLogger.LOG.beanManagerReferenceBoundTo(QUALIFIED_BEAN_MANAGER_JNDI_NAME);
                } catch (NamingException e) {
                    throw WeldServletLogger.LOG.couldNotBindBeanManagerReferenceToJNDI(e.getExplanation());
                }
            }
        } catch (NamingException e) {
            throw WeldServletLogger.LOG.couldNotCreateInitialContext(e.getExplanation());
        }
    }

    public void contextDestroyed(ServletContextEvent sce) {
        if (bound) {
            try {
                InitialContext ctx = new InitialContext();
                ctx.unbind(QUALIFIED_BEAN_MANAGER_JNDI_NAME);
                WeldServletLogger.LOG.successfullyUnboundBeanManagerReference();
            } catch (NamingException e) {
                WeldServletLogger.LOG.failedToUnbindBeanManagerReference();
            }
        }
    }
}