/*
 * JBoss, Home of Professional Open Source
 * Copyright 2007, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.ejb3.security;

import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.Principal;
import java.security.PrivilegedExceptionAction;

import javax.security.auth.Subject;

import org.jboss.aop.advice.Interceptor;
import org.jboss.aop.joinpoint.Invocation;
import org.jboss.aop.joinpoint.MethodInvocation;
import org.jboss.ejb3.Container;
import org.jboss.ejb3.EJBContainer;
import org.jboss.ejb3.annotation.SecurityDomain;
import org.jboss.logging.Logger;
import org.jboss.security.ISecurityManagement;
import org.jboss.security.RunAs;
import org.jboss.security.RunAsIdentity;
import org.jboss.security.SecurityContext;
import org.jboss.security.SecurityUtil;
import org.jboss.security.identity.Identity;
import org.jboss.security.identity.plugins.SimpleIdentity;
import org.jboss.security.javaee.EJBAuthenticationHelper;
import org.jboss.security.javaee.SecurityHelperFactory;

/**
 * Authentication Interceptor
 * 
 * @author <a href="mailto:bill@jboss.org">Bill Burke</a>
 * @author Anil.Saldhana@redhat.com
 * @since Aug 16, 2007
 * @version $Revision$
 */
public class Ejb3AuthenticationInterceptorv2 implements Interceptor {
	protected Logger log = Logger.getLogger(this.getClass());
	private EJBContainer container;

	public Ejb3AuthenticationInterceptorv2(Container container) {
		this.container = (EJBContainer) container;
	}

	public String getName() {
		return getClass().getName();
	}

	public Object invoke(Invocation invocation) throws Throwable {
		// Check for ejbTimeOutCallback or ejbTimeOut method
		SecurityHelper shelper = new SecurityHelper();
		MethodInvocation mi = (MethodInvocation) invocation;
		Method method = mi.getMethod();
		if (shelper.isEJBTimeOutCallback(method) || shelper.containsTimeoutAnnotation(container, method)
				|| shelper.isMDB(container))
			return invocation.invokeNext();

		SecurityContext prevSC = SecurityActions.getSecurityContext();
		try {
			// See org.jboss.ejb3.security.client.SecurityClientInterceptor
			SecurityContext invSC = (SecurityContext) invocation.getMetaData("security", "context");

			SecurityDomain domain = container.getAnnotation(SecurityDomain.class);

			boolean domainExists = domain != null && domain.value() != null
					&& domain.value().length() > 0;

			/**
			 * TODO: Decide if you want to allow zero security based on
			 * non-availability of a security domain, as per the configuration
			 * on the container
			 */
			if (domainExists) {
				String domainValue = canonicalizeSecurityDomain(domain.value());

				/*
				 * Need to establish the security context. For local calls, we
				 * pick the outgoing runas of the existing sc. For remote calls,
				 * we create a new security context with the information from
				 * the invocation sc
				 */
				final SecurityContext sc = SecurityActions.createSecurityContext(domainValue);

				if (invSC == null) {
					if (prevSC == null)
						throw new IllegalStateException("Local Call: Security Context is null");
					populateSecurityContext(sc, prevSC);
				} else {
					populateSecurityContext(sc, invSC);
				}

				SecurityActions.setSecurityContext(sc);

				// TODO: Need to get the SecurityManagement instance
				AccessController.doPrivileged(new PrivilegedExceptionAction<Object>() {
					public Object run() throws Exception {
						sc.setSecurityManagement(getSecurityManagement());
						return null;
					}
				});

				// Check if there is a RunAs configured and can be trusted
				EJBAuthenticationHelper helper = null;
				try {
					helper = SecurityHelperFactory.getEJBAuthenticationHelper(sc);
				} catch (Exception e) {
					throw new RuntimeException(e);
				}
				boolean trustedCaller = hasIncomingRunAsIdentity(sc) || helper.isTrusted();
				if (!trustedCaller) {
					Subject subject = new Subject();
					/**
					 * Special Case: Invocation has no principal set, but an
					 * unauthenticatedPrincipal has been configured in JBoss DD
					 */
					Principal userPrincipal = sc.getUtil().getUserPrincipal();
					String unauthenticatedPrincipal = domain.unauthenticatedPrincipal();
					if (userPrincipal == null && unauthenticatedPrincipal != null
							&& unauthenticatedPrincipal.length() > 0) {
						Identity unauthenticatedIdentity = new SimpleIdentity(unauthenticatedPrincipal);
						sc.getSubjectInfo().addIdentity(unauthenticatedIdentity);
						subject.getPrincipals().add(unauthenticatedIdentity.asPrincipal());
					} else {
						// Authenticate the caller now
						if (!helper.isValid(subject, method.getName())) {
							Exception ex = (Exception) sc.getData().get("org.jboss.security.exception");
							throw ex;
						}
					}
					helper.pushSubjectContext(subject);
				} else {
					// Trusted caller. No need for authentication. Straight to
					// authorization
				}
			} else {
				// domain == null
				/**
				 * Special Case when a bean with no security domain defined
				 * comes with a security context attached.
				 */
				if (invSC != null) {
					SecurityActions.setSecurityContext(invSC);
				}
			}
			return invocation.invokeNext();
		} finally {
			SecurityActions.setSecurityContext(prevSC);
		}
	}

	private String canonicalizeSecurityDomain(String securityDomain) {
		return SecurityUtil.unprefixSecurityDomain(securityDomain);
	}

	private void populateSecurityContext(SecurityContext to, SecurityContext from) {
		SecurityActions.setSubjectInfo(to, from.getSubjectInfo());
		SecurityActions.setIncomingRunAs(to, from.getOutgoingRunAs());
	}

	/**
	 * TODO: This needs to be injectable
	 * 
	 * @return
	 * @throws Exception
	 */
	private ISecurityManagement getSecurityManagement() throws Exception {
		Class<?> clazz = SecurityActions
				.loadClass("org.jboss.security.integration.JNDIBasedSecurityManagement");
		return (ISecurityManagement) clazz.newInstance();
	}

	private boolean hasIncomingRunAsIdentity(SecurityContext sc) {
		RunAs incomingRunAs = sc.getIncomingRunAs();
		return incomingRunAs != null && incomingRunAs instanceof RunAsIdentity;
	}
}