/*
 * Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * 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.springframework.security.web.authentication.rememberme;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.event.InteractiveAuthenticationSuccessEvent;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.AuthenticationSuccessHandler;
import org.springframework.security.web.authentication.RememberMeServices;
import org.springframework.util.Assert;
import org.springframework.web.filter.GenericFilterBean;

/**
 * Detects if there is no {@code Authentication} object in the {@code SecurityContext},
 * and populates the context with a remember-me authentication token if a
 * {@link RememberMeServices} implementation so requests.
 * <p>
 * Concrete {@code RememberMeServices} implementations will have their
 * {@link RememberMeServices#autoLogin(HttpServletRequest, HttpServletResponse)} method
 * called by this filter. If this method returns a non-null {@code Authentication} object,
 * it will be passed to the {@code AuthenticationManager}, so that any
 * authentication-specific behaviour can be achieved. The resulting {@code Authentication}
 * (if successful) will be placed into the {@code SecurityContext}.
 * <p>
 * If authentication is successful, an {@link InteractiveAuthenticationSuccessEvent} will
 * be published to the application context. No events will be published if authentication
 * was unsuccessful, because this would generally be recorded via an
 * {@code AuthenticationManager}-specific application event.
 * <p>
 * Normally the request will be allowed to proceed regardless of whether authentication
 * succeeds or fails. If some control over the destination for authenticated users is
 * required, an {@link AuthenticationSuccessHandler} can be injected
 *
 * @author Ben Alex
 * @author Luke Taylor
 */
public class RememberMeAuthenticationFilter extends GenericFilterBean implements
		ApplicationEventPublisherAware {

	// ~ Instance fields
	// ================================================================================================

	private ApplicationEventPublisher eventPublisher;
	private AuthenticationSuccessHandler successHandler;
	private AuthenticationManager authenticationManager;
	private RememberMeServices rememberMeServices;

	public RememberMeAuthenticationFilter(AuthenticationManager authenticationManager,
			RememberMeServices rememberMeServices) {
		Assert.notNull(authenticationManager, "authenticationManager cannot be null");
		Assert.notNull(rememberMeServices, "rememberMeServices cannot be null");
		this.authenticationManager = authenticationManager;
		this.rememberMeServices = rememberMeServices;
	}

	// ~ Methods
	// ========================================================================================================

	@Override
	public void afterPropertiesSet() {
		Assert.notNull(authenticationManager, "authenticationManager must be specified");
		Assert.notNull(rememberMeServices, "rememberMeServices must be specified");
	}

	public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
			throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;
		HttpServletResponse response = (HttpServletResponse) res;

		if (SecurityContextHolder.getContext().getAuthentication() == null) {
			Authentication rememberMeAuth = rememberMeServices.autoLogin(request,
					response);

			if (rememberMeAuth != null) {
				// Attempt authenticaton via AuthenticationManager
				try {
					rememberMeAuth = authenticationManager.authenticate(rememberMeAuth);

					// Store to SecurityContextHolder
					SecurityContextHolder.getContext().setAuthentication(rememberMeAuth);

					onSuccessfulAuthentication(request, response, rememberMeAuth);

					if (logger.isDebugEnabled()) {
						logger.debug("SecurityContextHolder populated with remember-me token: '"
								+ SecurityContextHolder.getContext().getAuthentication()
								+ "'");
					}

					// Fire event
					if (this.eventPublisher != null) {
						eventPublisher
								.publishEvent(new InteractiveAuthenticationSuccessEvent(
										SecurityContextHolder.getContext()
												.getAuthentication(), this.getClass()));
					}

					if (successHandler != null) {
						successHandler.onAuthenticationSuccess(request, response,
								rememberMeAuth);

						return;
					}

				}
				catch (AuthenticationException authenticationException) {
					if (logger.isDebugEnabled()) {
						logger.debug(
								"SecurityContextHolder not populated with remember-me token, as "
										+ "AuthenticationManager rejected Authentication returned by RememberMeServices: '"
										+ rememberMeAuth
										+ "'; invalidating remember-me token",
								authenticationException);
					}

					rememberMeServices.loginFail(request, response);

					onUnsuccessfulAuthentication(request, response,
							authenticationException);
				}
			}

			chain.doFilter(request, response);
		}
		else {
			if (logger.isDebugEnabled()) {
				logger.debug("SecurityContextHolder not populated with remember-me token, as it already contained: '"
						+ SecurityContextHolder.getContext().getAuthentication() + "'");
			}

			chain.doFilter(request, response);
		}
	}

	/**
	 * Called if a remember-me token is presented and successfully authenticated by the
	 * {@code RememberMeServices} {@code autoLogin} method and the
	 * {@code AuthenticationManager}.
	 */
	protected void onSuccessfulAuthentication(HttpServletRequest request,
			HttpServletResponse response, Authentication authResult) {
	}

	/**
	 * Called if the {@code AuthenticationManager} rejects the authentication object
	 * returned from the {@code RememberMeServices} {@code autoLogin} method. This method
	 * will not be called when no remember-me token is present in the request and
	 * {@code autoLogin} reurns null.
	 */
	protected void onUnsuccessfulAuthentication(HttpServletRequest request,
			HttpServletResponse response, AuthenticationException failed) {
	}

	public RememberMeServices getRememberMeServices() {
		return rememberMeServices;
	}

	public void setApplicationEventPublisher(ApplicationEventPublisher eventPublisher) {
		this.eventPublisher = eventPublisher;
	}

	/**
	 * Allows control over the destination a remembered user is sent to when they are
	 * successfully authenticated. By default, the filter will just allow the current
	 * request to proceed, but if an {@code AuthenticationSuccessHandler} is set, it will
	 * be invoked and the {@code doFilter()} method will return immediately, thus allowing
	 * the application to redirect the user to a specific URL, regardless of whatthe
	 * original request was for.
	 *
	 * @param successHandler the strategy to invoke immediately before returning from
	 * {@code doFilter()}.
	 */
	public void setAuthenticationSuccessHandler(
			AuthenticationSuccessHandler successHandler) {
		Assert.notNull(successHandler, "successHandler cannot be null");
		this.successHandler = successHandler;
	}

}
