/*
 * Copyright 2002-2016 the original author or authors.
 *
 * 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.authentication;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.*;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.security.authentication.event.AbstractAuthenticationEvent;
import org.springframework.security.authentication.event.AbstractAuthenticationFailureEvent;
import org.springframework.security.authentication.event.AuthenticationFailureBadCredentialsEvent;
import org.springframework.security.authentication.event.AuthenticationFailureCredentialsExpiredEvent;
import org.springframework.security.authentication.event.AuthenticationFailureDisabledEvent;
import org.springframework.security.authentication.event.AuthenticationFailureExpiredEvent;
import org.springframework.security.authentication.event.AuthenticationFailureLockedEvent;
import org.springframework.security.authentication.event.AuthenticationFailureProviderNotFoundEvent;
import org.springframework.security.authentication.event.AuthenticationFailureProxyUntrustedEvent;
import org.springframework.security.authentication.event.AuthenticationFailureServiceExceptionEvent;
import org.springframework.security.authentication.event.AuthenticationSuccessEvent;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.util.Assert;

/**
 * The default strategy for publishing authentication events.
 * <p>
 * Maps well-known <tt>AuthenticationException</tt> types to events and publishes them via
 * the application context. If configured as a bean, it will pick up the
 * <tt>ApplicationEventPublisher</tt> automatically. Otherwise, the constructor which
 * takes the publisher as an argument should be used.
 * <p>
 * The exception-mapping system can be fine-tuned by setting the
 * <tt>additionalExceptionMappings</tt> as a <code>java.util.Properties</code> object. In
 * the properties object, each of the keys represent the fully qualified classname of the
 * exception, and each of the values represent the name of an event class which subclasses
 * {@link org.springframework.security.authentication.event.AbstractAuthenticationFailureEvent}
 * and provides its constructor. The <tt>additionalExceptionMappings</tt> will be merged
 * with the default ones.
 *
 * @author Luke Taylor
 * @since 3.0
 */
public class DefaultAuthenticationEventPublisher implements AuthenticationEventPublisher,
		ApplicationEventPublisherAware {
	private final Log logger = LogFactory.getLog(getClass());

	private ApplicationEventPublisher applicationEventPublisher;
	private final HashMap<String, Constructor<? extends AbstractAuthenticationEvent>> exceptionMappings = new HashMap<String, Constructor<? extends AbstractAuthenticationEvent>>();

	public DefaultAuthenticationEventPublisher() {
		this(null);
	}

	public DefaultAuthenticationEventPublisher(
			ApplicationEventPublisher applicationEventPublisher) {
		this.applicationEventPublisher = applicationEventPublisher;

		addMapping(BadCredentialsException.class.getName(),
				AuthenticationFailureBadCredentialsEvent.class);
		addMapping(UsernameNotFoundException.class.getName(),
				AuthenticationFailureBadCredentialsEvent.class);
		addMapping(AccountExpiredException.class.getName(),
				AuthenticationFailureExpiredEvent.class);
		addMapping(ProviderNotFoundException.class.getName(),
				AuthenticationFailureProviderNotFoundEvent.class);
		addMapping(DisabledException.class.getName(),
				AuthenticationFailureDisabledEvent.class);
		addMapping(LockedException.class.getName(),
				AuthenticationFailureLockedEvent.class);
		addMapping(AuthenticationServiceException.class.getName(),
				AuthenticationFailureServiceExceptionEvent.class);
		addMapping(CredentialsExpiredException.class.getName(),
				AuthenticationFailureCredentialsExpiredEvent.class);
		addMapping(
				"org.springframework.security.authentication.cas.ProxyUntrustedException",
				AuthenticationFailureProxyUntrustedEvent.class);
	}

	public void publishAuthenticationSuccess(Authentication authentication) {
		if (applicationEventPublisher != null) {
			applicationEventPublisher.publishEvent(new AuthenticationSuccessEvent(
					authentication));
		}
	}

	public void publishAuthenticationFailure(AuthenticationException exception,
			Authentication authentication) {
		Constructor<? extends AbstractAuthenticationEvent> constructor = exceptionMappings
				.get(exception.getClass().getName());
		AbstractAuthenticationEvent event = null;

		if (constructor != null) {
			try {
				event = constructor.newInstance(authentication, exception);
			}
			catch (IllegalAccessException ignored) {
			}
			catch (InstantiationException ignored) {
			}
			catch (InvocationTargetException ignored) {
			}
		}

		if (event != null) {
			if (applicationEventPublisher != null) {
				applicationEventPublisher.publishEvent(event);
			}
		}
		else {
			if (logger.isDebugEnabled()) {
				logger.debug("No event was found for the exception "
						+ exception.getClass().getName());
			}
		}
	}

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

	/**
	 * Sets additional exception to event mappings. These are automatically merged with
	 * the default exception to event mappings that <code>ProviderManager</code> defines.
	 *
	 * @param additionalExceptionMappings where keys are the fully-qualified string name
	 * of the exception class and the values are the fully-qualified string name of the
	 * event class to fire.
	 */
	@SuppressWarnings({ "unchecked" })
	public void setAdditionalExceptionMappings(Properties additionalExceptionMappings) {
		Assert.notNull(additionalExceptionMappings,
				"The exceptionMappings object must not be null");
		for (Object exceptionClass : additionalExceptionMappings.keySet()) {
			String eventClass = (String) additionalExceptionMappings.get(exceptionClass);
			try {
				Class<?> clazz = getClass().getClassLoader().loadClass(eventClass);
				Assert.isAssignable(AbstractAuthenticationFailureEvent.class, clazz);
				addMapping((String) exceptionClass,
						(Class<? extends AbstractAuthenticationFailureEvent>) clazz);
			}
			catch (ClassNotFoundException e) {
				throw new RuntimeException("Failed to load authentication event class "
						+ eventClass);
			}
		}
	}

	private void addMapping(String exceptionClass,
			Class<? extends AbstractAuthenticationFailureEvent> eventClass) {
		try {
			Constructor<? extends AbstractAuthenticationEvent> constructor = eventClass
					.getConstructor(Authentication.class, AuthenticationException.class);
			exceptionMappings.put(exceptionClass, constructor);
		}
		catch (NoSuchMethodException e) {
			throw new RuntimeException("Authentication event class "
					+ eventClass.getName() + " has no suitable constructor");
		}
	}
}
