/*
 * Copyright 2014-2018 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
 *
 *      https://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.session.data.redis.config.annotation.web.http;

import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.Executor;

import org.apache.commons.logging.LogFactory;

import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.EmbeddedValueResolverAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportAware;
import org.springframework.core.annotation.AnnotationAttributes;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.listener.ChannelTopic;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.session.MapSession;
import org.springframework.session.config.annotation.web.http.SpringHttpSessionConfiguration;
import org.springframework.session.data.redis.RedisFlushMode;
import org.springframework.session.data.redis.RedisOperationsSessionRepository;
import org.springframework.session.data.redis.config.ConfigureNotifyKeyspaceEventsAction;
import org.springframework.session.data.redis.config.ConfigureRedisAction;
import org.springframework.session.data.redis.config.annotation.SpringSessionRedisConnectionFactory;
import org.springframework.session.web.http.SessionRepositoryFilter;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.util.StringValueResolver;

/**
 * Exposes the {@link SessionRepositoryFilter} as a bean named
 * {@code springSessionRepositoryFilter}. In order to use this a single
 * {@link RedisConnectionFactory} must be exposed as a Bean.
 *
 * @author Rob Winch
 * @author Eddú Meléndez
 * @author Vedran Pavic
 * @see EnableRedisHttpSession
 * @since 1.0
 */
@Configuration
@EnableScheduling
public class RedisHttpSessionConfiguration extends SpringHttpSessionConfiguration
		implements BeanClassLoaderAware, EmbeddedValueResolverAware, ImportAware,
		SchedulingConfigurer {

	static final String DEFAULT_CLEANUP_CRON = "0 * * * * *";

	private Integer maxInactiveIntervalInSeconds = MapSession.DEFAULT_MAX_INACTIVE_INTERVAL_SECONDS;

	private String redisNamespace = RedisOperationsSessionRepository.DEFAULT_NAMESPACE;

	private RedisFlushMode redisFlushMode = RedisFlushMode.ON_SAVE;

	private String cleanupCron = DEFAULT_CLEANUP_CRON;

	private ConfigureRedisAction configureRedisAction = new ConfigureNotifyKeyspaceEventsAction();

	private RedisConnectionFactory redisConnectionFactory;

	private RedisSerializer<Object> defaultRedisSerializer;

	private ApplicationEventPublisher applicationEventPublisher;

	private Executor redisTaskExecutor;

	private Executor redisSubscriptionExecutor;

	private ClassLoader classLoader;

	private StringValueResolver embeddedValueResolver;

	@Bean
	public RedisOperationsSessionRepository sessionRepository() {
		RedisTemplate<Object, Object> redisTemplate = createRedisTemplate();
		RedisOperationsSessionRepository sessionRepository = new RedisOperationsSessionRepository(
				redisTemplate);
		sessionRepository.setApplicationEventPublisher(this.applicationEventPublisher);
		if (this.defaultRedisSerializer != null) {
			sessionRepository.setDefaultSerializer(this.defaultRedisSerializer);
		}
		sessionRepository
				.setDefaultMaxInactiveInterval(this.maxInactiveIntervalInSeconds);
		if (StringUtils.hasText(this.redisNamespace)) {
			sessionRepository.setRedisKeyNamespace(this.redisNamespace);
		}
		sessionRepository.setRedisFlushMode(this.redisFlushMode);
		int database = resolveDatabase();
		sessionRepository.setDatabase(database);
		return sessionRepository;
	}

	@Bean
	public RedisMessageListenerContainer redisMessageListenerContainer() {
		RedisMessageListenerContainer container = new RedisMessageListenerContainer();
		container.setConnectionFactory(this.redisConnectionFactory);
		if (this.redisTaskExecutor != null) {
			container.setTaskExecutor(this.redisTaskExecutor);
		}
		if (this.redisSubscriptionExecutor != null) {
			container.setSubscriptionExecutor(this.redisSubscriptionExecutor);
		}
		container.addMessageListener(sessionRepository(), Arrays.asList(
				new ChannelTopic(sessionRepository().getSessionDeletedChannel()),
				new ChannelTopic(sessionRepository().getSessionExpiredChannel())));
		container.addMessageListener(sessionRepository(),
				Collections.singletonList(new PatternTopic(
						sessionRepository().getSessionCreatedChannelPrefix() + "*")));
		return container;
	}

	@Bean
	public InitializingBean enableRedisKeyspaceNotificationsInitializer() {
		return new EnableRedisKeyspaceNotificationsInitializer(
				this.redisConnectionFactory, this.configureRedisAction);
	}

	public void setMaxInactiveIntervalInSeconds(int maxInactiveIntervalInSeconds) {
		this.maxInactiveIntervalInSeconds = maxInactiveIntervalInSeconds;
	}

	public void setRedisNamespace(String namespace) {
		this.redisNamespace = namespace;
	}

	public void setRedisFlushMode(RedisFlushMode redisFlushMode) {
		Assert.notNull(redisFlushMode, "redisFlushMode cannot be null");
		this.redisFlushMode = redisFlushMode;
	}

	public void setCleanupCron(String cleanupCron) {
		this.cleanupCron = cleanupCron;
	}

	/**
	 * Sets the action to perform for configuring Redis.
	 *
	 * @param configureRedisAction the configureRedis to set. The default is
	 * {@link ConfigureNotifyKeyspaceEventsAction}.
	 */
	@Autowired(required = false)
	public void setConfigureRedisAction(ConfigureRedisAction configureRedisAction) {
		this.configureRedisAction = configureRedisAction;
	}

	@Autowired
	public void setRedisConnectionFactory(
			@SpringSessionRedisConnectionFactory ObjectProvider<RedisConnectionFactory> springSessionRedisConnectionFactory,
			ObjectProvider<RedisConnectionFactory> redisConnectionFactory) {
		RedisConnectionFactory redisConnectionFactoryToUse = springSessionRedisConnectionFactory
				.getIfAvailable();
		if (redisConnectionFactoryToUse == null) {
			redisConnectionFactoryToUse = redisConnectionFactory.getObject();
		}
		this.redisConnectionFactory = redisConnectionFactoryToUse;
	}

	@Autowired(required = false)
	@Qualifier("springSessionDefaultRedisSerializer")
	public void setDefaultRedisSerializer(
			RedisSerializer<Object> defaultRedisSerializer) {
		this.defaultRedisSerializer = defaultRedisSerializer;
	}

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

	@Autowired(required = false)
	@Qualifier("springSessionRedisTaskExecutor")
	public void setRedisTaskExecutor(Executor redisTaskExecutor) {
		this.redisTaskExecutor = redisTaskExecutor;
	}

	@Autowired(required = false)
	@Qualifier("springSessionRedisSubscriptionExecutor")
	public void setRedisSubscriptionExecutor(Executor redisSubscriptionExecutor) {
		this.redisSubscriptionExecutor = redisSubscriptionExecutor;
	}

	@Override
	public void setBeanClassLoader(ClassLoader classLoader) {
		this.classLoader = classLoader;
	}

	@Override
	public void setEmbeddedValueResolver(StringValueResolver resolver) {
		this.embeddedValueResolver = resolver;
	}

	@Override
	public void setImportMetadata(AnnotationMetadata importMetadata) {
		Map<String, Object> attributeMap = importMetadata
				.getAnnotationAttributes(EnableRedisHttpSession.class.getName());
		AnnotationAttributes attributes = AnnotationAttributes.fromMap(attributeMap);
		this.maxInactiveIntervalInSeconds = attributes
				.getNumber("maxInactiveIntervalInSeconds");
		String redisNamespaceValue = attributes.getString("redisNamespace");
		if (StringUtils.hasText(redisNamespaceValue)) {
			this.redisNamespace = this.embeddedValueResolver
					.resolveStringValue(redisNamespaceValue);
		}
		this.redisFlushMode = attributes.getEnum("redisFlushMode");
		String cleanupCron = attributes.getString("cleanupCron");
		if (StringUtils.hasText(cleanupCron)) {
			this.cleanupCron = cleanupCron;
		}
	}

	@Override
	public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
		taskRegistrar.addCronTask(() -> sessionRepository().cleanupExpiredSessions(),
				this.cleanupCron);
	}

	private RedisTemplate<Object, Object> createRedisTemplate() {
		RedisTemplate<Object, Object> redisTemplate = new RedisTemplate<>();
		redisTemplate.setKeySerializer(new StringRedisSerializer());
		redisTemplate.setHashKeySerializer(new StringRedisSerializer());
		if (this.defaultRedisSerializer != null) {
			redisTemplate.setDefaultSerializer(this.defaultRedisSerializer);
		}
		redisTemplate.setConnectionFactory(this.redisConnectionFactory);
		redisTemplate.setBeanClassLoader(this.classLoader);
		redisTemplate.afterPropertiesSet();
		return redisTemplate;
	}

	private int resolveDatabase() {
		if (ClassUtils.isPresent("io.lettuce.core.RedisClient", null)
				&& this.redisConnectionFactory instanceof LettuceConnectionFactory) {
			return ((LettuceConnectionFactory) this.redisConnectionFactory).getDatabase();
		}
		if (ClassUtils.isPresent("redis.clients.jedis.Jedis", null)
				&& this.redisConnectionFactory instanceof JedisConnectionFactory) {
			return ((JedisConnectionFactory) this.redisConnectionFactory).getDatabase();
		}
		return RedisOperationsSessionRepository.DEFAULT_DATABASE;
	}

	/**
	 * Ensures that Redis is configured to send keyspace notifications. This is important
	 * to ensure that expiration and deletion of sessions trigger SessionDestroyedEvents.
	 * Without the SessionDestroyedEvent resources may not get cleaned up properly. For
	 * example, the mapping of the Session to WebSocket connections may not get cleaned
	 * up.
	 */
	static class EnableRedisKeyspaceNotificationsInitializer implements InitializingBean {

		private final RedisConnectionFactory connectionFactory;

		private ConfigureRedisAction configure;

		EnableRedisKeyspaceNotificationsInitializer(
				RedisConnectionFactory connectionFactory,
				ConfigureRedisAction configure) {
			this.connectionFactory = connectionFactory;
			this.configure = configure;
		}

		@Override
		public void afterPropertiesSet() throws Exception {
			if (this.configure == ConfigureRedisAction.NO_OP) {
				return;
			}
			RedisConnection connection = this.connectionFactory.getConnection();
			try {
				this.configure.configure(connection);
			}
			finally {
				try {
					connection.close();
				}
				catch (Exception ex) {
					LogFactory.getLog(getClass()).error("Error closing RedisConnection",
							ex);
				}
			}
		}

	}

}
