/*
 * Copyright (c) 2012-2018 The original author or authors
 * ------------------------------------------------------
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Apache License v2.0 which accompanies this distribution.
 *
 * The Eclipse Public License is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * The Apache License v2.0 is available at
 * http://www.opensource.org/licenses/apache2.0.php
 *
 * You may elect to redistribute this code under either of these licenses.
 */

package io.moquette.server;

import com.hazelcast.config.ClasspathXmlConfig;
import com.hazelcast.config.Config;
import com.hazelcast.config.FileSystemXmlConfig;
import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.HazelcastInstanceNotActiveException;
import com.hazelcast.core.ITopic;
import io.moquette.BrokerConstants;
import io.moquette.connections.IConnectionsManager;
import io.moquette.interception.HazelcastInterceptHandler;
import io.moquette.interception.HazelcastMsg;
import io.moquette.interception.InterceptHandler;
import io.moquette.server.config.*;
import io.moquette.server.netty.NettyAcceptor;
import io.moquette.spi.impl.ProtocolProcessor;
import io.moquette.spi.impl.ProtocolProcessorBootstrapper;
import io.moquette.spi.impl.subscriptions.Subscription;
import io.moquette.spi.security.IAuthenticator;
import io.moquette.spi.security.IAuthorizator;
import io.moquette.spi.security.ISslContextCreator;
import io.netty.handler.codec.mqtt.MqttPublishMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;

import static io.moquette.logging.LoggingUtils.getInterceptorIds;

/**
 * Launch a configured version of the server.
 */
public class Server {

    private static final Logger LOG = LoggerFactory.getLogger(Server.class);

    private static final String HZ_INTERCEPT_HANDLER = HazelcastInterceptHandler.class.getCanonicalName();

    private ServerAcceptor m_acceptor;

    private volatile boolean m_initialized;

    private ProtocolProcessor m_processor;

    private HazelcastInstance hazelcastInstance;

    private ProtocolProcessorBootstrapper m_processorBootstrapper;

    private ScheduledExecutorService scheduler;

    public static void main(String[] args) throws IOException {
        final Server server = new Server();
        server.startServer();
        System.out.println("Server started, version 0.12-SNAPSHOT");
        //Bind  a shutdown hook
        Runtime.getRuntime().addShutdownHook(new Thread(server::stopServer));
    }

    /**
     * Starts Moquette bringing the configuration from the file located at m_config/moquette.conf
     *
     * @throws IOException in case of any IO error.
     */
    public void startServer() throws IOException {
        File defaultConfigurationFile = defaultConfigFile();
        LOG.info("Starting Moquette server. Configuration file path={}", defaultConfigurationFile.getAbsolutePath());
        IResourceLoader filesystemLoader = new FileResourceLoader(defaultConfigurationFile);
        final IConfig config = new ResourceLoaderConfig(filesystemLoader);
        startServer(config);
    }

    private static File defaultConfigFile() {
        String configPath = System.getProperty("moquette.path", null);
        return new File(configPath, IConfig.DEFAULT_CONFIG);
    }

    /**
     * Starts Moquette bringing the configuration from the given file
     *
     * @param configFile text file that contains the configuration.
     * @throws IOException in case of any IO Error.
     */
    public void startServer(File configFile) throws IOException {
        LOG.info("Starting Moquette server. Configuration file path={}", configFile.getAbsolutePath());
        IResourceLoader filesystemLoader = new FileResourceLoader(configFile);
        final IConfig config = new ResourceLoaderConfig(filesystemLoader);
        startServer(config);
    }

    /**
     * Starts the server with the given properties.
     * <p>
     * Its suggested to at least have the following properties:
     * <ul>
     * <li>port</li>
     * <li>password_file</li>
     * </ul>
     *
     * @param configProps the properties map to use as configuration.
     * @throws IOException in case of any IO Error.
     */
    public void startServer(Properties configProps) throws IOException {
        LOG.debug("Starting Moquette server using properties object");
        final IConfig config = new MemoryConfig(configProps);
        startServer(config);
    }

    /**
     * Starts Moquette bringing the configuration files from the given Config implementation.
     *
     * @param config the configuration to use to start the broker.
     * @throws IOException in case of any IO Error.
     */
    public void startServer(IConfig config) throws IOException {
        LOG.debug("Starting Moquette server using IConfig instance");
        startServer(config, null);
    }

    /**
     * Starts Moquette with config provided by an implementation of IConfig class and with the set
     * of InterceptHandler.
     *
     * @param config   the configuration to use to start the broker.
     * @param handlers the handlers to install in the broker.
     * @throws IOException in case of any IO Error.
     */
    public void startServer(IConfig config, List<? extends InterceptHandler> handlers) throws IOException {
        LOG.debug("Starting moquette server using IConfig instance and intercept handlers");
        startServer(config, handlers, null, null, null);
    }

    public void startServer(IConfig config, List<? extends InterceptHandler> handlers, ISslContextCreator sslCtxCreator,
                            IAuthenticator authenticator, IAuthorizator authorizator) throws IOException {
        final long start = System.currentTimeMillis();
        if (handlers == null) {
            handlers = Collections.emptyList();
        }
        LOG.trace("Starting Moquette Server. MQTT message interceptors={}", getInterceptorIds(handlers));

        scheduler = Executors.newScheduledThreadPool(1);

        final String handlerProp = System.getProperty(BrokerConstants.INTERCEPT_HANDLER_PROPERTY_NAME);
        if (handlerProp != null) {
            config.setProperty(BrokerConstants.INTERCEPT_HANDLER_PROPERTY_NAME, handlerProp);
        }
        configureCluster(config);
        final String persistencePath = config.getProperty(BrokerConstants.PERSISTENT_STORE_PROPERTY_NAME);
        LOG.debug("Configuring Using persistent store file, path={}", persistencePath);
        m_processorBootstrapper = new ProtocolProcessorBootstrapper();
        final ProtocolProcessor processor = m_processorBootstrapper.init(config, handlers, authenticator, authorizator,
            this);
        LOG.debug("Initialized MQTT protocol processor");
        if (sslCtxCreator == null) {
            LOG.info("Using default SSL context creator");
            sslCtxCreator = new DefaultMoquetteSslContextCreator(config);
        }

        m_acceptor = new NettyAcceptor();
        m_acceptor.initialize(processor, config, sslCtxCreator);
        m_processor = processor;

        final long startTime = System.currentTimeMillis() - start;
        LOG.info("Moquette server has been started successfully in {} ms", startTime);
        m_initialized = true;
    }

    private void configureCluster(IConfig config) throws FileNotFoundException {
        LOG.info("Configuring embedded Hazelcast instance");
        String interceptHandlerClassname = config.getProperty(BrokerConstants.INTERCEPT_HANDLER_PROPERTY_NAME);
        if (interceptHandlerClassname == null || !HZ_INTERCEPT_HANDLER.equals(interceptHandlerClassname)) {
            LOG.info("There are no Hazelcast intercept handlers. The server won't start a Hazelcast instance.");
            return;
        }
        String hzConfigPath = config.getProperty(BrokerConstants.HAZELCAST_CONFIGURATION);
        if (hzConfigPath != null) {
            boolean isHzConfigOnClasspath = this.getClass().getClassLoader().getResource(hzConfigPath) != null;
            Config hzconfig = isHzConfigOnClasspath
                ? new ClasspathXmlConfig(hzConfigPath)
                : new FileSystemXmlConfig(hzConfigPath);
            LOG.info("Starting Hazelcast instance. ConfigurationFile={}", hzconfig);
            hazelcastInstance = Hazelcast.newHazelcastInstance(hzconfig);
        } else {
            LOG.info("Starting Hazelcast instance with default configuration");
            hazelcastInstance = Hazelcast.newHazelcastInstance();
        }
        listenOnHazelCastMsg();
    }

    private void listenOnHazelCastMsg() {
        LOG.info("Subscribing to Hazelcast topic. TopicName={}", "moquette");
        HazelcastInstance hz = getHazelcastInstance();
        ITopic<HazelcastMsg> topic = hz.getTopic("moquette");
        topic.addMessageListener(new HazelcastListener(this));
    }

    public HazelcastInstance getHazelcastInstance() {
        return hazelcastInstance;
    }

    /**
     * Use the broker to publish a message. It's intended for embedding applications. It can be used
     * only after the server is correctly started with startServer.
     *
     * @param msg      the message to forward.
     * @param clientId the id of the sending server.
     * @throws IllegalStateException if the server is not yet started
     */
    public void internalPublish(MqttPublishMessage msg, final String clientId) {
        final int messageID = msg.variableHeader().messageId();
        if (!m_initialized) {
            LOG.error("Moquette is not started, internal message cannot be published. CId={}, messageId={}", clientId,
                messageID);
            throw new IllegalStateException("Can't publish on a server is not yet started");
        }
        LOG.debug("Publishing message. CId={}, messageId={}", clientId, messageID);
        m_processor.internalPublish(msg, clientId);
    }

    public void stopServer() {
        LOG.info("Unbinding server from the configured ports");
        m_acceptor.close();
        LOG.trace("Stopping MQTT protocol processor");
        m_processorBootstrapper.shutdown();
        m_initialized = false;
        if (hazelcastInstance != null) {
            LOG.trace("Stopping embedded Hazelcast instance");
            try {
                hazelcastInstance.shutdown();
            } catch (HazelcastInstanceNotActiveException e) {
                LOG.warn("embedded Hazelcast instance is already shut down.");
            }
        }

        scheduler.shutdown();

        LOG.info("Moquette server has been stopped.");
    }

    /**
     * SPI method used by Broker embedded applications to get list of subscribers. Returns null if
     * the broker is not started.
     *
     * @return list of subscriptions.
     */
    public List<Subscription> getSubscriptions() {
        if (m_processorBootstrapper == null) {
            return null;
        }
        return m_processorBootstrapper.getSubscriptions();
    }

    /**
     * SPI method used by Broker embedded applications to add intercept handlers.
     *
     * @param interceptHandler the handler to add.
     */
    public void addInterceptHandler(InterceptHandler interceptHandler) {
        if (!m_initialized) {
            LOG.error("Moquette is not started, MQTT message interceptor cannot be added. InterceptorId={}",
                interceptHandler.getID());
            throw new IllegalStateException("Can't register interceptors on a server that is not yet started");
        }
        LOG.info("Adding MQTT message interceptor. InterceptorId={}", interceptHandler.getID());
        m_processor.addInterceptHandler(interceptHandler);
    }

    /**
     * SPI method used by Broker embedded applications to remove intercept handlers.
     *
     * @param interceptHandler the handler to remove.
     */
    public void removeInterceptHandler(InterceptHandler interceptHandler) {
        if (!m_initialized) {
            LOG.error("Moquette is not started, MQTT message interceptor cannot be removed. InterceptorId={}",
                interceptHandler.getID());
            throw new IllegalStateException("Can't deregister interceptors from a server that is not yet started");
        }
        LOG.info("Removing MQTT message interceptor. InterceptorId={}", interceptHandler.getID());
        m_processor.removeInterceptHandler(interceptHandler);
    }

    /**
     * Returns the connections manager of this broker.
     *
     * @return IConnectionsManager the instance used bt the broker.
     */
    public IConnectionsManager getConnectionsManager() {
        return m_processorBootstrapper.getConnectionDescriptors();
    }

    public ProtocolProcessor getProcessor() {
        return m_processor;
    }

    public ScheduledExecutorService getScheduler() {
        return scheduler;
    }
}