/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.nifi.registry;

import org.apache.nifi.registry.jetty.JettyServer;
import org.apache.nifi.registry.properties.NiFiRegistryProperties;
import org.apache.nifi.registry.properties.NiFiRegistryPropertiesLoader;
import org.apache.nifi.registry.properties.SensitivePropertyProtectionException;
import org.apache.nifi.registry.security.crypto.BootstrapFileCryptoKeyProvider;
import org.apache.nifi.registry.security.crypto.CryptoKeyProvider;
import org.apache.nifi.registry.security.crypto.MissingCryptoKeyException;
import org.apache.nifi.registry.util.FileUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.bridge.SLF4JBridgeHandler;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.concurrent.TimeUnit;

/**
 * Main entry point for NiFiRegistry.
 */
public class NiFiRegistry {

    private static final Logger LOGGER = LoggerFactory.getLogger(NiFiRegistry.class);

    public static final String BOOTSTRAP_PORT_PROPERTY = "nifi.registry.bootstrap.listen.port";

    public static final String NIFI_REGISTRY_PROPERTIES_FILE_PATH_PROPERTY = "nifi.registry.properties.file.path";
    public static final String NIFI_REGISTRY_BOOTSTRAP_FILE_PATH_PROPERTY = "nifi.registry.bootstrap.config.file.path";
    public static final String NIFI_REGISTRY_BOOTSTRAP_DOCS_DIR_PROPERTY = "nifi.registry.bootstrap.config.docs.dir";

    public static final String RELATIVE_BOOTSTRAP_FILE_LOCATION = "conf/bootstrap.conf";
    public static final String RELATIVE_PROPERTIES_FILE_LOCATION = "conf/nifi-registry.properties";
    public static final String RELATIVE_DOCS_LOCATION = "docs";

    private final JettyServer server;
    private final BootstrapListener bootstrapListener;
    private volatile boolean shutdown = false;

    public NiFiRegistry(final NiFiRegistryProperties properties, CryptoKeyProvider masterKeyProvider)
            throws ClassNotFoundException, IOException, NoSuchMethodException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {

        Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(final Thread t, final Throwable e) {
                LOGGER.error("An Unknown Error Occurred in Thread {}: {}", t, e.toString());
                LOGGER.error("", e);
            }
        });

        // register the shutdown hook
        Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
            @Override
            public void run() {
                // shutdown the jetty server
                shutdownHook();
            }
        }));

        final String bootstrapPort = System.getProperty(BOOTSTRAP_PORT_PROPERTY);
        if (bootstrapPort != null) {
            try {
                final int port = Integer.parseInt(bootstrapPort);

                if (port < 1 || port > 65535) {
                    throw new RuntimeException("Failed to start NiFi Registry because system property '" + BOOTSTRAP_PORT_PROPERTY + "' is not a valid integer in the range 1 - 65535");
                }

                bootstrapListener = new BootstrapListener(this, port);
                bootstrapListener.start();
            } catch (final NumberFormatException nfe) {
                throw new RuntimeException("Failed to start NiFi Registry because system property '" + BOOTSTRAP_PORT_PROPERTY + "' is not a valid integer in the range 1 - 65535");
            }
        } else {
            LOGGER.info("NiFi Registry started without Bootstrap Port information provided; will not listen for requests from Bootstrap");
            bootstrapListener = null;
        }

        // delete the web working dir - if the application does not start successfully
        // the web app directories might be in an invalid state. when this happens
        // jetty will not attempt to re-extract the war into the directory. by removing
        // the working directory, we can be assured that it will attempt to extract the
        // war every time the application starts.
        File webWorkingDir = properties.getWebWorkingDirectory();
        FileUtils.deleteFilesInDirectory(webWorkingDir, null, LOGGER, true, true);
        FileUtils.deleteFile(webWorkingDir, LOGGER, 3);

        // redirect JUL log events
        SLF4JBridgeHandler.removeHandlersForRootLogger();
        SLF4JBridgeHandler.install();

        final String docsDir = System.getProperty(NIFI_REGISTRY_BOOTSTRAP_DOCS_DIR_PROPERTY, RELATIVE_DOCS_LOCATION);

        final long startTime = System.nanoTime();
        server = new JettyServer(properties, masterKeyProvider, docsDir);

        if (shutdown) {
            LOGGER.info("NiFi Registry has been shutdown via NiFi Registry Bootstrap. Will not start Controller");
        } else {
            server.start();

            if (bootstrapListener != null) {
                bootstrapListener.sendStartedStatus(true);
            }

            final long duration = System.nanoTime() - startTime;
            LOGGER.info("Registry initialization took " + duration + " nanoseconds "
                    + "(" + (int) TimeUnit.SECONDS.convert(duration, TimeUnit.NANOSECONDS) + " seconds).");
        }
    }

    protected void shutdownHook() {
        try {
            this.shutdown = true;

            LOGGER.info("Initiating shutdown of Jetty web server...");
            if (server != null) {
                server.stop();
            }
            if (bootstrapListener != null) {
                bootstrapListener.stop();
            }
            LOGGER.info("Jetty web server shutdown completed (nicely or otherwise).");
        } catch (final Throwable t) {
            LOGGER.warn("Problem occurred ensuring Jetty web server was properly terminated due to " + t);
        }
    }

    /**
     * Main entry point of the application.
     *
     * @param args things which are ignored
     */
    public static void main(String[] args) {
        LOGGER.info("Launching NiFi Registry...");

        final CryptoKeyProvider masterKeyProvider;
        final NiFiRegistryProperties properties;
        try {
            masterKeyProvider = getMasterKeyProvider();
            properties = initializeProperties(masterKeyProvider);
        } catch (final IllegalArgumentException iae) {
            throw new RuntimeException("Unable to load properties: " + iae, iae);
        }

        try {
            new NiFiRegistry(properties, masterKeyProvider);
        } catch (final Throwable t) {
            LOGGER.error("Failure to launch NiFi Registry due to " + t, t);
        }
    }

    public static CryptoKeyProvider getMasterKeyProvider() {
        final String bootstrapConfigFilePath = System.getProperty(NIFI_REGISTRY_BOOTSTRAP_FILE_PATH_PROPERTY, RELATIVE_BOOTSTRAP_FILE_LOCATION);
        CryptoKeyProvider masterKeyProvider = new BootstrapFileCryptoKeyProvider(bootstrapConfigFilePath);
        LOGGER.info("Read property protection key from {}", bootstrapConfigFilePath);
        return masterKeyProvider;
    }

    public static NiFiRegistryProperties initializeProperties(CryptoKeyProvider masterKeyProvider) {
        String key = CryptoKeyProvider.EMPTY_KEY;
        try {
            key = masterKeyProvider.getKey();
        } catch (MissingCryptoKeyException e) {
            LOGGER.debug("CryptoKeyProvider provided to initializeProperties method was empty - did not contain a key.");
            // Do nothing. The key can be empty when it is passed to the loader as the loader will only use it if any properties are protected.
        }

        try {
            try {
                // Load properties using key. If properties are protected and key missing, throw RuntimeException
                final String nifiRegistryPropertiesFilePath = System.getProperty(NIFI_REGISTRY_PROPERTIES_FILE_PATH_PROPERTY, RELATIVE_PROPERTIES_FILE_LOCATION);
                final NiFiRegistryProperties properties = NiFiRegistryPropertiesLoader.withKey(key).load(nifiRegistryPropertiesFilePath);
                LOGGER.info("Loaded {} properties", properties.size());
                return properties;
            } catch (SensitivePropertyProtectionException e) {
                final String msg = "There was an issue decrypting protected properties";
                LOGGER.error(msg, e);
                throw new IllegalArgumentException(msg);
            }
        } catch (IllegalArgumentException e) {
            final String msg = "The bootstrap process did not provide a valid key and there are protected properties present in the properties file";
            LOGGER.error(msg, e);
            throw new IllegalArgumentException(msg);
        }
    }

}