/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * 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 io.undertow.examples.http2;

import static io.undertow.Handlers.predicate;
import static io.undertow.Handlers.resource;
import static io.undertow.predicate.Predicates.secure;

import java.io.InputStream;
import java.net.URI;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyStore;

import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;

import io.undertow.Handlers;
import io.undertow.Undertow;
import io.undertow.UndertowOptions;
import io.undertow.attribute.ExchangeAttributes;
import io.undertow.examples.UndertowExample;
import io.undertow.protocols.ssl.UndertowXnioSsl;
import io.undertow.server.HttpHandler;
import io.undertow.server.HttpServerExchange;
import io.undertow.server.handlers.LearningPushHandler;
import io.undertow.server.handlers.proxy.LoadBalancingProxyClient;
import io.undertow.server.handlers.proxy.ProxyHandler;
import io.undertow.server.handlers.resource.PathResourceManager;
import io.undertow.server.session.InMemorySessionManager;
import io.undertow.server.session.SessionAttachmentHandler;
import io.undertow.server.session.SessionCookieConfig;
import io.undertow.util.Headers;
import io.undertow.util.StatusCodes;
import org.xnio.OptionMap;
import org.xnio.Xnio;

/**
 * @author Stuart Douglas
 */
@UndertowExample(value = "HTTP2", location = "https://localhost:8443")
public class Http2Server {

    private static final char[] STORE_PASSWORD = "password".toCharArray();

    public static void main(final String[] args) throws Exception {
        String version = System.getProperty("java.version");
        System.out.println("Java version " + version);
        if(version.charAt(0) == '1' && Integer.parseInt(version.charAt(2) + "") < 8 ) {
            System.out.println("This example requires Java 1.8 or later");
            System.out.println("The HTTP2 spec requires certain cyphers that are not present in older JVM's");
            System.out.println("See section 9.2.2 of the HTTP2 specification for details");
            System.exit(1);
        }
        String bindAddress = System.getProperty("bind.address", "localhost");
        SSLContext sslContext = createSSLContext(loadKeyStore("server.keystore"), loadKeyStore("server.truststore"));
        Undertow server = Undertow.builder()
                .setServerOption(UndertowOptions.ENABLE_HTTP2, true)
                .addHttpListener(8080, bindAddress)
                .addHttpsListener(8443, bindAddress, sslContext)
                .setHandler(new SessionAttachmentHandler(new LearningPushHandler(100, -1, Handlers.header(predicate(secure(), resource(new PathResourceManager(Paths.get(System.getProperty("example.directory", System.getProperty("user.home"))), 100))
                        .setDirectoryListingEnabled(true), new HttpHandler() {
                    @Override
                    public void handleRequest(HttpServerExchange exchange) throws Exception {
                        exchange.getResponseHeaders().add(Headers.LOCATION, "https://" + exchange.getHostName() + ":" + (exchange.getHostPort() + 363) + exchange.getRelativePath());
                        exchange.setStatusCode(StatusCodes.TEMPORARY_REDIRECT);
                    }
                }), "x-undertow-transport", ExchangeAttributes.transportProtocol())), new InMemorySessionManager("test"), new SessionCookieConfig())).build();

        server.start();

        SSLContext clientSslContext = createSSLContext(loadKeyStore("client.keystore"), loadKeyStore("client.truststore"));
        LoadBalancingProxyClient proxy = new LoadBalancingProxyClient()
                .addHost(new URI("https://localhost:8443"), null, new UndertowXnioSsl(Xnio.getInstance(), OptionMap.EMPTY, clientSslContext), OptionMap.create(UndertowOptions.ENABLE_HTTP2, true))
                .setConnectionsPerThread(20);

        Undertow reverseProxy = Undertow.builder()
                .setServerOption(UndertowOptions.ENABLE_HTTP2, true)
                .addHttpListener(8081, bindAddress)
                .addHttpsListener(8444, bindAddress, sslContext)
                .setHandler(ProxyHandler.builder().setProxyClient(proxy).setMaxRequestTime( 30000).build())
                .build();
        reverseProxy.start();

    }

    private static KeyStore loadKeyStore(String name) throws Exception {
        String storeLoc = System.getProperty(name);
        final InputStream stream;
        if(storeLoc == null) {
            stream = Http2Server.class.getResourceAsStream(name);
        } else {
            stream = Files.newInputStream(Paths.get(storeLoc));
        }

        if(stream == null) {
            throw new RuntimeException("Could not load keystore");
        }
        try(InputStream is = stream) {
            KeyStore loadedKeystore = KeyStore.getInstance("JKS");
            loadedKeystore.load(is, password(name));
            return loadedKeystore;
        }
    }

    static char[] password(String name) {
        String pw = System.getProperty(name + ".password");
        return pw != null ? pw.toCharArray() : STORE_PASSWORD;
    }


    private static SSLContext createSSLContext(final KeyStore keyStore, final KeyStore trustStore) throws Exception {
        KeyManager[] keyManagers;
        KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        keyManagerFactory.init(keyStore, password("key"));
        keyManagers = keyManagerFactory.getKeyManagers();

        TrustManager[] trustManagers;
        TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
        trustManagerFactory.init(trustStore);
        trustManagers = trustManagerFactory.getTrustManagers();

        SSLContext sslContext;
        sslContext = SSLContext.getInstance("TLS");
        sslContext.init(keyManagers, trustManagers, null);

        return sslContext;
    }

}
