/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

import org.testng.annotations.Test;

import javax.net.ssl.KeyManagerFactory;

import javax.net.ssl.SSLContext;

import javax.net.ssl.SSLEngine;

import javax.net.ssl.SSLParameters;

import javax.net.ssl.TrustManagerFactory;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.nio.ByteBuffer;

import java.security.KeyManagementException;

import java.security.KeyStore;

import java.security.KeyStoreException;

import java.security.NoSuchAlgorithmException;

import java.security.UnrecoverableKeyException;

import java.security.cert.CertificateException;

import java.util.List;

import java.util.StringTokenizer;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Flow;

import java.util.concurrent.ForkJoinPool;

import java.util.concurrent.SubmissionPublisher;

import java.util.concurrent.atomic.AtomicLong;

public class AbstractSSLTubeTest extends AbstractRandomTest {

    public static final long COUNTER = 600;

    public static final int LONGS_PER_BUF = 800;

    public static final long TOTAL_LONGS = COUNTER * LONGS_PER_BUF;

    public static final ByteBuffer SENTINEL = ByteBuffer.allocate(0);

    // This is a hack to work around an issue with SubmissionPublisher.

    // SubmissionPublisher will call onComplete immediately without forwarding

    // remaining pending data if SubmissionPublisher.close() is called when

    // there is no demand. In other words, it doesn't wait for the subscriber

    // to pull all the data before calling onComplete.

    // We use a CountDownLatch to figure out when it is safe to call close().

    // This may cause the test to hang if data are buffered.

    protected final CountDownLatch allBytesReceived = new CountDownLatch(1);

    protected static ByteBuffer getBuffer(long startingAt) {

        ByteBuffer buf = ByteBuffer.allocate(LONGS_PER_BUF * 8);

        for (int j = 0; j < LONGS_PER_BUF; j++) {

            buf.putLong(startingAt++);

        }

        buf.flip();

        return buf;

    }

    protected void run(FlowTube server,

                       ExecutorService sslExecutor,

                       CountDownLatch allBytesReceived) throws IOException {

        FlowTube client = new SSLTube(createSSLEngine(true),

                                      sslExecutor,

                                      server);

        SubmissionPublisher<List<ByteBuffer>> p =

                new SubmissionPublisher<>(ForkJoinPool.commonPool(),

                                          Integer.MAX_VALUE);

        FlowTube.TubePublisher begin = p::subscribe;

        CompletableFuture<Void> completion = new CompletableFuture<>();

        EndSubscriber end = new EndSubscriber(TOTAL_LONGS, completion, allBytesReceived);

        client.connectFlows(begin, end);

        /* End of wiring */

        long count = 0;

        System.out.printf("Submitting %d buffer arrays\n", COUNTER);

        System.out.printf("LoopCount should be %d\n", TOTAL_LONGS);

        for (long i = 0; i < COUNTER; i++) {

            ByteBuffer b = getBuffer(count);

            count += LONGS_PER_BUF;

            p.submit(List.of(b));

        }

        System.out.println("Finished submission. Waiting for loopback");

        completion.whenComplete((r,t) -> allBytesReceived.countDown());

        try {

            allBytesReceived.await();

        } catch (InterruptedException e) {

            throw new IOException(e);

        }

        p.close();

        System.out.println("All bytes received: calling publisher.close()");

        try {

            completion.join();

            System.out.println("OK");

        } finally {

            sslExecutor.shutdownNow();

        }

    }

    protected static void sleep(long millis) {

        try {

            Thread.sleep(millis);

        } catch (InterruptedException e) {

        }

    }

    /**

     * The final subscriber which receives the decrypted looped-back data. Just

     * needs to compare the data with what was sent. The given CF is either

     * completed exceptionally with an error or normally on success.

     */

    protected static class EndSubscriber implements FlowTube.TubeSubscriber {

        private static final int REQUEST_WINDOW = 13;

        private final long nbytes;

        private final AtomicLong counter = new AtomicLong();

        private final CompletableFuture<?> completion;

        private final CountDownLatch allBytesReceived;

        private volatile Flow.Subscription subscription;

        private long unfulfilled;

        EndSubscriber(long nbytes, CompletableFuture<?> completion,

                      CountDownLatch allBytesReceived) {

            this.nbytes = nbytes;

            this.completion = completion;

            this.allBytesReceived = allBytesReceived;

        }

        @Override

        public void onSubscribe(Flow.Subscription subscription) {

            this.subscription = subscription;

            unfulfilled = REQUEST_WINDOW;

            System.out.println("EndSubscriber request " + REQUEST_WINDOW);

            subscription.request(REQUEST_WINDOW);

        }

        public static String info(List<ByteBuffer> i) {

            StringBuilder sb = new StringBuilder();

            sb.append("size: ").append(Integer.toString(i.size()));

            int x = 0;

            for (ByteBuffer b : i)

                x += b.remaining();

            sb.append(" bytes: ").append(x);

            return sb.toString();

        }

        @Override

        public void onNext(List<ByteBuffer> buffers) {

            if (--unfulfilled == (REQUEST_WINDOW / 2)) {

                long req = REQUEST_WINDOW - unfulfilled;

                System.out.println("EndSubscriber request " + req);

                unfulfilled = REQUEST_WINDOW;

                subscription.request(req);

            }

            long currval = counter.get();

            if (currval % 500 == 0) {

                System.out.println("EndSubscriber: " + currval);

            }

            System.out.println("EndSubscriber onNext " + Utils.remaining(buffers));

            for (ByteBuffer buf : buffers) {

                while (buf.hasRemaining()) {

                    long n = buf.getLong();

                    if (currval > (TOTAL_LONGS - 50)) {

                        System.out.println("End: " + currval);

                    }

                    if (n != currval++) {

                        System.out.println("ERROR at " + n + " != " + (currval - 1));

                        completion.completeExceptionally(new RuntimeException("ERROR"));

                        subscription.cancel();

                        return;

                    }

                }

            }

            counter.set(currval);

            if (currval >= TOTAL_LONGS) {

                allBytesReceived.countDown();

            }

        }

        @Override

        public void onError(Throwable throwable) {

            System.out.println("EndSubscriber onError " + throwable);

            completion.completeExceptionally(throwable);

            allBytesReceived.countDown();

        }

        @Override

        public void onComplete() {

            long n = counter.get();

            if (n != nbytes) {

                System.out.printf("nbytes=%d n=%d\n", nbytes, n);

                completion.completeExceptionally(new RuntimeException("ERROR AT END"));

            } else {

                System.out.println("DONE OK");

                completion.complete(null);

            }

            allBytesReceived.countDown();

        }

        @Override

        public String toString() {

            return "EndSubscriber";

        }

    }

    protected static SSLEngine createSSLEngine(boolean client) throws IOException {

        SSLContext context = (new SimpleSSLContext()).get();

        SSLEngine engine = context.createSSLEngine();

        SSLParameters params = context.getSupportedSSLParameters();

        params.setProtocols(new String[]{"TLSv1.2"}); // TODO: This is essential. Needs to be protocol impl

        if (client) {

            params.setApplicationProtocols(new String[]{"proto1", "proto2"}); // server will choose proto2

        } else {

            params.setApplicationProtocols(new String[]{"proto2"}); // server will choose proto2

        }

        engine.setSSLParameters(params);

        engine.setUseClientMode(client);

        return engine;

    }

    /**

     * Creates a simple usable SSLContext for SSLSocketFactory or a HttpsServer

     * using either a given keystore or a default one in the test tree.

     *

     * Using this class with a security manager requires the following

     * permissions to be granted:

     *

     * permission "java.util.PropertyPermission" "test.src.path", "read";

     * permission java.io.FilePermission "${test.src}/../../../../lib/testlibrary/jdk/testlibrary/testkeys",

     * "read"; The exact path above depends on the location of the test.

     */

    protected static class SimpleSSLContext {

        private final SSLContext ssl;

        /**

         * Loads default keystore from SimpleSSLContext source directory

         */

        public SimpleSSLContext() throws IOException {

            String paths = System.getProperty("test.src.path");

            StringTokenizer st = new StringTokenizer(paths, File.pathSeparator);

            boolean securityExceptions = false;

            SSLContext sslContext = null;

            while (st.hasMoreTokens()) {

                String path = st.nextToken();

                try {

                    File f = new File(path, "../../../../lib/testlibrary/jdk/testlibrary/testkeys");

                    if (f.exists()) {

                        try (FileInputStream fis = new FileInputStream(f)) {

                            sslContext = init(fis);

                            break;

                        }

                    }

                } catch (SecurityException e) {

                    // catch and ignore because permission only required

                    // for one entry on path (at most)

                    securityExceptions = true;

                }

            }

            if (securityExceptions) {

                System.err.println("SecurityExceptions thrown on loading testkeys");

            }

            ssl = sslContext;

        }

        private SSLContext init(InputStream i) throws IOException {

            try {

                char[] passphrase = "passphrase".toCharArray();

                KeyStore ks = KeyStore.getInstance("JKS");

                ks.load(i, passphrase);

                KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");

                kmf.init(ks, passphrase);

                TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509");

                tmf.init(ks);

                SSLContext ssl = SSLContext.getInstance("TLS");

                ssl.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);

                return ssl;

            } catch (KeyManagementException | KeyStoreException |

                    UnrecoverableKeyException | CertificateException |

                    NoSuchAlgorithmException e) {

                throw new RuntimeException(e.getMessage());

            }

        }

        public SSLContext get() {

            return ssl;

        }

    }

}