/*

 * 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

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 */

package jdk.incubator.http;

import jdk.incubator.http.internal.common.Demand;

import jdk.incubator.http.internal.common.FlowTube;

import jdk.incubator.http.internal.common.SSLTube;

import jdk.incubator.http.internal.common.SequentialScheduler;

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.Queue;

import java.util.StringTokenizer;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.ConcurrentLinkedQueue;

import java.util.concurrent.Executor;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Flow;

import java.util.concurrent.ForkJoinPool;

import java.util.concurrent.SubmissionPublisher;

import java.util.concurrent.atomic.AtomicBoolean;

import java.util.concurrent.atomic.AtomicLong;

@Test

public class SSLTubeTest {

    private static final long COUNTER = 600;

    private static final int LONGS_PER_BUF = 800;

    private static final long TOTAL_LONGS = COUNTER * LONGS_PER_BUF;

    private 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;

    }

    @Test(timeOut = 30000)

    public void run() throws IOException {

        /* Start of wiring */

        ExecutorService sslExecutor = Executors.newCachedThreadPool();

        /* Emulates an echo server */

        FlowTube server = new SSLTube(createSSLEngine(false),

                                      sslExecutor,

                                      new EchoTube(16));

        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);

        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");

        p.close();

        try {

            completion.join();

            System.out.println("OK");

        } finally {

            sslExecutor.shutdownNow();

        }

    }

    private static final class EchoTube implements FlowTube {

        private final static Object EOF = new Object();

        private final Executor executor = Executors.newSingleThreadExecutor();

        private final Queue<Object> queue = new ConcurrentLinkedQueue<>();

        private final int maxQueueSize;

        private final SequentialScheduler processingScheduler =

                new SequentialScheduler(createProcessingTask());

        /* Writing into this tube */

        private long unfulfilled;

        private Flow.Subscription subscription;

        /* Reading from this tube */

        private final Demand demand = new Demand();

        private final AtomicBoolean cancelled = new AtomicBoolean();

        private Flow.Subscriber<? super List<ByteBuffer>> subscriber;

        private EchoTube(int maxBufferSize) {

            if (maxBufferSize < 1)

                throw new IllegalArgumentException();

            this.maxQueueSize = maxBufferSize;

        }

        @Override

        public void subscribe(Flow.Subscriber<? super List<ByteBuffer>> subscriber) {

            this.subscriber = subscriber;

            this.subscriber.onSubscribe(new InternalSubscription());

        }

        @Override

        public void onSubscribe(Flow.Subscription subscription) {

            unfulfilled = maxQueueSize;

            (this.subscription = subscription).request(maxQueueSize);

        }

        @Override

        public void onNext(List<ByteBuffer> item) {

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

                subscription.request(maxQueueSize - unfulfilled);

                unfulfilled = maxQueueSize;

            }

            queue.add(item);

            processingScheduler.deferOrSchedule(executor);

        }

        @Override

        public void onError(Throwable throwable) {

            queue.add(throwable);

            processingScheduler.deferOrSchedule(executor);

        }

        @Override

        public void onComplete() {

            queue.add(EOF);

            processingScheduler.deferOrSchedule(executor);

        }

        @Override

        public boolean isFinished() {

            return false;

        }

        private class InternalSubscription implements Flow.Subscription {

            @Override

            public void request(long n) {

                if (n <= 0) {

                    throw new InternalError();

                }

                demand.increase(n);

                processingScheduler.runOrSchedule();

            }

            @Override

            public void cancel() {

                cancelled.set(true);

            }

        }

        private SequentialScheduler.RestartableTask createProcessingTask() {

            return new SequentialScheduler.CompleteRestartableTask() {

                @Override

                protected void run() {

                    while (!cancelled.get()) {

                        Object item = queue.peek();

                        if (item == null)

                            return;

                        try {

                            if (item instanceof List) {

                                if (!demand.tryDecrement())

                                    return;

                                @SuppressWarnings("unchecked")

                                List<ByteBuffer> bytes = (List<ByteBuffer>) item;

                                subscriber.onNext(bytes);

                            } else if (item instanceof Throwable) {

                                cancelled.set(true);

                                subscriber.onError((Throwable) item);

                            } else if (item == EOF) {

                                cancelled.set(true);

                                subscriber.onComplete();

                            } else {

                                throw new InternalError(String.valueOf(item));

                            }

                        } finally {

                            Object removed = queue.remove();

                            assert removed == item;

                        }

                    }

                }

            };

        }

    }

    /**

     * 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.

     */

    private 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 volatile Flow.Subscription subscription;

        private long unfulfilled;

        EndSubscriber(long nbytes, CompletableFuture<?> completion) {

            this.nbytes = nbytes;

            this.completion = completion;

        }

        @Override

        public void onSubscribe(Flow.Subscription subscription) {

            this.subscription = subscription;

            unfulfilled = 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)) {

                subscription.request(REQUEST_WINDOW - unfulfilled);

                unfulfilled = REQUEST_WINDOW;

            }

            long currval = counter.get();

            if (currval % 500 == 0) {

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

            }

            for (ByteBuffer buf : buffers) {

                while (buf.hasRemaining()) {

                    long n = buf.getLong();

                    if (currval > (SSLTubeTest.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);

        }

        @Override

        public void onError(Throwable throwable) {

            completion.completeExceptionally(throwable);

        }

        @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);

            }

        }

    }

    private 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.

     */

    private 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;

        }

    }

}