/*
 * Copyright (c) 2017, 2018, 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.
 */

package jdk.internal.net.http;

import jdk.internal.net.http.common.FlowTube;
import jdk.internal.net.http.common.SSLTube;
import jdk.internal.net.http.common.Utils;
import org.testng.annotations.Test;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLParameters;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
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;
    }
}
