/*

 * 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.

 */

package jdk.incubator.http;

import java.io.BufferedOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.Socket;

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.Random;

import java.util.StringTokenizer;

import java.util.concurrent.BlockingQueue;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.Flow;

import java.util.concurrent.Flow.Subscriber;

import java.util.concurrent.LinkedBlockingQueue;

import java.util.concurrent.SubmissionPublisher;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.concurrent.atomic.AtomicLong;

import javax.net.ssl.KeyManagerFactory;

import javax.net.ssl.*;

import javax.net.ssl.TrustManagerFactory;

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

import org.testng.annotations.Test;

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

@Test

public class FlowTest {

    private final SubmissionPublisher<List<ByteBuffer>> srcPublisher;

    private final ExecutorService executor;

    private static final long COUNTER = 3000;

    private static final int LONGS_PER_BUF = 800;

    static final long TOTAL_LONGS = COUNTER * LONGS_PER_BUF;

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

    static volatile String alpn;

    private final CompletableFuture<Void> completion;

    public FlowTest() throws IOException {

        executor = Executors.newCachedThreadPool();

        srcPublisher = new SubmissionPublisher<>(executor, 20,

                                                 this::handlePublisherException);

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

        SSLEngine engineClient = ctx.createSSLEngine();

        SSLParameters params = ctx.getSupportedSSLParameters();

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

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

        engineClient.setSSLParameters(params);

        engineClient.setUseClientMode(true);

        completion = new CompletableFuture<>();

        SSLLoopbackSubscriber looper = new SSLLoopbackSubscriber(ctx, executor);

        looper.start();

        EndSubscriber end = new EndSubscriber(TOTAL_LONGS, completion);

        SSLFlowDelegate sslClient = new SSLFlowDelegate(engineClient, executor, end, looper);

        // going to measure how long handshake takes

        final long start = System.currentTimeMillis();

        sslClient.alpn().whenComplete((String s, Throwable t) -> {

            if (t != null)

                t.printStackTrace();

            long endTime = System.currentTimeMillis();

            alpn = s;

            System.out.println("ALPN: " + alpn);

            long period = (endTime - start);

            System.out.printf("Handshake took %d ms\n", period);

        });

        Subscriber<List<ByteBuffer>> reader = sslClient.upstreamReader();

        Subscriber<List<ByteBuffer>> writer = sslClient.upstreamWriter();

        looper.setReturnSubscriber(reader);

        // now connect all the pieces

        srcPublisher.subscribe(writer);

        String aa = sslClient.alpn().join();

        System.out.println("AAALPN = " + aa);

    }

    static Random rand = new Random();

    static int randomRange(int lower, int upper) {

        if (lower > upper)

            throw new IllegalArgumentException("lower > upper");

        int diff = upper - lower;

        int r = lower + rand.nextInt(diff);

        return r - (r % 8); // round down to multiple of 8 (align for longs)

    }

    private void handlePublisherException(Object o, Throwable t) {

        System.out.println("Src Publisher exception");

        t.printStackTrace(System.out);

    }

    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

    public void run() {

        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;

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

        }

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

        srcPublisher.close();

        try {

            completion.join();

            if (!alpn.equals("proto2")) {

                throw new RuntimeException("wrong alpn received");

            }

            System.out.println("OK");

        } finally {

            executor.shutdownNow();

        }

    }

/*

    public static void main(String[]args) throws Exception {

        FlowTest test = new FlowTest();

        test.run();

    }

*/

    /**

     * This Subscriber simulates an SSL loopback network. The object itself

     * accepts outgoing SSL encrypted data which is looped back via two sockets

     * (one of which is an SSLSocket emulating a server). The method

     * {@link #setReturnSubscriber(java.util.concurrent.Flow.Subscriber) }

     * is used to provide the Subscriber which feeds the incoming side

     * of SSLFlowDelegate. Three threads are used to implement this behavior

     * and a SubmissionPublisher drives the incoming read side.

     * <p>

     * A thread reads from the buffer, writes

     * to the client j.n.Socket which is connected to a SSLSocket operating

     * in server mode. A second thread loops back data read from the SSLSocket back to the

     * client again. A third thread reads the client socket and pushes the data to

     * a SubmissionPublisher that drives the reader side of the SSLFlowDelegate

     */

    static class SSLLoopbackSubscriber implements Subscriber<List<ByteBuffer>> {

        private final BlockingQueue<ByteBuffer> buffer;

        private final Socket clientSock;

        private final SSLSocket serverSock;

        private final Thread thread1, thread2, thread3;

        private volatile Flow.Subscription clientSubscription;

        private final SubmissionPublisher<List<ByteBuffer>> publisher;

        SSLLoopbackSubscriber(SSLContext ctx, ExecutorService exec) throws IOException {

            SSLServerSocketFactory fac = ctx.getServerSocketFactory();

            SSLServerSocket serv = (SSLServerSocket) fac.createServerSocket(0);

            SSLParameters params = serv.getSSLParameters();

            params.setApplicationProtocols(new String[]{"proto2"});

            serv.setSSLParameters(params);

            int serverPort = serv.getLocalPort();

            clientSock = new Socket("127.0.0.1", serverPort);

            serverSock = (SSLSocket) serv.accept();

            this.buffer = new LinkedBlockingQueue<>();

            thread1 = new Thread(this::clientWriter, "clientWriter");

            thread2 = new Thread(this::serverLoopback, "serverLoopback");

            thread3 = new Thread(this::clientReader, "clientReader");

            publisher = new SubmissionPublisher<>(exec, Flow.defaultBufferSize(),

                    this::handlePublisherException);

            SSLFlowDelegate.Monitor.add(this::monitor);

        }

        public void start() {

            thread1.start();

            thread2.start();

            thread3.start();

        }

        private void handlePublisherException(Object o, Throwable t) {

            System.out.println("Loopback Publisher exception");

            t.printStackTrace(System.out);

        }

        private final AtomicInteger readCount = new AtomicInteger();

        // reads off the SSLSocket the data from the "server"

        private void clientReader() {

            try {

                InputStream is = clientSock.getInputStream();

                final int bufsize = FlowTest.randomRange(512, 16 * 1024);

                System.out.println("clientReader: bufsize = " + bufsize);

                while (true) {

                    byte[] buf = new byte[bufsize];

                    int n = is.read(buf);

                    if (n == -1) {

                        System.out.println("clientReader close");

                        publisher.close();

                        Utils.sleep(2000);

                        Utils.close(is, clientSock);

                        return;

                    }

                    ByteBuffer bb = ByteBuffer.wrap(buf, 0, n);

                    readCount.addAndGet(n);

                    publisher.submit(List.of(bb));

                }

            } catch (Throwable e) {

                e.printStackTrace();

                Utils.close(clientSock);

            }

        }

        // writes the encrypted data from SSLFLowDelegate to the j.n.Socket

        // which is connected to the SSLSocket emulating a server.

        private void clientWriter() {

            try {

                OutputStream os =

                        new BufferedOutputStream(clientSock.getOutputStream());

                while (true) {

                    ByteBuffer buf = buffer.take();

                    if (buf == FlowTest.SENTINEL) {

                        // finished

                        //Utils.sleep(2000);

                        System.out.println("clientWriter close");

                        clientSock.shutdownOutput();

                        System.out.println("clientWriter close return");

                        return;

                    }

                    writeToStream(os, buf);

                    clientSubscription.request(1);

                }

            } catch (Throwable e) {

                e.printStackTrace();

            }

        }

        private void writeToStream(OutputStream os, ByteBuffer buf) throws IOException {

            byte[] b = buf.array();

            int offset = buf.arrayOffset() + buf.position();

            int n = buf.limit() - buf.position();

            os.write(b, offset, n);

            buf.position(buf.limit());

            os.flush();

        }

        private final AtomicInteger loopCount = new AtomicInteger();

        public String monitor() {

            return "serverLoopback: loopcount = " + loopCount.toString()

                    + " clientRead: count = " + readCount.toString();

        }

        // thread2

        private void serverLoopback() {

            try {

                InputStream is = serverSock.getInputStream();

                OutputStream os = serverSock.getOutputStream();

                final int bufsize = FlowTest.randomRange(512, 16 * 1024);

                System.out.println("serverLoopback: bufsize = " + bufsize);

                byte[] bb = new byte[bufsize];

                while (true) {

                    int n = is.read(bb);

                    if (n == -1) {

                        Utils.sleep(2000);

                        is.close();

                        serverSock.close();

                        return;

                    }

                    os.write(bb, 0, n);

                    os.flush();

                    loopCount.addAndGet(n);

                }

            } catch (Throwable e) {

                e.printStackTrace();

            }

        }

        /**

         * This needs to be called before the chain is subscribed. It can't be

         * supplied in the constructor.

         */

        public void setReturnSubscriber(Subscriber<List<ByteBuffer>> returnSubscriber) {

            publisher.subscribe(returnSubscriber);

        }

        @Override

        public void onSubscribe(Flow.Subscription subscription) {

            clientSubscription = subscription;

            clientSubscription.request(5);

        }

        @Override

        public void onNext(List<ByteBuffer> item) {

            try {

                for (ByteBuffer b : item)

                    buffer.put(b);

            } catch (InterruptedException e) {

                e.printStackTrace();

                Utils.close(clientSock);

            }

        }

        @Override

        public void onError(Throwable throwable) {

            throwable.printStackTrace();

            Utils.close(clientSock);

        }

        @Override

        public void onComplete() {

            try {

                buffer.put(FlowTest.SENTINEL);

            } catch (InterruptedException e) {

                e.printStackTrace();

                Utils.close(clientSock);

            }

        }

    }

    /**

     * 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.

     */

    static class EndSubscriber implements Subscriber<List<ByteBuffer>> {

        private final long nbytes;

        private final AtomicLong counter;

        private volatile Flow.Subscription subscription;

        private final CompletableFuture<Void> completion;

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

            counter = new AtomicLong(0);

            this.nbytes = nbytes;

            this.completion = completion;

        }

        @Override

        public void onSubscribe(Flow.Subscription subscription) {

            this.subscription = subscription;

            subscription.request(5);

        }

        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: " + Integer.toString(x));

            return sb.toString();

        }

        @Override

        public void onNext(List<ByteBuffer> buffers) {

            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 > (FlowTest.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);

            subscription.request(1);

        }

        @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: counter = " + n);

                completion.complete(null);

            }

        }

    }

    /**

     * Creates a simple usable SSLContext for SSLSocketFactory

     * or a HttpsServer using either a given keystore or a default

     * one in the test tree.

     * <p>

     * Using this class with a security manager requires the following

     * permissions to be granted:

     * <p>

     * 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.

     */

    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.out.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;

        }

    }

}