/*

 * Copyright (c) 2018, 2019, 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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 * questions.

 */

/*

 * @test

 * @bug 8196389

 * @summary Should HttpClient support SETTINGS_MAX_CONCURRENT_STREAMS from the server

 *

 * @modules java.base/sun.net.www.http

 *          java.net.http/jdk.internal.net.http.common

 *          java.net.http/jdk.internal.net.http.frame

 *          java.net.http/jdk.internal.net.http.hpack

 *          java.logging

 *          jdk.httpserver

 * @library /test/lib http2/server

 * @build Http2TestServer

 * @build jdk.test.lib.net.SimpleSSLContext

 * @run testng/othervm -ea -esa MaxStreams

 */

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import java.net.URI;

import java.util.List;

import java.util.LinkedList;

import java.util.Properties;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.concurrent.CompletableFuture;

import java.util.concurrent.CompletionException;

import java.util.concurrent.CountDownLatch;

import java.util.concurrent.Executors;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Semaphore;

import javax.net.ssl.SSLContext;

import java.net.http.HttpClient;

import java.net.http.HttpRequest;

import java.net.http.HttpResponse;

import java.net.http.HttpResponse.BodyHandler;

import java.net.http.HttpResponse.BodyHandlers;

import jdk.test.lib.net.SimpleSSLContext;

import org.testng.annotations.AfterTest;

import org.testng.annotations.BeforeTest;

import org.testng.annotations.DataProvider;

import org.testng.annotations.Test;

import static java.nio.charset.StandardCharsets.UTF_8;

import static java.net.http.HttpResponse.BodyHandlers.discarding;

import static org.testng.Assert.assertEquals;

import static org.testng.Assert.assertFalse;

import static org.testng.Assert.fail;

public class MaxStreams {

    Http2TestServer http2TestServer;   // HTTP/2 ( h2c )

    Http2TestServer https2TestServer;   // HTTP/2 ( h2 )

    final Http2FixedHandler handler = new Http2FixedHandler();

    SSLContext ctx;

    String http2FixedURI;

    String https2FixedURI;

    volatile CountDownLatch latch;

    ExecutorService exec;

    final Semaphore canStartTestRun = new Semaphore(1);

    // we send an initial warm up request, then MAX_STREAMS+1 requests

    // in parallel. The last of them should hit the limit.

    // Then we wait for all the responses and send a further request

    // which should succeed. The server should see (and respond to)

    // MAX_STREAMS+2 requests per test run.

    static final int MAX_STREAMS = 10;

    static final String RESPONSE = "Hello world";

    @DataProvider(name = "uris")

    public Object[][] variants() {

        return new Object[][]{

                {http2FixedURI},

                {https2FixedURI},

                {http2FixedURI},

                {https2FixedURI}

        };

    }

    @Test(dataProvider = "uris", timeOut=20000)

    void testAsString(String uri) throws Exception {

        System.err.println("Semaphore acquire");

        canStartTestRun.acquire();

        latch = new CountDownLatch(1);

        handler.setLatch(latch);

        HttpClient client = HttpClient.newBuilder().sslContext(ctx).build();

        List<CompletableFuture<HttpResponse<String>>> responses = new LinkedList<>();

        HttpRequest request = HttpRequest.newBuilder(URI.create(uri))

                                         .version(HttpClient.Version.HTTP_2)

                                         .GET()

                                         .build();

        // send warmup to ensure we only have one Http2Connection

        System.err.println("Sending warmup request");

        HttpResponse<String> warmup = client.send(request, BodyHandlers.ofString());

        if (warmup.statusCode() != 200 || !warmup.body().equals(RESPONSE))

            throw new RuntimeException();

        for (int i=0;i<MAX_STREAMS+1; i++) {

            System.err.println("Sending request " + i);

            responses.add(client.sendAsync(request, BodyHandlers.ofString()));

        }

        // wait until we get local exception before allow server to proceed

        try {

            System.err.println("Waiting for first exception");

            CompletableFuture.anyOf(responses.toArray(new CompletableFuture<?>[0])).join();

        } catch (Exception ee) {

            System.err.println("Expected exception 1 " + ee);

        }

        latch.countDown();

        // check the first MAX_STREAMS requests succeeded

        try {

            System.err.println("Waiting for second exception");

            CompletableFuture.allOf(responses.toArray(new CompletableFuture<?>[0])).join();

            System.err.println("Did not get Expected exception 2 ");

        } catch (Exception ee) {

            System.err.println("Expected exception 2 " + ee);

        }

        int count = 0;

        int failures = 0;

        for (CompletableFuture<HttpResponse<String>> cf : responses) {

            HttpResponse<String> r = null;

            try {

                count++;

                r = cf.join();

                if (r.statusCode() != 200 || !r.body().equals(RESPONSE))

                    throw new RuntimeException();

            } catch (Throwable t) {

                failures++;

                System.err.printf("Failure %d at count %d\n", failures, count);

                System.err.println(t);

                t.printStackTrace();

            }

        }

        if (failures != 1) {

            String msg = "Expected 1 failure. Got " + failures;

            throw new RuntimeException(msg);

        }

        System.err.println("Sending last request");

        // make sure it succeeds now as number of streams == 0 now

        HttpResponse<String> warmdown = client.send(request, BodyHandlers.ofString());

        if (warmdown.statusCode() != 200 || !warmdown.body().equals(RESPONSE))

            throw new RuntimeException();

        System.err.println("Test OK");

    }

    @BeforeTest

    public void setup() throws Exception {

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

        exec = Executors.newCachedThreadPool();

        InetSocketAddress sa = new InetSocketAddress(InetAddress.getLoopbackAddress(), 0);

        Properties props = new Properties();

        props.setProperty("http2server.settings.max_concurrent_streams", Integer.toString(MAX_STREAMS));

        http2TestServer = new Http2TestServer("localhost", false, 0, exec, 10, props, null);

        http2TestServer.addHandler(handler, "/http2/fixed");

        http2FixedURI = "http://" + http2TestServer.serverAuthority()+ "/http2/fixed";

        http2TestServer.start();

        https2TestServer = new Http2TestServer("localhost", true, 0, exec, 10, props, ctx);

        https2TestServer.addHandler(handler, "/https2/fixed");

        https2FixedURI = "https://" + https2TestServer.serverAuthority()+ "/https2/fixed";

        https2TestServer.start();

    }

    @AfterTest

    public void teardown() throws Exception {

        System.err.println("Stopping test server now");

        http2TestServer.stop();

    }

    class Http2FixedHandler implements Http2Handler {

        final AtomicInteger counter = new AtomicInteger(0);

        volatile CountDownLatch latch;

        synchronized void setLatch(CountDownLatch latch) {

            this.latch = latch;

        }

        synchronized CountDownLatch getLatch() {

            return latch;

        }

        @Override

        public void handle(Http2TestExchange t) throws IOException {

            int c = -1;

            try (InputStream is = t.getRequestBody();

                 OutputStream os = t.getResponseBody()) {

                is.readAllBytes();

                c = counter.getAndIncrement();

                if (c > 0 && c <= MAX_STREAMS) {

                    // Wait for latch.

                    try {

                        // don't send any replies until all requests are sent

                        System.err.println("Latch await");

                        getLatch().await();

                        System.err.println("Latch resume");

                    } catch (InterruptedException ee) {}

                }

                t.sendResponseHeaders(200, RESPONSE.length());

                os.write(RESPONSE.getBytes());

            } finally {

                // client issues MAX_STREAMS + 3 requests in total

                // but server should only see MAX_STREAMS + 2 in total. One is rejected by client

                // counter c captured before increment so final value is MAX_STREAMS + 1

                if (c == MAX_STREAMS + 1) {

                    System.err.println("Semaphore release");

                    counter.set(0);

                    canStartTestRun.release();

                }

            }

        }

    }

}