/*

 * Copyright (c) 2015, 2016, 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.

 */

/**

 * @test

 * @bug 8087112

 * @library /lib/testlibrary/

 * @build jdk.testlibrary.SimpleSSLContext

 * @compile ../../../com/sun/net/httpserver/LogFilter.java

 * @compile ../../../com/sun/net/httpserver/FileServerHandler.java

 * @run main/othervm ManyRequests

 * @summary Send a large number of requests asynchronously

 */

//package javaapplication16;

import com.sun.net.httpserver.HttpsConfigurator;

import com.sun.net.httpserver.HttpsServer;

import java.io.IOException;

import java.io.UncheckedIOException;

import java.net.http.HttpClient;

import java.net.http.HttpRequest;

import java.net.http.HttpResponse;

import java.net.InetSocketAddress;

import java.net.URI;

import java.util.Arrays;

import java.util.HashMap;

import java.util.LinkedList;

import java.util.Random;

import java.util.concurrent.CompletableFuture;

import javax.net.ssl.SSLContext;

import jdk.testlibrary.SimpleSSLContext;

public class ManyRequests {

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

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

        InetSocketAddress addr = new InetSocketAddress(0);

        HttpsServer server = HttpsServer.create(addr, 0);

        server.setHttpsConfigurator(new HttpsConfigurator(ctx));

        HttpClient client = HttpClient.create()

                                      .sslContext(ctx)

                                      .build();

        try {

            test(server, client);

            System.out.println("OK");

        } finally {

            server.stop(0);

            client.executorService().shutdownNow();

        }

    }

    static final int REQUESTS = 1000;

    static void test(HttpsServer server, HttpClient client) throws Exception {

        int port = server.getAddress().getPort();

        URI uri = new URI("https://127.0.0.1:" + port + "/foo/x");

        server.createContext("/foo", new EchoHandler());

        server.start();

        RequestLimiter limiter = new RequestLimiter(40);

        Random rand = new Random();

        CompletableFuture<Void>[] results = new CompletableFuture[REQUESTS];

        HashMap<HttpRequest,byte[]> bodies = new HashMap<>();

        for (int i=0; i<REQUESTS; i++) {

            byte[] buf = new byte[i+1];  // different size bodies

            rand.nextBytes(buf);

            HttpRequest r = client.request(uri)

                                  .body(HttpRequest.fromByteArray(buf))

                                  .POST();

            bodies.put(r, buf);

            results[i] =

                limiter.whenOkToSend()

                       .thenCompose((v) -> r.responseAsync())

                       .thenCompose((resp) -> {

                           limiter.requestComplete();

                           if (resp.statusCode() != 200) {

                               resp.bodyAsync(HttpResponse.ignoreBody());

                               String s = "Expected 200, got: " + resp.statusCode();

                               return completedWithIOException(s);

                           }

                           return resp.bodyAsync(HttpResponse.asByteArray())

                                      .thenApply((b) -> new Pair<>(resp, b));

                       })

                      .thenAccept((pair) -> {

                          HttpRequest request = pair.t.request();

                          byte[] requestBody = bodies.get(request);

                          check(Arrays.equals(requestBody, pair.u),

                                "bodies not equal");

                      });

        }

        // wait for them all to complete and throw exception in case of error

        CompletableFuture.allOf(results).join();

    }

    static <T> CompletableFuture<T> completedWithIOException(String message) {

        CompletableFuture<T> cf = new CompletableFuture<>();

        cf.completeExceptionally(new IOException(message));

        return cf;

    }

    static final class Pair<T,U> {

        Pair(T t, U u) {

            this.t = t; this.u = u;

        }

        T t;

        U u;

    }

    /**

     * A simple limiter for controlling the number of requests to be run in

     * parallel whenOkToSend() is called which returns a CF<Void> that allows

     * each individual request to proceed, or block temporarily (blocking occurs

     * on the waiters list here. As each request actually completes

     * requestComplete() is called to notify this object, and allow some

     * requests to continue.

     */

    static class RequestLimiter {

        static final CompletableFuture<Void> COMPLETED_FUTURE =

                CompletableFuture.completedFuture(null);

        final int maxnumber;

        final LinkedList<CompletableFuture<Void>> waiters;

        int number;

        boolean blocked;

        RequestLimiter(int maximum) {

            waiters = new LinkedList<>();

            maxnumber = maximum;

        }

        synchronized void requestComplete() {

            number--;

            // don't unblock until number of requests has halved.

            if ((blocked && number <= maxnumber / 2) ||

                        (!blocked && waiters.size() > 0)) {

                int toRelease = Math.min(maxnumber - number, waiters.size());

                for (int i=0; i<toRelease; i++) {

                    CompletableFuture<Void> f = waiters.remove();

                    number ++;

                    f.complete(null);

                }

                blocked = number >= maxnumber;

            }

        }

        synchronized CompletableFuture<Void> whenOkToSend() {

            if (blocked || number + 1 >= maxnumber) {

                blocked = true;

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

                waiters.add(r);

                return r;

            } else {

                number++;

                return COMPLETED_FUTURE;

            }

        }

    }

    static void check(boolean cond, Object... msg) {

        if (cond)

            return;

        StringBuilder sb = new StringBuilder();

        for (Object o : msg)

            sb.append(o);

        throw new RuntimeException(sb.toString());

    }

}