/*
 * Copyright (c) 2018, 2023, 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 8201186
 * @summary Tests an asynchronous BodySubscriber that completes
 *          immediately with a Publisher<List<ByteBuffer>>
 * @library /test/lib /test/jdk/java/net/httpclient/lib
 * @build jdk.test.lib.net.SimpleSSLContext jdk.httpclient.test.lib.common.HttpServerAdapters
 * @run testng/othervm ResponsePublisher
 */

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;
import com.sun.net.httpserver.HttpsConfigurator;
import com.sun.net.httpserver.HttpsServer;
import jdk.internal.net.http.common.OperationTrackers;
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 javax.net.ssl.SSLContext;
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.net.http.HttpClient;
import java.net.http.HttpHeaders;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpResponse.BodyHandler;
import java.net.http.HttpResponse.BodyHandlers;
import java.net.http.HttpResponse.BodySubscriber;
import java.net.http.HttpResponse.BodySubscribers;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Objects;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.Flow;
import java.util.concurrent.Flow.Publisher;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;
import jdk.httpclient.test.lib.common.HttpServerAdapters;
import jdk.httpclient.test.lib.http2.Http2TestServer;

import static java.lang.System.out;
import static java.net.http.HttpClient.Version.HTTP_1_1;
import static java.net.http.HttpClient.Version.HTTP_2;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertNotNull;
import static org.testng.Assert.assertTrue;

public class ResponsePublisher implements HttpServerAdapters {

    SSLContext sslContext;
    HttpTestServer httpTestServer;    // HTTP/1.1    [ 4 servers ]
    HttpTestServer httpsTestServer;   // HTTPS/1.1
    HttpTestServer http2TestServer;   // HTTP/2 ( h2c )
    HttpTestServer https2TestServer;  // HTTP/2 ( h2  )
    String httpURI_fixed;
    String httpURI_chunk;
    String httpsURI_fixed;
    String httpsURI_chunk;
    String http2URI_fixed;
    String http2URI_chunk;
    String https2URI_fixed;
    String https2URI_chunk;

    static final int ITERATION_COUNT = 3;
    // a shared executor helps reduce the amount of threads created by the test
    static final Executor executor = Executors.newCachedThreadPool();

    static final long start = System.nanoTime();

    public static String now() {
        long now = System.nanoTime() - start;
        long secs = now / 1000_000_000;
        long mill = (now % 1000_000_000) / 1000_000;
        long nan = now % 1000_000;
        return String.format("[%d s, %d ms, %d ns] ", secs, mill, nan);
    }

    interface BHS extends Supplier<BodyHandler<Publisher<List<ByteBuffer>>>> {
        static BHS of(BHS impl, String name) {
            return new BHSImpl(impl, name);
        }
    }

    static final class BHSImpl implements BHS {
        final BHS supplier;
        final String name;
        BHSImpl(BHS impl, String name) {
            this.supplier = impl;
            this.name = name;
        }
        @Override
        public String toString() {
            return name;
        }

        @Override
        public BodyHandler<Publisher<List<ByteBuffer>>> get() {
            return supplier.get();
        }
    }

    static final Supplier<BodyHandler<Publisher<List<ByteBuffer>>>> OF_PUBLISHER_API =
            BHS.of(BodyHandlers::ofPublisher, "BodyHandlers::ofPublisher");
    static final Supplier<BodyHandler<Publisher<List<ByteBuffer>>>> OF_PUBLISHER_TEST =
            BHS.of(PublishingBodyHandler::new, "PublishingBodyHandler::new");

    @DataProvider(name = "variants")
    public Object[][] variants() {
        return new Object[][]{
                { httpURI_fixed,    false, OF_PUBLISHER_API },
                { httpURI_chunk,    false, OF_PUBLISHER_API },
                { httpsURI_fixed,   false, OF_PUBLISHER_API },
                { httpsURI_chunk,   false, OF_PUBLISHER_API },
                { http2URI_fixed,   false, OF_PUBLISHER_API },
                { http2URI_chunk,   false, OF_PUBLISHER_API },
                { https2URI_fixed,  false, OF_PUBLISHER_API },
                { https2URI_chunk,  false, OF_PUBLISHER_API },

                { httpURI_fixed,    true, OF_PUBLISHER_API },
                { httpURI_chunk,    true, OF_PUBLISHER_API },
                { httpsURI_fixed,   true, OF_PUBLISHER_API },
                { httpsURI_chunk,   true, OF_PUBLISHER_API },
                { http2URI_fixed,   true, OF_PUBLISHER_API },
                { http2URI_chunk,   true, OF_PUBLISHER_API },
                { https2URI_fixed,  true, OF_PUBLISHER_API },
                { https2URI_chunk,  true, OF_PUBLISHER_API },

                { httpURI_fixed,    false, OF_PUBLISHER_TEST },
                { httpURI_chunk,    false, OF_PUBLISHER_TEST },
                { httpsURI_fixed,   false, OF_PUBLISHER_TEST },
                { httpsURI_chunk,   false, OF_PUBLISHER_TEST },
                { http2URI_fixed,   false, OF_PUBLISHER_TEST },
                { http2URI_chunk,   false, OF_PUBLISHER_TEST },
                { https2URI_fixed,  false, OF_PUBLISHER_TEST },
                { https2URI_chunk,  false, OF_PUBLISHER_TEST },

                { httpURI_fixed,    true, OF_PUBLISHER_TEST },
                { httpURI_chunk,    true, OF_PUBLISHER_TEST },
                { httpsURI_fixed,   true, OF_PUBLISHER_TEST },
                { httpsURI_chunk,   true, OF_PUBLISHER_TEST },
                { http2URI_fixed,   true, OF_PUBLISHER_TEST },
                { http2URI_chunk,   true, OF_PUBLISHER_TEST },
                { https2URI_fixed,  true, OF_PUBLISHER_TEST },
                { https2URI_chunk,  true, OF_PUBLISHER_TEST },
        };
    }

    final ReferenceTracker TRACKER = ReferenceTracker.INSTANCE;
    HttpClient newHttpClient() {
        return TRACKER.track(HttpClient.newBuilder()
                         .executor(executor)
                         .sslContext(sslContext)
                         .build());
    }

    @Test(dataProvider = "variants")
    public void testExceptions(String uri, boolean sameClient, BHS handlers) throws Exception {
        HttpClient client = null;
        for (int i=0; i< ITERATION_COUNT; i++) {
            if (!sameClient || client == null)
                client = newHttpClient();

            HttpRequest req = HttpRequest.newBuilder(URI.create(uri))
                    .build();
            BodyHandler<Publisher<List<ByteBuffer>>> handler = handlers.get();
            HttpResponse<Publisher<List<ByteBuffer>>> response = client.send(req, handler);
            try {
                response.body().subscribe(null);
                throw new RuntimeException("Expected NPE not thrown");
            } catch (NullPointerException x) {
                System.out.println("Got expected NPE: " + x);
            }
            // We can reuse our BodySubscribers implementations to subscribe to the
            // Publisher<List<ByteBuffer>>
            BodySubscriber<String> ofString = BodySubscribers.ofString(UTF_8);
            response.body().subscribe(ofString);

            BodySubscriber<String> ofString2 = BodySubscribers.ofString(UTF_8);
            response.body().subscribe(ofString2);
            try {
                ofString2.getBody().toCompletableFuture().join();
                throw new RuntimeException("Expected ISE not thrown");
            } catch (CompletionException x) {
                Throwable cause = x.getCause();
                if (cause instanceof  IllegalStateException) {
                    System.out.println("Got expected ISE: " + cause);
                } else {
                    throw x;
                }
            }
            // Get the final result and compare it with the expected body
            String body = ofString.getBody().toCompletableFuture().get();
            assertEquals(body, "");
            // ensure client closes before next iteration
            if (!sameClient) {
                var tracker = TRACKER.getTracker(client);
                client = null;
                clientCleanup(tracker);
            }
        }
    }

    @Test(dataProvider = "variants")
    public void testNoBody(String uri, boolean sameClient, BHS handlers) throws Exception {
        HttpClient client = null;
        for (int i=0; i< ITERATION_COUNT; i++) {
            if (!sameClient || client == null)
                client = newHttpClient();

            HttpRequest req = HttpRequest.newBuilder(URI.create(uri))
                    .build();
            BodyHandler<Publisher<List<ByteBuffer>>> handler = handlers.get();
            HttpResponse<Publisher<List<ByteBuffer>>> response = client.send(req, handler);
            // We can reuse our BodySubscribers implementations to subscribe to the
            // Publisher<List<ByteBuffer>>
            BodySubscriber<String> ofString = BodySubscribers.ofString(UTF_8);
            // get the Publisher<List<ByteBuffer>> and
            // subscribe to it.
            response.body().subscribe(ofString);
            // Get the final result and compare it with the expected body
            String body = ofString.getBody().toCompletableFuture().get();
            assertEquals(body, "");
            // ensure client closes before next iteration
            if (!sameClient) {
                var tracker = TRACKER.getTracker(client);
                client = null;
                clientCleanup(tracker);
            }
        }
    }

    @Test(dataProvider = "variants")
    public void testNoBodyAsync(String uri, boolean sameClient, BHS handlers) throws Exception {
        HttpClient client = null;
        for (int i=0; i< ITERATION_COUNT; i++) {
            if (!sameClient || client == null)
                client = newHttpClient();

            HttpRequest req = HttpRequest.newBuilder(URI.create(uri))
                    .build();
            BodyHandler<Publisher<List<ByteBuffer>>> handler = handlers.get();
            // We can reuse our BodySubscribers implementations to subscribe to the
            // Publisher<List<ByteBuffer>>
            BodySubscriber<String> ofString = BodySubscribers.ofString(UTF_8);
            CompletableFuture<String> result =
                    client.sendAsync(req, handler).thenCompose(
                            (responsePublisher) -> {
                                // get the Publisher<List<ByteBuffer>> and
                                // subscribe to it.
                                responsePublisher.body().subscribe(ofString);
                                return ofString.getBody();
                            });
            // Get the final result and compare it with the expected body
            assertEquals(result.get(), "");
            // ensure client closes before next iteration
            if (!sameClient) {
                var tracker = TRACKER.getTracker(client);
                client = null;
                clientCleanup(tracker);
            }
        }
    }

    @Test(dataProvider = "variants")
    public void testAsString(String uri, boolean sameClient, BHS handlers) throws Exception {
        HttpClient client = null;
        for (int i=0; i< ITERATION_COUNT; i++) {
            if (!sameClient || client == null)
                client = newHttpClient();

            HttpRequest req = HttpRequest.newBuilder(URI.create(uri+"/withBody"))
                    .build();
            BodyHandler<Publisher<List<ByteBuffer>>> handler = handlers.get();
            HttpResponse<Publisher<List<ByteBuffer>>> response = client.send(req, handler);
            // We can reuse our BodySubscribers implementations to subscribe to the
            // Publisher<List<ByteBuffer>>
            BodySubscriber<String> ofString = BodySubscribers.ofString(UTF_8);
            // get the Publisher<List<ByteBuffer>> and
            // subscribe to it.
            response.body().subscribe(ofString);
            // Get the final result and compare it with the expected body
            String body = ofString.getBody().toCompletableFuture().get();
            assertEquals(body, WITH_BODY);
            // ensure client closes before next iteration
            if (!sameClient) {
                var tracker = TRACKER.getTracker(client);
                client = null;
                clientCleanup(tracker);
            }
        }
    }

    @Test(dataProvider = "variants")
    public void testAsStringAsync(String uri, boolean sameClient, BHS handlers) throws Exception {
        HttpClient client = null;
        for (int i=0; i< ITERATION_COUNT; i++) {
            if (!sameClient || client == null)
                client = newHttpClient();

            HttpRequest req = HttpRequest.newBuilder(URI.create(uri+"/withBody"))
                    .build();
            BodyHandler<Publisher<List<ByteBuffer>>> handler = handlers.get();
            // We can reuse our BodySubscribers implementations to subscribe to the
            // Publisher<List<ByteBuffer>>
            BodySubscriber<String> ofString = BodySubscribers.ofString(UTF_8);
            CompletableFuture<String> result = client.sendAsync(req, handler)
                    .thenCompose((responsePublisher) -> {
                        // get the Publisher<List<ByteBuffer>> and
                        // subscribe to it.
                        responsePublisher.body().subscribe(ofString);
                        return ofString.getBody();
                    });
            // Get the final result and compare it with the expected body
            String body = result.get();
            assertEquals(body, WITH_BODY);
            // ensure client closes before next iteration
            if (!sameClient) {
                var tracker = TRACKER.getTracker(client);
                client = null;
                clientCleanup(tracker);
            }
        }
    }

    // A BodyHandler that returns PublishingBodySubscriber instances
    static class PublishingBodyHandler implements BodyHandler<Publisher<List<ByteBuffer>>> {
        @Override
        public BodySubscriber<Publisher<List<ByteBuffer>>> apply(HttpResponse.ResponseInfo rinfo) {
            assertEquals(rinfo.statusCode(), 200);
            return new PublishingBodySubscriber();
        }
    }

    // A BodySubscriber that returns a Publisher<List<ByteBuffer>>
    static class PublishingBodySubscriber implements BodySubscriber<Publisher<List<ByteBuffer>>> {
        private final CompletableFuture<Flow.Subscription> subscriptionCF = new CompletableFuture<>();
        private final CompletableFuture<Flow.Subscriber<? super List<ByteBuffer>>> subscribedCF = new CompletableFuture<>();
        private AtomicReference<Flow.Subscriber<? super List<ByteBuffer>>> subscriberRef = new AtomicReference<>();
        private final CompletionStage<Publisher<List<ByteBuffer>>> body =
                subscriptionCF.thenCompose((s) -> CompletableFuture.completedStage(this::subscribe));
                //CompletableFuture.completedStage(this::subscribe);

        private void subscribe(Flow.Subscriber<? super List<ByteBuffer>> subscriber) {
            Objects.requireNonNull(subscriber, "subscriber must not be null");
            if (subscriberRef.compareAndSet(null, subscriber)) {
                subscriptionCF.thenAccept((s) -> {
                    subscriber.onSubscribe(s);
                    subscribedCF.complete(subscriber);
                });
            } else {
                subscriber.onSubscribe(new Flow.Subscription() {
                    @Override public void request(long n) { }
                    @Override public void cancel() { }
                });
                subscriber.onError(
                        new IllegalStateException("This publisher has already one subscriber"));
            }
        }

        @Override
        public void onSubscribe(Flow.Subscription subscription) {
            subscriptionCF.complete(subscription);
        }

        @Override
        public void onNext(List<ByteBuffer> item) {
            assert subscriptionCF.isDone(); // cannot be called before onSubscribe()
            Flow.Subscriber<? super List<ByteBuffer>> subscriber = subscriberRef.get();
            assert subscriber != null; // cannot be called before subscriber calls request(1)
            subscriber.onNext(item);
        }

        @Override
        public void onError(Throwable throwable) {
            assert subscriptionCF.isDone(); // cannot be called before onSubscribe()
            // onError can be called before request(1), and therefore can
            // be called before subscriberRef is set.
            subscribedCF.thenAccept(s -> s.onError(throwable));
        }

        @Override
        public void onComplete() {
            assert subscriptionCF.isDone(); // cannot be called before onSubscribe()
            // onComplete can be called before request(1), and therefore can
            // be called before subscriberRef is set.
            subscribedCF.thenAccept(s -> s.onComplete());
        }

        @Override
        public CompletionStage<Publisher<List<ByteBuffer>>> getBody() {
            return body;
        }
    }

    static String serverAuthority(HttpServer server) {
        return InetAddress.getLoopbackAddress().getHostName() + ":"
                + server.getAddress().getPort();
    }

    @BeforeTest
    public void setup() throws Exception {
        sslContext = new SimpleSSLContext().get();
        if (sslContext == null)
            throw new AssertionError("Unexpected null sslContext");

        // HTTP/1.1
        HttpTestHandler h1_fixedLengthHandler = new HTTP_FixedLengthHandler();
        HttpTestHandler h1_chunkHandler = new HTTP_VariableLengthHandler();
        httpTestServer = HttpTestServer.create(HTTP_1_1);
        httpTestServer.addHandler( h1_fixedLengthHandler, "/http1/fixed");
        httpTestServer.addHandler(h1_chunkHandler,"/http1/chunk");
        httpURI_fixed = "http://" + httpTestServer.serverAuthority() + "/http1/fixed";
        httpURI_chunk = "http://" + httpTestServer.serverAuthority() + "/http1/chunk";

        httpsTestServer = HttpTestServer.create(HTTP_1_1, sslContext);
        httpsTestServer.addHandler(h1_fixedLengthHandler, "/https1/fixed");
        httpsTestServer.addHandler(h1_chunkHandler, "/https1/chunk");
        httpsURI_fixed = "https://" + httpsTestServer.serverAuthority() + "/https1/fixed";
        httpsURI_chunk = "https://" + httpsTestServer.serverAuthority() + "/https1/chunk";

        // HTTP/2
        HttpTestHandler h2_fixedLengthHandler = new HTTP_FixedLengthHandler();
        HttpTestHandler h2_chunkedHandler = new HTTP_VariableLengthHandler();

        http2TestServer = HttpTestServer.create(HTTP_2);
        http2TestServer.addHandler(h2_fixedLengthHandler, "/http2/fixed");
        http2TestServer.addHandler(h2_chunkedHandler, "/http2/chunk");
        http2URI_fixed = "http://" + http2TestServer.serverAuthority() + "/http2/fixed";
        http2URI_chunk = "http://" + http2TestServer.serverAuthority() + "/http2/chunk";

        https2TestServer = HttpTestServer.create(HTTP_2, sslContext);
        https2TestServer.addHandler(h2_fixedLengthHandler, "/https2/fixed");
        https2TestServer.addHandler(h2_chunkedHandler, "/https2/chunk");
        https2URI_fixed = "https://" + https2TestServer.serverAuthority() + "/https2/fixed";
        https2URI_chunk = "https://" + https2TestServer.serverAuthority() + "/https2/chunk";

        httpTestServer.start();
        httpsTestServer.start();
        http2TestServer.start();
        https2TestServer.start();
    }

    @AfterTest
    public void teardown() throws Exception {
        Thread.sleep(100);
        AssertionError fail = TRACKER.check(500);
        try {
            httpTestServer.stop();
            httpsTestServer.stop();
            http2TestServer.stop();
            https2TestServer.stop();
        } finally {
            if (fail != null) {
                throw fail;
            }
        }
    }

    // Wait for the client to be garbage collected.
    // we use the ReferenceTracker API rather than HttpClient::close here,
    // because we want to get some diagnosis if a client doesn't release
    // its resources and terminates as expected
    // By using the ReferenceTracker, we will get some diagnosis about what
    // is keeping the client alive if it doesn't get GC'ed within the
    // expected time frame.
    public void clientCleanup(OperationTrackers.Tracker tracker){
        System.gc();
        System.out.println(now() + "waiting for client to shutdown: " + tracker.getName());
        System.err.println(now() + "waiting for client to shutdown: " + tracker.getName());
        var error = TRACKER.check(tracker, 10000);
        if (error != null) throw error;
        System.out.println(now() + "client shutdown normally: " + tracker.getName());
        System.err.println(now() + "client shutdown normally: " + tracker.getName());
    }

    static final String WITH_BODY = "Lorem ipsum dolor sit amet, consectetur" +
            " adipiscing elit, sed do eiusmod tempor incididunt ut labore et" +
            " dolore magna aliqua. Ut enim ad minim veniam, quis nostrud" +
            " exercitation ullamco laboris nisi ut aliquip ex ea" +
            " commodo consequat. Duis aute irure dolor in reprehenderit in " +
            "voluptate velit esse cillum dolore eu fugiat nulla pariatur." +
            " Excepteur sint occaecat cupidatat non proident, sunt in culpa qui" +
            " officia deserunt mollit anim id est laborum.";

    static class HTTP_FixedLengthHandler implements HttpTestHandler {
        @Override
        public void handle(HttpTestExchange t) throws IOException {
            out.println("HTTP_FixedLengthHandler received request to " + t.getRequestURI());
            try (InputStream is = t.getRequestBody()) {
                is.readAllBytes();
            }
            if (t.getRequestURI().getPath().endsWith("/withBody")) {
                byte[] bytes = WITH_BODY.getBytes(UTF_8);
                t.sendResponseHeaders(200, bytes.length);  // body
                try (OutputStream os = t.getResponseBody()) {
                    os.write(bytes);
                }
            } else {
                t.sendResponseHeaders(200, 0);  //no body
            }
        }
    }

    static class HTTP_VariableLengthHandler implements HttpTestHandler {
        @Override
        public void handle(HttpTestExchange t) throws IOException {
            out.println("HTTP_VariableLengthHandler received request to " + t.getRequestURI());
            try (InputStream is = t.getRequestBody()) {
                is.readAllBytes();
            }
            t.sendResponseHeaders(200, -1);  //chunked or variable
            if (t.getRequestURI().getPath().endsWith("/withBody")) {
                byte[] bytes = WITH_BODY.getBytes(UTF_8);
                try (OutputStream os = t.getResponseBody()) {
                    int chunkLen = bytes.length/10;
                    if (chunkLen == 0) {
                        os.write(bytes);
                    } else {
                        int count = 0;
                        for (int i=0; i<10; i++) {
                            os.write(bytes, count, chunkLen);
                            os.flush();
                            count += chunkLen;
                        }
                        os.write(bytes, count, bytes.length % chunkLen);
                        count += bytes.length % chunkLen;
                        assert count == bytes.length;
                    }
                }
            } else {
                t.getResponseBody().close();   // no body
            }
        }
    }
}