/*
    * ====================================================================
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   */
  package org.apache.hc.core5.http2.examples;
  
  import java.io.IOException;
  import java.net.InetSocketAddress;
  import java.time.Instant;
  import java.util.List;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.Future;
  
  import org.apache.hc.core5.http.ContentType;
  import org.apache.hc.core5.http.EndpointDetails;
  import org.apache.hc.core5.http.EntityDetails;
  import org.apache.hc.core5.http.Header;
  import org.apache.hc.core5.http.HttpException;
  import org.apache.hc.core5.http.HttpHeaders;
  import org.apache.hc.core5.http.HttpRequest;
  import org.apache.hc.core5.http.HttpResponse;
  import org.apache.hc.core5.http.Message;
  import org.apache.hc.core5.http.NameValuePair;
  import org.apache.hc.core5.http.URIScheme;
  import org.apache.hc.core5.http.impl.bootstrap.HttpAsyncServer;
  import org.apache.hc.core5.http.message.BasicHttpResponse;
  import org.apache.hc.core5.http.nio.AsyncEntityConsumer;
  import org.apache.hc.core5.http.nio.AsyncRequestConsumer;
  import org.apache.hc.core5.http.nio.AsyncServerRequestHandler;
  import org.apache.hc.core5.http.nio.entity.AsyncEntityProducers;
  import org.apache.hc.core5.http.nio.entity.DiscardingEntityConsumer;
  import org.apache.hc.core5.http.nio.entity.StringAsyncEntityConsumer;
  import org.apache.hc.core5.http.nio.support.AbstractServerExchangeHandler;
  import org.apache.hc.core5.http.nio.support.BasicRequestConsumer;
  import org.apache.hc.core5.http.nio.support.BasicResponseProducer;
  import org.apache.hc.core5.http.protocol.HttpContext;
  import org.apache.hc.core5.http.protocol.HttpCoreContext;
  import org.apache.hc.core5.http2.HttpVersionPolicy;
  import org.apache.hc.core5.http2.config.H2Config;
  import org.apache.hc.core5.http2.impl.nio.bootstrap.H2ServerBootstrap;
  import org.apache.hc.core5.io.CloseMode;
  import org.apache.hc.core5.net.WWWFormCodec;
  import org.apache.hc.core5.reactor.IOReactorConfig;
  import org.apache.hc.core5.reactor.ListenerEndpoint;
  import org.apache.hc.core5.util.TimeValue;
  
  /**
   * Example HTTP2 server that reads an entity body and responds back with a greeting.
   *
   * <pre>
   * {@code
   * $ curl  -id name=bob localhost:8080
   * HTTP/1.1 200 OK
   * Date: Sat, 25 May 2019 03:44:49 GMT
   * Server: Apache-HttpCore/5.0-beta8-SNAPSHOT (Java/1.8.0_202)
   * Transfer-Encoding: chunked
   * Content-Type: text/plain; charset=ISO-8859-1
   *
   * Hello bob
   * }</pre>
   * <p>
   * This examples uses a {@link AbstractServerExchangeHandler} for the basic request / response processing cycle.
   */
  public class H2GreetingServer {
      public static void main(final String[] args) throws ExecutionException, InterruptedException {
          int port = 8080;
          if (args.length >= 1) {
              port = Integer.parseInt(args[0]);
          }
  
          final HttpAsyncServer server = H2ServerBootstrap.bootstrap()
                  .setH2Config(H2Config.DEFAULT)
                  .setIOReactorConfig(IOReactorConfig.DEFAULT)
                  .setVersionPolicy(HttpVersionPolicy.NEGOTIATE) // fallback to HTTP/1 as needed
  
                  // wildcard path matcher:
                  .register("*", CustomServerExchangeHandler::new)
                 .create();
 
 
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
             System.out.println("HTTP server shutting down");
             server.close(CloseMode.GRACEFUL);
         }));
 
         server.start();
         final Future<ListenerEndpoint> future = server.listen(new InetSocketAddress(port), URIScheme.HTTP);
         final ListenerEndpoint listenerEndpoint = future.get();
         System.out.println("Listening on " + listenerEndpoint.getAddress());
         server.awaitShutdown(TimeValue.ofDays(Long.MAX_VALUE));
     }
 
     static class CustomServerExchangeHandler extends AbstractServerExchangeHandler<Message<HttpRequest, String>> {
 
 
         @Override
         protected AsyncRequestConsumer<Message<HttpRequest, String>> supplyConsumer(
                 final HttpRequest request,
                 final EntityDetails entityDetails,
                 final HttpContext context) {
             // if there's no body don't try to parse entity:
             AsyncEntityConsumer<String> entityConsumer = new DiscardingEntityConsumer<>();
 
             if (entityDetails != null) {
                 entityConsumer = new StringAsyncEntityConsumer();
             }
             //noinspection unchecked
             return new BasicRequestConsumer<>(entityConsumer);
 
         }
 
         @Override
         protected void handle(final Message<HttpRequest, String> requestMessage,
                               final AsyncServerRequestHandler.ResponseTrigger responseTrigger,
                               final HttpContext context) throws HttpException, IOException {
 
             final HttpCoreContext coreContext = HttpCoreContext.adapt(context);
             final EndpointDetails endpoint = coreContext.getEndpointDetails();
             final HttpRequest req = requestMessage.getHead();
             final String httpEntity = requestMessage.getBody();
 
             // generic success response:
             final HttpResponse resp = new BasicHttpResponse(200);
 
             // recording the request
             System.out.printf("[%s] %s %s %s%n", Instant.now(),
                     endpoint.getRemoteAddress(),
                     req.getMethod(),
                     req.getPath());
 
             // Request without an entity - GET/HEAD/DELETE
             if (httpEntity == null) {
                 responseTrigger.submitResponse(
                         new BasicResponseProducer(resp), context);
                 return;
             }
 
             // Request with an entity - POST/PUT
             final Header cth = req.getHeader(HttpHeaders.CONTENT_TYPE);
             final ContentType contentType = cth != null ? ContentType.parse(cth.getValue()) : null;
             String name = "stranger";
             if (contentType != null && contentType.isSameMimeType(ContentType.APPLICATION_FORM_URLENCODED)) {
 
                 // decoding the form entity into key/value pairs:
                 final List<NameValuePair> args = WWWFormCodec.parse(httpEntity, contentType.getCharset());
                 if (!args.isEmpty()) {
                     name = args.get(0).getValue();
                 }
             }
 
             // composing greeting:
             final String greeting = String.format("Hello %s\n", name);
             responseTrigger.submitResponse(
                     new BasicResponseProducer(resp, AsyncEntityProducers.create(greeting)), context);
         }
     }
 
 }