package org.jboss.resteasy.test.response;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.lang.management.GarbageCollectorMXBean;
import java.lang.management.ManagementFactory;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import javax.management.Notification;
import javax.management.NotificationEmitter;
import javax.management.NotificationListener;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.Invocation.Builder;

import org.apache.commons.io.IOUtils;
import org.jboss.arquillian.container.test.api.Deployment;
import org.jboss.arquillian.container.test.api.RunAsClient;
import org.jboss.arquillian.junit.Arquillian;
import org.jboss.resteasy.test.response.resource.TestResourceImpl;
import org.jboss.resteasy.utils.PortProviderUtil;
import org.jboss.resteasy.utils.TestUtil;
import org.jboss.shrinkwrap.api.Archive;
import org.jboss.shrinkwrap.api.spec.WebArchive;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.Assert;

@RunWith(Arquillian.class)
@RunAsClient
public class ResponseStreamPrematurelyClosedTest {

   static Client client;

   @Deployment
   public static Archive<?> deploy() throws Exception {
      WebArchive war = TestUtil.prepareArchive(ResponseStreamPrematurelyClosedTest.class.getSimpleName());
      return TestUtil.finishContainerPrepare(war, null, TestResourceImpl.class);
   }

   @BeforeClass
   public static void init() {
      client = ClientBuilder.newClient();
   }

   @AfterClass
   public static void after() throws Exception {
      client.close();
   }

   private String generateURL(String path) {
      return PortProviderUtil.generateURL(path, ResponseStreamPrematurelyClosedTest.class.getSimpleName());
   }

   @Test
   public void testStream() throws Exception {
      Builder builder = client.target(generateURL("/test/document/abc/content")).request();

      try (MyByteArrayOutputStream baos = new MyByteArrayOutputStream()) {

         if (! TestUtil.isIbmJdk()) {
            //builder.get().readEntity explicitly on the same line below and not saved in any temp variable
            //to let the JVM try finalizing the ClientResponse object
            InputStream ins = builder.get().readEntity(InputStream.class);
            //suggest jvm to do gc and wait the gc notification
            final CountDownLatch coutDown = new CountDownLatch(1);

            List<GarbageCollectorMXBean> gcbeans = ManagementFactory.getGarbageCollectorMXBeans();
            NotificationListener listener = new NotificationListener() {
               public void handleNotification(Notification notification, Object handback) {
                  coutDown.countDown();
               }
            };
            try {
               for (GarbageCollectorMXBean gcbean : gcbeans) {
                  NotificationEmitter emitter = (NotificationEmitter) gcbean;
                  emitter.addNotificationListener(listener, null, null);
               }
               System.gc();
               coutDown.await(10, TimeUnit.SECONDS);

               IOUtils.copy(ins, baos);
               Assert.assertEquals("Received string: " + baos.toShortString(), 10000000, baos.size());
            } finally {
               //remove the listener
               for (GarbageCollectorMXBean gcbean : gcbeans) {
                  ((NotificationEmitter) gcbean).removeNotificationListener(listener);
               }
            }
         } else { // workaround for Ibm jdk - doesn't allow to use NotificationEmitter with GarbageCollectorMXBean
            //builder.get().readEntity explicitly on the same line below and not saved in any temp variable
            //to let the JVM try finalizing the ClientResponse object
            IOUtils.copy(builder.get().readEntity(InputStream.class), baos);
            Assert.assertEquals(100000000, baos.size());
         }
      }
   }

   private static class MyByteArrayOutputStream extends ByteArrayOutputStream {

      public String getSubstring(int from, int to) {
         if (from < 0 || to > count) {
            throw new IllegalArgumentException();
         }
         return new String(buf, from, to);
      }

      public String toShortString() {
         int s = size();
         if (s <= 14000) {
            return toString();
         } else {
            return getSubstring(0, 1000) + "..." + getSubstring(s - 13000, 13000);
         }
      }
   }
}
