/*
    * 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
    *
    *      https://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.
   */
  package org.apache.commons.net.ntp;
  
  import java.io.IOException;
  import java.net.InetAddress;
  import java.time.Duration;
  
  import org.apache.commons.net.examples.ntp.SimpleNTPServer;
  import org.junit.AfterClass;
  import org.junit.Assert;
  import org.junit.BeforeClass;
  import org.junit.Test;
  
  /**
   * JUnit test class for NtpClient using SimpleNTPServer
   */
  public class TestNtpClient {
  
      private static SimpleNTPServer server;
  
      @BeforeClass
      public static void oneTimeSetUp() throws IOException {
          // one-time initialization code
          server = new SimpleNTPServer(0);
          server.connect();
  
          try {
              server.start();
          } catch (final IOException e) {
              Assert.fail("failed to start NTP server: " + e);
          }
          Assert.assertTrue(server.isStarted());
          // System.out.println("XXX: time server started");
          boolean running = false;
          for (int retries = 0; retries < 5; retries++) {
              running = server.isRunning();
              if (running) {
                  break;
              }
              // if not running then sleep 2 seconds and try again
              try {
                  Thread.sleep(2000);
              } catch (final InterruptedException e) {
                  // ignore
              }
          }
          Assert.assertTrue(running);
      }
  
      @AfterClass
      public static void oneTimeTearDown() {
          // one-time cleanup code
          if (server != null) {
              server.stop();
              server = null;
          }
      }
  
      @Test
      public void testGetTime() throws IOException {
          final long currentTimeMillis = System.currentTimeMillis();
          final NTPUDPClient client = new NTPUDPClient();
          // timeout if response takes longer than 2 seconds
          client.setDefaultTimeout(Duration.ofSeconds(2));
          try {
              // Java 1.7: use InetAddress.getLoopbackAddress() instead
              final InetAddress addr = InetAddress.getByAddress("loopback", new byte[] { 127, 0, 0, 1 });
              final TimeInfo timeInfo = client.getTime(addr, server.getPort());
              Assert.assertNotNull(timeInfo);
              Assert.assertTrue(timeInfo.getReturnTime() >= currentTimeMillis);
              final NtpV3Packet message = timeInfo.getMessage();
              Assert.assertNotNull(message);
  
              final TimeStamp rcvTimeStamp = message.getReceiveTimeStamp();
              final TimeStamp xmitTimeStamp = message.getTransmitTimeStamp();
              Assert.assertTrue(xmitTimeStamp.compareTo(rcvTimeStamp) >= 0);
  
              final TimeStamp originateTimeStamp = message.getOriginateTimeStamp();
              Assert.assertNotNull(originateTimeStamp);
              Assert.assertTrue(originateTimeStamp.getTime() >= currentTimeMillis);
  
              Assert.assertEquals(NtpV3Packet.MODE_SERVER, message.getMode());
  
              // following assertions are specific to the SimpleNTPServer
 
             final TimeStamp referenceTimeStamp = message.getReferenceTimeStamp();
             Assert.assertNotNull(referenceTimeStamp);
             Assert.assertTrue(referenceTimeStamp.getTime() >= currentTimeMillis);
 
             Assert.assertEquals(NtpV3Packet.VERSION_3, message.getVersion());
             Assert.assertEquals(1, message.getStratum());
 
             Assert.assertEquals("LCL", NtpUtils.getReferenceClock(message));
         } finally {
             client.close();
         }
     }
 
 }