/*
    * 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.
   */
  
  package org.apache.commons.net.examples.unix;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.InterruptedIOException;
  import java.io.OutputStreamWriter;
  import java.io.PrintWriter;
  import java.net.InetAddress;
  import java.net.SocketException;
  import java.nio.charset.Charset;
  import java.time.Duration;
  
  import org.apache.commons.net.echo.EchoTCPClient;
  import org.apache.commons.net.echo.EchoUDPClient;
  
  /**
   * This is an example program demonstrating how to use the EchoTCPClient and EchoUDPClient classes. This program connects to the default echo service port of a
   * specified server, then reads lines from standard input, writing them to the echo server, and then printing the echo. The default is to use the TCP port. Use
   * the -udp flag to use the UDP port.
   * <p>
   * Usage: echo [-udp] <hostname>
   * </p>
   */
  public final class echo {
  
      public static void echoTCP(final String host) throws IOException {
          final EchoTCPClient client = new EchoTCPClient();
          String line;
  
          // We want to timeout if a response takes longer than 60 seconds
          client.setDefaultTimeout(60000);
          client.connect(host);
          try {
              System.out.println("Connected to " + host + ".");
              final Charset charset = Charset.defaultCharset();
              final BufferedReader input = new BufferedReader(new InputStreamReader(System.in, charset));
              try (PrintWriter echoOutput = new PrintWriter(new OutputStreamWriter(client.getOutputStream(), charset), true);
                      BufferedReader echoInput = new BufferedReader(new InputStreamReader(client.getInputStream(), charset))) {
                  while ((line = input.readLine()) != null) {
                      echoOutput.println(line);
                      System.out.println(echoInput.readLine());
                  }
              }
              // Don't close System.in
          } finally {
              client.disconnect();
          }
      }
  
      public static void echoUDP(final String host) throws IOException {
          int length, count;
          byte[] data;
          String line;
          final BufferedReader input;
          final InetAddress address;
  
          final Charset charset = Charset.defaultCharset();
          input = new BufferedReader(new InputStreamReader(System.in, charset));
          address = InetAddress.getByName(host);
          try (EchoUDPClient client = new EchoUDPClient()) {
  
              client.open();
              // If we don't receive an echo within 5 seconds, assume the packet is lost.
              client.setSoTimeout(Duration.ofSeconds(5));
              System.out.println("Ready to echo to " + host + ".");
  
              // Remember, there are no guarantees about the ordering of returned
              // UDP packets, so there is a chance the output may be jumbled.
              while ((line = input.readLine()) != null) {
                  data = line.getBytes(charset);
                  client.send(data, address);
                  count = 0;
                  do {
                      try {
                          length = client.receive(data);
                      }
                      // Here we catch both SocketException and InterruptedIOException,
                      // because even though the JDK 1.1 docs claim that
                      // InterruptedIOException is thrown on a timeout, it seems
                      // SocketException is also thrown.
                      catch (final SocketException e) {
                         // We timed out and assume the packet is lost.
                         System.err.println("SocketException: Timed out and dropped packet");
                         break;
                     } catch (final InterruptedIOException e) {
                         // We timed out and assume the packet is lost.
                         System.err.println("InterruptedIOException: Timed out and dropped packet");
                         break;
                     }
                     System.out.print(new String(data, 0, length, charset));
                     count += length;
                 } while (count < data.length);
 
                 System.out.println();
             }
 
         }
     }
 
     public static void main(final String[] args) {
 
         if (args.length == 1) {
             try {
                 echoTCP(args[0]);
             } catch (final IOException e) {
                 e.printStackTrace();
                 System.exit(1);
             }
         } else if (args.length == 2 && args[0].equals("-udp")) {
             try {
                 echoUDP(args[1]);
             } catch (final IOException e) {
                 e.printStackTrace();
                 System.exit(1);
             }
         } else {
             System.err.println("Usage: echo [-udp] <hostname>");
             System.exit(1);
         }
 
     }
 
 }