/*
    * 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.examples.mail;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.util.Locale;
  
  import org.apache.commons.net.examples.PrintCommandListeners;
  import org.apache.commons.net.pop3.POP3Client;
  import org.apache.commons.net.pop3.POP3MessageInfo;
  import org.apache.commons.net.pop3.POP3SClient;
  
  /**
   * This is an example program demonstrating how to use the POP3[S]Client class. This program connects to a POP3[S] server and retrieves the message headers of
   * all the messages, printing the {@code From:} and {@code Subject:} header entries for each message.
   * <p>
   * See main() method for usage details
   */
  public final class POP3Mail {
  
      public static void main(final String[] args) {
          if (args.length < 3) {
              System.err.println("Usage: POP3Mail <server[:port]> <username> <password|-|*|VARNAME> [TLS [true=implicit]]");
              System.exit(1);
          }
  
          final String[] arg0 = args[0].split(":");
          final String server = arg0[0];
          final String username = args[1];
          String password = args[2];
          // prompt for the password if necessary
          try {
              password = Utils.getPassword(username, password);
          } catch (final IOException e1) {
              System.err.println("Could not retrieve password: " + e1.getMessage());
              return;
          }
  
          final String proto = args.length > 3 ? args[3] : null;
          final boolean implicit = args.length > 4 && Boolean.parseBoolean(args[4]);
  
          final POP3Client pop3;
  
          if (proto != null) {
              System.out.println("Using secure protocol: " + proto);
              pop3 = new POP3SClient(proto, implicit);
          } else {
              pop3 = new POP3Client();
          }
  
          final int port;
          if (arg0.length == 2) {
              port = Integer.parseInt(arg0[1]);
          } else {
              port = pop3.getDefaultPort();
          }
          System.out.println("Connecting to server " + server + " on " + port);
  
          // We want to timeout if a response takes longer than 60 seconds
          pop3.setDefaultTimeout(60000);
  
          // suppress login details
          pop3.addProtocolCommandListener(PrintCommandListeners.sysOutPrintCommandListener());
  
          try {
              pop3.connect(server);
          } catch (final IOException e) {
              System.err.println("Could not connect to server.");
              e.printStackTrace();
              return;
          }
  
          try {
              if (!pop3.login(username, password)) {
                  System.err.println("Could not login to server.  Check password.");
                  pop3.disconnect();
                  return;
              }
  
              final POP3MessageInfo status = pop3.status();
              if (status == null) {
                  System.err.println("Could not retrieve status.");
                  pop3.logout();
                 pop3.disconnect();
                 return;
             }
 
             System.out.println("Status: " + status);
 
             final POP3MessageInfo[] messages = pop3.listMessages();
 
             if (messages == null) {
                 System.err.println("Could not retrieve message list.");
                 pop3.logout();
                 pop3.disconnect();
                 return;
             }
             if (messages.length == 0) {
                 System.out.println("No messages");
                 pop3.logout();
                 pop3.disconnect();
                 return;
             }
 
             System.out.println("Message count: " + messages.length);
 
             for (final POP3MessageInfo msginfo : messages) {
                 final BufferedReader reader = (BufferedReader) pop3.retrieveMessageTop(msginfo.number, 0);
 
                 if (reader == null) {
                     System.err.println("Could not retrieve message header.");
                     pop3.logout();
                     pop3.disconnect();
                     return;
                 }
                 printMessageInfo(reader, msginfo.number);
             }
 
             pop3.logout();
             pop3.disconnect();
         } catch (final IOException e) {
             e.printStackTrace();
         }
     }
 
     public static void printMessageInfo(final BufferedReader reader, final int id) throws IOException {
         String from = "";
         String subject = "";
         String line;
         while ((line = reader.readLine()) != null) {
             final String lower = line.toLowerCase(Locale.ENGLISH);
             if (lower.startsWith("from: ")) {
                 from = line.substring(6).trim();
             } else if (lower.startsWith("subject: ")) {
                 subject = line.substring(9).trim();
             }
         }
 
         System.out.println(Integer.toString(id) + " From: " + from + "  Subject: " + subject);
     }
 }