/*

  *   SONEWS News Server

  *   see AUTHORS for the list of contributors

  *

  *   This program is free software: you can redistribute it and/or modify

  *   it under the terms of the GNU General Public License as published by

  *   the Free Software Foundation, either version 3 of the License, or

  *   (at your option) any later version.

  *

  *   This program is distributed in the hope that it will be useful,

  *   but WITHOUT ANY WARRANTY; without even the implied warranty of

  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  *   GNU General Public License for more details.

  *

  *   You should have received a copy of the GNU General Public License

  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.

  */

 package org.sonews.mlgw;

 import java.io.IOException;

 import org.sonews.daemon.Config;

 import org.sonews.daemon.storage.Article;

 import org.sonews.util.io.ArticleInputStream;

 import org.sonews.daemon.storage.Database;

 import java.sql.SQLException;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.Properties;

 import javax.mail.Address;

 import javax.mail.Authenticator;

 import javax.mail.Message;

 import javax.mail.MessagingException;

 import javax.mail.PasswordAuthentication;

 import javax.mail.Session;

 import javax.mail.Transport;

 import javax.mail.internet.InternetAddress;

 import javax.mail.internet.MimeMessage;

 import org.sonews.daemon.storage.Headers;

 import org.sonews.util.Log;

 import org.sonews.util.Stats;

 /**

  * Dispatches messages from mailing list or newsserver or vice versa.

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public class Dispatcher 

 {

   static class PasswordAuthenticator extends Authenticator

   {

     @Override

     public PasswordAuthentication getPasswordAuthentication()

     {

       final String username = 

         Config.getInstance().get(Config.MLSEND_USER, "user");

       final String password = 

         Config.getInstance().get(Config.MLSEND_PASSWORD, "mysecret");

       return new PasswordAuthentication(username, password);

     }

   }

   /**

    * Posts a message that was received from a mailing list to the 

    * appropriate newsgroup.

    * @param msg

    */

   public static boolean toGroup(final Message msg)

   {

     try

     {

       Address[] to = msg.getAllRecipients(); // includes TO/CC/BCC

       if(to == null || to.length <= 0)

       {

         Log.msg("Skipping message because no receipient!", true);

         return false;

       }

       else

       {

         boolean posted = false;

         for(Address toa : to) // Address can have '<' '>' around

         {

           if(!(toa instanceof InternetAddress))

           {

             continue;

           }

           String group = Database.getInstance()

             .getGroupForList((InternetAddress)toa);

           if(group != null)

           {

             Log.msg("Posting to group " + group, true);

             // Create new Article object

             Article article = new Article(msg);

             article.setGroup(group);

             // Write article to database

             if(!Database.getInstance().isArticleExisting(article.getMessageID()))

             {

               Database.getInstance().addArticle(article);

               Stats.getInstance().mailGatewayed(

                 article.getHeader(Headers.NEWSGROUPS)[0]);

             }

             else

             {

               Log.msg("Article " + article.getMessageID() + " already existing.", true);

               // TODO: It may be possible that a ML mail is posted to several

               // ML addresses...

             }

             posted = true;

           }

           else

           {

             Log.msg("No group for " + toa, true);

           }

         } // end for

         return posted;

       }

     }

     catch(Exception ex)

     {

       ex.printStackTrace();

       return false;

     }

   }

   /**

    * Mails a message received through NNTP to the appropriate mailing list.

    */

   public static void toList(Article article)

     throws IOException, MessagingException, SQLException

   {

     // Get mailing lists for the group of this article

     List<String> listAddresses = new ArrayList<String>();

     String[]     groupnames    = article.getHeader(Headers.NEWSGROUPS)[0].split(",");

     for(String groupname : groupnames)

     {

       String listAddress = Database.getInstance().getListForGroup(groupname);

       if(listAddress != null)

       {

         listAddresses.add(listAddress);

       }

     }

     for(String listAddress : listAddresses)

     {

       // Compose message and send it via given SMTP-Host

       String smtpHost = Config.getInstance().get(Config.MLSEND_HOST, "localhost");

       int    smtpPort = Config.getInstance().get(Config.MLSEND_PORT, 25);

       String smtpUser = Config.getInstance().get(Config.MLSEND_USER, "user");

       String smtpPw   = Config.getInstance().get(Config.MLSEND_PASSWORD, "mysecret");

       Properties props    = System.getProperties();

       props.put("mail.smtp.localhost", 

         Config.getInstance().get(Config.HOSTNAME, "localhost"));

       props.put("mail.smtp.from",  // Used for MAIL FROM command

         Config.getInstance().get(

           Config.MLSEND_ADDRESS, article.getHeader(Headers.FROM)[0]));

       props.put("mail.smtp.host", smtpHost);

       props.put("mail.smtp.port", smtpPort);

       props.put("mail.smtp.auth", "true");

       Address[] address = new Address[1];

       address[0] = new InternetAddress(listAddress);

       ArticleInputStream in = new ArticleInputStream(article);

       Session session = Session.getDefaultInstance(props, new PasswordAuthenticator());

       MimeMessage msg = new MimeMessage(session, in);

       msg.setRecipient(Message.RecipientType.TO, address[0]);

       msg.setReplyTo(address);

       msg.removeHeader(Headers.NEWSGROUPS);

       msg.removeHeader(Headers.PATH);

       msg.removeHeader(Headers.LINES);

       msg.removeHeader(Headers.BYTES);

       if(Config.getInstance().get(Config.MLSEND_RW_SENDER, false))

       {

         rewriteSenderAddress(msg); // Set the SENDER address

       }

       if(Config.getInstance().get(Config.MLSEND_RW_FROM, false))

       {

         rewriteFromAddress(msg);   // Set the FROM address

       }

       msg.saveChanges();

       // Send the mail

       Transport transport = session.getTransport("smtp");

       transport.connect(smtpHost, smtpPort, smtpUser, smtpPw);

       transport.sendMessage(msg, msg.getAllRecipients());

       transport.close();

       Stats.getInstance().mailGatewayed(article.getHeader(Headers.NEWSGROUPS)[0]);

       Log.msg("MLGateway: Mail " + article.getHeader("Subject")[0] 

         + " was delivered to " + listAddress + ".", true);

     }

   }

   /**

    * Sets the SENDER header of the given MimeMessage. This might be necessary

    * for moderated groups that does not allow the "normal" FROM sender.

    * @param msg

    * @throws javax.mail.MessagingException

    */

   private static void rewriteSenderAddress(MimeMessage msg)

     throws MessagingException

   {

     String mlAddress = Config.getInstance().get(Config.MLSEND_ADDRESS, null);

     if(mlAddress != null)

     {

       msg.setSender(new InternetAddress(mlAddress));

     }

     else

     {

       throw new MessagingException("Cannot rewrite SENDER header!");

     }

   }

   /**

    * Sets the FROM header of the given MimeMessage. This might be necessary

    * for moderated groups that does not allow the "normal" FROM sender.

    * @param msg

    * @throws javax.mail.MessagingException

    */

   private static void rewriteFromAddress(MimeMessage msg)

     throws MessagingException

   {

     Address[] froms  = msg.getFrom();

     String mlAddress = Config.getInstance().get(Config.MLSEND_ADDRESS, null);

     if(froms.length > 0 && froms[0] instanceof InternetAddress 

       && mlAddress != null)

     {

       InternetAddress from = (InternetAddress)froms[0];

       from.setAddress(mlAddress);

       msg.setFrom(from);

     }

     else

     {

       throw new MessagingException("Cannot rewrite FROM header!");

     }    

   }

 }