/*

  *   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.daemon.command;

 import java.io.IOException;

 import java.util.List;

 import java.util.Locale;

 import java.util.regex.PatternSyntaxException;

 import org.sonews.daemon.NNTPConnection;

 import org.sonews.storage.StorageBackendException;

 import org.sonews.storage.StorageManager;

 import org.sonews.util.Pair;

 /**

  * <pre>

  *   XPAT header range|<message-id> pat [pat...]

  *

  *   The XPAT command is used to retrieve specific headers from

  *   specific articles, based on pattern matching on the contents of

  *   the header. This command was first available in INN.

  *

  *   The required header parameter is the name of a header line (e.g.

  *   "subject") in a news group article. See RFC-1036 for a list

  *   of valid header lines. The required range argument may be

  *   any of the following:

  *               an article number

  *               an article number followed by a dash to indicate

  *                  all following

  *               an article number followed by a dash followed by

  *                  another article number

  *

  *   The required message-id argument indicates a specific

  *   article. The range and message-id arguments are mutually

  *   exclusive. At least one pattern in wildmat must be specified

  *   as well. If there are additional arguments the are joined

  *   together separated by a single space to form one complete

  *   pattern. Successful responses start with a 221 response

  *   followed by a the headers from all messages in which the

  *   pattern matched the contents of the specified header line. This

  *   includes an empty list. Once the output is complete, a period

  *   is sent on a line by itself. If the optional argument is a

  *   message-id and no such article exists, the 430 error response

  *   is returned. A 502 response will be returned if the client only

  *   has permission to transfer articles.

  *

  *   Responses

  *

  *       221 Header follows

  *       430 no such article

  *       502 no permission

  *

  *   Response Data:

  *

  *       art_nr fitting_header_value

  * 

  * </pre>

  * [Source:"draft-ietf-nntp-imp-02.txt"] [Copyright: 1998 S. Barber]

  * 

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public class XPatCommand implements Command

 {

   @Override

   public String[] getSupportedCommandStrings()

   {

     return new String[]{"XPAT"};

   }

   @Override

   public boolean hasFinished()

   {

     return true;

   }

   @Override

   public String impliedCapability()

   {

     return null;

   }

   @Override

   public boolean isStateful()

   {

     return false;

   }

   @Override

   public void processLine(NNTPConnection conn, final String line, byte[] raw)

     throws IOException, StorageBackendException

   {

     if(conn.getCurrentChannel() == null)

     {

       conn.println("430 no group selected");

       return;

     }

     String[] command = line.split("\\p{Space}+");

     // There may be multiple patterns and Thunderbird produces

     // additional spaces between range and pattern

     if(command.length >= 4)

     {

       String header  = command[1].toLowerCase(Locale.US);

       String range   = command[2];

       String pattern = command[3];

       long start = -1;

       long end   = -1;

       if(range.contains("-"))

       {

         String[] rsplit = range.split("-", 2);

         start = Long.parseLong(rsplit[0]);

         if(rsplit[1].length() > 0)

         {

           end = Long.parseLong(rsplit[1]);

         }

       }

       else // TODO: Handle Message-IDs

       {

         start = Long.parseLong(range);

       }

       try

       {

         List<Pair<Long, String>> heads = StorageManager.current().

           getArticleHeaders(conn.getCurrentChannel(), start, end, header, pattern);

         conn.println("221 header follows");

         for(Pair<Long, String> head : heads)

         {

           conn.println(head.getA() + " " + head.getB());

         }

         conn.println(".");

       }

       catch(PatternSyntaxException ex)

       {

         ex.printStackTrace();

         conn.println("500 invalid pattern syntax");

       }

       catch(StorageBackendException ex)

       {

         ex.printStackTrace();

         conn.println("500 internal server error");

       }

     }

     else

     {

       conn.println("430 invalid command usage");

     }

   }

 }