/*

  *   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.regex.Matcher;

 import java.util.regex.Pattern;

 import java.util.regex.PatternSyntaxException;

 import org.sonews.daemon.NNTPConnection;

 import org.sonews.storage.Channel;

 import org.sonews.storage.StorageBackendException;

 import org.sonews.util.Log;

 /**

  * Class handling the LIST command.

  * @author Christian Lins

  * @author Dennis Schwerdel

  * @since n3tpd/0.1

  */

 public class ListCommand implements Command

 {

   @Override

   public String[] getSupportedCommandStrings()

   {

     return new String[]{"LIST"};

   }

   @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

   {

     final String[] command = line.split(" ");

     if(command.length >= 2)

     {

       if(command[1].equalsIgnoreCase("OVERVIEW.FMT"))

       {

         conn.println("215 information follows");

         conn.println("Subject:\nFrom:\nDate:\nMessage-ID:\nReferences:\nBytes:\nLines:\nXref");

         conn.println(".");

       }

       else if(command[1].equalsIgnoreCase("NEWSGROUPS"))

       {

         conn.println("215 information follows");

         final List<Channel> list = Channel.getAll();

         for (Channel g : list)

         {

           conn.println(g.getName() + "\t" + "-");

         }

         conn.println(".");

       }

       else if(command[1].equalsIgnoreCase("SUBSCRIPTIONS"))

       {

         conn.println("215 information follows");

         conn.println(".");

       }

       else if(command[1].equalsIgnoreCase("EXTENSIONS"))

       {

         conn.println("202 Supported NNTP extensions.");

         conn.println("LISTGROUP");

         conn.println("XDAEMON");

         conn.println("XPAT");

         conn.println(".");

       }

       else if(command[1].equalsIgnoreCase("ACTIVE"))

       {

         String  pattern  = command.length == 2

           ? null : command[2].replace("*", "\\w*");

         printGroupInfo(conn, pattern);

       }

       else

       {

         conn.println("500 unknown argument to LIST command");

       }

     }

     else

     {

       printGroupInfo(conn, null);

     }

   }

   private void printGroupInfo(NNTPConnection conn, String pattern)

     throws IOException, StorageBackendException

   {

     final List<Channel> groups = Channel.getAll();

     if(groups != null)

     {

       conn.println("215 list of newsgroups follows");

       for(Channel g : groups)

       {

         try

         {

           Matcher matcher = pattern == null ?

             null : Pattern.compile(pattern).matcher(g.getName());

           if(!g.isDeleted() &&

             (matcher == null || matcher.find()))

           {

             String writeable = g.isWriteable() ? " y" : " n";

             // Indeed first the higher article number then the lower

             conn.println(g.getName() + " " + g.getLastArticleNumber() + " "

               + g.getFirstArticleNumber() + writeable);

           }

         }

         catch(PatternSyntaxException ex)

         {

           Log.get().info(ex.toString());

         }

       }

       conn.println(".");

     }

     else

     {

       conn.println("500 server backend malfunction");

     }

   }

 }