/*

 *   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");

    }

  }

}