/*

  *   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");

 		}

 	}

 }