/*

 *   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");

		}

	}

}