/*

  *   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.util.io;

 import java.io.BufferedInputStream;

 import java.io.BufferedOutputStream;

 import java.io.ByteArrayOutputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.UnsupportedEncodingException;

 import java.net.Socket;

 import java.net.UnknownHostException;

 import org.sonews.config.Config;

 import org.sonews.util.Log;

 /**

  * Reads an news article from a NNTP server.

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public class ArticleReader

 {

 	private BufferedOutputStream out;

 	private BufferedInputStream in;

 	private String messageID;

 	public ArticleReader(String host, int port, String messageID)

 		throws IOException, UnknownHostException

 	{

 		this.messageID = messageID;

 		// Connect to NNTP server

 		Socket socket = new Socket(host, port);

 		this.out = new BufferedOutputStream(socket.getOutputStream());

 		this.in = new BufferedInputStream(socket.getInputStream());

 		String line = readln(this.in);

 		if (!line.startsWith("200 ")) {

 			throw new IOException("Invalid hello from server: " + line);

 		}

 	}

 	private boolean eofArticle(byte[] buf)

 	{

 		if (buf.length < 4) {

 			return false;

 		}

 		int l = buf.length - 1;

 		return buf[l - 3] == 10 // '*\n'

 			&& buf[l - 2] == '.' // '.'

 			&& buf[l - 1] == 13 && buf[l] == 10;  // '\r\n'

 	}

 	public byte[] getArticleData()

 		throws IOException, UnsupportedEncodingException

 	{

 		long maxSize = Config.inst().get(Config.ARTICLE_MAXSIZE, 1024) * 1024L;

 		try {

 			this.out.write(("ARTICLE " + this.messageID + "\r\n").getBytes("UTF-8"));

 			this.out.flush();

 			String line = readln(this.in);

 			if (line.startsWith("220 ")) {

 				ByteArrayOutputStream buf = new ByteArrayOutputStream();

 				while (!eofArticle(buf.toByteArray())) {

 					for (int b = in.read(); b != 10; b = in.read()) {

 						buf.write(b);

 					}

 					buf.write(10);

 					if (buf.size() > maxSize) {

 						Log.get().warning("Skipping message that is too large: " + buf.size());

 						return null;

 					}

 				}

 				return buf.toByteArray();

 			} else {

 				Log.get().warning("ArticleReader: " + line);

 				return null;

 			}

 		} catch (IOException ex) {

 			throw ex;

 		} finally {

 			this.out.write("QUIT\r\n".getBytes("UTF-8"));

 			this.out.flush();

 			this.out.close();

 		}

 	}

 	private String readln(InputStream in)

 		throws IOException

 	{

 		ByteArrayOutputStream buf = new ByteArrayOutputStream();

 		for (int b = in.read(); b != 10 /* \n */; b = in.read()) {

 			buf.write(b);

 		}

 		return new String(buf.toByteArray());

 	}

 }