/*

  *   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());

   }

 }