/*

  *   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.io.ByteArrayInputStream;

 import java.io.ByteArrayOutputStream;

 import java.sql.SQLException;

 import java.util.Arrays;

 import javax.mail.MessagingException;

 import javax.mail.internet.AddressException;

 import javax.mail.internet.InternetHeaders;

 import org.sonews.config.Config;

 import org.sonews.util.Log;

 import org.sonews.mlgw.Dispatcher;

 import org.sonews.storage.Article;

 import org.sonews.storage.Group;

 import org.sonews.daemon.NNTPConnection;

 import org.sonews.storage.Headers;

 import org.sonews.storage.StorageBackendException;

 import org.sonews.storage.StorageManager;

 import org.sonews.feed.FeedManager;

 import org.sonews.util.Stats;

 /**

  * Implementation of the POST command. This command requires multiple lines

  * from the client, so the handling of asynchronous reading is a little tricky

  * to handle.

  * @author Christian Lins

  * @since sonews/0.5.0

  */

 public class PostCommand implements Command

 {

   private final Article article   = new Article();

   private int           lineCount = 0;

   private long          bodySize  = 0;

   private InternetHeaders headers = null;

   private long          maxBodySize  = 

     Config.inst().get(Config.ARTICLE_MAXSIZE, 128) * 1024L; // Size in bytes

   private PostState     state     = PostState.WaitForLineOne;

   private final ByteArrayOutputStream bufBody   = new ByteArrayOutputStream();

   private final StringBuilder         strHead   = new StringBuilder();

   @Override

   public String[] getSupportedCommandStrings()

   {

     return new String[]{"POST"};

   }

   @Override

   public boolean hasFinished()

   {

     return this.state == PostState.Finished;

   }

   @Override

   public String impliedCapability()

   {

     return null;

   }

   @Override

   public boolean isStateful()

   {

     return true;

   }

   /**

    * Process the given line String. line.trim() was called by NNTPConnection.

    * @param line

    * @throws java.io.IOException

    * @throws java.sql.SQLException

    */

   @Override // TODO: Refactor this method to reduce complexity!

   public void processLine(NNTPConnection conn, String line, byte[] raw)

     throws IOException, StorageBackendException

   {

     switch(state)

     {

       case WaitForLineOne:

       {

         if(line.equalsIgnoreCase("POST"))

         {

           conn.println("340 send article to be posted. End with <CR-LF>.<CR-LF>");

           state = PostState.ReadingHeaders;

         }

         else

         {

           conn.println("500 invalid command usage");

         }

         break;

       }

       case ReadingHeaders:

       {

         strHead.append(line);

         strHead.append(NNTPConnection.NEWLINE);

         if("".equals(line) || ".".equals(line))

         {

           // we finally met the blank line

           // separating headers from body

           try

           {

             // Parse the header using the InternetHeader class from JavaMail API

             headers = new InternetHeaders(

               new ByteArrayInputStream(strHead.toString().trim()

                 .getBytes(conn.getCurrentCharset())));

             // add the header entries for the article

             article.setHeaders(headers);

           }

           catch (MessagingException e)

           {

             e.printStackTrace();

             conn.println("500 posting failed - invalid header");

             state = PostState.Finished;

             break;

           }

           // Change charset for reading body; 

           // for multipart messages UTF-8 is returned

           //conn.setCurrentCharset(article.getBodyCharset());

           state = PostState.ReadingBody;

           if(".".equals(line))

           {

             // Post an article without body

             postArticle(conn, article);

             state = PostState.Finished;

           }

         }

         break;

       }

       case ReadingBody:

       {

         if(".".equals(line))

         {    

           // Set some headers needed for Over command

           headers.setHeader(Headers.LINES, Integer.toString(lineCount));

           headers.setHeader(Headers.BYTES, Long.toString(bodySize));

           byte[] body = bufBody.toByteArray();

           if(body.length >= 2)

           {

             // Remove trailing CRLF

             body = Arrays.copyOf(body, body.length - 2);

           }

           article.setBody(body); // set the article body

           postArticle(conn, article);

           state = PostState.Finished;

         }

         else

         {

           bodySize += line.length() + 1;

           lineCount++;

           // Add line to body buffer

           bufBody.write(raw, 0, raw.length);

           bufBody.write(NNTPConnection.NEWLINE.getBytes());

           if(bodySize > maxBodySize)

           {

             conn.println("500 article is too long");

             state = PostState.Finished;

             break;

           }

         }

         break;

       }

       default:

       {

         // Should never happen

         Log.get().severe("PostCommand::processLine(): already finished...");

       }

     }

   }

   /**

    * Article is a control message and needs special handling.

    * @param article

    */

   private void controlMessage(NNTPConnection conn, Article article)

     throws IOException

   {

     String[] ctrl = article.getHeader(Headers.CONTROL)[0].split(" ");

     if(ctrl.length == 2) // "cancel <mid>"

     {

       try

       {

         StorageManager.current().delete(ctrl[1]);

         // Move cancel message to "control" group

         article.setHeader(Headers.NEWSGROUPS, "control");

         StorageManager.current().addArticle(article);

         conn.println("240 article cancelled");

       }

       catch(StorageBackendException ex)

       {

         Log.get().severe(ex.toString());

         conn.println("500 internal server error");

       }

     }

     else

     {

       conn.println("441 unknown control header");

     }

   }

   private void supersedeMessage(NNTPConnection conn, Article article)

     throws IOException

   {

     try

     {

       String oldMsg = article.getHeader(Headers.SUPERSEDES)[0];

       StorageManager.current().delete(oldMsg);

       StorageManager.current().addArticle(article);

       conn.println("240 article replaced");

     }

     catch(StorageBackendException ex)

     {

       Log.get().severe(ex.toString());

       conn.println("500 internal server error");

     }

   }

   private void postArticle(NNTPConnection conn, Article article)

     throws IOException

   {

     if(article.getHeader(Headers.CONTROL)[0].length() > 0)

     {

       controlMessage(conn, article);

     }

     else if(article.getHeader(Headers.SUPERSEDES)[0].length() > 0)

     {

       supersedeMessage(conn, article);

     }

     else // Post the article regularily

     {

       // Circle check; note that Path can already contain the hostname here

       String host = Config.inst().get(Config.HOSTNAME, "localhost");

       if(article.getHeader(Headers.PATH)[0].indexOf(host + "!", 1) > 0)

       {

         Log.get().info(article.getMessageID() + " skipped for host " + host);

         conn.println("441 I know this article already");

         return;

       }

       // Try to create the article in the database or post it to

       // appropriate mailing list

       try

       {

         boolean success = false;

         String[] groupnames = article.getHeader(Headers.NEWSGROUPS)[0].split(",");

         for(String groupname : groupnames)

         {          

           Group group = StorageManager.current().getGroup(groupname);

           if(group != null && !group.isDeleted())

           {

             if(group.isMailingList() && !conn.isLocalConnection())

             {

               // Send to mailing list; the Dispatcher writes 

               // statistics to database

               Dispatcher.toList(article, group.getName());

               success = true;

             }

             else

             {

               // Store in database

               if(!StorageManager.current().isArticleExisting(article.getMessageID()))

               {

                 StorageManager.current().addArticle(article);

                 // Log this posting to statistics

                 Stats.getInstance().mailPosted(

                   article.getHeader(Headers.NEWSGROUPS)[0]);

               }

               success = true;

             }

           }

         } // end for

         if(success)

         {

           conn.println("240 article posted ok");

           FeedManager.queueForPush(article);

         }

         else

         {

           conn.println("441 newsgroup not found");

         }

       }

       catch(AddressException ex)

       {

         Log.get().warning(ex.getMessage());

         conn.println("441 invalid sender address");

       }

       catch(MessagingException ex)

       {

         // A MessageException is thrown when the sender email address is

         // invalid or something is wrong with the SMTP server.

         System.err.println(ex.getLocalizedMessage());

         conn.println("441 " + ex.getClass().getCanonicalName() + ": " + ex.getLocalizedMessage());

       }

       catch(StorageBackendException ex)

       {

         ex.printStackTrace();

         conn.println("500 internal server error");

       }

     }

   }

 }