/*

  *   StarOffice 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 com.so.news;

 import java.io.BufferedReader;

 import java.io.BufferedWriter;

 import java.io.File;

 import java.io.InputStreamReader;

 import java.io.IOException;

 import java.io.OutputStreamWriter;

 import java.net.Socket;

 import java.net.SocketException;

 import java.text.SimpleDateFormat;

 import java.util.Date;

 import java.util.LinkedList;

 import java.util.List;

 import com.so.news.command.ArticleCommand;

 import com.so.news.command.GroupCommand;

 import com.so.news.command.ListCommand;

 import com.so.news.command.PostCommand;

 import com.so.news.command.OverCommand;

 import com.so.news.storage.Article;

 import com.so.news.storage.Group;

 /**

  * Represents the connection between the server and one client.

  * @author Christian Lins (christian.lins@web.de)

  */

 public class NNTPConnection extends Thread

 {

   public static final String NEWLINE            = "\r\n";

   public static final String MESSAGE_ID_PATTERN = "<[^>]+>";

   private boolean            debug              

     = Boolean.parseBoolean(Config.getInstance().get("n3tpd.debug", "false"));

   private Socket             socket;

   private boolean            exit               = false;

   private BufferedWriter     out;

   private BufferedReader     in;

   private Article            currentArticle     = null;

   private Group              currentGroup       = null;

   /**

    * Creates a new NNTPConnection instance using the given connected Socket.

    * @param socket

    * @throws java.io.IOException

    */

   public NNTPConnection(Socket socket) 

     throws IOException

   {

     this.socket = socket;

     this.in     = new BufferedReader(new InputStreamReader(socket.getInputStream()));

     this.out    = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));

     // TODO: The output stream should be of type PrintStream so that many

     // of the printX() methods of this class can go to trash

     setDaemon(true); // Exits if the main thread is killed

   }

   /**

    * Closes the associated socket end exits the Thread.

    */

   public void exit()

   {

     try

     {

       exit = true;

       socket.close();

     }

     catch (Exception e)

     {

       e.printStackTrace();

     }

   }

   /**

    * Prints a CharSequence to the sockets output stream.

    */

   public void print(CharSequence s) throws IOException

   {

     out.append(s);

   }

   public void println(CharSequence s) throws IOException

   {

     print(s);

     print(NEWLINE);

     if (debug)

       System.out.println("<<< " + s);

   }

   public void printStatus(int code, String description) throws IOException

   {

     println("" + code + " " + description);

     flush();

   }

   public void printTextLine(CharSequence line) throws IOException

   {

     if (line.length() > 0 && line.charAt(0) == '.')

       print("..");

     println(line);

   }

   public void printTextPart(CharSequence text) throws IOException

   {

     String[] lines = text.toString().split(NEWLINE);

     for (String line : lines)

       printTextLine(line);

   }

   public void printText(CharSequence text) throws IOException

   {

     printTextPart(text);

     println(".");

     flush();

   }

   public void flush() throws IOException

   {

     out.flush();

   }

   public String readln() throws IOException

   {

     String s = in.readLine();

     if (s == null)

       throw new IOException("Socket closed");

     if (debug)

       System.out.println(">>> " + s);

     return s;

   }

   public String[] readCommand() throws IOException

   {

     return readln().split("[ ]+");

   }

   public List<String> readText() throws IOException

   {

     List<String> l = new LinkedList<String>();

     String s;

     do

     {

       s = readln();

       if (!s.equals("."))

       {

         if (s.startsWith(".."))

           s = s.substring(1);

         l.add(s);

       }

     }

     while (!s.equals("."));

     return l;

   }

   public String readTextLine() throws IOException

   {

     String s = null;

     do

     {

       s = readln();

     }

     while (s == null);

     if (s.equals("."))

       return null;

     if (s.startsWith(".."))

       s = s.substring(1);

     return s;

   }

   public void setCurrentArticle(Article current)

   {

     currentArticle = current;

   }

   public Article getCurrentArticle()

   {

     return currentArticle;

   }

   public void setCurrentGroup(Group current)

   {

     currentGroup = current;

   }

   public Group getCurrentGroup()

   {

     return currentGroup;

   }

   private void processCommand(String[] command) 

     throws Exception

   {

     if (command.length == 0)

       return; // TODO Error

     String commandName = command[0];

     // RFC977

     // TODO HELP command

     // TODO NEWGROUPS command

     // TODO NEWNEWS command

     // RFC2980

     // TODO LIST ACTIVE command

     // TODO LIST ACTIVE.TIMES command

     // TODO LIST DISTRIBUTIONS command

     // TODO LIST DISTRIB.PATS command

     // TODO XGTITLE command

     // TODO XHDR command

     // TODO XPAT command

     // TODO XPATH command

     // TODO XROVER command

     // TODO XTHREAD command

     // TODO AUTHINFO command

     // STANDARD COMMANDS

     if (commandName.equalsIgnoreCase("ARTICLE")

         || commandName.equalsIgnoreCase("STAT")

         || commandName.equalsIgnoreCase("HEAD") 

         || commandName.equalsIgnoreCase("BODY"))

     {

       ArticleCommand cmd = new ArticleCommand(this);

       cmd.process(command);

     }

     else if (commandName.equalsIgnoreCase("LIST"))

     {

       ListCommand cmd = new ListCommand(this);

       cmd.process(command);

     }

     else if (commandName.equalsIgnoreCase("GROUP"))

     {

       GroupCommand cmd = new GroupCommand(this);

       cmd.process(command);

     }

     else if(commandName.equalsIgnoreCase("POST"))

     {

       PostCommand cmd = new PostCommand(this);

       cmd.process(command);

     }

     else if (commandName.equalsIgnoreCase("CHECK")

         || commandName.equalsIgnoreCase("TAKETHIS"))

     {

       // untested, RFC2980 compliant

       printStatus(400, "not accepting articles");

       return;

     }

     else if (commandName.equalsIgnoreCase("IHAVE")

         || commandName.equalsIgnoreCase("XREPLIC"))

     {

       // untested, RFC977 compliant

       printStatus(435, "article not wanted - do not send it");

       return;

     }

     else if (commandName.equalsIgnoreCase("XCREATEGROUP"))

     {

       return;

     }

     else if (commandName.equalsIgnoreCase("SLAVE"))

     {

       // untested, RFC977 compliant

       printStatus(202, "slave status noted");

       return;

     }

     else if (commandName.equalsIgnoreCase("XINDEX"))

     {

       // untested, RFC2980 compliant

       printStatus(418, "no tin-style index is available for this news group");

       return;

     }

     else if (commandName.equalsIgnoreCase("DATE"))

     {

       printStatus(111, new SimpleDateFormat("yyyyMMddHHmmss")

           .format(new Date()));

       return;

     }

     else if (commandName.equalsIgnoreCase("MODE"))

     {

       if (command[1].equalsIgnoreCase("READER"))

       {

         // untested, RFC2980 compliant

         printStatus(200, "Hello, you can post");

       }

       else if (command[1].equalsIgnoreCase("STREAM"))

       {

         printStatus(203, "Streaming is OK");

       }

       else

         printStatus(501, "Command not supported");

     }

     else if (commandName.equalsIgnoreCase("QUIT"))

     {

       // untested, RFC977 compliant

       printStatus(205, "closing connection - goodbye!");

       exit();

       return;

     }  

     else if (commandName.equalsIgnoreCase("XSHUTDOWN"))

     {

       printStatus(205, "closing connection - goodbye!");

       exit();

       return;

     }

     // X COMMANDS

     else if(commandName.equalsIgnoreCase("XOVER")

        || commandName.equalsIgnoreCase("OVER"))

     {

       OverCommand cmd = new OverCommand(this);

       cmd.process(command);

     }

     else

       printStatus(501, "Command not supported");

   }

   /**

    * Runloop of this Thread.

    * @throws RuntimeException if this method is called directly.

    */

   @Override

   public void run()

   {

     assert !this.equals(Thread.currentThread());

     try

     {

       printStatus(200, Config.getInstance().get("n3tpd.hostname", "localhost")

           + " " + Main.VERSION + " news server ready - (posting ok).");

     }

     catch (IOException e1)

     {

       exit();

     }

     while (!exit)

     {

       try

       {

         processCommand(readCommand());

       }

       catch (SocketException e)

       {

         if (exit)

           return;

         exit();

         e.printStackTrace();

       }

       catch (IOException e)

       {

         if (exit)

           return;

         exit();

         e.printStackTrace();

       }

       catch (Throwable e)

       {

         if (exit)

           return;

         e.printStackTrace();

         // silently ignore

       }

     }

   }

 }