/*

 *   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

      }

    }

  }

}