/*

  *   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.command;

 import java.text.SimpleDateFormat;

 import java.util.Locale;

 import com.so.news.Debug;

 import com.so.news.NNTPConnection;

 import com.so.news.storage.Article;

 /**

  * Class handling the OVER/XOVER command.

  * 

  * Description of the XOVER command:

  * 

  * XOVER [range]

  *

  * The XOVER command returns information from the overview

  * database for the article(s) specified.

  *

  * The optional range argument may be any of the following:

  *              an article number

  *              an article number followed by a dash to indicate

  *                 all following

  *              an article number followed by a dash followed by

  *                 another article number

  *

  * If no argument is specified, then information from the

  * current article is displayed. Successful responses start

  * with a 224 response followed by the overview information

  * for all matched messages. Once the output is complete, a

  * period is sent on a line by itself. If no argument is

  * specified, the information for the current article is

  * returned.  A news group must have been selected earlier,

  * else a 412 error response is returned. If no articles are

  * in the range specified, a 420 error response is returned

  * by the server. A 502 response will be returned if the

  * client only has permission to transfer articles.

  *

  * Each line of output will be formatted with the article number,

  * followed by each of the headers in the overview database or the

  * article itself (when the data is not available in the overview

  * database) for that article separated by a tab character.  The

  * sequence of fields must be in this order: subject, author,

  * date, message-id, references, byte count, and line count. Other

  * optional fields may follow line count. Other optional fields may

  * follow line count. These fields are specified by examining the

  * response to the LIST OVERVIEW.FMT command. Where no data exists,

  * a null field must be provided (i.e. the output will have two tab

  * characters adjacent to each other). Servers should not output

  * fields for articles that have been removed since the XOVER database

  * was created.

  *

  * The LIST OVERVIEW.FMT command should be implemented if XOVER

  * is implemented. A client can use LIST OVERVIEW.FMT to determine

  * what optional fields  and in which order all fields will be

  * supplied by the XOVER command. 

  *

  * Note that any tab and end-of-line characters in any header

  * data that is returned will be converted to a space character.

  *

  * Responses:

  *

  *   224 Overview information follows

  *   412 No news group current selected

  *   420 No article(s) selected

  *   502 no permission

  * 

  * @author Christian Lins

  */

 public class OverCommand extends Command

 {

   public OverCommand(NNTPConnection conn)

   {

     super(conn);

   }

   public boolean process(String[] command)

     throws Exception

   {

     if(getCurrentGroup() == null)

     {

       printStatus(412, "No news group current selected");

       return false;

     }

     // If no parameter was specified, show information about

     // the currently selected article(s)

     if(command.length == 1)

     {

       Article art = getCurrentArticle();

       if(art == null)

       {

         printStatus(420, "No article(s) selected");

         return false;

       }

       String o = buildOverview(art, -1);

       printText(o);

     }

     // otherwise print information about the specified range

     else

     {

       int artStart = -1;

       int artEnd   = -1;

       String[] nums = command[1].split("-");

       if(nums.length > 1)

       {

         try

         {

           artStart = Integer.parseInt(nums[0]);

         }

         catch(Exception e) 

         {

           artStart = Integer.parseInt(command[1]);

         }

         try

         {

           artEnd = Integer.parseInt(nums[1]);

         }

         catch(Exception e) {}

       }

       printStatus(224, "Overview information follows");

       for(int n = artStart; n <= artEnd; n++)

       {

         Article art = Article.getByNumberInGroup(getCurrentGroup(), n);

         if(art == null)

         {

           Debug.getInstance().log("Article (gid=" + getCurrentGroup() + ", art=" + n + " is null!");

         }

         else

         {

           printTextPart(buildOverview(art, n) + NEWLINE);

         }

       }

       println(".");

       flush();

     }

     return true;

   }

   private String buildOverview(Article art, int nr)

   {

     SimpleDateFormat sdf = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z", Locale.US);

     StringBuilder overview = new StringBuilder();

     overview.append(nr);

     overview.append('\t');

     overview.append(art.getHeader().get("Subject"));

     overview.append('\t');

     overview.append(art.getHeader().get("From"));

     overview.append('\t');

     overview.append(sdf.format(art.getDate()));

     overview.append('\t');

     overview.append(art.getHeader().get("Message-ID"));

     overview.append('\t');

     overview.append(art.getHeader().get("References"));

     overview.append('\t');

     overview.append(art.getHeader().get("Bytes"));

     overview.append('\t');

     overview.append(art.getHeader().get("Lines"));

     return overview.toString();

   }

 }