/*
    *  XNap - A P2P framework and client.
    *
    *  See the file AUTHORS for copyright information.
    *
    *  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.
    *
   *  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, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.xnap.plugin.opennap.net;
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Properties;
  
  import org.apache.log4j.Logger;
  import org.xnap.util.FileHelper;
  import org.xnap.util.Preferences;
  
  /***
   * Provides a repository that handles the resume information for
   * downloads in the incomplete directory.
   * 
   * <p>This class is mostly thread safe (except for {@link #iterator()}).
   */
  public class OpenNapResumeRepository {
  
      //--- Constant(s) ---
  	
  	/***
  	 * The prefix used for resume files.
  	 */
  	public static final String FILENAME_PREFIX = ".xnap-openap-resume";
      
      //--- Data Field(s) ---
  
      private static Logger logger
  		= Logger.getLogger(OpenNapResumeRepository.class);
  
      private List list = new LinkedList();
  
      //--- Constructor(s) ---
      
      public OpenNapResumeRepository()
      {
      }
  
      //--- Method(s) ---
  
      /***
       * Adds a download to the repository. Creates a resume data file in path.
  	 *
  	 * @param path the incomplete directory
       */
      public synchronized void add
  		(File path, OpenNapDownloadContainerData download)
      {
  		list.add(download);
  		if (download.resumeFile == null) {
  			try {
  				download.resumeFile 
  					= FileHelper.createUnique
  					(path, 
  					 FILENAME_PREFIX + "." + download.filename + ".xnap3");
  				write(download);
  			}
  			catch(IOException e) {
  				logger.error("Could not create resume file.", e);
  			}
  		}
      }
  
      /***
       * Returns an iterator over all items in the repository.
       */
      public Iterator iterator()
      {
  		return list.iterator();
      }
  
     /***
      * Removes a download from the repository, i.e. when the download
      * has succeeded.
 	 */
     public synchronized void remove(OpenNapDownloadContainerData download)
     {
 		if (download.resumeFile != null) {
 			download.resumeFile.delete();
 		}
 		list.remove(download);
     }
 
     /***
      * Restores a download from file.
      */
 	private synchronized OpenNapDownloadContainerData read(File file)
 		throws IOException
 	{
 		InputStream in = new BufferedInputStream(new FileInputStream(file));
 		try {
 			Properties p = new Properties();
 			p.load(in);
 
 			OpenNapDownloadContainerData data
 				= new OpenNapDownloadContainerData();
 			data.setAutoSearchingEnabled
 				(p.getProperty
 				 ("autoSearchingEnabled", 
 				  Preferences.getInstance().getAlwaysAutoDownload() + ""));
 			data.setFilename(p.getProperty("filename"));
 			data.setFilesize(p.getProperty("filesize"));
 			data.setRealm(p.getProperty("searchRealm"));
 			data.setSearchText(p.getProperty("searchText"));
 
 			// restore segments
 			List segments = new LinkedList();
 			int i = 0;
 			while (p.getProperty("segment." + i + ".filename") != null) {
 				try {
 					OpenNapSegmentData segment = new OpenNapSegmentData();
 					segment.setFile
 						(file.getParentFile(), 
 						 p.getProperty("segment." + i + ".filename"));
 					segment.setStart
 						(p.getProperty("segment." + i + ".start"));
 					segment.setMergeFailCount
 						(p.getProperty("segment." + i + ".mergeFailCount"));
 					
 					segments.add(segment);
 				}
 				catch (IllegalArgumentException e) {
 					// invalid segment, ignore
 					logger.warn("Invalid segment: " + i + ", " 
 								+ file.getAbsolutePath());
 				}
 				
 				i++;
 			}
 			data.setSegments
 				((OpenNapSegmentData[])segments.toArray(new OpenNapSegmentData[0]));
 			
 			data.resumeFile = file;
 			return data;
 		}
 		catch (IllegalArgumentException e) {
 			throw new IOException("Invalid data");
 		}
 		finally {
 			try {
 				in.close();
 			}
 			catch (IOException e) {
 				// this exception gets lost
 			}
 		}
 	}
 	
     /***
      * Scans a directory for resume files and adds the found downloads.
      *
      * @param path the directory to scan
      * @see #add(OpenNapDownloadContainerData)
      */
     public synchronized void restore(File path)
     {
 		logger.debug("Restoring resumes from " + path.getAbsolutePath());
 		
 		File[] files = path.listFiles();
 		if (files != null) {
 			for (int i = 0; i < files.length; i++) {
 				if (!files[i].isDirectory() 
 					&& files[i].getName().startsWith(FILENAME_PREFIX)) {
 
 					try {
 						OpenNapDownloadContainerData data = read(files[i]);
 						add(path, data);
 					}
 					catch (IOException e) {
 						logger.warn("Could not restore incomplete file", e);
 					}
 				}
 			}
 		}
     }
 
 
     /***
      * Writes repository content to <code>filename</code>.
      */
     public synchronized void save(File path) 
     {
 		for (Iterator i = list.iterator(); i.hasNext();) {
 			try {
 				OpenNapDownloadContainerData data
 					= (OpenNapDownloadContainerData)i.next();
 				write(data);
 			}
 			catch(IOException e) {
 				logger.warn("Could not write resume data", e);
 			}
 		}
     }
 
     /***
      * Saves the resume information for data.
      */
 	private synchronized void write(OpenNapDownloadContainerData data)
 		throws IOException
 	{
 		OutputStream out 
 			= new BufferedOutputStream(new FileOutputStream(data.resumeFile));
 		try {
 			Properties p = new Properties();
 
 			p.setProperty("autoSearchingEnabled", 
 						  data.autoSearchingEnabled + "");
 			p.setProperty("filename", data.filename);
 			p.setProperty("filesize", data.filesize + "");
 			if (data.realm != null) {
 				p.setProperty("searchRealm", data.realm);
 			}
 			p.setProperty("searchText", data.searchText);
 
 			// save segments
 			if (data.segments != null) {
 				int c = 0;
 				for (int i = 0; i < data.segments.length; i++) {
 					if (data.segments[i].file == null) {
 						// no need to keep track of empty segments
 						continue;
 					}
 
 					p.setProperty
 						("segment." + c + ".filename",
 						 data.segments[i].file.getAbsolutePath());
 					p.setProperty
 						("segment." + c + ".start", 
 						 data.segments[i].start + "");
 					p.setProperty
 						("segment." + c + ".mergeFailCount",
 						 data.segments[i].mergeFailCount + "");
 					c++;
 				}
 			}
 
 			p.store(out, "Automatically generated XNap OpenNap resume file - do not modify");
 		}
 		finally {
 			try {
 				out.close();
 			}
 			catch (IOException e) {
 				// this exception gets lost
 			}
 		}
 	}
 
 }