/*

  * Entagged Audio Tag library

  * Copyright (c) 2003-2005 Rapha�l Slinckx <raphael@slinckx.net>

  * 

  * This library is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public

  * License as published by the Free Software Foundation; either

  * version 2.1 of the License, or (at your option) any later version.

  *  

  * This library 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

  * Lesser General Public License for more details.

  * 

  * You should have received a copy of the GNU Lesser General Public

  * License along with this library; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

  */

 package org.jaudiotagger.audio.generic;

 import org.jaudiotagger.audio.AudioFile;

 import org.jaudiotagger.audio.exceptions.CannotReadException;

 import org.jaudiotagger.audio.exceptions.CannotWriteException;

 import org.jaudiotagger.audio.exceptions.ModifyVetoException;

 import org.jaudiotagger.audio.exceptions.UnableToRenameFileException;

 import org.jaudiotagger.logging.ErrorMessage;

 import org.jaudiotagger.tag.Tag;

 import java.io.File;

 import java.io.IOException;

 import java.io.RandomAccessFile;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 /**

  * This abstract class is the skeleton for tag writers.

  * <p/>

  * <p>It handles the creation/closing of the randomaccessfile objects and then call the subclass

  * method writeTag or deleteTag. These two method have to be implemented in the

  * subclass.

  *

  * @author Raphael Slinckx

  * @version $Id: AudioFileWriter.java,v 1.18 2008/11/28 22:14:44 paultaylor Exp $

  * @since v0.02

  */

 public abstract class AudioFileWriter

 {

     private static final String TEMP_FILENAME_SUFFIX = ".tmp";

     private static final String WRITE_MODE = "rw";

     private static final int MINIMUM_FILESIZE = 150;

     // Logger Object

     public static Logger logger = Logger.getLogger("org.jaudiotagger.audio.generic");

     /**

      * If not <code>null</code>, this listener is used to notify the listener

      * about modification events.<br>

      */

     private AudioFileModificationListener modificationListener = null;

     /**

      * Delete the tag (if any) present in the given file

      *

      * @param af The file to process

      * @throws CannotWriteException if anything went wrong

      */

     public synchronized void delete(AudioFile af) throws CannotReadException, CannotWriteException

     {

         if (!af.getFile().canWrite())

         {

             throw new CannotWriteException(ErrorMessage.GENERAL_DELETE_FAILED.getMsg(af.getFile().getPath()));

         }

         if (af.getFile().length() <= MINIMUM_FILESIZE)

         {

             throw new CannotWriteException(ErrorMessage.GENERAL_DELETE_FAILED.getMsg(af.getFile().getPath()));

         }

         RandomAccessFile raf = null;

         RandomAccessFile rafTemp = null;

         File tempF = null;

         //Will be set to true on VetoException, causing the finally block to discard the tempfile.

         boolean revert = false;

         try

         {

             tempF = File.createTempFile(af.getFile().getName().replace('.', '_'), TEMP_FILENAME_SUFFIX, af.getFile().getParentFile());

             rafTemp = new RandomAccessFile(tempF, WRITE_MODE);

             raf = new RandomAccessFile(af.getFile(), WRITE_MODE);

             raf.seek(0);

             rafTemp.seek(0);

             try

             {

                 if (this.modificationListener != null)

                 {

                     this.modificationListener.fileWillBeModified(af, true);

                 }

                 deleteTag(raf, rafTemp);

                 if (this.modificationListener != null)

                 {

                     this.modificationListener.fileModified(af, tempF);

                 }

             }

             catch (ModifyVetoException veto)

             {

                 throw new CannotWriteException(veto);

             }

         }

         catch (Exception e)

         {

             revert = true;

             throw new CannotWriteException("\"" + af.getFile().getAbsolutePath() + "\" :" + e, e);

         }

         finally

         {

             // will be set to the remaining file.

             File result = af.getFile();

             try

             {

                 if (raf != null)

                 {

                     raf.close();

                 }

                 if (rafTemp != null)

                 {

                     rafTemp.close();

                 }

                 if (tempF.length() > 0 && !revert)

                 {

                     boolean deleteResult = af.getFile().delete();

                     if (deleteResult == false)

                     {

                         logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_ORIGINAL_FILE.getMsg(af.getFile().getPath(), tempF.getPath()));

                         throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_ORIGINAL_FILE.getMsg(af.getFile().getPath(), tempF.getPath()));

                     }

                     boolean renameResult = tempF.renameTo(af.getFile());

                     if (renameResult == false)

                     {

                         logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_TO_ORIGINAL_FILE.getMsg(af.getFile().getPath(), tempF.getPath()));

                         throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_TO_ORIGINAL_FILE.getMsg(af.getFile().getPath(), tempF.getPath()));

                     }

                     result = tempF;

                     //If still exists we can now delete

                     if(tempF.exists())

                     {

                         if(!tempF.delete())

                         {

                             //Non critical failed deletion

                             logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_TEMPORARY_FILE.getMsg(tempF.getPath()));

                         }

                     }

                 }

                 else

                 {

                     //It was created but never used

                     if(!tempF.delete())

                     {

                         //Non critical failed deletion

                         logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_TEMPORARY_FILE.getMsg(tempF.getPath()));

                     }

                 }

             }

             catch (Exception ex)

             {

                 logger.severe("AudioFileWriter exception cleaning up delete:" + af.getFile().getPath() + " or" + tempF.getAbsolutePath() + ":" + ex);

             }

             // Notify listener

             if (this.modificationListener != null)

             {

                 this.modificationListener.fileOperationFinished(result);

             }

         }

     }

     /**

      * Delete the tag (if any) present in the given randomaccessfile, and do not

      * close it at the end.

      *

      * @param raf     The source file, already opened in r-write mode

      * @param tempRaf The temporary file opened in r-write mode

      * @throws CannotWriteException if anything went wrong

      */

     public synchronized void delete(RandomAccessFile raf, RandomAccessFile tempRaf) throws CannotReadException, CannotWriteException, IOException

     {

         raf.seek(0);

         tempRaf.seek(0);

         deleteTag(raf, tempRaf);

     }

     /**

      * Same as above, but delete tag in the file.

      *

      * @throws IOException          is thrown when the RandomAccessFile operations throw it

      *                              (you should never throw them manually)

      * @throws CannotWriteException when an error occured during the deletion of the tag

      */

     protected abstract void deleteTag(RandomAccessFile raf, RandomAccessFile tempRaf) throws CannotReadException, CannotWriteException, IOException;

     /**

      * This method sets the {@link AudioFileModificationListener}.<br>

      * There is only one listener allowed, if you want more instances to be

      * supported, use the {@link ModificationHandler} to broadcast those events.<br>

      *

      * @param listener The listener. <code>null</code> allowed to deregister.

      */

     public synchronized void setAudioFileModificationListener(AudioFileModificationListener listener)

     {

         this.modificationListener = listener;

     }

     /**

      * Prechecks before normal write

      * <p/>

      * <ul>

      * <li>If the tag is actually empty, remove the tag</li>

      * <li>if the file is not writable, throw exception<li>

      * <li>If the file is too small to be a valid file, throw exception<li>

      * </ul>

      *

      * @param af

      * @throws CannotWriteException

      */

     private void precheckWrite(AudioFile af) throws CannotWriteException

     {

         // Preliminary checks

         try

         {

             if (af.getTag().isEmpty())

             {

                 delete(af);

                 return;

             }

         }

         catch (CannotReadException re)

         {

             throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED.getMsg(af.getFile().getPath()));

         }

         if (!af.getFile().canWrite())

         {

             logger.severe(ErrorMessage.GENERAL_WRITE_FAILED.getMsg(af.getFile().getPath()));

             throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED.getMsg(af.getFile().getPath()));

         }

         if (af.getFile().length() <= MINIMUM_FILESIZE)

         {

             logger.severe(ErrorMessage.GENERAL_WRITE_FAILED_BECAUSE_FILE_IS_TOO_SMALL.getMsg(af.getFile().getPath()));

             throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_BECAUSE_FILE_IS_TOO_SMALL.getMsg(af.getFile().getPath()));

         }

     }

     /**

      * Write the tag (if not empty) present in the AudioFile in the associated

      * File

      *

      * @param af The file we want to process

      * @throws CannotWriteException if anything went wrong

      */

     //TODO Creates temp file in same folder as the original file, this is safe but would impose a performance

     //overhead if the original file is on a networked drive

     public synchronized void write(AudioFile af) throws CannotWriteException

     {

         logger.info("Started writing tag data for file:" + af.getFile().getName());

         //Prechecks

         precheckWrite(af);

         RandomAccessFile raf = null;

         RandomAccessFile rafTemp = null;

         File newFile = null;

         File result = null;

         //Create temporary File

         try

         {

             newFile = File.createTempFile(af.getFile().getName().replace('.', '_'), TEMP_FILENAME_SUFFIX, af.getFile().getParentFile());

         }

         //Unable to create temporary file, can happen in Vista if have Create Files/Write Data set to Deny

         catch(IOException ioe)

         {

             logger.log(Level.SEVERE, ErrorMessage.GENERAL_WRITE_FAILED_TO_CREATE_TEMPORARY_FILE_IN_FOLDER.getMsg(af.getFile().getName(), af.getFile().getParentFile().getAbsolutePath()), ioe);

             throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_TO_CREATE_TEMPORARY_FILE_IN_FOLDER.getMsg(af.getFile().getName(),

                     af.getFile().getParentFile().getAbsolutePath()));

         }

         //Open temporary file and actual file for Editing

         try

         {

             rafTemp = new RandomAccessFile(newFile, WRITE_MODE);

             raf     = new RandomAccessFile(af.getFile(), WRITE_MODE);

         }

         //Unable to write to writable file, can happen in Vista if have Create Folders/Append Data set to Deny

         catch(IOException ioe)

         {

             logger.log(Level.SEVERE, ErrorMessage.GENERAL_WRITE_FAILED_TO_OPEN_FILE_FOR_EDITING.getMsg(af.getFile().getAbsolutePath()), ioe);

             //If we managed to open either file, delete it.

             try

             {

                 if (raf != null)

                 {

                     raf.close();

                 }

                 if (rafTemp != null)

                 {

                     rafTemp.close();

                 }

             }

             catch (IOException ioe2)

             {

                 //Warn but assume has worked okay

                 logger.log(Level.WARNING, ErrorMessage.GENERAL_WRITE_PROBLEM_CLOSING_FILE_HANDLE.getMsg(af.getFile(), ioe.getMessage()), ioe2);

             }

             //Delete the temp file ( we cannot delet until closed correpsonding rafTemp)

             if(!newFile.delete())

             {

                 //Non critical failed deletion

                 logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_TEMPORARY_FILE.getMsg(newFile.getAbsolutePath()));

             }

             throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_TO_OPEN_FILE_FOR_EDITING.getMsg(af.getFile().getAbsolutePath()));

         }

         //Write data to File

         try

         {

             raf.seek(0);

             rafTemp.seek(0);

             try

             {

                 if (this.modificationListener != null)

                 {

                     this.modificationListener.fileWillBeModified(af, false);

                 }

                 writeTag(af.getTag(), raf, rafTemp);

                 if (this.modificationListener != null)

                 {

                     this.modificationListener.fileModified(af, newFile);

                 }

             }

             catch (ModifyVetoException veto)

             {

                 throw new CannotWriteException(veto);

             }

         }

         catch (Exception e)

         {

             logger.log(Level.SEVERE, ErrorMessage.GENERAL_WRITE_FAILED_BECAUSE.getMsg(af.getFile(), e.getMessage()), e);

             try

             {

                 if (raf != null)

                 {

                     raf.close();

                 }

                 if (rafTemp != null)

                 {

                     rafTemp.close();

                 }

             }

             catch (IOException ioe)

             {

                 //Warn but assume has worked okay

                 logger.log(Level.WARNING, ErrorMessage.GENERAL_WRITE_PROBLEM_CLOSING_FILE_HANDLE.getMsg(af.getFile().getAbsolutePath(), ioe.getMessage()), ioe);

             }

             //Delete the temporary file because either it was never used so lets just tidy up or we did start writing to it but

             //the write failed and we havent renamed it back to the original file so we can just delete it.

             if(!newFile.delete())

             {

                  //Non critical failed deletion

                  logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_TEMPORARY_FILE.getMsg(newFile.getAbsolutePath()));   

             }

             throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_BECAUSE.getMsg(af.getFile(), e.getMessage()));

         }

         finally

         {

             try

             {

                 if (raf != null)

                 {

                     raf.close();

                 }

                 if (rafTemp != null)

                 {

                     rafTemp.close();

                 }

             }

             catch (IOException ioe)

             {

                 //Warn but assume has worked okay

                 logger.log(Level.WARNING, ErrorMessage.GENERAL_WRITE_PROBLEM_CLOSING_FILE_HANDLE.getMsg(af.getFile().getAbsolutePath(), ioe.getMessage()), ioe);

             }

         }

         //Result held in this file

         result = af.getFile();

          //If the temporary file was used

         if (newFile.length() > 0)

         {

             //Rename Original File

             //Can fail on Vista if have Special Permission 'Delete' set Deny

             File originalFileBackup = new File(af.getFile().getParentFile().getPath(), AudioFile.getBaseFilename(af.getFile())+ ".old");

             boolean renameResult = af.getFile().renameTo(originalFileBackup);

             if (renameResult == false)

             {

                 logger.log(Level.SEVERE,ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_ORIGINAL_FILE_TO_BACKUP.getMsg(af.getFile().getPath(), originalFileBackup.getName()));

                 throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_ORIGINAL_FILE_TO_BACKUP.getMsg(af.getFile().getPath(), originalFileBackup.getName()));

             }

             //Rename Temp File to Original File

             renameResult = newFile.renameTo(af.getFile());

             if (!renameResult)

             {

                  //Renamed failed so lets do some checks rename the backup back to the original file

                 //New File doesnt exist

                 if(!newFile.exists())

                 {

                     logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_NEW_FILE_DOESNT_EXIST.getMsg(newFile.getAbsolutePath()));

                 }

                 //Rename the backup back to the original

                 if(!originalFileBackup.renameTo(af.getFile()))

                 {

                     //TODO now if this happens we are left with testfile.old instead of testfile.mp4

                     logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_ORIGINAL_BACKUP_TO_ORIGINAL.getMsg(originalFileBackup.getAbsolutePath(),af.getFile().getName()));

                 }

                 logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_TO_ORIGINAL_FILE.getMsg(af.getFile().getAbsolutePath(), newFile.getName()));

                 throw new CannotWriteException(ErrorMessage.GENERAL_WRITE_FAILED_TO_RENAME_TO_ORIGINAL_FILE.getMsg(af.getFile().getAbsolutePath(), newFile.getName()));

             }

             else

             {

                 //Rename was okay so we can now delete the backup of the original

                 boolean deleteResult=originalFileBackup.delete();

                 if(!deleteResult)

                 {

                     //Not a disaster but can't delete the backup so make a warning

                     logger.warning(ErrorMessage.GENERAL_WRITE_WARNING_UNABLE_TO_DELETE_BACKUP_FILE.getMsg(originalFileBackup.getAbsolutePath()));

                 }

             }

             //Delete the temporary file if still exists

             if(newFile.exists())

             {

                 if(!newFile.delete())

                 {

                     //Non critical failed deletion

                     logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_TEMPORARY_FILE.getMsg(newFile.getPath()));

                 }

             }

         }

         else

         {

             //Delete the temporary file that wasn't ever used           

             if(!newFile.delete())

             {

                 //Non critical failed deletion

                 logger.warning(ErrorMessage.GENERAL_WRITE_FAILED_TO_DELETE_TEMPORARY_FILE.getMsg(newFile.getPath()));

             }

         }

         if (this.modificationListener != null)

         {

             this.modificationListener.fileOperationFinished(result);

         }

     }

     /**

      * This is called when a tag has to be written in a file. Three parameters

      * are provided, the tag to write (not empty) Two randomaccessfiles, the

      * first points to the file where we want to write the given tag, and the

      * second is an empty temporary file that can be used if e.g. the file has

      * to be bigger than the original.

      * <p/>

      * If something has been written in the temporary file, when this method

      * returns, the original file is deleted, and the temporary file is renamed

      * the the original name

      * <p/>

      * If nothing has been written to it, it is simply deleted.

      * <p/>

      * This method can assume the raf, rafTemp are pointing to the first byte of

      * the file. The subclass must not close these two files when the method

      * returns.

      *

      * @throws IOException          is thrown when the RandomAccessFile operations throw it

      *                              (you should never throw them manually)

      * @throws CannotWriteException when an error occured during the generation of the tag

      */

     protected abstract void writeTag(Tag tag, RandomAccessFile raf, RandomAccessFile rafTemp) throws CannotReadException, CannotWriteException, IOException;

 }