package org.apache.archiva.transaction;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import org.apache.archiva.checksum.ChecksumAlgorithm;
  import org.apache.archiva.checksum.ChecksummedFile;
  import org.apache.commons.io.FileUtils;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.nio.file.Paths;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  import java.util.stream.Stream;
  
  /**
   * Abstract class for the TransactionEvents
   *
   *
   */
  public abstract class AbstractTransactionEvent
      implements TransactionEvent
  {
      private Map<Path, Path> backups = new HashMap<>();
  
      private List<Path> createdDirs = new ArrayList<>();
  
      private List<Path> createdFiles = new ArrayList<>();
  
      private List<ChecksumAlgorithm> checksumAlgorithms;
  
      protected AbstractTransactionEvent()
      {
          this( new ArrayList<ChecksumAlgorithm>( 0 ) );
      }
  
      protected AbstractTransactionEvent( List<ChecksumAlgorithm> checksumAlgorithms)
      {
          this.checksumAlgorithms = checksumAlgorithms;
      }
  
      protected List<ChecksumAlgorithm> getChecksumAlgorithms()
      {
          return checksumAlgorithms;
      }
  
      /**
       * Method that creates a directory as well as all the parent directories needed
       *
       * @param dir The File directory to be created
       * @throws IOException when an unrecoverable error occurred
       */
      protected void mkDirs( Path dir )
          throws IOException
      {
          List<Path> createDirs = new ArrayList<>();
  
          Path parent = dir;
          while ( !Files.exists(parent) || !Files.isDirectory(parent) )
          {
              createDirs.add( parent );
  
              parent = parent.getParent();
          }
  
          while ( !createDirs.isEmpty() )
          {
              Path directory = createDirs.remove( createDirs.size() - 1 );
              Files.createDirectories(directory);
              createdDirs.add( directory );
          }
      }
  
      protected void revertMkDirs()
          throws IOException
      {
         if ( createdDirs != null )
         {
             Collections.reverse( createdDirs );
 
             while ( !createdDirs.isEmpty() )
             {
                 Path dir = createdDirs.remove( 0 );
 
                 if ( Files.isDirectory(dir))
                 {
                     try(Stream<Path> str = Files.list(dir)) {
                         if (str.count()==0) {
                             org.apache.archiva.common.utils.FileUtils.deleteDirectory(dir);
                         }
                     }
                 }
                 else
                 {
                     //cannot rollback created directory if it still contains files
                     break;
                 }
             }
         }
     }
 
     protected void revertFilesCreated()
         throws IOException
     {
         Iterator<Path> it = createdFiles.iterator();
         while ( it.hasNext() )
         {
             Path file = it.next();
             Files.deleteIfExists(file);
             it.remove();
         }
     }
 
     protected void createBackup( Path file )
         throws IOException
     {
         if ( Files.exists(file) && Files.isRegularFile(file) )
         {
             Path backup = Files.createTempFile( "temp-", ".backup" );
 
             FileUtils.copyFile( file.toFile(), backup.toFile() );
 
             backup.toFile().deleteOnExit();
 
             backups.put( file, backup );
         }
     }
 
     protected void restoreBackups()
         throws IOException
     {
         for ( Map.Entry<Path, Path> entry : backups.entrySet() )
         {
             FileUtils.copyFile( entry.getValue().toFile(), entry.getKey().toFile() );
         }
     }
 
     protected void restoreBackup( Path file )
         throws IOException
     {
         Path backup = backups.get( file );
         if ( backup != null )
         {
             FileUtils.copyFile( backup.toFile(), file.toFile() );
         }
     }
 
     /**
      * Create checksums of file using all digesters defined at construction time.
      *
      * @param file
      * @param force whether existing checksums should be overwritten or not
      * @throws IOException
      */
     protected void createChecksums( Path file, boolean force )
         throws IOException
     {
         for ( ChecksumAlgorithm checksumAlgorithm : getChecksumAlgorithms() )
         {
             Path checksumFile = Paths.get( file.toAbsolutePath( ) + "." + getChecksumFileExtension( checksumAlgorithm ) );
             if ( Files.exists( checksumFile ) )
             {
                 if ( !force )
                 {
                     continue;
                 }
                 createBackup( checksumFile );
             }
             else
             {
                 createdFiles.add( checksumFile );
             }
         }
         ChecksummedFile csFile = new ChecksummedFile( file );
         csFile.fixChecksums( getChecksumAlgorithms() );
     }
 
     /**
      * TODO: Remove in favor of using FileUtils directly.
      */
     protected void writeStringToFile( Path file, String content )
         throws IOException
     {
         org.apache.archiva.common.utils.FileUtils.writeStringToFile( file, Charset.defaultCharset(), content );
     }
 
     /**
      * File extension for checksums
      * TODO should be moved to plexus-digester ?
      */
     protected String getChecksumFileExtension( ChecksumAlgorithm algorithm )
     {
         return algorithm.getExt().get(0);
     }
 
 }