package org.apache.archiva.repository.storage;
   
   /*
    * 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.common.filelock.FileLockException;
  import org.apache.archiva.common.filelock.FileLockManager;
  import org.apache.archiva.common.filelock.FileLockTimeoutException;
  import org.apache.archiva.common.filelock.Lock;
  import org.apache.commons.lang3.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.nio.channels.FileChannel;
  import java.nio.channels.ReadableByteChannel;
  import java.nio.channels.WritableByteChannel;
  import java.nio.file.*;
  import java.util.HashSet;
  import java.util.function.Consumer;
  
  /**
   *
   * Utility class for assets. Allows to copy, move between different storage instances and
   * recursively consume the tree.
   *
   * @author Martin Stockhammer <martin_s@apache.org>
   */
  public class StorageUtil
  {
      private static final int DEFAULT_BUFFER_SIZE = 4096;
      private static final Logger log = LoggerFactory.getLogger(StorageUtil.class);
  
      /**
       * Copies the source asset to the target. The assets may be from different RepositoryStorage instances.
       * If you know that source and asset are from the same storage instance, the copy method of the storage
       * instance may be faster.
       *
       * @param source The source asset
       * @param target The target asset
       * @param locked If true, a readlock is set on the source and a write lock is set on the target.
       * @param copyOptions Copy options
       * @throws IOException
       */
      public static final void copyAsset( final StorageAsset source,
                                          final StorageAsset target,
                                          boolean locked,
                                          final CopyOption... copyOptions ) throws IOException
      {
          if (source.isFileBased() && target.isFileBased()) {
              // Short cut for FS operations
              final Path sourcePath = source.getFilePath();
              final Path targetPath = target.getFilePath( );
              if (locked) {
                  final FileLockManager lmSource = ((FilesystemStorage)source.getStorage()).getFileLockManager();
                  final FileLockManager lmTarget = ((FilesystemStorage)target.getStorage()).getFileLockManager();
                  Lock lockRead = null;
                  Lock lockWrite = null;
                  try {
                      lockRead = lmSource.readFileLock(sourcePath);
                  } catch (Exception e) {
                      log.error("Could not create read lock on {}", sourcePath);
                      throw new IOException(e);
                  }
                  try {
                      lockWrite = lmTarget.writeFileLock(targetPath);
                  } catch (Exception e) {
                      log.error("Could not create write lock on {}", targetPath);
                      throw new IOException(e);
                  }
                  try {
                      Files.copy(sourcePath, targetPath, copyOptions);
                  } finally {
                      if (lockRead!=null) {
                          try {
                              lmSource.release(lockRead);
                          } catch (FileLockException e) {
                              log.error("Error during lock release of read lock {}", lockRead.getFile());
                          }
                      }
                      if (lockWrite!=null) {
                          try {
                             lmTarget.release(lockWrite);
                         } catch (FileLockException e) {
                             log.error("Error during lock release of write lock {}", lockWrite.getFile());
                         }
                     }
                 }
             } else
             {
                 Files.copy( sourcePath, targetPath, copyOptions );
             }
         } else {
             try {
                 final RepositoryStorage sourceStorage = source.getStorage();
                 final RepositoryStorage targetStorage = target.getStorage();
                 sourceStorage.consumeDataFromChannel( source, is -> wrapWriteFunction( is, targetStorage, target, locked ), locked);
             }  catch (IOException e) {
                 throw e;
             }  catch (Throwable e) {
                 Throwable cause = e.getCause();
                 if (cause instanceof IOException) {
                     throw (IOException)cause;
                 } else
                 {
                     throw new IOException( e );
                 }
             }
         }
     }
 
     /**
      * Moves a asset between different storage instances.
      * If you know that source and asset are from the same storage instance, the move method of the storage
      * instance may be faster.
      *
      * @param source The source asset
      * @param target The target asset
      * @param locked If true, a lock is used for the move operation.
      * @param copyOptions Options for copying
      * @throws IOException If the move fails
      */
     public static final void moveAsset(StorageAsset source, StorageAsset target, boolean locked, CopyOption... copyOptions) throws IOException
     {
         if (source.isFileBased() && target.isFileBased()) {
             // Short cut for FS operations
             // Move is atomic operation
             if (!Files.exists(target.getFilePath().getParent())) {
                 Files.createDirectories(target.getFilePath().getParent());
             }
             Files.move( source.getFilePath(), target.getFilePath(), copyOptions );
         } else {
             try {
                 final RepositoryStorage sourceStorage = source.getStorage();
                 final RepositoryStorage targetStorage = target.getStorage();
                 sourceStorage.consumeDataFromChannel( source, is -> wrapWriteFunction( is, targetStorage, target, locked ), locked);
                 sourceStorage.removeAsset( source );
             }  catch (IOException e) {
                 throw e;
             }  catch (Throwable e) {
                 Throwable cause = e.getCause();
                 if (cause instanceof IOException) {
                     throw (IOException)cause;
                 } else
                 {
                     throw new IOException( e );
                 }
             }
         }
 
     }
 
     private static final void wrapWriteFunction(ReadableByteChannel is, RepositoryStorage targetStorage, StorageAsset target, boolean locked) {
         try {
             targetStorage.writeDataToChannel( target, os -> copy(is, os), locked );
         } catch (Exception e) {
             throw new RuntimeException( e );
         }
     }
 
 
     private static final void copy( final ReadableByteChannel is, final WritableByteChannel os ) {
         if (is instanceof FileChannel) {
             copy( (FileChannel) is, os );
         } else if (os instanceof FileChannel) {
             copy(is, (FileChannel)os);
         } else
         {
             try
             {
                 ByteBuffer buffer = ByteBuffer.allocate( DEFAULT_BUFFER_SIZE );
                 while ( is.read( buffer ) != -1 )
                 {
                     buffer.flip( );
                     while ( buffer.hasRemaining( ) )
                     {
                         os.write( buffer );
                     }
                     buffer.clear( );
                 }
             }
             catch ( IOException e )
             {
                 throw new RuntimeException( e );
             }
         }
     }
 
     private static final void copy( final FileChannel is, final WritableByteChannel os ) {
         try
         {
             is.transferTo( 0, is.size( ), os );
         }
         catch ( IOException e )
         {
             throw new RuntimeException( e );
         }
     }
 
     private static final void copy( final ReadableByteChannel is, final FileChannel os ) {
         try
         {
             os.transferFrom( is, 0, Long.MAX_VALUE );
         }
         catch ( IOException e )
         {
             throw new RuntimeException( e );
         }
     }
 
     /**
      * Runs the consumer function recursively on each asset found starting at the base path
      * @param baseAsset The base path where to start search
      * @param consumer The consumer function applied to each found asset
      * @param depthFirst If true, the deepest elements are consumed first.
      * @param maxDepth The maximum depth to recurse into. 0 means, only the baseAsset is consumed, 1 the base asset and its children and so forth.
      */
     public static final void recurse(final StorageAsset baseAsset, final Consumer<StorageAsset> consumer, final boolean depthFirst, final int maxDepth) throws IOException {
         recurse(baseAsset, consumer, depthFirst, maxDepth, 0);
     }
 
     /**
      * Runs the consumer function recursively on each asset found starting at the base path. The function descends into
      * maximum depth.
      *
      * @param baseAsset The base path where to start search
      * @param consumer The consumer function applied to each found asset
      * @param depthFirst If true, the deepest elements are consumed first.
      */
     public static final void recurse(final StorageAsset baseAsset, final Consumer<StorageAsset> consumer, final boolean depthFirst) throws IOException {
         recurse(baseAsset, consumer, depthFirst, Integer.MAX_VALUE, 0);
     }
 
     /**
      * Runs the consumer function recursively on each asset found starting at the base path. It does not recurse with
      * depth first and stops only if there are no more children available.
      *
      * @param baseAsset The base path where to start search
      * @param consumer The consumer function applied to each found asset
      */
     public static final void recurse(final StorageAsset baseAsset, final Consumer<StorageAsset> consumer) throws IOException {
         recurse(baseAsset, consumer, false, Integer.MAX_VALUE, 0);
     }
 
     private static final void recurse(final StorageAsset baseAsset, final Consumer<StorageAsset> consumer, final boolean depthFirst, final int maxDepth, final int currentDepth)
     throws IOException {
         if (!depthFirst) {
             consumer.accept(baseAsset);
         }
         if (currentDepth<maxDepth && baseAsset.isContainer()) {
             for(StorageAsset asset : baseAsset.list() ) {
                 recurse(asset, consumer, depthFirst, maxDepth, currentDepth+1);
             }
         }
         if (depthFirst) {
             consumer.accept(baseAsset);
         }
     }
 
     /**
      * Deletes the given asset and all child assets recursively.
      * @param baseDir The base asset to remove.
      * @throws IOException
      */
     public static final void deleteRecursively(StorageAsset baseDir) throws IOException {
         recurse(baseDir, a -> {
             try {
                 a.getStorage().removeAsset(a);
             } catch (IOException e) {
                 log.error("Could not delete asset {}", a.getPath());
             }
         },true);
     }
 
     /**
      * Returns the extension of the name of a given asset. Extension is the substring after the last occurence of '.' in the
      * string. If no '.' is found, the empty string is returned.
      *
      * @param asset The asset from which to return the extension string.
      * @return The extension.
      */
     public static final String getExtension(StorageAsset asset) {
         return StringUtils.substringAfterLast(asset.getName(),".");
     }
 
     public static final void copyToLocalFile(StorageAsset asset, Path destination, CopyOption... copyOptions) throws IOException {
         if (asset.isFileBased()) {
             Files.copy(asset.getFilePath(), destination, copyOptions);
         } else {
             try {
 
                 HashSet<OpenOption> openOptions = new HashSet<>();
                 for (CopyOption option : copyOptions) {
                     if (option == StandardCopyOption.REPLACE_EXISTING) {
                         openOptions.add(StandardOpenOption.CREATE);
                         openOptions.add(StandardOpenOption.TRUNCATE_EXISTING);
                         openOptions.add(StandardOpenOption.WRITE);
                     } else {
                         openOptions.add(StandardOpenOption.WRITE);
                         openOptions.add(StandardOpenOption.CREATE_NEW);
                     }
                 }
                 asset.getStorage().consumeDataFromChannel(asset, channel -> {
                     try {
                         FileChannel.open(destination, openOptions).transferFrom(channel, 0, Long.MAX_VALUE);
                     } catch (IOException e) {
                         throw new RuntimeException(e);
                     }
                 }, false);
             } catch (Throwable e) {
                 if (e.getCause() instanceof IOException) {
                     throw (IOException)e.getCause();
                 } else {
                     throw new IOException(e);
                 }
             }
         }
     }
 
     public static class PathInformation {
         final Path path ;
         final boolean tmpFile;
 
         PathInformation(Path path, boolean tmpFile) {
             this.path = path;
             this.tmpFile = tmpFile;
         }
 
         public Path getPath() {
             return path;
         }
 
         public boolean isTmpFile() {
             return tmpFile;
         }
 
     }
 
     public static final PathInformation getAssetDataAsPath(StorageAsset asset) throws IOException {
         if (!asset.exists()) {
             throw new IOException("Asset does not exist");
         }
         if (asset.isFileBased()) {
             return new PathInformation(asset.getFilePath(), false);
         } else {
             Path tmpFile = Files.createTempFile(asset.getName(), getExtension(asset));
             copyToLocalFile(asset, tmpFile, StandardCopyOption.REPLACE_EXISTING);
             return new PathInformation(tmpFile, true);
         }
     }
 
 }