/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * Licensed 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.
   */
  package org.argeo.maintenance.backup.vfs;
  
  import org.apache.commons.vfs2.FileObject;
  import org.apache.commons.vfs2.FileSystemManager;
  import org.apache.commons.vfs2.FileSystemOptions;
  import org.apache.commons.vfs2.provider.sftp.SftpFileSystemConfigBuilder;
  import org.argeo.maintenance.MaintenanceException;
  
  /**
   * Simplify atomic backups implementation, especially by managing VFS.
   */
  public abstract class AbstractAtomicBackup implements AtomicBackup {
  	private String name;
  	private String compression = "bz2";
  
  	protected abstract void writeBackup(FileObject targetFo);
  
  	public AbstractAtomicBackup() {
  	}
  
  	public AbstractAtomicBackup(String name) {
  		this.name = name;
  	}
  
  	public void init() {
  		if (name == null)
  			throw new MaintenanceException("Atomic backup name must be set");
  	}
  
  	public void destroy() {
  
  	}
  
  	@Override
  	public String backup(FileSystemManager fileSystemManager,
  			String backupsBase, BackupContext backupContext,
  			FileSystemOptions opts) {
  		if (name == null)
  			throw new MaintenanceException("Atomic backup name must be set");
  
  		FileObject targetFo = null;
  		try {
  			if (backupsBase.startsWith("sftp:"))
  				SftpFileSystemConfigBuilder.getInstance()
  						.setStrictHostKeyChecking(opts, "no");
  			if (compression == null || compression.equals("none"))
  				targetFo = fileSystemManager.resolveFile(backupsBase + '/'
  						+ backupContext.getRelativeFolder() + '/' + name, opts);
  			else if (compression.equals("bz2"))
  				targetFo = fileSystemManager.resolveFile("bz2:" + backupsBase
  						+ '/' + backupContext.getRelativeFolder() + '/' + name
  						+ ".bz2" + "!" + name, opts);
  			else if (compression.equals("gz"))
  				targetFo = fileSystemManager.resolveFile("gz:" + backupsBase
  						+ '/' + backupContext.getRelativeFolder() + '/' + name
  						+ ".gz" + "!" + name, opts);
  			else
  				throw new MaintenanceException("Unsupported compression "
  						+ compression);
  
  			writeBackup(targetFo);
  
  			return targetFo.toString();
  		} catch (Exception e) {
  			throw new MaintenanceException("Cannot backup " + name + " to "
  					+ targetFo, e);
  		} finally {
  			BackupUtils.closeFOQuietly(targetFo);
  		}
  	}
  
  	public void setName(String name) {
  		this.name = name;
  	}
  
  	public String getName() {
  		return name;
  	}
  
  	public void setCompression(String compression) {
  		this.compression = compression;
  	}
  }