/*
    * 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.slc.jsch;
  
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.argeo.slc.SlcException;
  import org.springframework.core.io.Resource;
  
  import com.jcraft.jsch.Channel;
  import com.jcraft.jsch.ChannelExec;
  import com.jcraft.jsch.Session;
  
  public class ScpFrom extends AbstractJschTask {
  	private final static Log log = LogFactory.getLog(ScpFrom.class);
  
  	private Resource localResource;
  	private String remotePath;
  	private Boolean mkdir = false;
  
  	public void run(Session session) {
  		if (localResource != null) {
  			File lFile;
  			try {
  				lFile = localResource.getFile();
  			} catch (IOException e) {
  				throw new SlcException("Cannot interpret resource "
  						+ localResource + " as file.", e);
  			}
  			downloadFile(session, lFile, remotePath);
  		}
  	}
  
  	protected void downloadFile(Session session, File localFile,
  			String remoteFile) {
  		OutputStream out = null;
  		OutputStream channelOut;
  		InputStream channelIn;
  		try {
  			// exec 'scp -f rfile' remotely
  			String command = "scp -f " + remoteFile;
  			Channel channel = session.openChannel("exec");
  			((ChannelExec) channel).setCommand(command);
  
  			// get I/O streams for remote scp
  			channelOut = channel.getOutputStream();
  			channelIn = channel.getInputStream();
  
  			channel.connect();
  
  			byte[] buf = new byte[1024];
  
  			// send '\0'
  			buf[0] = 0;
  			channelOut.write(buf, 0, 1);
  			channelOut.flush();
  
  			while (true) {
  				int c = checkAck(channelIn);
  				if (c != 'C') {
  					break;
  				}
  
  				// read '0644 '
  				channelIn.read(buf, 0, 5);
  
  				long filesize = 0L;
  				while (true) {
  					if (channelIn.read(buf, 0, 1) < 0) {
  						// error
  						break;
  					}
  					if (buf[0] == ' ')
  						break;
  					filesize = filesize * 10L + (long) (buf[0] - '0');
  				}
  
  				String remoteFileName = null;
  				for (int i = 0;; i++) {
 					channelIn.read(buf, i, 1);
 					if (buf[i] == (byte) 0x0a) {
 						remoteFileName = new String(buf, 0, i);
 						break;
 					}
 				}
 
 				// System.out.println("filesize="+filesize+", file="+file);
 
 				// send '\0'
 				buf[0] = 0;
 				channelOut.write(buf, 0, 1);
 				channelOut.flush();
 
 				// Create a s adirectory if it doesn't exists
 				if (!localFile.exists() && mkdir)
 					localFile.mkdirs();
 
 				// read a content of lfile
 				String localPath = localFile.isDirectory() ? localFile
 						.getPath()
 						+ File.separator + remoteFileName : localFile.getPath();
 
 				out = new FileOutputStream(localPath);
 				int foo;
 				while (true) {
 					if (buf.length < filesize)
 						foo = buf.length;
 					else
 						foo = (int) filesize;
 					foo = channelIn.read(buf, 0, foo);
 					if (foo < 0) {
 						// error
 						break;
 					}
 					out.write(buf, 0, foo);
 					filesize -= foo;
 					if (filesize == 0L)
 						break;
 				}
 
 				checkAck(channelIn);
 
 				// send '\0'
 				buf[0] = 0;
 				channelOut.write(buf, 0, 1);
 				channelOut.flush();
 
 				if (log.isDebugEnabled())
 					log.debug("Finished downloading " + remoteFile + " on "
 							+ getSshTarget() + " to " + localPath);
 			}
 
 			channel.disconnect();
 			// session.disconnect();
 		} catch (Exception e) {
 			throw new SlcException("Cannot download " + remoteFile + " to "
 					+ localFile, e);
 		} finally {
 			IOUtils.closeQuietly(out);
 		}
 	}
 
 	public void setLocalResource(Resource localFile) {
 		this.localResource = localFile;
 	}
 
 	public void setRemotePath(String remoteFile) {
 		this.remotePath = remoteFile;
 	}
 
 	public void setMkdir(Boolean mkdir) {
 		this.mkdir = mkdir;
 	}
 }