package org.apache.maven.wagon.providers.ssh.jsch;

/*
 * 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 java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.maven.wagon.InputData;
import org.apache.maven.wagon.OutputData;
import org.apache.maven.wagon.PathUtils;
import org.apache.maven.wagon.ResourceDoesNotExistException;
import org.apache.maven.wagon.TransferFailedException;
import org.apache.maven.wagon.authentication.AuthenticationException;
import org.apache.maven.wagon.authorization.AuthorizationException;
import org.apache.maven.wagon.events.TransferEvent;
import org.apache.maven.wagon.providers.ssh.ScpHelper;
import org.apache.maven.wagon.repository.RepositoryPermissions;
import org.apache.maven.wagon.resource.Resource;

import com.jcraft.jsch.ChannelSftp;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.SftpATTRS;
import com.jcraft.jsch.SftpException;

/**
 * SFTP protocol wagon.
 *
 * @author <a href="mailto:brett@apache.org">Brett Porter</a>
 *
 * @todo [BP] add compression flag
 * @todo see if SftpProgressMonitor allows us to do streaming (without it, we can't do checksums as the input stream is lost)
 * 
 * @plexus.component role="org.apache.maven.wagon.Wagon" 
 *   role-hint="sftp"
 *   instantiation-strategy="per-lookup"
 */
public class SftpWagon
    extends AbstractJschWagon
{
    private static final String SFTP_CHANNEL = "sftp";

    private static final int S_IFDIR = 0x4000;

    private static final long MILLIS_PER_SEC = 1000L;

    private ChannelSftp channel;
    
    public void closeConnection()
    {
        if ( channel != null )
        {
            channel.disconnect();
        }
        super.closeConnection();
    }

    public void openConnectionInternal()
        throws AuthenticationException
    {
        super.openConnectionInternal();

        try
        {
            channel = (ChannelSftp) session.openChannel( SFTP_CHANNEL );

            channel.connect();
        }
        catch ( JSchException e )
        {
            throw new AuthenticationException( "Error connecting to remote repository: " + getRepository().getUrl(),
                                               e );
        }
    }

    private void returnToParentDirectory( Resource resource )
    {
        try
        {
            String dir = ScpHelper.getResourceDirectory( resource.getName() );
            String[] dirs = PathUtils.dirnames( dir );
            for ( String d : dirs )
            {
                channel.cd( ".." );
            }
        }
        catch ( SftpException e )
        {
            fireTransferDebug( "Error returning to parent directory: " + e.getMessage() );
        }
    }

    private void putFile( File source, Resource resource, RepositoryPermissions permissions )
        throws SftpException, TransferFailedException
    {
        resource.setContentLength( source.length() );
        
        resource.setLastModified( source.lastModified() );
        
        String filename = ScpHelper.getResourceFilename( resource.getName() );

        firePutStarted( resource, source );

        channel.put( source.getAbsolutePath(), filename );

        postProcessListeners( resource, source, TransferEvent.REQUEST_PUT );

        if ( permissions != null && permissions.getGroup() != null )
        {
            setGroup( filename, permissions );
        }

        if ( permissions != null && permissions.getFileMode() != null )
        {
            setFileMode( filename, permissions );
        }

        firePutCompleted( resource, source );
    }

    private void setGroup( String filename, RepositoryPermissions permissions )
    {
        try
        {
            int group = Integer.valueOf( permissions.getGroup() ).intValue();
            channel.chgrp( group, filename );
        }
        catch ( NumberFormatException e )
        {
            // TODO: warning level
            fireTransferDebug( "Not setting group: must be a numerical GID for SFTP" );
        }
        catch ( SftpException e )
        {
            fireTransferDebug( "Not setting group: " + e.getMessage() );            
        }
    }

    private void setFileMode( String filename, RepositoryPermissions permissions )
    {
        try
        {
            int mode = getOctalMode( permissions.getFileMode() );
            channel.chmod( mode, filename );
        }
        catch ( NumberFormatException e )
        {
            // TODO: warning level
            fireTransferDebug( "Not setting mode: must be a numerical mode for SFTP" );
        }
        catch ( SftpException e )
        {
            fireTransferDebug( "Not setting mode: " + e.getMessage() );            
        }
    }

    private void mkdirs( String resourceName, int mode )
        throws SftpException, TransferFailedException
    {
        String[] dirs = PathUtils.dirnames( resourceName );
        for ( String dir : dirs )
        {
            mkdir( dir, mode );

            channel.cd( dir );
        }
    }

    private void mkdir( String dir, int mode )
        throws TransferFailedException, SftpException
    {
        try
        {
            SftpATTRS attrs = channel.stat( dir );
            if ( ( attrs.getPermissions() & S_IFDIR ) == 0 )
            {
                throw new TransferFailedException( "Remote path is not a directory: " + dir );
            }
        }
        catch ( SftpException e )
        {
            // doesn't exist, make it and try again
            channel.mkdir( dir );
            if ( mode != -1 )
            {
                try
                {
                    channel.chmod( mode, dir );
                }
                catch ( SftpException e1 )
                {
                    // for some extrange reason we recive this exception,
                    // even when chmod success
                }
            }
        }
    }

    private SftpATTRS changeToRepositoryDirectory( String dir, String filename )
        throws ResourceDoesNotExistException, SftpException
    {
        // This must be called first to ensure that if the file doesn't exist it throws an exception
        SftpATTRS attrs;
        try
        {
            channel.cd( repository.getBasedir() );

            if ( dir.length() > 0 )
            {
                channel.cd( dir );
            }

            if ( filename.length() == 0 )
            {
                filename = ".";
            }
            
            attrs = channel.stat( filename );
        }
        catch ( SftpException e )
        {
            if ( e.toString().trim().endsWith( "No such file" ) )
            {
                throw new ResourceDoesNotExistException( e.toString(), e );
            }
            else if ( e.toString().trim().contains( "Can't change directory" ) )
            {
                throw new ResourceDoesNotExistException( e.toString(), e );
            }   
            else
            {
                throw e;
            }
        }
        return attrs;
    }

    public void putDirectory( File sourceDirectory, String destinationDirectory )
        throws TransferFailedException, ResourceDoesNotExistException, AuthorizationException
    {
        final RepositoryPermissions permissions = repository.getPermissions();

        try
        {
            channel.cd( "/" );
            
            String basedir = getRepository().getBasedir();
            int directoryMode = getDirectoryMode( permissions );
            
            mkdirs( basedir + "/", directoryMode );
            
            fireTransferDebug( "Recursively uploading directory " + sourceDirectory.getAbsolutePath() + " as "
                + destinationDirectory );
            
            mkdirs( destinationDirectory, directoryMode );
            ftpRecursivePut( sourceDirectory, null, ScpHelper.getResourceFilename( destinationDirectory ),
                             directoryMode );
        }
        catch ( SftpException e )
        {
            String msg =
                "Error occurred while deploying '" + sourceDirectory.getAbsolutePath() + "' " + "to remote repository: "
                    + getRepository().getUrl() + ": " + e.getMessage();

            throw new TransferFailedException( msg, e );
        }
    }

    private void ftpRecursivePut( File sourceFile, String prefix, String fileName, int directoryMode )
        throws TransferFailedException, SftpException
    {
        final RepositoryPermissions permissions = repository.getPermissions();

        if ( sourceFile.isDirectory() )
        {
            // ScpHelper.getResourceFilename( destinationDirectory ) - could return empty string
            if ( !fileName.equals( "." ) && !fileName.equals( "" ) )
            {
                prefix = getFileName( prefix, fileName );
                mkdir( fileName, directoryMode );
                channel.cd( fileName );
            }

            File[] files = sourceFile.listFiles();
            if ( files != null && files.length > 0 )
            {
                // Directories first, then files. Let's go deep early.
                for ( File file : files )
                {
                    if ( file.isDirectory() )
                    {
                        ftpRecursivePut( file, prefix, file.getName(), directoryMode );
                    }
                }
                for ( File file : files )
                {
                    if ( !file.isDirectory() )
                    {
                        ftpRecursivePut( file, prefix, file.getName(), directoryMode );
                    }
                }
            }
            
            channel.cd( ".." );
        }
        else
        {
            Resource resource = ScpHelper.getResource( getFileName( prefix, fileName ) );

            firePutInitiated( resource, sourceFile );

            putFile( sourceFile, resource, permissions );
        }
    }

    private String getFileName( String prefix, String fileName )
    {
        if ( prefix != null )
        {
            prefix = prefix + "/" + fileName;
        }
        else
        {
            prefix = fileName;
        }
        return prefix;
    }
    
    public List<String> getFileList( String destinationDirectory )
        throws TransferFailedException, ResourceDoesNotExistException, AuthorizationException
    {
        if ( destinationDirectory.length() == 0 )
        {
            destinationDirectory = ".";
        }
        
        String filename = ScpHelper.getResourceFilename( destinationDirectory );

        String dir = ScpHelper.getResourceDirectory( destinationDirectory );

        // we already setuped the root directory. Ignore beginning /
        if ( dir.length() > 0 && dir.charAt( 0 ) == ScpHelper.PATH_SEPARATOR )
        {
            dir = dir.substring( 1 );
        }

        try
        {
            SftpATTRS attrs = changeToRepositoryDirectory( dir, filename );
            if ( ( attrs.getPermissions() & S_IFDIR ) == 0 )
            {
                throw new TransferFailedException( "Remote path is not a directory:" + dir );
            }

            @SuppressWarnings( "unchecked" )
            List<ChannelSftp.LsEntry> fileList = channel.ls( filename );
            List<String> files = new ArrayList<String>( fileList.size() );
            for ( ChannelSftp.LsEntry entry : fileList )
            {
                String name = entry.getFilename();
                if ( entry.getAttrs().isDir() )
                {
                    if ( !name.equals( "." ) && !name.equals( ".." ) )
                    {
                        if ( !name.endsWith( "/" ) )
                        {
                            name += "/";
                        }
                        files.add( name );
                    }
                }
                else
                {
                    files.add( name );
                }
            }
            return files;
        }
        catch ( SftpException e )
        {
            String msg =
                "Error occurred while listing '" + destinationDirectory + "' " + "on remote repository: "
                    + getRepository().getUrl() + ": " + e.getMessage();

            throw new TransferFailedException( msg, e );
        }
    }
    
    public boolean resourceExists( String resourceName )
        throws TransferFailedException, AuthorizationException
    {
        String filename = ScpHelper.getResourceFilename( resourceName );

        String dir = ScpHelper.getResourceDirectory( resourceName );

        // we already setuped the root directory. Ignore beginning /
        if ( dir.length() > 0 && dir.charAt( 0 ) == ScpHelper.PATH_SEPARATOR )
        {
            dir = dir.substring( 1 );
        }

        try
        {
            changeToRepositoryDirectory( dir, filename );
            
            return true;
        }
        catch ( ResourceDoesNotExistException e )
        {
            return false;
        }
        catch ( SftpException e )
        {
            String msg =
                "Error occurred while looking for '" + resourceName + "' " + "on remote repository: "
                    + getRepository().getUrl() + ": " + e.getMessage();

            throw new TransferFailedException( msg, e );
        }
    }

    protected void cleanupGetTransfer( Resource resource )
    {
        returnToParentDirectory( resource );
    }
    
    protected void cleanupPutTransfer( Resource resource )
    {
        returnToParentDirectory( resource );
    }

    protected void finishPutTransfer( Resource resource, InputStream input, OutputStream output )
        throws TransferFailedException
    {
        RepositoryPermissions permissions = getRepository().getPermissions();

        String filename = ScpHelper.getResourceFilename( resource.getName() );
        if ( permissions != null && permissions.getGroup() != null )
        {
            setGroup( filename, permissions );
        }
        
        if ( permissions != null && permissions.getFileMode() != null )
        {
            setFileMode( filename, permissions );
        }
    }

    public void fillInputData( InputData inputData )
        throws TransferFailedException, ResourceDoesNotExistException
    {
        Resource resource = inputData.getResource();
        
        String filename = ScpHelper.getResourceFilename( resource.getName() );

        String dir = ScpHelper.getResourceDirectory( resource.getName() );

        // we already setuped the root directory. Ignore beginning /
        if ( dir.length() > 0 && dir.charAt( 0 ) == ScpHelper.PATH_SEPARATOR )
        {
            dir = dir.substring( 1 );
        }

        try
        {
            SftpATTRS attrs = changeToRepositoryDirectory( dir, filename );

            long lastModified = attrs.getMTime() * MILLIS_PER_SEC;
            resource.setContentLength( attrs.getSize() );

            resource.setLastModified( lastModified );
            
            inputData.setInputStream( channel.get( filename ) );
        }
        catch ( SftpException e )
        {
            handleGetException( resource, e );
        }
    }

    public void fillOutputData( OutputData outputData )
        throws TransferFailedException
    {
        int directoryMode = getDirectoryMode( getRepository().getPermissions() );

        Resource resource = outputData.getResource();
        
        try
        {
            channel.cd( "/" );

            String basedir = getRepository().getBasedir();
            mkdirs( basedir + "/", directoryMode );

            mkdirs( resource.getName(), directoryMode );

            String filename = ScpHelper.getResourceFilename( resource.getName() );
            outputData.setOutputStream( channel.put( filename ) );
        }
        catch ( TransferFailedException e )
        {
            fireTransferError( resource, e, TransferEvent.REQUEST_PUT );

            throw e;
        }
        catch ( SftpException e )
        {
            fireTransferError( resource, e, TransferEvent.REQUEST_PUT );

            String msg =
                "Error occurred while deploying '" + resource.getName() + "' " + "to remote repository: "
                    + getRepository().getUrl() + ": " + e.getMessage();

            throw new TransferFailedException( msg, e );
        }
    }
    
    /**
     * @param permissions repository's permissions
     * @return the directory mode for the repository or <code>-1</code> if it
     *         wasn't set
     */
    public int getDirectoryMode( RepositoryPermissions permissions )
    {
        int ret = -1;

        if ( permissions != null )
        {
            ret = getOctalMode( permissions.getDirectoryMode() );
        }

        return ret;
    }

    public int getOctalMode( String mode )
    {
        int ret;
        try
        {
            ret = Integer.valueOf( mode, 8 ).intValue();
        }
        catch ( NumberFormatException e )
        {
            // TODO: warning level
            fireTransferDebug( "the file mode must be a numerical mode for SFTP" );
            ret = -1;
        }
        return ret;
    }
}