/*
    * 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.
   */
  package org.apache.commons.vfs2.provider.sftp;
  
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.Collections;
  
  import org.apache.commons.vfs2.Capability;
  import org.apache.commons.vfs2.FileName;
  import org.apache.commons.vfs2.FileSystem;
  import org.apache.commons.vfs2.FileSystemConfigBuilder;
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.commons.vfs2.FileSystemOptions;
  import org.apache.commons.vfs2.UserAuthenticationData;
  import org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider;
  import org.apache.commons.vfs2.provider.GenericFileName;
  import org.apache.commons.vfs2.util.UserAuthenticatorUtils;
  
  import com.jcraft.jsch.Session;
  
  /**
   * A provider for accessing files over SFTP.
   */
  public class SftpFileProvider extends AbstractOriginatingFileProvider {
  
      /** User Information. */
      public static final String ATTR_USER_INFO = "UI";
  
      /** Authentication types. */
      public static final UserAuthenticationData.Type[] AUTHENTICATOR_TYPES = {
              UserAuthenticationData.USERNAME, UserAuthenticationData.PASSWORD };
  
      /** The provider's capabilities. */
      protected static final Collection<Capability> capabilities = Collections.unmodifiableCollection(Arrays.asList(Capability.CREATE, Capability.DELETE,
          Capability.RENAME, Capability.GET_TYPE, Capability.LIST_CHILDREN, Capability.READ_CONTENT, Capability.URI, Capability.WRITE_CONTENT,
          Capability.GET_LAST_MODIFIED, Capability.SET_LAST_MODIFIED_FILE, Capability.RANDOM_ACCESS_READ, Capability.APPEND_CONTENT));
  
      /**
       * Creates a new Session.
       *
       * @return A Session, never null.
       */
      static Session createSession(final GenericFileName rootName, final FileSystemOptions fileSystemOptions)
              throws FileSystemException {
          UserAuthenticationData authData = null;
          try {
              authData = UserAuthenticatorUtils.authenticate(fileSystemOptions, AUTHENTICATOR_TYPES);
  
              return SftpClientFactory.createConnection(rootName.getHostName(), rootName.getPort(),
                      UserAuthenticatorUtils.getData(authData, UserAuthenticationData.USERNAME,
                              UserAuthenticatorUtils.toChar(rootName.getUserName())),
                      UserAuthenticatorUtils.getData(authData, UserAuthenticationData.PASSWORD,
                              UserAuthenticatorUtils.toChar(rootName.getPassword())),
                      fileSystemOptions);
          } catch (final Exception e) {
              throw new FileSystemException("vfs.provider.sftp/connect.error", rootName, e);
          } finally {
              UserAuthenticatorUtils.cleanup(authData);
          }
      }
  
      /**
       * Constructs a new provider.
       */
      public SftpFileProvider() {
          setFileNameParser(SftpFileNameParser.getInstance());
      }
  
      /**
       * Creates a {@link FileSystem}.
       */
      @Override
      protected FileSystem doCreateFileSystem(final FileName name, final FileSystemOptions fileSystemOptions)
              throws FileSystemException {
          // Create the file system
          return new SftpFileSystem((GenericFileName) name, createSession((GenericFileName) name, fileSystemOptions),
                  fileSystemOptions);
      }
  
      @Override
      public Collection<Capability> getCapabilities() {
          return capabilities;
      }
  
     @Override
     public FileSystemConfigBuilder getConfigBuilder() {
         return SftpFileSystemConfigBuilder.getInstance();
     }
 }