/*
    * 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.ftp;
  
  import java.io.DataInputStream;
  import java.io.FilterInputStream;
  import java.io.IOException;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.vfs2.FileSystemException;
  import org.apache.commons.vfs2.provider.AbstractRandomAccessStreamContent;
  import org.apache.commons.vfs2.util.RandomAccessMode;
  
  /**
   * Implements FTP stream-based random access.
   */
  final class FtpRandomAccessContent extends AbstractRandomAccessStreamContent {
  
      protected long filePointer;
  
      private final FtpFileObject fileObject;
      private DataInputStream dis;
      private FtpFileObject.FtpInputStream mis;
  
      FtpRandomAccessContent(final FtpFileObject fileObject, final RandomAccessMode mode) {
          super(mode);
  
          this.fileObject = fileObject;
          // fileSystem = (FtpFileSystem) this.fileObject.getFileSystem();
      }
  
      @Override
      public void close() throws IOException {
          if (dis != null) {
              mis.abort();
  
              // this is to avoid recursive close
              final DataInputStream oldDis = dis;
              dis = null;
              oldDis.close();
              mis = null;
          }
      }
  
      @Override
      protected DataInputStream getDataInputStream() throws IOException {
          if (dis != null) {
              return dis;
          }
  
          // FtpClient client = fileSystem.getClient();
          mis = fileObject.getInputStream(filePointer);
          dis = new DataInputStream(new FilterInputStream(mis) {
              @Override
              public void close() throws IOException {
                  FtpRandomAccessContent.this.close();
              }
  
              @Override
              public int read() throws IOException {
                  final int ret = super.read();
                  if (ret > -1) {
                      filePointer++;
                  }
                  return ret;
              }
  
              @Override
              public int read(final byte[] b) throws IOException {
                  final int ret = super.read(b);
                  if (ret > -1) {
                      filePointer += ret;
                  }
                  return ret;
              }
  
              @Override
              public int read(final byte[] b, final int off, final int len) throws IOException {
                  final int ret = super.read(b, off, len);
                  if (ret > -1) {
                      filePointer += ret;
                  }
                  return ret;
              }
          });
 
         return dis;
     }
 
     @Override
     public long getFilePointer() throws IOException {
         return filePointer;
     }
 
     @Override
     public long length() throws IOException {
         return fileObject.getContent().getSize();
     }
 
     @Override
     public void seek(final long pos) throws IOException {
         if (pos == filePointer) {
             // no change
             return;
         }
         if (pos < 0) {
             throw new FileSystemException("vfs.provider/random-access-invalid-position.error", Long.valueOf(pos));
         }
         IOUtils.close(dis);
         filePointer = pos;
     }
 }