/*
 * Copyright (c) 2001-2008 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.hessian4.io;

import java.io.IOException;
import java.io.InputStream;

import java.util.logging.*;

/**
 * Input stream for Hessian 2 streaming requests using WebSocket.
 * 
 * For best performance, use HessianFactory:
 * 
 * <code><pre>
 * HessianFactory factory = new HessianFactory();
 * Hessian2StreamingInput hIn = factory.createHessian2StreamingInput(is);
 * </pre></code>
 */
public class Hessian2StreamingInput
{
  private static final Logger log
    = Logger.getLogger(Hessian2StreamingInput.class.getName());
  
  private StreamingInputStream _is;
  private Hessian2Input _in;
  
  /**
   * Creates a new Hessian input stream, initialized with an
   * underlying input stream.
   *
   * @param is the underlying output stream.
   */
  public Hessian2StreamingInput(InputStream is)
  {
    _is = new StreamingInputStream(is);
    _in = new Hessian2Input(_is);
  }

  public void setSerializerFactory(SerializerFactory factory)
  {
    _in.setSerializerFactory(factory);
  }

  public boolean isDataAvailable()
  {
    StreamingInputStream is = _is;
    
    return is != null && is.isDataAvailable();
  }

  public Hessian2Input startPacket()
    throws IOException
  {
    if (_is.startPacket()) {
      _in.resetReferences();
      _in.resetBuffer(); // XXX:
      return _in;
    }
    else
      return null;
  }

  public void endPacket()
    throws IOException
  {
    _is.endPacket();
    _in.resetBuffer(); // XXX:
  }

  public Hessian2Input getHessianInput()
  {
    return _in;
  }

  /**
   * Read the next object
   */
  public Object readObject()
    throws IOException
  {
    _is.startPacket();
    
    Object obj = _in.readStreamingObject();

    _is.endPacket();

    return obj;
  }

  /**
   * Close the output.
   */
  public void close()
    throws IOException
  {
    _in.close();
  }

  static class StreamingInputStream extends InputStream {
    private InputStream _is;
    
    private int _length;
    private boolean _isPacketEnd;

    StreamingInputStream(InputStream is)
    {
      _is = is;
    }

    public boolean isDataAvailable()
    {
      try {
        return _is != null && _is.available() > 0;
      } catch (IOException e) {
        log.log(Level.FINER, e.toString(), e);

        return true;
      }
    }

    public boolean startPacket()
      throws IOException
    {
      // skip zero-length packets
      do {
        _isPacketEnd = false;
      } while ((_length = readChunkLength(_is)) == 0);

      return _length > 0;
    }

    public void endPacket()
      throws IOException
    {
      while (! _isPacketEnd) {
        if (_length <= 0)
          _length = readChunkLength(_is);

        if (_length > 0) {
          _is.skip(_length);
          _length = 0;
        }
      }
      
      if (_length > 0) {
        _is.skip(_length);
        _length = 0;
      }
    }

    public int read()
      throws IOException
    {
      InputStream is = _is;
      
      if (_length == 0) {
        if (_isPacketEnd)
          return -1;
        
        _length = readChunkLength(is);

        if (_length <= 0)
          return -1;
      }

      _length--;
      
      return is.read();
    }

    @Override
    public int read(byte []buffer, int offset, int length)
      throws IOException
    {
      InputStream is = _is;
      
      if (_length <= 0) {
        if (_isPacketEnd)
          return -1;
        
        _length = readChunkLength(is);

        if (_length <= 0)
          return -1;
      }

      int sublen = _length;
      if (length < sublen)
        sublen = length;
      
      sublen = is.read(buffer, offset, sublen);

      if (sublen < 0)
        return -1;

      _length -= sublen;

      return sublen;
    }

    private int readChunkLength(InputStream is)
      throws IOException
    {
      if (_isPacketEnd)
        return -1;
      
      int length = 0;

      int code = is.read();

      if (code < 0) {
        _isPacketEnd = true;
        return -1;
      }
      
      _isPacketEnd = (code & 0x80) == 0;
      
      int len = is.read() & 0x7f;
      
      if (len < 0x7e) {
        length = len;
      }
      else if (len == 0x7e) {
        length = (((is.read() & 0xff) << 8)
                  + (is.read() & 0xff));
      }
      else {
        length = (((is.read() & 0xff) << 56)
                  + ((is.read() & 0xff) << 48)
                  + ((is.read() & 0xff) << 40)
                  + ((is.read() & 0xff) << 32)
                  + ((is.read() & 0xff) << 24)
                  + ((is.read() & 0xff) << 16)
                  + ((is.read() & 0xff) << 8)
                  + ((is.read() & 0xff)));
      }

      return length;
    }
  }
}
