/*
 * 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.alibaba.com.caucho.hessian.io;

import java.io.IOException;
import java.io.InputStream;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Input stream for Hessian 2 streaming requests using WebSocket.
 * <p>
 * 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;
        }
    }
}