/*
 *
 * 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.qpid.server.protocol.v1_0.framing;

import java.util.Formatter;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.qpid.server.protocol.v1_0.AMQPConnection_1_0;
import org.apache.qpid.server.protocol.v1_0.ConnectionHandler;
import org.apache.qpid.server.protocol.v1_0.codec.ProtocolHandler;
import org.apache.qpid.server.protocol.v1_0.codec.ValueHandler;
import org.apache.qpid.server.protocol.v1_0.type.AmqpErrorException;
import org.apache.qpid.server.protocol.v1_0.type.ErrorCondition;
import org.apache.qpid.server.protocol.v1_0.type.transport.ConnectionError;
import org.apache.qpid.server.protocol.v1_0.type.transport.Error;
import org.apache.qpid.server.protocol.v1_0.type.transport.Transfer;
import org.apache.qpid.bytebuffer.QpidByteBuffer;

public class FrameHandler implements ProtocolHandler
{
    public static Logger LOGGER = LoggerFactory.getLogger(FrameHandler.class);
    private final boolean _isSasl;

    private ConnectionHandler _connection;
    private ValueHandler _typeHandler;
    private boolean _errored = false;

    public FrameHandler(final AMQPConnection_1_0 connection, final boolean sasl)
    {
        _connection = connection;
        _typeHandler = new ValueHandler(connection.getDescribedTypeRegistry());
        _isSasl = sasl;

    }

    public ProtocolHandler parse(QpidByteBuffer in)
    {
        try
        {
            Error frameParsingError = null;
            int size;

            int remaining;
            while ((remaining = in.remaining()) >=8 && frameParsingError == null)
            {

                size = in.getInt();
                if(remaining < size)
                {
                    in.position(in.position()-4);
                    break;
                }
                int dataOffset = (in.get() << 2) & 0x3FF;

                if (size < 8)
                {
                    frameParsingError = createFramingError(
                            "specified frame size %d smaller than minimum frame header size %d",
                            size,
                            8);
                    break;
                }

                if(size > _connection.getMaxFrameSize())
                {
                    frameParsingError = createFramingError(
                            "specified frame size %d larger than maximum frame header size %d",
                            size,
                            _connection.getMaxFrameSize());
                    break;
                }

                if (dataOffset < 8)
                {
                    frameParsingError = createFramingError(
                            "specified frame data offset %d smaller than minimum frame header size %d",
                            dataOffset,
                            8);
                    break;
                }

                if (dataOffset > size)
                {
                    frameParsingError = createFramingError(
                            "specified frame data offset %d larger than the frame size %d",
                            dataOffset,
                            size);
                    break;
                }


                byte type = in.get();

                switch(type)
                {
                    case 0:
                        if(_isSasl)
                        {
                            frameParsingError = createFramingError("received an AMQP frame type when expecting an SASL frame");
                        }
                        break;
                    case 1:
                        if(!_isSasl)
                        {
                            frameParsingError = createFramingError("received a SASL frame type when expecting an AMQP frame");
                        }
                        break;
                    default:
                        frameParsingError = createFramingError("unknown frame type: %d", type);
                }

                if(frameParsingError != null)
                {
                    break;
                }

                int channel = ((int)in.getShort()) & 0xffff;

                if (dataOffset != 8)
                {
                    in.position(in.position() + dataOffset - 8);
                }

                QpidByteBuffer dup = in.slice();
                dup.limit(size - dataOffset);
                in.position(in.position() + size - dataOffset);

                try
                {
                    Object val = dup.hasRemaining() ? _typeHandler.parse(dup) : null;

                    if (dup.hasRemaining())
                    {
                        if (val instanceof Transfer)
                        {
                            ((Transfer) val).setPayload(dup.slice());
                        }
                        else
                        {
                            frameParsingError = createFramingError(
                                    "Frame length %d larger than contained frame body %s.",
                                    size,
                                    val);
                        }
                    }
                    _connection.receive((short) channel, val);
                }
                catch (AmqpErrorException ex)
                {
                    frameParsingError = ex.getError();
                }
                finally
                {
                    dup.dispose();
                }
            }

            if (frameParsingError != null)
            {
                _connection.handleError(frameParsingError);
                _errored = true;

            }
        }
        catch (RuntimeException e)
        {
            LOGGER.warn("Unexpected exception handling frame", e);
            // This exception is unexpected. The up layer should handle error condition gracefully
            _connection.handleError(this.createError(ConnectionError.CONNECTION_FORCED, e.toString()));
        }
        return this;
    }

    private Error createFramingError(String description, Object... args)
    {
        return createError(ConnectionError.FRAMING_ERROR, description, args);
    }

    private Error createError(final ErrorCondition framingError,
                              final String description,
                              final Object... args)
    {
        Error error = new Error();
        error.setCondition(framingError);
        Formatter formatter = new Formatter();
        error.setDescription(formatter.format(description, args).toString());
        return error;
    }

    public boolean isDone()
    {
        return _errored|| _connection.closedForInput();
    }
}