/*
 * 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.usergrid.mongo.testproxy;


import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class MongoMessageFrame extends FrameDecoder {

    @SuppressWarnings("unused")
    private static final Logger logger = LoggerFactory.getLogger( MongoMessageFrame.class );


    @Override
    protected Object decode( ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf ) throws Exception {

        if ( buf.readableBytes() < 4 ) {
            return null;
        }

        // logger.info("Mongo message decoding...");

        int length = buf.getInt( buf.readerIndex() );

        if ( length < 0 ) {
            return null;
        }

        if ( buf.readableBytes() < length ) {
            return null;
        }

        ChannelBuffer frame = buf.readSlice( length );
        return frame;
    }
}