/*
 * Copyright 2012 - 2013 Anton Tananaev (anton.tananaev@gmail.com)
 *
 * Licensed 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.traccar;

import java.net.SocketAddress;
import java.util.Properties;

import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelHandlerContext;
import static org.jboss.netty.channel.Channels.fireMessageReceived;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.handler.codec.oneone.OneToOneDecoder;

import org.traccar.database.DataManager;

/**
 * Base class for protocol decoders
 */
public abstract class BaseProtocolDecoder extends OneToOneDecoder {

    private final DataManager dataManager;
    private final String protocol;
    private final Properties properties;

    public final DataManager getDataManager() {
        return dataManager;
    }

    public final String getProtocol() {
        return protocol;
    }
    
    public final Properties getProperties() {
        return properties;
    }

    
    public BaseProtocolDecoder(DataManager dataManager, String protocol, Properties properties) {
        this.dataManager = dataManager;
        this.protocol = protocol;
        this.properties = properties;
    }
    
    @Override
    public void handleUpstream(
            ChannelHandlerContext ctx, ChannelEvent evt) throws Exception {
        if (!(evt instanceof MessageEvent)) {
            ctx.sendUpstream(evt);
            return;
        }

        MessageEvent e = (MessageEvent) evt;
        Object originalMessage = e.getMessage();
        Object decodedMessage = decode(ctx, e.getChannel(), e.getRemoteAddress(), originalMessage);
        if (originalMessage == decodedMessage) {
            ctx.sendUpstream(evt);
        } else if (decodedMessage != null) {
            fireMessageReceived(ctx, decodedMessage, e.getRemoteAddress());
        }
    }
    
    protected Object decode(
            ChannelHandlerContext ctx, Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {
        
        return decode(ctx, channel, msg);
        
    }
    
    @Override
    protected Object decode(
            ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
        
        return null; // default implementation
        
    }

}