/**
 * 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.camel.component.netty.handlers;

import org.apache.camel.CamelException;
import org.apache.camel.Exchange;
import org.apache.camel.ExchangePattern;
import org.apache.camel.component.netty.NettyConstants;
import org.apache.camel.component.netty.NettyConsumer;
import org.apache.camel.component.netty.NettyHelper;
import org.apache.camel.component.netty.NettyPayloadHelper;
import org.apache.camel.processor.Logger;
import org.apache.camel.util.ExchangeHelper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelPipelineCoverage;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;

@ChannelPipelineCoverage("all")
public class ServerChannelHandler extends SimpleChannelUpstreamHandler {
    private static final transient Log LOG = LogFactory.getLog(ServerChannelHandler.class);
    private NettyConsumer consumer;
    private Logger noReplyLogger;

    public ServerChannelHandler(NettyConsumer consumer) {
        super();
        this.consumer = consumer;    
        this.noReplyLogger = new Logger(LOG, consumer.getConfiguration().getNoReplyLogLevel());
    }

    @Override
    public void channelOpen(ChannelHandlerContext ctx, ChannelStateEvent channelStateEvent) throws Exception {
        // to keep track of open sockets
        consumer.getAllChannels().add(channelStateEvent.getChannel());
    }

    @Override
    public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        LOG.debug("Channel closed: " + e.getChannel());
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent exceptionEvent) throws Exception {
        LOG.warn("Closing channel as an exception was thrown from Netty", exceptionEvent.getCause());

        // close channel in case an exception was thrown
        NettyHelper.close(exceptionEvent.getChannel());
    }
    
    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent messageEvent) throws Exception {
        Object in = messageEvent.getMessage();
        if (LOG.isDebugEnabled()) {
            if (in instanceof byte[]) {
                // byte arrays is not readable so convert to string
                in = consumer.getEndpoint().getCamelContext().getTypeConverter().convertTo(String.class, in);
            }
            LOG.debug("Incoming message: " + in);
        }
        
        // create Exchange and let the consumer process it
        Exchange exchange = consumer.getEndpoint().createExchange(ctx, messageEvent);
        if (consumer.getConfiguration().isSync()) {
            exchange.setPattern(ExchangePattern.InOut);
        }

        try {
            consumer.getProcessor().process(exchange);
        } catch (Throwable e) {
            consumer.getExceptionHandler().handleException(e);
        }

        // send back response if the communication is synchronous
        if (consumer.getConfiguration().isSync()) {
            sendResponse(messageEvent, exchange);
        }
    }

    private void sendResponse(MessageEvent messageEvent, Exchange exchange) throws Exception {
        Object body;
        if (ExchangeHelper.isOutCapable(exchange)) {
            body = NettyPayloadHelper.getOut(consumer.getEndpoint(), exchange);
        } else {
            body = NettyPayloadHelper.getIn(consumer.getEndpoint(), exchange);
        }

        boolean failed = exchange.isFailed();
        if (failed && !consumer.getEndpoint().getConfiguration().isTransferExchange()) {
            if (exchange.getException() != null) {
                body = exchange.getException();
            } else {
                // failed and no exception, must be a fault
                body = exchange.getOut().getBody();
            }
        }

        if (body == null) {
            noReplyLogger.log("No payload to send as reply for exchange: " + exchange);
            if (consumer.getConfiguration().isDisconnectOnNoReply()) {
                // must close session if no data to write otherwise client will never receive a response
                // and wait forever (if not timing out)
                if (LOG.isDebugEnabled()) {
                    LOG.debug("Closing channel as no payload to send as reply at address: " + messageEvent.getRemoteAddress());
                }
                NettyHelper.close(messageEvent.getChannel());
            }
        } else {
            // we got a body to write
            if (LOG.isDebugEnabled()) {
                LOG.debug("Writing body: " + body);
            }
            if (consumer.getConfiguration().getProtocol().equalsIgnoreCase("udp")) {
                NettyHelper.writeBody(messageEvent.getChannel(), messageEvent.getRemoteAddress(), body, exchange);
            } else {
                NettyHelper.writeBody(messageEvent.getChannel(), null, body, exchange);
            }
        }

        // should channel be closed after complete?
        Boolean close;
        if (ExchangeHelper.isOutCapable(exchange)) {
            close = exchange.getOut().getHeader(NettyConstants.NETTY_CLOSE_CHANNEL_WHEN_COMPLETE, Boolean.class);
        } else {
            close = exchange.getIn().getHeader(NettyConstants.NETTY_CLOSE_CHANNEL_WHEN_COMPLETE, Boolean.class);
        }

        // should we disconnect, the header can override the configuration
        boolean disconnect = consumer.getConfiguration().isDisconnect();
        if (close != null) {
            disconnect = close;
        }
        if (disconnect) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Closing channel when complete at address: " + messageEvent.getRemoteAddress());
            }
            NettyHelper.close(messageEvent.getChannel());
        }
    }

}
