/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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.jboss.netty.example.telnet;

import java.net.InetAddress;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelFutureListener;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;

/**
 * Handles a server-side channel.
 */
public class TelnetServerHandler extends SimpleChannelUpstreamHandler {

    private static final Logger logger = Logger.getLogger(
            TelnetServerHandler.class.getName());

    @Override
    public void handleUpstream(
            ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
        if (e instanceof ChannelStateEvent) {
            logger.info(e.toString());
        }
        super.handleUpstream(ctx, e);
    }

    @Override
    public void channelConnected(
            ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        // Send greeting for a new connection.
        e.getChannel().write(
                "Welcome to " + InetAddress.getLocalHost().getHostName() + "!\r\n");
        e.getChannel().write("It is " + new Date() + " now.\r\n");
    }

    @Override
    public void messageReceived(
            ChannelHandlerContext ctx, MessageEvent e) {

        // Cast to a String first.
        // We know it is a String because we put some codec in TelnetPipelineFactory.
        String request = (String) e.getMessage();

        // Generate and write a response.
        String response;
        boolean close = false;
        if (request.length() == 0) {
            response = "Please type something.\r\n";
        } else if (request.toLowerCase().equals("bye")) {
            response = "Have a good day!\r\n";
            close = true;
        } else {
            response = "Did you say '" + request + "'?\r\n";
        }

        // We do not need to write a ChannelBuffer here.
        // We know the encoder inserted at TelnetPipelineFactory will do the conversion.
        ChannelFuture future = e.getChannel().write(response);

        // Close the connection after sending 'Have a good day!'
        // if the client has sent 'bye'.
        if (close) {
            future.addListener(ChannelFutureListener.CLOSE);
        }
    }

    @Override
    public void exceptionCaught(
            ChannelHandlerContext ctx, ExceptionEvent e) {
        logger.log(
                Level.WARNING,
                "Unexpected exception from downstream.",
                e.getCause());
        e.getChannel().close();
    }
}
