/*
 * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */

package org.opendaylight.controller.netconf.nettyutil.handler.ssh.client;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOutboundHandlerAdapter;
import io.netty.channel.ChannelPromise;
import java.io.IOException;
import java.net.SocketAddress;
import org.opendaylight.controller.netconf.nettyutil.handler.ssh.authentication.AuthenticationHandler;
import org.opendaylight.controller.netconf.nettyutil.handler.ssh.virtualsocket.VirtualSocket;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Netty SSH handler class. Acts as interface between Netty and SSH library. All standard Netty message handling
 * stops at instance of this class. All downstream events are handed of to wrapped {@link org.opendaylight.controller.netconf.nettyutil.handler.ssh.client.SshClientAdapter};
 */
public class SshHandler extends ChannelOutboundHandlerAdapter {
    private static final Logger logger = LoggerFactory.getLogger(SshHandler.class);
    private static final String SOCKET = "socket";

    private final VirtualSocket virtualSocket = new VirtualSocket();
    private final SshClientAdapter sshClientAdapter;


    public static SshHandler createForNetconfSubsystem(AuthenticationHandler authenticationHandler) throws IOException {
        return new SshHandler(authenticationHandler, Invoker.netconfSubsystem());
    }


    public SshHandler(AuthenticationHandler authenticationHandler, Invoker invoker) throws IOException {
        SshClient sshClient = new SshClient(virtualSocket, authenticationHandler);
        this.sshClientAdapter = new SshClientAdapter(sshClient, invoker);
    }

    @Override
    public void handlerAdded(ChannelHandlerContext ctx){
        if (ctx.channel().pipeline().get(SOCKET) == null) {
            ctx.channel().pipeline().addFirst(SOCKET, virtualSocket);
        }
    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) {
        if (ctx.channel().pipeline().get(SOCKET) != null) {
            ctx.channel().pipeline().remove(SOCKET);
        }
    }

    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws IOException {
        this.sshClientAdapter.write((ByteBuf) msg);
    }

    @Override
    public void connect(final ChannelHandlerContext ctx,
                        SocketAddress remoteAddress,
                        SocketAddress localAddress,
                        ChannelPromise promise) {
        ctx.connect(remoteAddress, localAddress, promise);

        promise.addListener(new ChannelFutureListener() {
            public void operationComplete(ChannelFuture channelFuture) {
                if (channelFuture.isSuccess()) {
                    sshClientAdapter.start(ctx, channelFuture);
                } else {
                    logger.debug("Failed to connect to remote host");
                }
            }}
        );
    }

    @Override
    public void disconnect(ChannelHandlerContext ctx, ChannelPromise promise) {
        sshClientAdapter.stop(promise);
    }
}