import java.net.*;
import java.io.*;

class TestTcpNet {
    public static void main(String[] arg) {
        try {
            if (arg.length >= 2) {
                if (arg[0].equals("server")) {
                    InetAddress addr = null;
                    int port;
                    if (arg.length >= 3) {
                        addr = InetAddress.getByName(arg[1]);
                        port = Integer.parseInt(arg[2]);
                    } else {
                        port = Integer.parseInt(arg[1]);
                    }
                    startServer(addr, port);
                } else if (arg[0].equals("client") && arg.length >= 3) {
                    InetAddress addr = InetAddress.getByName(arg[1]);
                    int port = Integer.parseInt(arg[2]);
                    startClient(addr, port);
                }
            }
        }
        catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    private static void startServer(InetAddress addr, int port) throws IOException {
        ServerSocket servSock = new ServerSocket(port, 5, addr);
        // ServerScoket servSock = new ServerSocket();
        // servSock.bind(new InetSocketAddress(addr, port));
        System.out.println("Server has been started");
        while (servSock.isBound()) {
            final Socket clientSock = servSock.accept();
            new Thread() {
                public void run() {
                    try {
                        BufferedReader in = new BufferedReader(new InputStreamReader(clientSock.getInputStream()));
                        PrintWriter out = new PrintWriter(clientSock.getOutputStream(), true /*auto flushing*/);
                        while (!clientSock.isClosed() && clientSock.isConnected()) {
                            String s = in.readLine();
                            System.out.println("Client> " + s);
                            if (s.toLowerCase().equals("hello")) {
                                out.println("Server: 123");
                            } else if (s.toLowerCase().equals("quit")) {
                                out.println("Bye!");
                                clientSock.close();
                            } else {
                                out.println("Nothing to say");
                            }
                        }
                    }
                    catch (Exception ex) {
                        ex.printStackTrace();
                    }
                }
            }.start();
        }
    }

    private static void startClient(InetAddress addr, int port) throws IOException {
        Socket sock = new Socket(addr, port);
        // Socket sock = new Socket();
        // sock.connect(new InetSocketAddress(addr, port));
        BufferedReader in = new BufferedReader(new InputStreamReader(sock.getInputStream()));
        PrintWriter out = new PrintWriter(sock.getOutputStream(), true /*auto flushing*/);
        BufferedReader systemIn = new BufferedReader(new InputStreamReader(System.in));
        while (!sock.isClosed() && sock.isConnected()) {
            String s = systemIn.readLine();
            out.println(s);
            s = in.readLine();
            System.out.println(s);
        }
    }
}