import java.io.*;
import java.net.*;
import java.util.StringTokenizer;

class CalculateClientRefactored {
    private InetAddress serverHost;
    private int serverPort;
    private Socket calculate;
    private DataInputStream reply;
    private DataOutputStream request;

    public CalculateClientRefactored(
            String host, int port )
        throws IOException
    {
	/* determine the address of the server and connect to it */
	serverHost = InetAddress.getByName( host );
	serverPort = port;
	calculate = new Socket( serverHost, serverPort );

	/* get the output stream */
	OutputStream out = calculate.getOutputStream();
	request = new DataOutputStream( new BufferedOutputStream( out ));

	/* get the input stream */
	InputStream in = calculate.getInputStream();
	reply = new DataInputStream( new BufferedInputStream( in ));
    }

    private int doAdd( int a, int b ) throws IOException {
        request.writeInt( CalculatorCommands.ADD );
        request.writeInt( a );
        request.writeInt( b );
        request.flush();
        return reply.readInt();
    }

    private int doSub( int a, int b ) throws IOException {
        request.writeInt( CalculatorCommands.SUBTRACT );
        request.writeInt( a );
        request.writeInt( b );
        request.flush();
        return reply.readInt();
    }

    private int doMult( int a, int b ) throws IOException {
        request.writeInt( CalculatorCommands.MULT );
        request.writeInt( a );
        request.writeInt( b );
        request.flush();
        return reply.readInt();
    }

    private int doDivide( int a, int b ) throws IOException {
        request.writeInt( CalculatorCommands.DIVIDE );
        request.writeInt( a );
        request.writeInt( b );
        request.flush();
        return reply.readInt();
    }

    private void doExit() throws IOException {
        request.writeInt( CalculatorCommands.EXIT );
        request.flush();
    }

    public void handleUserInput() throws IOException {
	BufferedReader user =
            new BufferedReader( 
                new InputStreamReader( System.in ) );

	System.out.print("calc: ");
	String line = null;
        while( (line=user.readLine()) != null ) {
	    StringTokenizer parse = new StringTokenizer( line );
	    if ( !parse.hasMoreTokens() ) continue;
	    String cmd = parse.nextToken();
	    if ( cmd.equals("add") ) {
		int a = Integer.parseInt( parse.nextToken() );
		int b = Integer.parseInt( parse.nextToken() );
		System.out.println( "result = " + doAdd(a,b) );
	    }
	    else if ( cmd.equals("mult") ) {
		int a = Integer.parseInt( parse.nextToken() );
		int b = Integer.parseInt( parse.nextToken() );
		System.out.println( "result = " + doMult(a,b) );
	    }
	    else if ( cmd.equals("sub") ) {
		int a = Integer.parseInt( parse.nextToken() );
		int b = Integer.parseInt( parse.nextToken() );
		System.out.println( "result = " + doSub(a,b) );
	    }
	    else if ( cmd.equals("divide") ) {
		int a = Integer.parseInt( parse.nextToken() );
		int b = Integer.parseInt( parse.nextToken() );
		System.out.println( "result = " + doDivide(a,b) );
	    }
	    else if ( cmd.equals("exit") ) {
                doExit();
		break; // exit
	    }
	    System.out.print("calc: ");
	}
	request.close();
	reply.close();
    }


    public static void main( String[] args ) {
	int port = 0;
	String host = null;
	try {
	    host = args[0];
	    port = Integer.parseInt( args[1] );
	}
	catch( NumberFormatException e ) {
	    System.out.println("bad port number");
	    System.exit(0);
	}
	catch( IndexOutOfBoundsException e ) {
	    System.out.println("usage: cmd host port");
	    System.exit(0);
	}

	try {
	    CalculateClient calc = new CalculateClient( host, port );
	    calc.handleUserInput();
	}
	catch( UnknownHostException e ) {
	    System.out.println("bad host name");
	    System.exit(0);
	}
	catch( IOException e ) {
	    System.out.println("io error:" + e);
	    System.exit(0);
	}
    }
}