import java.applet.*;
import java.awt.*;

public class ATM extends Applet
{
	private final int	START_MODE = 0,
							DEPOSIT_MODE = 1,
							WITHDRAW_MODE = 2;
	private int mode;
	
	private TextField	display = new TextField();
	private Keypad	pad = new Keypad();
	private Button	clear = new Button("Clear"),
						enter = new Button("Enter"),
						deposit = new Button("Deposit"),
						withdraw = new Button("Withdraw");
	private TextArea	help = new TextArea(6, 18);
	
	public void init()
	{
		Panel p1 = new Panel();
		p1.setLayout(new GridLayout(4, 1, 0, 3));
		p1.add(clear);
		p1.add(enter);
		p1.add(deposit);
		p1.add(withdraw);
		
		Panel p2 = new Panel();
		p2.setLayout(new BorderLayout(3, 0));
		p2.add("Center", pad);
		p2.add("East", p1);
		
		Panel p3 = new Panel();
		p3.setLayout(new BorderLayout());
		p3.add("North", display);
		p3.add("Center", p2);
		
		this.setLayout(new BorderLayout(5, 5));
		this.add("Center", p3);
		this.add("East", help);
		this.setBackground(Color.lightGray);
		this.resize(325, 150);
		
		introStart();
	}
	
	public boolean action(Event e, Object obj)
	{
		switch (mode)
		{
		case START_MODE:
			if (e.target == deposit)
				introDeposit();
			else if (e.target == withdraw)
				introWithdraw();
			else if (e.target == clear)
				// LATER
			return true;
		case DEPOSIT_MODE:
			if (e.target == enter)
				handleDeposit();
			else if (e.target == clear)
				display.setText("");
			else if (e.target == pad)
				// LATER
			return true;
		case WITHDRAW_MODE:
			if (e.target == enter)
				handleWithdrawal();
			else if (e.target == clear)
				display.setText("");
			else if (e.target == pad)
				// LATER
			return true;
		}
		return false;
	}
	
	private void introStart()
	{
		help.setText("         W E L C O M E\n\n");
		help.appendText("Press the Deposit or Withdraw buttons ");
		help.appendText("to make a transaction.\n\n");
		help.appendText("Press Clear to end this session.");
		
		mode = START_MODE;
		enter.disable();
		deposit.enable();
		withdraw.enable();
	}
	
	private void introDeposit()
	{
		help.setText("           D E P O S I T\n\n");
		help.appendText("Key in the amount of your deposit ");
		help.appendText("and then press Enter to finish.\n\n");
		help.appendText("If you make a mistake, press Clear, ");
		help.appendText("key in your deposit again, ");
		help.appendText("and then press Enter. ");
		
		mode = DEPOSIT_MODE;
		enter.enable();
		deposit.disable();
		withdraw.disable();
	}
	
	private void introWithdraw()
	{
		help.setText("         W I T H D R A W A L\n\n");
		help.appendText("Key in the amount of your withdrawal ");
		help.appendText("and then press Enter to finish.\n\n");
		help.appendText("If you make a mistake, press Clear, ");
		help.appendText("key in your withdrawal again, ");
		help.appendText("and then press Enter. ");
		
		mode = WITHDRAW_MODE;
		enter.enable();
		deposit.disable();
		withdraw.disable();
	}
	
	private void handleDeposit()
	// A deposit request has been made.  Check whether the amount in
	// display is nonzero.  If so, just go back to start mode.  If not,
	// display a help message.
	{
		introStart();
	}
	
	private void handleWithdrawal()
	// A withdrawal request has been made.  Check whether the amount in
	// display is nonzero.  If so, just go back to start mode.  If not,
	// display a help message.
	{
		introStart();
	}
}

//-------------------------------------------------------------

class Keypad extends Panel
{
	private Button	b0 = new Button("0"),
						b1 = new Button("1"),
						b2 = new Button("2"),
						b3 = new Button("3"),
						b4 = new Button("4"),
						b5 = new Button("5"),
						b6 = new Button("6"),
						b7 = new Button("7"),
						b8 = new Button("8"),
						b9 = new Button("9"),
						bPoint = new Button(".");
	
	public Keypad()
	{
		setLayout(new GridLayout(4, 3, 2, 2));
		add(b7);
		add(b8);
		add(b9);
		add(b4);
		add(b5);
		add(b6);
		add(b1);
		add(b2);
		add(b3);
		add(b0);
		add(bPoint);
	}
}