//======================================================================
//  PROJECT:            _programming.java_
//  FILE:               ATM.java
//  PURPOSE:            Chapter 7 demo program, final version
//  VERSION:            2.0
//  TARGET:             Java v1.1
//  UPDATE HISTORY:     2.0    11/2/98    1.1 event model
//                      1.0    7/4/96     the version in _p.j_
//======================================================================

//------------------------------ IMPORTS -------------------------------

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import Utilities.*;       // Our own package, for the Keypad and NumField classes

//============================= ATM CLASS ==============================

/**
 * This applet simulates the action of an automatic teller machine,
 * consisting of a keypad, a collection of control buttons, a
 * numeric display field, and a text area for instructions.
 * <BR>
 * See _programming.java_, Chapter 7, for details and specification.
 */
public class ATM extends Applet implements ActionListener
{
    private final int   START_MODE = 0,
                        DEPOSIT_MODE = 1,
                        WITHDRAW_MODE = 2;
    private int         mode;
	
    private NumField    display = new NumField();
	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, 35);
	
    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);
		
        setLayout(new BorderLayout(5, 5));
        add("Center", p3);
        add("East", help);
        help.setEditable(false);
        this.setBackground(Color.lightGray);
        
        clear.addActionListener(this);
        enter.addActionListener(this);
        deposit.addActionListener(this);
        withdraw.addActionListener(this);
        pad.addActionListener(this);
		
        introStart();
    }
	
    public void actionPerformed(ActionEvent e)
    {
        Object source = e.getSource();
        switch (mode)
        {
        case START_MODE:
            if (source == deposit)
            {
                mode = DEPOSIT_MODE;
                introDeposit();
            }
            else if (source == withdraw)
            {
                mode = WITHDRAW_MODE;
                introWithdraw();
            }
            else if (source == clear)
            {
                doQuit();
            }
            else if (source == enter)
            {
                mode = START_MODE;
                introStart();
            }
            break;
			
        case DEPOSIT_MODE:
            if (source == enter)
            {
                handleDeposit();
            }
            else if (source == clear)
            {
                display.clear();
            }
            else
            {
                String name = ((Button)source).getLabel();
                display.append(name);
            }
            break;
			
        case WITHDRAW_MODE:
            if (source == enter)
            {
                handleWithdrawal();
            }
            else if (source == clear)
            {
                display.clear();
            }
            else
            {
                String name = ((Button)source).getLabel();
                display.append(name);
            }
            break;
        }
    }
	
    private void introStart()
    {
        help.setText("             W E L C O M E\n\n");
        help.appendText("Press the Deposit or Withdraw buttons\n");
        help.appendText("to make a transaction.\n\n");
        help.appendText("Press Clear to end this session.");
		
        display.clear();
        clear.setEnabled(true);
        enter.setEnabled(false);
        deposit.setEnabled(true);
        withdraw.setEnabled(true);
    }
	
    private void introDeposit()
    {
        help.setText("               D E P O S I T\n\n");
        help.appendText("Key in the amount of your deposit\n");
        showGeneralMessage();
		
        display.clear();
        clear.setEnabled(true);
        enter.setEnabled(true);
        deposit.setEnabled(false);
        withdraw.setEnabled(false);
    }
	
    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\n");
        showGeneralMessage();
		
        display.clear();
        clear.setEnabled(true);
        enter.setEnabled(true);
        deposit.setEnabled(false);
        withdraw.setEnabled(false);
    }
    
    /**
     * 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.
     */
    private void handleDeposit()
    {
        if (display.getValue() == 0.0)
        {
            help.setText("*** oops!  The amount can't be zero\n\n");
            help.appendText("Key in the amount of your deposit\n");
            showGeneralMessage();
        }
        else
        {
            mode = START_MODE;
            introStart();
        }
    }
    
    /**
     * 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.
     */
    private void handleWithdrawal()
    {
        if (display.getValue() == 0.0)
        {
            help.setText("*** oops!  The amount can't be zero\n\n");
            help.appendText("Key in the amount of your withdrawal\n");
            showGeneralMessage();
        }
        else
        {
            mode = START_MODE;
            introStart();
        }
    }
	
    private void doQuit()
    {
        help.setText("Thank you for your business.\n\n");
        help.appendText("Have a nice day.\n\n\n");
        help.appendText("Press the Enter button to start.");
		
        display.clear();
        clear.setEnabled(false);
        enter.setEnabled(true);
        deposit.setEnabled(false);
        withdraw.setEnabled(false);
    }
	
    private void showGeneralMessage()
    {
        help.appendText("and then press Enter to finish.\n\n");
        help.appendText("If you make a mistake, press Clear,\n");
        help.appendText("key in your amount again,\n");
        help.appendText("and then press Enter. ");
    }
}