/*
 * Calculator GUI
 *
 * Developed for "Rethinking CS101", a project of Lynn Andrea Stein's AP Group.
 * For more information, see <a href="http://www.ai.mit.edu/projects/cs101">the
 * CS101 homepage</a> or email <las@ai.mit.edu>.
 *
 * Copyright (C) 1996 Massachusetts Institute of Technology.
 * Please do not redistribute without obtaining permission.
 */
package Calculator;

import java.awt.*;
import java.awt.event.*;
import cs101.util.IntBuffer;

/**
 * This is an implementation of the GUI for a basic four-function
 * calculator.  It relies on a ButtonHandler (Runnable) to repeatedly
 * call getButton() and consume the buttonIDs that the Calculator
 * object produces.
 *
 * <P>This follows the interactive-control-loop design described in the
 * early parts of 6.096 and as a part of the 
 *      <a href="http://www.ai.mit.edu/projects/cs101/">
 *                    Rethinking CS101
 * </a> project of Lynn Andrea Stein's AP Group at the MIT
 * Artificial Intelligence Laboratory.
 *
 * <P>Copyright (c) 1998 Massachusetts Institute of Technology
 *
 * @author:  Todd C. Parnell, tparnell@ai.mit.edu
 * @author:  Emil Sit, sit@mit.edu
 * @author:  Lynn Andrea Stein, las@ai.mit.edu
 * @version: $Id: CalculatorGUI.java,v 1.6 1998/07/24 16:37:14 tparnell Exp $
 *
 * @see Calculator.ButtonHandler
 * @see cs101.util.IntBuffer
 *
 */

public class CalculatorGUI extends Frame implements Calculator {

  /**
   * The "screen" of the calculator.  Private -- do not use.
   */
  private TextField display;            
    
  /**
   * Synchronized storage for put/getButton.  Private -- do not use.
   * Note:  currently package visible becuase buttonBuf is used by an
   * inner class.  This is a workaround for a bug in the JDK. (6 July 98)
   */
  /* private */ IntBuffer buttonBuf = new IntBuffer();  

  /**
   * The Button components themselves.  Private -- do not use.
   */
  private Button[] Buttons = new Button[Calculator.LAST];

  // Set up the labels w/ static initializer (only need to do this once).
  static {
    for ( int i = 0; i < 10; i++ ) {
      ButtonLabels[i] = String.valueOf( i );
    }
    ButtonLabels[Calculator.OP_DIV] = "/";
    ButtonLabels[Calculator.OP_MUL] = "*";
    ButtonLabels[Calculator.OP_ADD] = "+";
    ButtonLabels[Calculator.OP_SUB] = "-";
    ButtonLabels[Calculator.DOT]    = ".";
    ButtonLabels[Calculator.EQUALS] = "=";
    ButtonLabels[Calculator.CLEAR] = "clear";
  }

  /**
   * Initialize components and such at runtime.  Automagically called
   * by the java runtime.  You should not use it. 
   */
  public CalculatorGUI() {
    super("CS101 Calculator");

    this.setLayout( new GridLayout( 0, 1 ) );

    this.display = new TextField("");
    this.display.setEditable( false );
    this.display.setBackground( Color.white );
    this.display.setForeground( Color.blue );
    this.display.setFont( new Font("Monospaced", Font.BOLD, 24) );
    this.display.setCursor( new Cursor(Cursor.HAND_CURSOR) );

    this.add( this.display );

    for ( int i = 0; i < Calculator.LAST; i++ ) {
      this.Buttons[i] = new Button( Calculator.ButtonLabels[i] );
      // Add the ActionListener for this button
      this.Buttons[i].addActionListener(new ActionListener() {
  	public void actionPerformed(ActionEvent e) {
	  // Find out what button was pressed.  We cannot (unfortunately)
	  // simply use "i" here, so we do it the hard way.
 	  String label = ((Button)e.getSource()).getLabel();
 	  for ( int k = 0; k < Calculator.LAST; k++ ) {
 	    if (Calculator.ButtonLabels[k].equals(label)) {
 	      CalculatorGUI.this.buttonBuf.putButton( k );
 	      break;      // only one match is possible
 	    }
 	  }
  	}
      });
    }
    // Layout the keypad one row at a time.
    Panel numberPad = new Panel();
    numberPad.setBackground( Color.lightGray );
    numberPad.setForeground( Color.black );
    numberPad.setFont( new Font("Monospaced", Font.BOLD, 20) );
    numberPad.setCursor( new Cursor(Cursor.HAND_CURSOR) );

    numberPad.setLayout( new GridLayout( 0, 4, 1, 1 ) );
    numberPad.add( this.Buttons[7] );  // Row 1
    numberPad.add( this.Buttons[8] );
    numberPad.add( this.Buttons[9] );
    numberPad.add( this.Buttons[Calculator.OP_DIV] );
    numberPad.add( this.Buttons[4] );  // Row 2
    numberPad.add( this.Buttons[5] );
    numberPad.add( this.Buttons[6] );
    numberPad.add( this.Buttons[Calculator.OP_MUL] );
    numberPad.add( this.Buttons[1] );  // Row 3
    numberPad.add( this.Buttons[2] );
    numberPad.add( this.Buttons[3] );
    numberPad.add( this.Buttons[Calculator.OP_ADD] );
    numberPad.add( this.Buttons[0] );  // Row 4
    numberPad.add( this.Buttons[Calculator.DOT] );
    numberPad.add( this.Buttons[Calculator.EQUALS] );
    numberPad.add( this.Buttons[Calculator.OP_SUB] );
    numberPad.add( new Button("") );   // Row 5
    numberPad.add( new Button("") );   
    numberPad.add( new Button("") );   
    numberPad.add( this.Buttons[Calculator.CLEAR] ); // --BIG button
    this.add( numberPad );

    this.pack();      // Set the window size,
    this.show();      // pop it up,
    this.validate();  //
    this.setResizable(false);  //


    this.addWindowListener( new WindowAdapter() {
      public void windowClosing( WindowEvent e) {
	System.out.println("Exiting...");
	CalculatorGUI.this.dispose();
	System.exit(0);
      }
    });

  }

  /**
   * Get the next Button pressed.  The return value will be an int
   * between 0 and 9 (if the button was a number) or one of the
   * Calculator constants.
   *
   * @return the next button to be handled.
   */
  public int getButton() {
    return this.buttonBuf.getButton();
  }

  /**
   * Get the label for the given Button ID.  The argument 
   * should be an int between 0 and 9 (if the button was 
   * a number) or one of the Calculator constants, 
   * otherwise the empty string ("") will be returned.
   *
   * @return the button label as a String.
   */
  public String getButtonLabel(int buttonID) {
    if ((buttonID < 0) || (buttonID > Calculator.LAST)) {
      return "";
    } else { 
      return ButtonLabels[buttonID];
    }
  }

  /**
   * Get the text currently displayed on the Calculator.
   *
   * @return the text as a String.
   */
  public String getText() {
    return this.display.getText();
  }


  /**
   * Set the text currently displayed on the Calculator.
   *
   * @param newText the text to be displayed.
   */
  public void setText( String newText ) {
    this.display.setText( newText );
  }
}

/* Comments:
 *
 * History:
 *     $Log: CalculatorGUI.java,v $
 *     Revision 1.6  1998/07/24 16:37:14  tparnell
 *     Placate new javadoc behavior
 *
 *     Revision 1.5  1998/07/21 14:58:44  tparnell
 *     javadoc fix
 *
 *     Revision 1.4  1998/07/07 14:22:00  tparnell
 *     changed refrences to Frame.HAND_CURSOR to Cursor.HAND_CURSOR
 *
 *     Revision 1.3  1998/07/06 20:08:32  tparnell
 *     removed some JDK1.0 code still present in file.  minor redesign of event
 *     handling.  CalculatorGUI used to implement ActionListener and handled
 *     events from the various buttons.  Now that work is done by an anonymous
 *     inner class.
 *
 *     Revision 1.2  1998/06/05 05:19:29  craigh
 *     added getButtonLabel() to Calculator interface.  Implemented the
 *     method in CalculatorGUI, and made use of it in ButtonHandler.
 *
 *     Revision 1.1  1998/02/26 17:25:45  tparnell
 *     Reconstruction from hard drive failure.  Everything appears intact.
 *
 *     Revision 1.3  1997/10/05 21:11:20  shong
 *     Updated for fall97, to Java 1.1
 *     changed GUI, using 1.1 Event Model
 *
 *     Revision 1.2  1997/07/16 14:15:21  tparnell
 *     *** empty log message ***
 *
 *     Revision 1.2  1996/10/04 19:02:26  las
 *     Fixed the location of the clear button so that it's not quite so
 *     grotesque.  (I suppose that the right answer is a GridBagLayout....)
 *
 *     Revision 1.1  1996/10/04 16:20:21  las
 *     Transformed Calculator into an application and made it a package.  See
 *     STAFF_SETUP for which files are public.  To run, use Calculator.Main.
 *
 *     Specifics:
 *         Added Main.java, which starts the calculator program (both
 *     CalculatorGUI and ButtonHandler);
 *         Made Calculator an interface;
 *         Moved GUI implementation (previously in Calculator) to
 *     CalculatorGUI.
 *         Added clear button, which looks pretty gross right now.  (It can
 *     be deleted in a single line, though.)
 *
 *     Revision 1.1.1.1  1996/07/18 17:26:12  sit
 *     Import from summer 6.80s web tree
 *
 *
 */