/*   Author: Seren Thompson    Created: Dec. 1999     Last modified: June 2001

 You may redistribute this code freely provided that you do not charge for it
and I am notified of any changes to the code or inclusion of it in other works.
 If you put this up on a web page, please let me know (I'd like to know where this gets to).

 Send bug reports via: http://www.seren.net/contact


Revisions:
June 12:
 Fixed problem when typing within blocks of text (the cursor would jump around).
 The problem is actually a bug in Netscape's implementation of java, but a 
 modification of the code works around the problem.

 Removed the cursor position display.
 
 Added undo functionality to the Clear button.
 

*/


import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.lang.*;

public class KeystrokeConverter extends Applet implements ActionListener, KeyListener, MouseListener{

	// Char arrays that list the keys that change between qwerty and dvorak
	private char qwertyKeys[] = {
	'-','=','\\',
	'_','+','|',
	'q','w','e','r','t','y','u','i','o','p','[',']',
	'Q','W','E','R','T','Y','U','I','O','P','{','}',
	'a','s','d','f','g','h','j','k','l',';','\'',
	'A','S','D','F','G','H','J','K','L',':','"',
	'z','x','c','v','b','n','m',',','.','/',
	'Z','X','C','V','B','N','M','<','>','?'
	};
	private char dvorakKeys[] = {
	'[',']','\\',
	'{','}','|',
	'\'',',','.','p','y','f','g','c','r','l','/','=',
	'"','<','>','P','Y','F','G','C','R','L','?','+',
	'a','o','e','u','i','d','h','t','n','s','-',
	'A','O','E','U','I','D','H','T','N','S','_',
	';','q','j','k','x','b','m','w','v','z',
	':','Q','J','K','X','B','M','W','V','Z'
	};

	private Hashtable KeyTable = new Hashtable();

	/** GUI components */
	TextArea typingArea = new TextArea(
		"Text in here is converted to dvorak\n\n Click here to start", 12, 70, 1);
	TextArea keyTypedArea = new TextArea("Text in here is qwerty", 1, 35, 3);
	Button clearButton = new Button("Clear");
	Button undoButton = new Button("Undo");

	/** Variables used when converting key strokes */
	String keyUnconverted;
	String keyConverted;

	/** This is for erasing the instructions the text areas when the user first clicks */
	boolean firstClick = true;

	/** This is for storing text that may be accidentally erased by the user */
	String undoBuffer;



    public void init() {

	/*
	 * Construct KeyTable.
	 */
		 
		/** Check to make sure the character arrays are the same size */
		if (qwertyKeys.length != dvorakKeys.length) {
			System.out.println( "Character maps are different lengths!");
			System.exit(0);
		} 		

        /** Convert char arrays to Strings */
        String qwertyKeysString = new String( qwertyKeys );
        String dvorakKeysString = new String( dvorakKeys );


        /* Build a hashtable of the character arrays, using
         * the qwerty characters as the hash keys. */
        for (int i = 0; i < qwertyKeysString.length(); i++ ) {
                KeyTable.put( String.valueOf(qwertyKeysString.charAt(i)),
                        String.valueOf(dvorakKeysString.charAt(i)) );
		}

	/*
	 * Set up the display area.
	 */
		setLayout( new BorderLayout() );

		Panel bottom = new Panel();
		bottom.setLayout( new BorderLayout() );
		add(bottom, "South");

		Panel bottomcenter = new Panel();
		bottom.add(bottomcenter, "Center");


		/** Add components to panels */
		add(typingArea, "Center");
		bottom.add(keyTypedArea, "West");
		bottomcenter.add(undoButton);
		bottomcenter.add(clearButton);
	
		/** Set the typing area to be the only component to accept input */
		typingArea.setEditable(true);
		keyTypedArea.setEditable(false);
	
		/** Add listeners to the typing area and buttons */
		typingArea.addKeyListener(this);
		typingArea.addMouseListener(this);
		clearButton.addActionListener(this);
		undoButton.addActionListener(this);

		/** Set the button's action commands */
		clearButton.setActionCommand("clear");
		undoButton.setActionCommand("undo");
	}
	


	public void keyTyped( KeyEvent k ) {
		/* This copies any selected text to the undo buffer in case they scew up
		 * and hit the wrong control key (ex: Ctrl-I instead of Ctrl-C). */
		if (k.isControlDown() == true) {
			undoBuffer = typingArea.getSelectedText();
		}			

		/** Replace the typed letter in the key buffer with it's Dvorak counterpart */
		try {
			keyUnconverted = String.valueOf(k.getKeyChar());         // Get the type character as a string.

			/** Add the qwerty key to the keyTypedArea display */
			keyTypedArea.append( String.valueOf(keyUnconverted) );


			keyConverted = (String)KeyTable.get( keyUnconverted );   // Returns a one-char string from the hash table.
			k.setKeyChar( keyConverted.charAt(0) );                  // Replace the typed character with the Dvorak one.
	
	

		} catch (Exception e) {}

	}



	public void mouseReleased( MouseEvent m ) {
		/** If they clicked in the typing area, update the location of the cursor */
		if (m.getSource() == typingArea) {
			/** If it's the first click, erase the instructions */
			if (firstClick == true) {
				clearFields();
				firstClick = false;
			}
		}
	}



	public void actionPerformed( ActionEvent e ) {
		/** If the clear command's recieved, clear the fields */
		if (e.getActionCommand().equals("clear")) {
			clearFields();
		}
		/** If they hit the undo button, insert the undo buffer at the cursor */
		if (e.getActionCommand().equals("undo")) {
			typingArea.insert( undoBuffer, typingArea.getCaretPosition());
		}
	}


	/** Gotta include these since we implement the KeyListener and MouserListener interfaces */
	public void keyPressed( KeyEvent k ) { }
	public void keyReleased( KeyEvent k ) { }
	public void mouseClicked( MouseEvent m ) { }
	public void mousePressed( MouseEvent m ) { }
	public void mouseEntered( MouseEvent m ) { }
	public void mouseExited( MouseEvent m ) { }


	/** This method clears the fields and resets the cursor position display */
	private void clearFields() {
		undoBuffer = typingArea.getText(); //Copy text in case they want to undo
		typingArea.setText("");
		keyTypedArea.setText("");
	}		
}