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

public class
Keyboard extends Panel implements KeyListener, FocusListener
{
	private final Applet	myApplet;
	private final int	myNumNotes;
	private final float	myFirstFrequency;
	private boolean		iHaveFocus = false;

	public
	Keyboard( Applet applet, float firstNote, int numNotes ) throws Exception
	{
		myApplet = applet;
		myNumNotes = numNotes;
		myFirstFrequency = firstNote;
		int[]	keys = new int[numNotes + 1];
		for( int i = 0; i < numNotes + 1; i++ )
			keys[ i ] = KeyEvent.VK_1 + i;
		initialize( keys );
	}
	public
	Keyboard( Applet applet, float firstNote, int[] keys ) throws Exception
	{
		myApplet = applet;
		myNumNotes = keys.length - 1;
		myFirstFrequency = firstNote;
		initialize( keys );
	}
	protected void
	initialize( int[] keys ) throws Exception
	{
		setVisible( false );
		setBounds( myApplet.getBounds() );
		setBackground( Color.lightGray );
		setForeground( Color.lightGray );
		setLayout( new GridLayout( 1, myNumNotes + 1, 1, 1 ) );
		if( myNumNotes < 1 )
			throw( new Exception( "Not enough notes!" ) );
		myApplet.showStatus( " Getting sounds from docbase "
					+ myApplet.getDocumentBase().toString() );
		build( keys );
		addKeyListener( this );
		addFocusListener( this );
		setVisible( true );
	}
	protected final int
	numberOfNotes()
	{
		return myNumNotes;
	}
	protected final Applet
	theApplet()
	{
		return myApplet;
	}
	protected void
	build( int[] keys )
	{
		try
		{
			float		freq = myFirstFrequency;
			final float	ratio = (float)Math.pow( 2.0, 1.0 / (float)numberOfNotes() );

			for( int i = 0; i < numberOfNotes() + 1; i++ )
			{
				myApplet.showStatus( "Getting sound file "
					+ String.valueOf( Math.round( freq ) ) + ".au" );

				add( new Key( Math.round( freq ), keys[ i ], myApplet ) );

				freq *= ratio;
			}
		}
		catch( Exception e )
		{
			System.err.println( "Keyboard caught exception: " + e.toString() ); 
		}
	}
	public Insets
	getInsets()			// Container method
	{
		return new Insets( 4, 20, 4, 20 );
	}
	public void
	focusGained( FocusEvent e )	// FocusListener method
	{
		iHaveFocus = true;
		setBackground( Color.darkGray );
		setForeground( Color.darkGray );
		repaint();
	}
	public void
	focusLost( FocusEvent e )	// FocusListener method
	{
		iHaveFocus = false;
		setBackground( Color.lightGray );
		setForeground( Color.lightGray );
		repaint();
	}
	public void
	paint( Graphics g )		// Component method
	{
		super.paint( g );
	}
	protected void
	processKeyEvent(KeyEvent e)
	{
System.err.println( "processKeyEvent " + e.toString() );
		super.processKeyEvent(e);
	}
	public void
	keyPressed( KeyEvent e )	// KeyListener method
	{
System.err.println( "Key pressed " + e.toString() );
		doKeyDown( e, true );
	}
	public void
	keyReleased( KeyEvent e )	// KeyListener method
	{
		doKeyDown( e, false );
	}
	private void
	doKeyDown( KeyEvent e, boolean down )
	{
		final Component[]	component = getComponents();
		Key			key;
	
		for( int i = 0; i < component.length; i++ )
			if( component[i] instanceof Key )
			{
				key = (Key)component[i];

				if( key.keyCode() == e.getKeyCode()
				&&  ( down && !key.isPressed()
					|| !down && key.isPressed() ) )
				{
					key.play( down );
					key.setKeyPressed( down );
					break;
				}
			}
	}
	public void
	keyTyped( KeyEvent e )		// KeyListener method
	{
System.err.println( "Key typed " + e.toString() );
	}
}