package Lect40CustomWidget;

import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import javax.swing.*;

// This custom widget draws a red square, but the position of
// that square is controllable through keyboard input via the arrow keys.
public class MovableRedSquareWidget extends JComponent {
	private Rectangle2D.Double rect;
	
	public MovableRedSquareWidget() {
		addKeyListener(new MovableRedSquareListener(this));
		setBackground(Color.WHITE);

		rect = new Rectangle2D.Double(50, 50, 50, 50);
	}
	
	public void setSquareX(int x) {
		rect.setRect(x, rect.getY(), rect.getWidth(), rect.getHeight());
		repaint();  // After model changes, force a repaint so view reflects updated model
	}
	
	public int getSquareX() {
		return (int)rect.getX();
	}
	
	public void setSquareY(int y) {
		rect.setRect(rect.getX(), y, rect.getWidth(), rect.getHeight());
		repaint();  // After model changes, force a repaint so view reflects updated model
	}
	
	public int getSquareY() {
		return (int)rect.getY();
	}
	
	// JComponents don't usually get keyboard focus, so to make it possible for them to,
	// we have to override this method.  
	public boolean isFocusTraversable() {
		return true;
	}
	
	public void paintComponent(Graphics g) {
		Graphics2D g2 = (Graphics2D)g;

		// First fill in background
        g2.setColor(getBackground());
        g2.fill(new Rectangle2D.Double(0, 0, getWidth(), getHeight()));
		
        // Then draw foreground (red square)
		g2.setColor(Color.RED);
		g2.fill(rect);
	}
}

// Respond to key events to move red square around
class MovableRedSquareListener implements KeyListener {
	private MovableRedSquareWidget widget;
	
	public MovableRedSquareListener(MovableRedSquareWidget widget) {
		this.widget = widget;
	}
	
	public void keyPressed(KeyEvent e) {
		int x = widget.getSquareX();
		int y = widget.getSquareY();

		switch (e.getKeyCode()) {
			case KeyEvent.VK_LEFT:
				widget.setSquareX(x - 1);
				break;
			case KeyEvent.VK_RIGHT:
				widget.setSquareX(x + 1);
				break;
			case KeyEvent.VK_UP:
				widget.setSquareY(y - 1);
				break;
			case KeyEvent.VK_DOWN:
				widget.setSquareY(y + 1);
				break;
		}
	}

	public void keyReleased(KeyEvent e) {}
	public void keyTyped(KeyEvent e) {}
}