import java.awt.*;
import javax.swing.JPanel;

public class KochPanel extends JPanel {
    private final int PANEL_WIDTH = 400;
    private final int PANEL_HEIGHT = 400;

    private final double SQ = Math.sqrt(3.0) / 6;

    private final int TOPX = 200;
    private final int TOPY = 20;
    private final int LEFTX = 60;
    private final int LEFTY = 300;
    private final int RIGHTX = 340;
    private final int RIGHTY = 300;
    
    private int current;

    public KochPanel(int currentOrder) {
	current = currentOrder;
	setBackground(Color.black);
	setPreferredSize(new Dimension(PANEL_WIDTH, PANEL_HEIGHT));

    }

    // recursively draw the fractal

    public void drawFractal(int order, int x1, int y1, 
			    int x5, int y5, Graphics panel) {

	int deltaX, deltaY, x2, y2, x3, y3, x4, y4;
	
	if (order == 1) {
	    panel.drawLine(x1, y1, x5, y5);
	} else {
	    deltaX = x5 - x1; // distance between end points
	    deltaY = y5 - y1; // distance between end points

	    x2 = x1 + deltaX / 3; // distance to first third
	    y2 = y1 + deltaY / 3; // distance to first third

	    x3 = (int)((x1 + x5) / 2 + SQ * (y1 - y5)); // tip of point
	    y3 = (int)((y1 + y5) / 2 + SQ * (x5 - x1)); // tip of point

	    x4 = x1 + deltaX * 2/3; // point for second third
	    y4 = y1 + deltaY * 2/3; // point for second third
	    
	    drawFractal(order-1, x1,y1, x2,y2, panel);
	    drawFractal(order-1, x2,y2, x3,y3, panel);
	    drawFractal(order-1, x3,y3, x4,y4, panel);
	    drawFractal(order-1, x4,y4, x5,y5, panel);
	}
    }

    public void paintComponent(Graphics panel) {

	super.paintComponent(panel);
	panel.setColor(Color.green);

	drawFractal(current, TOPX, TOPY, LEFTX, LEFTY, panel);	
	drawFractal(current, LEFTX, LEFTY,RIGHTX, RIGHTY, panel);
	drawFractal(current, RIGHTX, RIGHTY,TOPX, TOPY, panel);
    }
    
    public void setOrder(int o) {
	current = o;
    }
    public int getOrder() {
	return current;
    }
}