package pythagoras;

import java.applet.*;
import java.awt.*;
import psplot.*;
import real.*;

class babylonCanvas extends PlotCanvas {
	double A, B, C;
	PlotNode cn;
	RealPoint corner0, corner1;
	double delta = 1.0;
	
	public babylonCanvas(Applet a, int w, int h, double x, double y) {
		super(a, w, h);
		A = x; B = y;
		C = Math.sqrt(A*A + B*B);
		double W = 16, H = W*h/w;
		setCorners(-W, -H, W, H);
		corner0 = new RealPoint(-delta - A - B, -0.5*(A+B));
		corner1 = new RealPoint( delta, -0.5*(A+B));
		// set the origin at the centre
		cn = new PlotNode(this, 
			new RealPoint(corner0.x + B, corner0.y + A + B));
		mkFixedpaths();
		repaint();
	}
	
	PlotPath rightabsquare;
	
	PlotPath absquare;
	PlotPath csquare;
	
	void mkFixedpaths() {
		absquare = new PlotPath(this);
		absquare.moveto(corner0);
		absquare.rlineto(A+B, 0);
		absquare.rlineto(0, A+B);
		absquare.rlineto(-(A+B), 0);
		absquare.close();
		
		rightabsquare = new PlotPath(this);
		rightabsquare.moveto(corner1);
		rightabsquare.rlineto(A+B, 0);
		rightabsquare.rlineto(0, A+B);
		rightabsquare.rlineto(-(A+B), 0);
		rightabsquare.close();
	}
	
	boolean ready = true;

	public void draw() {
		ready = false;
		absquare.stroke(Color.black);
		
		PlotPath p = new PlotPath(this);
		p.moveto(corner0.x+A, corner0.y);
		p.rlineto(B, A);
		p.rlineto(-A, B);
		p.rlineto(-B, -A);
		p.close();
		p.fill(Color.blue);
		p.stroke(Color.black);

		cn.draw();

		p = new PlotPath(this);
		p.moveto(corner1.x + B, corner1.y + B);
		p.rlineto(A, 0);
		p.rlineto(0, A);
		p.rlineto(-A, 0);
		p.close();
		p.fill(Color.red);
		p.stroke(Color.black);
		
		p = new PlotPath(this);
		p.moveto(corner1);
		p.rlineto(B, 0);
		p.rlineto(0, B);
		p.rlineto(-B, 0);
		p.close();
		p.fill(Color.green);
		p.stroke(Color.black);
		
		p = new PlotPath(this);
		p.moveto(corner1.x, corner1.y + B);
		p.rlineto(B, A);
		p.rlineto(0, -A);
		p.close();
		p.stroke(Color.black);

		p = new PlotPath(this);
		p.moveto(corner1.x+B, corner1.y);
		p.rlineto(A, 0);
		p.rlineto(0, B);
		p.close();
		p.stroke(Color.black);
		
		// System.out.println(".");
		rightabsquare.stroke(Color.black);
		ready = true;
	}
	
	boolean active = false;

	public boolean mouseDown(Event evt, int x, int y) {
		// if (x, y) inside a node set mouseState = MouseActive
		RealPoint P = toRealPoint(x, y);
		if (cn.contains(P)) {
			active = true;
		}
		return true;
	}

	public boolean mouseDrag(Event evt, int x, int y) {
		if (active && ready) {
			RealPoint q = toRealPoint(x, y);
			if (q.x < corner0.x) {
				 q.x = corner0.x;
			}
			if (q.x >= -delta) q.x = -delta;
			q.y = corner0.y + A + B;
			cn.locate(q);
			double s = A+B;
			A = corner0.x + s - q.x;
			B = q.x - corner0.x;
			C = Math.sqrt(A*A + B*B);
			repaint();
		}
		return true;
	}

	public boolean mouseUp(Event evt, int x, int y) {
		// set nodes inactive
		active = false;
		return true;
	}
}

public class babylonApplet extends Applet {

	double a = 3, b = 4;
	babylonCanvas baby;
	
	public void init() {
		setBackground(Color.white);
		baby = new babylonCanvas(this, 500, 150, a, b);
		add(baby);
		show();
	}

}