import java.awt.*;
import java.applet.*;
import java.util.Vector;

public class BSPTreeApplet extends Applet
{
	private BSPCell bsp_tree;
	private Vector segments;
	private Vertex eye;
	private Vector traversed_segments;
	private Image dbuffer; 
	
	public void init() {
		//setBackground(Color.white);
		bsp_tree = new BSPCell();
		segments = new Vector();
		eye = new Vertex(Parameters.WIDTH/2, Parameters.HEIGHT/2);
		traversed_segments = bsp_tree.traverse(eye);
		dbuffer = createImage(Parameters.WIDTH+1, Parameters.HEIGHT+1);
	}
	
	public void update(Graphics g) {
		paint(g);
	}

	public void paint(Graphics g) {
		Graphics g2 = dbuffer.getGraphics();
		g2.clearRect(0, 0, Parameters.WIDTH+1, Parameters.HEIGHT+1);
		// draw the partitions
		g2.setColor(Color.darkGray);
		bsp_tree.draw(g2);
		// draw the line segments
		for (int i=0; i<segments.size(); i++)
			((Segment) segments.elementAt(i)).draw(g2, true);
		// draw the eye
		g2.setColor(Color.black);
		eye.draw(g2);
		// draw the inputed/modified segment or eye
		g2.setColor(Color.red);
		if (Parameters.mode == Parameters.SEGMENT_INPUT_MODE)
			s.draw(g2, false);
		if (Parameters.mode == Parameters.EYE_INPUT_MODE) {
			g2.setColor(Color.gray);
			bsp_tree.locate(eye).fill(g2);
			g2.setColor(Color.red);
			eye.draw(g2);
		}
		if (Parameters.show_ordering) {
			// label the order of drawing
			for (int i=0; i<traversed_segments.size(); i++) {
				Segment s = (Segment) traversed_segments.elementAt(i);
				g2.setColor(Color.red.darker().darker());
				g2.setFont(new Font(g2.getFont().getName(), Font.BOLD, 22));
				g2.drawString(""+(i+1), (int)((s.p.x + s.q.x)/2)-6, (int)((s.p.y + s.q.y)/2)+8);
				g2.drawString(""+(i+1), (int)((s.p.x + s.q.x)/2)-8, (int)((s.p.y + s.q.y)/2)+8);
				g2.drawString(""+(i+1), (int)((s.p.x + s.q.x)/2)-7, (int)((s.p.y + s.q.y)/2)+7);
				g2.drawString(""+(i+1), (int)((s.p.x + s.q.x)/2)-7, (int)((s.p.y + s.q.y)/2)+9);
				g2.setColor(Color.red);
				g2.setFont(new Font(g2.getFont().getName(), Font.BOLD, 22));
				g2.drawString(""+(i+1), (int)((s.p.x + s.q.x)/2)-7, (int)((s.p.y + s.q.y)/2)+8);
			}
		}
		
		g.drawImage(dbuffer, 0, 0, this);
	}
	
	private Vertex p, q;
	private Segment s;
	private int old_x, old_y;
	
	public boolean mouseDown(Event evt, int x, int y) {
		if (evt.metaDown()) {
			p = new Vertex(x, y);
			q = new Vertex(x, y);
			s = new Segment(p, q);
			Parameters.mode = Parameters.SEGMENT_INPUT_MODE;
		}
		else if (eye.contains(new Vertex(x, y)))
			Parameters.mode = Parameters.EYE_INPUT_MODE;
		else {
			p = new Vertex(x, y);
			s = this.getSegment(p);
			if (s != null) {
				Parameters.mode = s.pick(p);
			}
		}
		repaint();
		old_x = x;
		old_y = y;
		return true;
	}
	
	public boolean mouseUp(Event evt, int x, int y) {
		if (Parameters.mode == Parameters.SEGMENT_INPUT_MODE && !p.equals(q)) {
			segments.addElement(s);
			bsp_tree.insert(s);
		} 
		p = null;
		q = null;
		s = null;
		traversed_segments = bsp_tree.traverse(eye);
		Parameters.mode = Parameters.DEFAULT_MODE;
		repaint();
		return true;
	}
	
	public boolean mouseDrag(Event evt, int x, int y) {
		if (Parameters.mode == Parameters.EYE_INPUT_MODE) {
			eye = new Vertex(x, y);
			traversed_segments = bsp_tree.traverse(eye);
		} else if (Parameters.mode == Parameters.SEGMENT_INPUT_MODE) {
			q = new Vertex(x, y);
			s = new Segment(p, q);
		} else if (Parameters.mode == Parameters.P) {
			segments.removeElement(s);
			s = new Segment(new Vertex(x, y), s.q);
			segments.addElement(s);
			recomputeBSP();
		} else if (Parameters.mode == Parameters.Q) {
			segments.removeElement(s);
			s = new Segment(s.p, new Vertex(x, y));
			segments.addElement(s);
			recomputeBSP();
		} else if (Parameters.mode == Parameters.S) {
			segments.removeElement(s);
			int dx = x - old_x;
			int dy = y - old_y;
			s = new Segment(new Vertex(s.p.x + dx, s.p.y + dy), new Vertex(s.q.x + dx, s.q.y + dy));
			segments.addElement(s);
			recomputeBSP();
		}
		repaint();
		old_x = x;
		old_y = y;
		return true;
	}
	
	public boolean keyDown(Event evt, int key) {
		if (key == 'o' || key == 'O')
			Parameters.show_ordering = !Parameters.show_ordering;
		repaint();
		return true;
	}
	
	private Segment getSegment(Vertex v) {
		for (int i=0; i<segments.size(); i++) {
			s = (Segment) segments.elementAt(i);
			if (s.pick(v) != Parameters.NIL)
				return s;
		}
		return null;
	}
	
	private void recomputeBSP() {
		bsp_tree = new BSPCell();
		for (int i=0; i<segments.size(); i++)
			bsp_tree.insert((Segment) segments.elementAt(i));
		traversed_segments = bsp_tree.traverse(eye);
	}

}