package org.simantics.debug.graphical.model;

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.Line2D;
import java.awt.geom.Path2D;
import java.awt.geom.Point2D;

public class Edge {
    private static final double ARROW_LENGTH = 10.0;
    private static final double ARROW_MIDDLE_LENGTH = 8.0;
    private static final double ARROW_RADIUS = 4.0;
    
    Node a;
    Node b;
    Content content;
    
    public Edge(Node a, Node b) {
        this.a = a;
        this.b = b;
    }
    
    public Node getA() {
        return a;
    }
    
    public Node getB() {
        return b;
    }    
    
    public void setContent(Content content) {
        this.content = content;
    }
    
    public void render(Graphics2D g) {
        Point2D pa = a.clipLineFromCenter(b.x, b.y);
        Point2D pb = b.clipLineFromCenter(a.x, a.y);

        double dx, dy;
        double l;
        drawArrow: {
            Path2D path = new Path2D.Double();
            
            double x = pb.getX();
            double y = pb.getY();
            dx = pa.getX() - x;
            dy = pa.getY() - y;
            l = Math.sqrt(dx*dx + dy*dy);
            if(l < 0.1)
                break drawArrow;
            
            dx /= l;
            dy /= l;
            
            path.moveTo(x, y);
            path.lineTo(x+ARROW_LENGTH*dx+ARROW_RADIUS*dy, y+ARROW_LENGTH*dy-ARROW_RADIUS*dx);
            path.lineTo(x+ARROW_MIDDLE_LENGTH*dx, y+ARROW_MIDDLE_LENGTH*dy);
            path.lineTo(x+ARROW_LENGTH*dx-ARROW_RADIUS*dy, y+ARROW_LENGTH*dy+ARROW_RADIUS*dx);
            path.closePath();
            
            g.fill(path);
            
            pb.setLocation(pb.getX()+dx*ARROW_MIDDLE_LENGTH, 
                    pb.getY()+dy*ARROW_MIDDLE_LENGTH);
        }
        
        g.draw(new Line2D.Double(pa, pb));
        
        if(content != null) {
            if(l < content.radiusX*2.1) {
                /*double ss = - Math.abs(dy)*content.radiusX + Math.abs(dx)*content.radiusY + 3.0;
                double tx = 0.5*(pa.getX() + pb.getX()) - dy*ss;
                double ty = 0.5*(pa.getY() + pb.getY()) + dx*ss;        
                */
                double tx = 0.5*(pa.getX() + pb.getX()) + Math.signum(dy) * content.radiusX;
                double ty = 0.5*(pa.getY() + pb.getY()) - Math.signum(dx) * content.radiusY;
                
                content.render(g, tx, ty);
            }
            else {
                double ss = content.radiusY*0.5+1.0;
                double tx = 0.5*(pa.getX() + pb.getX()) - dy*ss;
                double ty = 0.5*(pa.getY() + pb.getY()) + dx*ss;
                
                content.render(g, new AffineTransform(-dx, -dy, dy, -dx, tx, ty));
            }
        }
    }
}