/*
  Distributed Systems: Practical Exercise 2
  
  This class represent a unidirectional channel between two nodes. 
  You should not change anything in this file.

  This template file (C) The University of Edinburgh, 2002

  Author: Yussuf Abu Shaaban

*/


import java.awt.*;
import java.awt.geom.*;

public class Channel extends Component implements Comparable{
    private static int channelCount = 0;
    private Color color = Color.black;

    private int id;
    private Node node1;
    private Node node2;
    Line2D.Double graphicalRep;
    
    public Channel(Node node1, Node node2, int id){
	this.id = id;
	this.node1 = node1;
	this.node2 = node2;
	Rectangle rn1 = node1.graphicalRep.getBounds();
	Rectangle rn2 = node2.graphicalRep.getBounds();
	this.graphicalRep = new Line2D.Double(rn1.x + (rn1.width)/2,
					      rn1.y + (rn1.height)/2,
					      rn2.x + (rn2.width)/2,
					      rn2.y + (rn2.height)/2);
	
    }
    
    public int getId(){
	return id;
    }
    
    public Node getNode1(){
	return node1;
    }

    public Node getNode2(){
	return node2;
    }

    public void paint(Graphics g){
	Graphics2D g2 = (Graphics2D) g;
	g2.setPaint(color);
	g2.draw(graphicalRep);
	drawArrow((int)graphicalRep.x1, (int)graphicalRep.y1, 
		  (int)graphicalRep.x2, (int)graphicalRep.y2, g2);
	
    }

    public int compareTo(Object o){
	Channel temp = (Channel) o;
	if(this.getId() < temp.getId()){ return -1;}
	else if(this.getId() == temp.getId()) { return 0;}
	else return 1;
    }
    
    private void drawArrow(int x1, int y1, int x2, int y2, Graphics2D g2){
	double thetaR;
	if(x2 != x1){
	    thetaR = Math.atan2(Math.abs(y2 - y1), Math.abs(x2 - x1));
	}
	else{
	    thetaR = Math.PI / 2;
	}
	double alpha = 30.0*Math.PI/180.0;

	int signX = (x1 > x2) ? 1 : -1;
	int signY = (y1 > y2) ? 1 : -1;
	
	int w = 10;
	double a = ((double)x2+(signX*w*Math.cos(thetaR-alpha)));
	double b = ((double)y2+(signY*w*Math.sin(thetaR-alpha)));
	g2.draw(new Line2D.Double(a, b, x2, y2));
	a = (double)x2+(signX*w*Math.cos(thetaR+alpha));
	b = (double)y2+(signY*w*Math.sin(thetaR+alpha));
	g2.draw(new Line2D.Double(a, b, x2, y2));
    }
	
}