import java.awt.*;

public class Wlk{
	Sen s;
	double posi;
	double speed;
	boolean revdir;

	public Wlk(Sen s, double speed, boolean revdir){
		this.s = s;
		this.speed = speed;
		this.revdir = revdir;
		posi = revdir ? s.len() : 0;
	}
	public Wlk(Sen s){
		this(s, s.len()/8, false);
	}
	public Point pt(){
		return s.pt(posi);
	}
	public void update(){
		posi += revdir ? -speed : speed;
		if(0<posi && posi <s.len()) return;
		Ten t = revdir ? s.s : s.e;
		turn(t);
	}
	void turn(Ten t){
		Sen from = s;
		do{
			int i = Rnd.get(0,t.lst.size()-1);			
			s = (Sen)t.lst.elementAt(i);
			if(t.lst.size()<=1) break;
		}while(s==from);
		double over = revdir ? -posi : posi-from.len();
		revdir = (t == s.e);
		posi = revdir ? s.len()-over : over;
	}
	public Point getDir(){
		return Pts.sign(Pts.mul(Pts.sub(s.e.pt(),s.s.pt()), revdir ? -1 : 1));
	}
}

// EOF