const Vector = p5.Vector;

function Segment(startx, starty, len, heading){
    this.start = new Vector(startx, starty);
    this.len = len;
    this.reference = 0;
    this.heading = heading;
    this.child = null;
    this.parent = null;
};

Segment.prototype.end = function(){
        angle = this.heading + this.reference;
        let x = this.len * cos(angle) + this.start.x;
        let y = this.len * sin(angle) + this.start.y;
        return new Vector(x,y);
};


Segment.prototype.update = function(){
    if(!this.parent) return;
    this.parent.heading = Vector.sub(this.start, this.parent.start).heading();
    this.parent.start.add(Vector.sub(this.start, this.parent.end()));
    this.parent.update();
};

Segment.prototype.setHeading = function(angle){
    this.heading = angle;
    this.update();
};

Segment.prototype.draw = function(){
        push();
        stroke(255);
        strokeWeight(5);
        line(
            this.start.x,
            this.start.y,
            this.end().x,
            this.end().y);
        pop();
};

Segment.prototype.expand_parent = function(stx, sty, len, heading){
        let next = new Segment(stx, sty, len, heading);
        next.child = this;
        this.parent = next;
        return next;
};

Segment.prototype.eats_parents = function(){
    let start = this.start;
    let end = this.end();
    for(let theSeg = this.parent.parent; theSeg != null; theSeg = theSeg.parent)
        if(doIntersect(start, end, theSeg.start, theSeg.end()))
            return true;
    return false;
};