bool on_segment(Point p, Point q, Point r)
{
    if (q.x <= max(p.x, r.x) && q.x >= min(p.x, r.x) &&
        q.y <= max(p.y, r.y) && q.y >= min(p.y, r.y))
       return true;

    return false;
}

int orientation(Point p, Point q, Point r)
{
    int val = (q.y - p.y) * (r.x - q.x) -
              (q.x - p.x) * (r.y - q.y);

    if (val == 0) return 0;

    return (val > 0)? 1: 2;
}

int calculate_intersections(){
	int intersections = 0;
	for(int i=0; i < number_colliders; i++){
		for(int j=i+1; j < number_colliders; j++){
			intersections += check_if_intersect(colliders[i], colliders[j]);
		}
	}
	return intersections;
}

int check_if_intersect(Collider c1, Collider c2){
	if(c1.src == c2.src || c1.tgt == c2.tgt || c1.src == c2.tgt || c1.tgt == c2.src){
		return 0;
	}

	int o1, o2, o3, o4;
	o1 = check_orientation(c1.src.point, c1.tgt.point, c2.src.point);
	o2 = check_orientation(c1.src.point, c1.tgt.point, c2.tgt.point);
	o3 = check_orientation(c2.src.point, c2.tgt.point, c1.src.point);
	o4 = check_orientation(c2.src.point, c2.tgt.point, c1.tgt.point);

	if (o1 != o2 && o3 != o4){
        return 1;
	}

    if (o1 == 0 && onSegment(c1.src.point, c1.tgt.point, c2.src.point)) return 1;

    if (o2 == 0 && onSegment(c1.src.point, c1.tgt.point, c2.tgt.point)) return 1;

    if (o3 == 0 && onSegment(c2.src.point, c2.tgt.point, c1.src.point)) return 1;

    if (o4 == 0 && onSegment(c2.src.point, c2.tgt.point, c1.tgt.point)) return 1;

    return 0;
}