#include <cmath>
#include <iostream>
#include "point.h"

Point::Point(double x_coord, double y_coord): x(x_coord), y(y_coord),
                                              is_polar_cached(false){
}

Point::Point(): x(0.0), y(0.0), 
                is_polar_cached(false){
}

double Point::getx () const{
  return x;
}

double Point::gety () const{
  return y;
}

double Point::getr () const {
  if (is_polar_cached)
    return r;
  else{
    do_polar_caching();
    return r;
  }
}

double Point::geta () const {
  if (is_polar_cached)
    return a;
  else{
    do_polar_caching();
    return a;
  }
}

void Point::do_polar_caching() const{  // Must be const, when called from another const method.
  std::cout << "Caching" << std::endl;
  r = sqrt(x*x + y*y);      // Now OK to update mutable data members
  a = atan2(y,y);            
  is_polar_cached = true;    
}

void Point::move(double dx, double dy){
    is_polar_cached = false;
    x += dx; y += dy;
}

double Point::distance_to(Point p) const{
    return sqrt((x - p.x) * (x - p.x) + (y - p.y) * (y - p.y));
}

std::ostream& operator<<(std::ostream& s, const Point& p){
  return s << "(" << p.getx() << "," << p.gety() << ")" ;
}