#include "toonz/cellpositionratio.h"

#include <stdexcept></stdexcept>

#include <algorithm></algorithm>

// Euclid's algorithm

static int greatestCommonDivisor(int a, int b) {

  a     = std::abs(a);

  b     = std::abs(b);

  int c = std::max(a, b);

  int d = std::min(a, b);

  while (d) {

    int q = c / d;

    int r = c % d;

    c     = d;

    d     = r;

  }

  return c;

}

#if 0 /* UNUSED */

int leastCommonMultiple(int a, int b) {

  return a * b / greatestCommonDivisor(a, b);

}

#endif

void Ratio::normalize() {

  int gcd = greatestCommonDivisor(m_num, m_denom);

  if (m_denom < 0) gcd = -gcd;

  m_num /= gcd;

  m_denom /= gcd;

}

Ratio Ratio::normalized() const {

  Ratio copy(*this);

  copy.normalize();

  return copy;

}

Ratio::Ratio(int num, int denom) : m_num(num), m_denom(denom) {

  if (!denom) throw std::runtime_error("ratio with denominator == 0");

  normalize();

}

Ratio operator*(const Ratio &a, const Ratio &b) {

  return Ratio(a.m_num * b.m_num, a.m_denom * b.m_denom);

}

Ratio operator/(const Ratio &a, const Ratio &b) {

  return Ratio(a.m_num * b.m_denom, a.m_denom * b.m_num);

}

Ratio operator+(const Ratio &a, const Ratio &b) {

  int gcd   = greatestCommonDivisor(a.m_denom, b.m_denom);

  int denom = a.m_denom * b.m_denom / gcd;

  int aMult = b.m_denom * gcd;

  int bMult = a.m_denom * gcd;

  return Ratio(a.m_num * aMult + b.m_num * bMult, denom);

}

Ratio operator-(const Ratio &a, const Ratio &b) {

  int gcd   = greatestCommonDivisor(a.m_denom, b.m_denom);

  int denom = a.m_denom * b.m_denom / gcd;

  int aMult = b.m_denom * gcd;

  int bMult = a.m_denom * gcd;

  return Ratio(a.m_num * aMult - b.m_num * bMult, denom);

}

int operator*(const Ratio &a, int b) { return a.m_num * b / a.m_denom; }