Gold Bazar: Cross-Platform Gold Laboratory Suite

type Units = { tola: number; masha: number; ratti: number };

const RATTI_PER_MASHA = 8;
const MASHA_PER_TOLA = 12;

export function normalizeUnits(u: Units): Units {
  // Borrowing logic: if impurity/kaat subtraction makes a unit negative,
  // borrow from the next higher unit and re-normalize.
  let tola = u.tola;
  let masha = u.masha;
  let ratti = u.ratti;

  while (ratti < 0) {
    masha -= 1;
    ratti += RATTI_PER_MASHA;
  }

  while (masha < 0) {
    tola -= 1;
    masha += MASHA_PER_TOLA;
  }

  // carry forward if values exceed their base
  if (ratti >= RATTI_PER_MASHA) {
    masha += Math.floor(ratti / RATTI_PER_MASHA);
    ratti = ratti % RATTI_PER_MASHA;
  }
  if (masha >= MASHA_PER_TOLA) {
    tola += Math.floor(masha / MASHA_PER_TOLA);
    masha = masha % MASHA_PER_TOLA;
  }

  return { tola, masha, ratti };
}