number-name/src/systems/en/getEuropeanLongKiloName.ts

import { Digit, GetKiloName } from '../../common'
import NAMES from './names'
import getKiloCombiningPrefix from './base/kilo/combiningPrefix'

const getEuropeanLongKiloName: GetKiloName = (thousandPower) => {
  if (thousandPower === 0n) {
    return ''
  }
  if (thousandPower === 1n) {
    return NAMES.thousand
  }
  const kilo = thousandPower
  const kiloHundreds = kilo / 2n / 100n
  const kiloTens = (Number(kilo / 2n / 10n) % 10) as Digit
  const kiloOnes = (Number(kilo / 2n) % 10) as Digit
  const kiloCombiningPrefix = getKiloCombiningPrefix(kiloHundreds, kiloTens, kiloOnes)

  return thousandPower % 2n === 0n
    ? kiloCombiningPrefix + NAMES.kiloEvenSuffix
    : kiloCombiningPrefix + NAMES.kiloOddSuffix
}

export default getEuropeanLongKiloName