number-name/src/systems/de/getLongKiloName.ts

import { GetKiloName } from '../../NumberSystem'
import NAMES from './names.json'
import getKiloCombiningPrefix from './base/kilo/combiningPrefix'

const capitalizeFirstLetter = (word: string) => word.slice(0, 1).toUpperCase() + word.slice(1)

const getLongKiloName: GetKiloName = (thousandPower) => {
  if (thousandPower === 0) {
    return ''
  }
  if (thousandPower === 1) {
    return capitalizeFirstLetter(NAMES.thousand)
  }
  const kilo = thousandPower
  const kiloHundreds = Math.floor(kilo / 2 / 100)
  const kiloTens = Math.floor((kilo / 2 / 10) % 10)
  const kiloOnes = Math.floor((kilo / 2) % 10)
  const kiloCombiningPrefix = getKiloCombiningPrefix(kiloHundreds, kiloTens, kiloOnes)

  return capitalizeFirstLetter(
    thousandPower % 2 === 0 ? kiloCombiningPrefix + NAMES.kiloEvenSuffix : kiloCombiningPrefix + NAMES.kiloOddSuffix,
  )
}

export default getLongKiloName