pfadi-bussle/helpers/bill.ts

import { MILAGE_TARIFS } from '../db/enums'
import { AdditionalCost } from '../db/bill'

function roundToCent(amount: number): number {
  return Math.round(amount * 100) / 100
}

export function getMilageCosts({ tarif, km }: { tarif: MILAGE_TARIFS; km: number }): number {
  if (tarif === MILAGE_TARIFS.NOCHARGE) {
    return 0
  }

  if (km <= 0) {
    return 0
  }

  let rate: number

  if (tarif === MILAGE_TARIFS.EXTERN) {
    if (km <= 200) {
      rate = 0.42
    } else if (km <= 1000) {
      rate = 0.25
    } else if (km <= 2000) {
      rate = 0.2
    } else {
      rate = 0.18
    }
  }

  if (tarif === MILAGE_TARIFS.INTERN) {
    if (km <= 200) {
      rate = 0.37
    } else if (km <= 1000) {
      rate = 0.22
    } else if (km <= 2000) {
      rate = 0.15
    } else {
      rate = 0.13
    }
  }

  if (rate === undefined) {
    throw Error('Unable to determine rate')
  }

  return roundToCent(km * rate)
}

export function getBillTotal({
  tarif,
  milage,
  additionalCosts,
}: {
  tarif: MILAGE_TARIFS
  milage?: number
  additionalCosts: AdditionalCost[]
}): number {
  const milageCosts = getMilageCosts({ tarif, km: milage })
  const additionalCostsSum = additionalCosts
    .map(({ value }) => value)
    .reduce((acc: number, value: number) => acc + value, 0)

  return roundToCent(milageCosts + additionalCostsSum)
}