import moment from 'moment'

const FRONTEND_FORMAT = 'DD.MM.YYYY'
const BACKEND_FORMAT = 'YYYY-MM-DD'

export function getDays({
  startDate,
  endDate,
}: {
  startDate: moment.MomentInput
  endDate: moment.MomentInput
}) {
  let currentDay = moment(startDate)
  const days = [dateFormatBackend(currentDay)]

  if (!endDate) {
    return days
  }

  const end = moment(endDate)
  while (currentDay < end) {
    currentDay = currentDay.add(1, 'day')
    days.push(dateFormatBackend(currentDay))
  }

  return days
}

function dateFormat(date: moment.MomentInput, format: string) {
  if (!date) {
    return null
  }
  return moment(date).format(format)
}

export function dateFormatBackend(date: moment.MomentInput) {
  return dateFormat(date, BACKEND_FORMAT)
}

export function dateFormatFrontend(date: moment.MomentInput) {
  return dateFormat(date, FRONTEND_FORMAT)
}

function dateParse(input: string, format: string) {
  const date = moment(input, format)
  if (date.isValid()) {
    return date.toDate()
  }

  return null
}

export function dateParseFrontend(input: string) {
  return dateParse(input, FRONTEND_FORMAT)
}