import { parse, parseISO, differenceInDays, differenceInHours, differenceInMinutes, differenceInMonths, differenceInSeconds, differenceInWeeks, differenceInYears } from 'date-fns'

// 「○秒前」「○分前」と表示する
export const diffTimeCalc = (base: Date, target: Date) => {
  const diffInSecs = differenceInSeconds(base, target)
  if (diffInSecs < 60) {
    return `${diffInSecs}秒前`
  }

  const diffInMins = differenceInMinutes(base, target)
  if (diffInMins < 60) {
    return `${diffInMins}分前`
  }

  const diffInHours = differenceInHours(base, target)
  if (diffInHours < 24) {
    return `${diffInHours}時間前`
  }

  const diffInDays = differenceInDays(base, target)
  if (diffInDays < 7) {
    return `${diffInDays}日前`
  }

  const diffInWeeks = differenceInWeeks(base, target)
  if (diffInWeeks < 4) {
    return `${diffInWeeks}週間前`
  }

  const diffInMonths = differenceInMonths(base, target)
  // 4週間前でも 0ヶ月前と表示されるため、条件を足して絞り込む
  if (diffInWeeks >= 4 && diffInMonths < 2) {
    return `1ヶ月前`
  } else if (diffInMonths < 12) {
    return `${diffInMonths}ヶ月前`
  }

  const diffInYears = differenceInYears(base, target)

  

  return `${diffInYears}年前`
}

export const diffTime = (_target: number) => {
  const base = new Date()
  const target = new Date(_target * 1000)
  return diffTimeCalc(base, target)
}

export const diffTimeFromYMD = (_target: string) => {
  const base = new Date()
  const target = parse(_target, 'yyyy-MM-dd', new Date())
  return diffTimeCalc(base, target)
}