/**
 * Shared ru-RU formatters — single source for dates/numbers across the app.
 * All timestamps are ISO strings from the API.
 */

const packetFmt = new Intl.NumberFormat('ru-RU', {
  notation: 'compact',
  maximumFractionDigits: 1,
})

const numberFmt = new Intl.NumberFormat('ru-RU')

const shortDateTimeFmt = new Intl.DateTimeFormat('ru-RU', {
  day: '2-digit',
  month: '2-digit',
  hour: '2-digit',
  minute: '2-digit',
})

const dateTimeFmt = new Intl.DateTimeFormat('ru-RU')

const stampDateTimeFmt = new Intl.DateTimeFormat('ru-RU', {
  day: '2-digit',
  month: '2-digit',
  year: 'numeric',
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
})

const timeFmt = new Intl.DateTimeFormat('ru-RU', {
  hour: '2-digit',
  minute: '2-digit',
  second: '2-digit',
})

const relativeFmt = new Intl.RelativeTimeFormat('ru-RU', { numeric: 'auto' })

/** Compact packet counter: 1,2K / 3,4M */
export function formatPackets(n: number | undefined | null): string {
  if (n === undefined || n === null) return '—'
  return packetFmt.format(n)
}

export function formatNumber(n: number | undefined | null): string {
  if (n === undefined || n === null) return '—'
  return numberFmt.format(n)
}

/** dd.MM HH:mm — dense "seen" stamps in grids/cards */
export function formatShortDateTime(iso: string | null | undefined): string {
  if (!iso) return '—'
  const t = Date.parse(iso)
  if (Number.isNaN(t)) return '—'
  return shortDateTimeFmt.format(new Date(t))
}

/** Full locale date-time for detail panels */
export function formatDateTime(iso: string | null | undefined): string {
  if (!iso) return '—'
  const t = Date.parse(iso)
  if (Number.isNaN(t)) return iso
  return dateTimeFmt.format(new Date(t))
}

/** dd.MM.yyyy HH:mm:ss — block-stats "seen" stamps */
export function formatStampDateTime(iso: string | null | undefined): string {
  if (!iso) return '—'
  const t = Date.parse(iso)
  if (Number.isNaN(t)) return iso
  return stampDateTimeFmt.format(new Date(t))
}

export function formatTime(d: Date): string {
  return timeFmt.format(d)
}

/** «2 минуты назад» / «5 часов назад»; старше 7 дней — полная дата. */
export function formatRelativeTime(iso: string | null | undefined): string {
  if (!iso) return '—'
  const t = Date.parse(iso)
  if (Number.isNaN(t)) return '—'
  const diffMs = t - Date.now()
  const absMin = Math.round(Math.abs(diffMs) / 60_000)
  if (absMin < 1) return 'только что'
  const sign = diffMs < 0 ? -1 : 1
  if (absMin < 60) return relativeFmt.format(sign * absMin, 'minute')
  const absHours = Math.round(absMin / 60)
  if (absHours < 24) return relativeFmt.format(sign * absHours, 'hour')
  const absDays = Math.round(absHours / 24)
  if (absDays < 7) return relativeFmt.format(sign * absDays, 'day')
  return formatDateTime(iso)
}