const persianDigits = '۰۱۲۳۴۵۶۷۸۹'
const numberFormatter = new Intl.NumberFormat('fa-IR', { useGrouping: true })

export function normalizeDigits(input: string): string {
  return input.replace(/[۰-۹]/g, (digit) => String(persianDigits.indexOf(digit)))
}

export function extractNumericString(input: string): string {
  return normalizeDigits(input).replace(/[^\d]/g, '')
}

export function parseFormattedNumber(value: string): number {
  const numeric = extractNumericString(value)
  return numeric ? Number(numeric) : 0
}

export function formatNumber(value: number): string {
  if (!Number.isFinite(value)) return '—'
  return numberFormatter.format(value)
}

export function formatCurrency(value: number): string {
  return `${formatNumber(value)} تومان`
}

export function formatMeterage(value: number): string {
  return `${formatNumber(value)} متر`
}

export function toPersianDigits(input: string | number): string {
  return String(input).replace(/\d/g, (d) => persianDigits[Number(d)]!)
}

const persianDateFormatter = new Intl.DateTimeFormat('fa-IR-u-ca-persian', {
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
})

const persianDateTimeFormatter = new Intl.DateTimeFormat('fa-IR-u-ca-persian', {
  year: 'numeric',
  month: '2-digit',
  day: '2-digit',
  hour: '2-digit',
  minute: '2-digit',
})

/** Detect already-Jalali date strings like 1403/07/30 or 1403-07-30 */
function isJalaliDateString(value: string): boolean {
  const normalized = normalizeDigits(value.trim()).replace(/-/g, '/')
  const match = normalized.match(/^(\d{4})\/(\d{1,2})\/(\d{1,2})/)
  if (!match) return false
  const year = Number(match[1])
  return year >= 1300 && year <= 1500
}

function toDateValue(date: string | Date): Date {
  if (typeof date !== 'string') return date
  const trimmed = date.trim()
  // فقط تاریخِ بدون ساعت (YYYY-MM-DD) را به‌صورت تقویم محلی بخوان تا شیفت UTC روز را جابه‌جا نکند.
  // رشته‌های دارای ساعت (…T10:30:00 یا … 10:30) باید کامل پارس شوند.
  const dateOnly = trimmed.match(/^(\d{4})-(\d{2})-(\d{2})$/)
  if (dateOnly && Number(dateOnly[1]) >= 1700) {
    return new Date(Number(dateOnly[1]), Number(dateOnly[2]) - 1, Number(dateOnly[3]))
  }
  const parsed = new Date(trimmed)
  if (Number.isNaN(parsed.getTime())) return new Date(NaN)
  return parsed
}

export function formatDate(date: string | Date | null | undefined): string {
  if (!date) return '—'
  if (typeof date === 'string' && isJalaliDateString(date)) {
    const normalized = normalizeDigits(date.trim()).replace(/-/g, '/')
    const match = normalized.match(/^(\d{4})\/(\d{1,2})\/(\d{1,2})/)
    if (!match) return toPersianDigits(normalized)
    const [, y, m, d] = match
    return toPersianDigits(`${y}/${m!.padStart(2, '0')}/${d!.padStart(2, '0')}`)
  }
  const value = toDateValue(date)
  if (Number.isNaN(value.getTime())) return '—'
  return persianDateFormatter.format(value)
}

export function formatDateTime(date: string | Date | null | undefined): string {
  if (!date) return '—'
  if (typeof date === 'string' && isJalaliDateString(date) && !/[T\s]\d/.test(date)) {
    return formatDate(date)
  }
  const value = toDateValue(date)
  if (Number.isNaN(value.getTime())) return '—'
  return persianDateTimeFormatter.format(value)
}

export function generateOrderNumber(): string {
  const year = new Intl.DateTimeFormat('fa-IR-u-ca-persian', { year: 'numeric' }).format(new Date())
  const persianYear = year.replace(/[^\d]/g, '') || '1403'
  const seq = Math.floor(Math.random() * 9000) + 1000
  return `ORD-${persianYear}-${seq}`
}