// SPDX-FileCopyrightText: © 2024 LEDGER SAS
// SPDX-License-Identifier: Apache-2.0

// Forked from @ledgerhq/live-currency-format/src/localeUtility.ts
const memoize = <T extends (arg: string) => ReturnType<T>>(
  fn: T
): ((arg: string) => ReturnType<T>) => {
  const cache: Record<string, ReturnType<T>> = {}
  return (arg: string) => {
    if (!(arg in cache)) {
      cache[arg] = fn(arg)
    }
    return cache[arg]
  }
}

const options = {
  style: 'currency' as const,
  currency: 'USD',
}
const localeNotAvailable = (1.2).toLocaleString('en', options) !== '$1.20'

const getFallback = (locale: string) =>
  staticFallback[Object.prototype.hasOwnProperty.call(staticFallback, locale) ? locale : 'en']

const staticFallback: Record<string, string[]> = {
  en: ['-$1.00', '10,000.2'],
  es: ['-1,00 US$', '10.000,2'],
  fr: ['-1,00 $US', '10 000,2'],
  ja: ['-US$1.00', '10,000.2'],
  ko: ['-US$1.00', '10,000.2'],
  ru: ['-1,00 $', '10 000,2'],
  zh: ['-US$1.00', '10,000.2'],
}

export const prefixFormat = ['sign', 'code', 'value'] as const
export const suffixFormat = ['sign', 'value', 'separator', 'code'] as const

export type GetSeparators = (locale: string) => {
  decimal: string | null | undefined
  thousands: string | null | undefined
}

export const getSeparators: GetSeparators = memoize((locale) => {
  const res = localeNotAvailable ? getFallback(locale)[1] : (10000.2).toLocaleString(locale)
  let decimal
  let thousands

  for (let i = 0; i < res.length; i++) {
    const c = res[i]
    if (/[0-9]/.test(c)) continue

    if (!thousands) {
      thousands = c
    } else {
      decimal = c
    }
  }

  return {
    decimal,
    thousands,
  }
})