/*
 * Implementation ported from from from https://github.com/melt-ui/melt-ui/blob/develop/src/lib/internal/helpers/date/placeholders.ts
*/

const supportedLocales = [
  'ach',
  'af',
  'am',
  'an',
  'ar',
  'ast',
  'az',
  'be',
  'bg',
  'bn',
  'br',
  'bs',
  'ca',
  'cak',
  'ckb',
  'cs',
  'cy',
  'da',
  'de',
  'dsb',
  'el',
  'en',
  'eo',
  'es',
  'et',
  'eu',
  'fa',
  'ff',
  'fi',
  'fr',
  'fy',
  'ga',
  'gd',
  'gl',
  'he',
  'hr',
  'hsb',
  'hu',
  'ia',
  'id',
  'it',
  'ja',
  'ka',
  'kk',
  'kn',
  'ko',
  'lb',
  'lo',
  'lt',
  'lv',
  'meh',
  'ml',
  'ms',
  'nl',
  'nn',
  'no',
  'oc',
  'pl',
  'pt',
  'rm',
  'ro',
  'ru',
  'sc',
  'scn',
  'sk',
  'sl',
  'sr',
  'sv',
  'szl',
  'tg',
  'th',
  'tr',
  'uk',
  'zh-CN',
  'zh-TW',
] as const

const placeholderFields = ['year', 'month', 'day'] as const

type PlaceholderField = (typeof placeholderFields)[number]
export type SupportedLocale = (typeof supportedLocales)[number]
export type PlaceholderMap = Record<SupportedLocale, Record<PlaceholderField, string>>

const placeholders: PlaceholderMap = {
  'ach': { year: 'mwaka', month: 'dwe', day: 'nino' },
  'af': { year: 'jjjj', month: 'mm', day: 'dd' },
  'am': { year: 'ዓዓዓዓ', month: 'ሚሜ', day: 'ቀቀ' },
  'an': { year: 'aaaa', month: 'mm', day: 'dd' },
  'ar': { year: 'سنة', month: 'شهر', day: 'يوم' },
  'ast': { year: 'aaaa', month: 'mm', day: 'dd' },
  'az': { year: 'iiii', month: 'aa', day: 'gg' },
  'be': { year: 'гггг', month: 'мм', day: 'дд' },
  'bg': { year: 'гггг', month: 'мм', day: 'дд' },
  'bn': { year: 'yyyy', month: 'মিমি', day: 'dd' },
  'br': { year: 'bbbb', month: 'mm', day: 'dd' },
  'bs': { year: 'gggg', month: 'mm', day: 'dd' },
  'ca': { year: 'aaaa', month: 'mm', day: 'dd' },
  'cak': { year: 'jjjj', month: 'ii', day: 'q\'q\'' },
  'ckb': { year: 'ساڵ', month: 'مانگ', day: 'ڕۆژ' },
  'cs': { year: 'rrrr', month: 'mm', day: 'dd' },
  'cy': { year: 'bbbb', month: 'mm', day: 'dd' },
  'da': { year: 'åååå', month: 'mm', day: 'dd' },
  'de': { year: 'jjjj', month: 'mm', day: 'tt' },
  'dsb': { year: 'llll', month: 'mm', day: 'źź' },
  'el': { year: 'εεεε', month: 'μμ', day: 'ηη' },
  'en': { year: 'yyyy', month: 'mm', day: 'dd' },
  'eo': { year: 'jjjj', month: 'mm', day: 'tt' },
  'es': { year: 'aaaa', month: 'mm', day: 'dd' },
  'et': { year: 'aaaa', month: 'kk', day: 'pp' },
  'eu': { year: 'uuuu', month: 'hh', day: 'ee' },
  'fa': { year: 'سال', month: 'ماه', day: 'روز' },
  'ff': { year: 'hhhh', month: 'll', day: 'ññ' },
  'fi': { year: 'vvvv', month: 'kk', day: 'pp' },
  'fr': { year: 'aaaa', month: 'mm', day: 'jj' },
  'fy': { year: 'jjjj', month: 'mm', day: 'dd' },
  'ga': { year: 'bbbb', month: 'mm', day: 'll' },
  'gd': { year: 'bbbb', month: 'mm', day: 'll' },
  'gl': { year: 'aaaa', month: 'mm', day: 'dd' },
  'he': { year: 'שנה', month: 'חודש', day: 'יום' },
  'hr': { year: 'gggg', month: 'mm', day: 'dd' },
  'hsb': { year: 'llll', month: 'mm', day: 'dd' },
  'hu': { year: 'éééé', month: 'hh', day: 'nn' },
  'ia': { year: 'aaaa', month: 'mm', day: 'dd' },
  'id': { year: 'tttt', month: 'bb', day: 'hh' },
  'it': { year: 'aaaa', month: 'mm', day: 'gg' },
  'ja': { year: ' 年 ', month: '月', day: '日' },
  'ka': { year: 'წწწწ', month: 'თთ', day: 'რრ' },
  'kk': { year: 'жжжж', month: 'аа', day: 'кк' },
  'kn': { year: 'ವವವವ', month: 'ಮಿಮೀ', day: 'ದಿದಿ' },
  'ko': { year: '연도', month: '월', day: '일' },
  'lb': { year: 'jjjj', month: 'mm', day: 'dd' },
  'lo': { year: 'ປປປປ', month: 'ດດ', day: 'ວວ' },
  'lt': { year: 'mmmm', month: 'mm', day: 'dd' },
  'lv': { year: 'gggg', month: 'mm', day: 'dd' },
  'meh': { year: 'aaaa', month: 'mm', day: 'dd' },
  'ml': { year: 'വർഷം', month: 'മാസം', day: 'തീയതി' },
  'ms': { year: 'tttt', month: 'mm', day: 'hh' },
  'nl': { year: 'jjjj', month: 'mm', day: 'dd' },
  'nn': { year: 'åååå', month: 'mm', day: 'dd' },
  'no': { year: 'åååå', month: 'mm', day: 'dd' },
  'oc': { year: 'aaaa', month: 'mm', day: 'jj' },
  'pl': { year: 'rrrr', month: 'mm', day: 'dd' },
  'pt': { year: 'aaaa', month: 'mm', day: 'dd' },
  'rm': { year: 'oooo', month: 'mm', day: 'dd' },
  'ro': { year: 'aaaa', month: 'll', day: 'zz' },
  'ru': { year: 'гггг', month: 'мм', day: 'дд' },
  'sc': { year: 'aaaa', month: 'mm', day: 'dd' },
  'scn': { year: 'aaaa', month: 'mm', day: 'jj' },
  'sk': { year: 'rrrr', month: 'mm', day: 'dd' },
  'sl': { year: 'llll', month: 'mm', day: 'dd' },
  'sr': { year: 'гггг', month: 'мм', day: 'дд' },
  'sv': { year: 'åååå', month: 'mm', day: 'dd' },
  'szl': { year: 'rrrr', month: 'mm', day: 'dd' },
  'tg': { year: 'сссс', month: 'мм', day: 'рр' },
  'th': { year: 'ปปปป', month: 'ดด', day: 'วว' },
  'tr': { year: 'yyyy', month: 'aa', day: 'gg' },
  'uk': { year: 'рррр', month: 'мм', day: 'дд' },
  'zh-CN': { year: '年', month: '月', day: '日' },
  'zh-TW': { year: '年', month: '月', day: '日' },
}

function getPlaceholderObj(locale: SupportedLocale | (string & {})) {
  if (!isSupportedLocale(locale)) {
    const localeLanguage = getLocaleLanguage(locale)
    if (!isSupportedLocale(localeLanguage))
      return placeholders.en

    else
      return placeholders[localeLanguage]
  }
  else {
    return placeholders[locale]
  }
}

type Field = 'era' | 'year' | 'month' | 'day' | 'hour' | 'minute' | 'second' | 'dayPeriod'

export function getPlaceholder(
  field: Field,
  value: string,
  locale: SupportedLocale | (string & {}),
) {
  if (isPlaceholderField(field))
    return getPlaceholderObj(locale)[field]

  if (isDefaultField(field))
    return value

  if (isTimeField(field))
    return '––'

  return ''
}

function isSupportedLocale(locale: string): locale is SupportedLocale {
  return supportedLocales.includes(locale as SupportedLocale)
}

function isPlaceholderField(field: unknown): field is PlaceholderField {
  return placeholderFields.includes(field as PlaceholderField)
}

function isTimeField(field: unknown): field is 'hour' | 'minute' | 'second' {
  return field === 'hour' || field === 'minute' || field === 'second'
}

function isDefaultField(field: unknown): field is 'era' | 'dayPeriod' {
  return field === 'era' || field === 'dayPeriod'
}

function getLocaleLanguage(locale: string) {
  if (Intl.Locale)
    return new Intl.Locale(locale).language

  return locale.split('-')[0]
}