import React from 'react' /**
 * Copyright (c) Nicolas Gallagher.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow strict
 */

import { isLocaleRTL } from './isLocaleRTL'

type Locale = string
type WritingDirection = 'ltr' | 'rtl'

type LocaleValue = {
  // Locale writing direction.
  direction: WritingDirection
  // Locale BCP47 language code: https://www.ietf.org/rfc/bcp/bcp47.txt
  locale: Locale | null
}

type ProviderProps = {
  children: any
} & LocaleValue

const defaultLocale = {
  direction: 'ltr',
  locale: 'en-US',
}

const LocaleContext = React.createContext<LocaleValue>(defaultLocale as any)

export function getLocaleDirection(locale: Locale): WritingDirection {
  return isLocaleRTL(locale) ? 'rtl' : 'ltr'
}

export function LocaleProvider(props: ProviderProps) {
  const { direction, locale, children } = props
  const needsContext = direction || locale

  return needsContext ? (
    <LocaleContext.Provider
      value={{
        direction: locale ? getLocaleDirection(locale) : direction,
        locale,
      }}
    >
      {children}
    </LocaleContext.Provider>
  ) : (
    children
  )
}

export function useLocaleContext(): LocaleValue {
  return React.useContext(LocaleContext)
}