import * as React from "react"
import { useLingui } from "@lingui/react"

import { I18nRuntimeContext } from "./context"
import { createIntlFormatters } from "./intl-formatters"
import type {
  IntlFormatters,
  LocaleDefinition,
  MessageDescriptor,
  MessageId,
  MessageOptions,
  MessageValues,
  TranslateFunction,
} from "./types"

export function useTranslate(): TranslateFunction {
  const { i18n } = useLingui()

  return React.useCallback(
    (descriptor, values) =>
      i18n._({
        ...descriptor,
        values: values ?? descriptor.values,
      }),
    [i18n]
  )
}

export function useMessage(descriptor: MessageDescriptor): string
export function useMessage(
  id: MessageId,
  values?: MessageValues,
  options?: MessageOptions
): string
export function useMessage(
  descriptorOrId: MessageDescriptor | MessageId,
  values?: MessageValues,
  options?: MessageOptions
) {
  const { i18n } = useLingui()

  return React.useMemo(
    () =>
      typeof descriptorOrId === "string"
        ? i18n._(descriptorOrId, values, options)
        : i18n._({
            ...descriptorOrId,
            values: values ?? descriptorOrId.values,
          }),
    [descriptorOrId, i18n, options, values]
  )
}

export function useLocale(): string {
  return useLocaleDefinition().locale
}

export function useLocaleDefinition(): LocaleDefinition {
  const runtime = React.useContext(I18nRuntimeContext)
  const { i18n } = useLingui()

  return (
    runtime?.locale ?? {
      label: i18n.locale,
      languageTag: i18n.locale,
      locale: i18n.locale,
    }
  )
}

export function useLocales(): readonly LocaleDefinition[] {
  const runtime = React.useContext(I18nRuntimeContext)
  const activeLocale = useLocaleDefinition()

  return runtime?.locales ?? [activeLocale]
}

export function useFormatters(): IntlFormatters {
  const runtime = React.useContext(I18nRuntimeContext)
  const locale = useLocaleDefinition()
  const fallbackFormatters = React.useMemo(
    () => createIntlFormatters(locale.languageTag ?? locale.locale),
    [locale.languageTag, locale.locale]
  )

  return runtime?.formatters ?? fallbackFormatters
}