import type {CookieRef} from "nuxt/app"

export function useContentPreference() {
  const config = useAppConfig()

  const locales = config.content.matrix.locale.list.map(l => l.code)
  const variants = config.content.matrix.variant.list.map(v => v.code)

  const localeCookie = useCookie<string>('locale', {
    sameSite: 'lax',
    maxAge: config.content.matrix.locale.cookieMaxAge
  })

  const variantCookie = useCookie<string>('variant', {
    sameSite: 'lax',
    maxAge: config.content.matrix.variant.cookieMaxAge
  })

  function prefer(list: string[], cookie: CookieRef<string>) {
    return (item: string) => {
      if (list.includes(item)) {
        cookie.value = item
      }
    }
  }

  function preferred(list: string[], cookie: CookieRef<string | undefined>, fallback: string) {
    return computed(() => {
      if (cookie.value!==undefined && list.includes(cookie.value)) {
        return cookie.value
      } else if (cookie.value !== undefined) {
        cookie.value = undefined
      }

      return fallback
    })
  }

  return {
    preferredLocale: preferred(locales, localeCookie, config.content.matrix.locale.default),
    preferLocale: prefer(locales, localeCookie),
    preferredVariant: preferred(variants, variantCookie, config.content.matrix.variant.default),
    preferVariant: prefer(variants, variantCookie)
  }
}