// #352 i18n 뼈대 — 로케일 목록/기본값

export const LOCALES = ["ko", "en", "ja", "es"] as const;
export type Locale = (typeof LOCALES)[number];

export const DEFAULT_LOCALE: Locale = "ko";
export const LOCALE_STORAGE_KEY = "tasteby_locale";

export const LOCALE_LABELS: Record<Locale, { flag: string; label: string; native: string }> = {
  ko: { flag: "🇰🇷", label: "Korean", native: "한국어" },
  en: { flag: "🇺🇸", label: "English", native: "English" },
  ja: { flag: "🇯🇵", label: "Japanese", native: "日本語" },
  es: { flag: "🇪🇸", label: "Spanish", native: "Español" },
};

export function isLocale(value: string | null | undefined): value is Locale {
  return value != null && (LOCALES as readonly string[]).includes(value);
}

/**
 * 브라우저 언어 감지 → 지원 로케일이면 그것, 아니면 기본값.
 * SSR-safe (typeof window 체크 호출자).
 */
export function detectBrowserLocale(): Locale {
  if (typeof navigator === "undefined") return DEFAULT_LOCALE;
  const code = navigator.language.split("-")[0].toLowerCase();
  return isLocale(code) ? code : DEFAULT_LOCALE;
}