// Supported locales for InfiPlot
export const DEFAULT_LOCALE = "zh-CN" as const;

export type Locale = "zh-CN" | "en" | "ja";

export const LOCALE_NAMES: Record<Locale, string> = {
  "zh-CN": "简体中文",
  "en": "English",
  "ja": "日本語",
};

export const LOCALES: Locale[] = Object.keys(LOCALE_NAMES) as Locale[];

// Locale storage key
export const LOCALE_STORAGE_KEY = "infiplot:locale";

// Get locale from localStorage or browser language
export function getInitialLocale(): Locale {
  if (typeof window === "undefined") return DEFAULT_LOCALE;

  try {
    const stored = localStorage.getItem(LOCALE_STORAGE_KEY);
    if (stored && LOCALES.includes(stored as Locale)) {
      return stored as Locale;
    }
  } catch {
    // ignore localStorage errors
  }

  // Try to match browser language
  const browserLang = navigator.language;
  const exactMatch = LOCALES.find((l) => l === browserLang);
  if (exactMatch) return exactMatch;

  // Try base language match (e.g., "zh" for "zh-TW")
  const baseLang = browserLang.split("-")[0];
  if (baseLang) {
    const baseMatch = LOCALES.find((l) => l.startsWith(baseLang));
    if (baseMatch) return baseMatch;
  }

  return DEFAULT_LOCALE;
}

// Save locale to localStorage
export function setLocale(locale: Locale): void {
  if (typeof window === "undefined") return;
  try {
    localStorage.setItem(LOCALE_STORAGE_KEY, locale);
  } catch {
    // ignore localStorage errors
  }
}

// Get RTL locales (right-to-left languages)
export const RTL_LOCALES: Set<Locale> = new Set();

export function isRTL(locale: Locale): boolean {
  return RTL_LOCALES.has(locale);
}