export const languages = [
	["en", "English"],
	["de", "Deutsch"],
	["fr", "Français"],
	["es", "Español"],
	["pt", "Português"],
	["it", "Italiano"],
	["nl", "Nederlands"],
	["zh-CN", "简体中文"],
	["zh-TW", "繁體中文"],
	["ja", "日本語"],
	["hi", "हिन्दी"],
	["ar", "العربية"],
	["he", "עברית"],
	["ru", "Русский"],
	["ko", "한국어"],
	["tr", "Türkçe"],
	["id", "Bahasa Indonesia"],
	["bn", "বাংলা"],
	["vi", "Tiếng Việt"],
	["fil", "Filipino"],
	["th", "ไทย"],
	["pl", "Polski"],
	["uk", "Українська"],
	["sv", "Svenska"],
	["no", "Norsk"],
	["da", "Dansk"],
	["fi", "Suomi"],
	["cs", "Čeština"],
	["el", "Ελληνικά"],
	["ro", "Română"],
] as const;

export type LangCode = (typeof languages)[number][0];
export const langCodes = languages.map(([code]) => code) as LangCode[];
export const rtlLangs = new Set<LangCode>(["ar", "he"]);

export const detectLanguage = (): LangCode => {
	for (const tag of navigator.languages.length
		? navigator.languages
		: [navigator.language]) {
		const normalized = tag.toLowerCase();
		if (normalized === "zh" || normalized.startsWith("zh-")) {
			if (
				normalized.startsWith("zh-hant") ||
				/-(?:tw|hk|mo)(?:-|$)/.test(normalized)
			) {
				return "zh-TW";
			}
			if (
				normalized.startsWith("zh-hans") ||
				/-(?:cn|sg)(?:-|$)/.test(normalized)
			) {
				return "zh-CN";
			}
			return "zh-CN";
		}

		const base = normalized.split("-", 1)[0];
		const match = langCodes.find(
			(code) => code.toLowerCase() === normalized || code === base,
		);
		if (match) return match;
	}

	return "en";
};