/**
 * Strip any display suffix from a timezone string and return a bare IANA id.
 *
 * @example
 * normalizeTimezone("America/New_York (GMT-5:00)") // "America/New_York"
 * normalizeTimezone("Asia/Kolkata (GMT+5:30)")     // "Asia/Kolkata"
 * normalizeTimezone("")                            // "UTC"
 */
declare function normalizeTimezone(timeZone: string | null | undefined): string;
/** Validate a bare IANA timezone id using the runtime Intl implementation */
declare function isValidIanaTimezone(timeZone: string): boolean;
/**
 * Normalise and validate in one step. Returns the IANA id if valid,
 * otherwise returns the fallback and logs a warning.
 */
declare function safeTimezone(timeZone: string | null | undefined, fallback?: string): string;
/**
 * Sanitise a timezone value before saving it to the database.
 * Strips any display suffix so only the bare IANA id is persisted.
 *
 * @example
 * site.TimeZone = sanitizeTimezoneForDB(req.body.TimeZone);
 */
declare function sanitizeTimezoneForDB(timeZone: string | null | undefined): string;

export { isValidIanaTimezone, normalizeTimezone, safeTimezone, sanitizeTimezoneForDB };