import { TZDate } from "@date-fns/tz";
/** Format a calendar Date to an ISO-8601 date-only string (`yyyy-MM-dd`) from its local Y/M/D. */
export declare function toIsoDate(value: Date | null | undefined): string;
/** Parse ISO string or Date — returns null for invalid values. */
export declare function parseDateInput(value: string | Date | null | undefined): Date | null;
/** Calendar date from react-day-picker — interpret Y/M/D in app timezone, not browser local. */
export declare function calendarDateToTZDate(date: Date, timezone: string): TZDate;
export declare function isValidHhmm(value: string): boolean;
/** Normalize loose input ("9:30") to canonical 24h "09:30". */
export declare function normalizeHhmm(value: string): string | null;
/** Map canonical HH:mm to a TZDate on today's calendar date in the given timezone. */
export declare function hhmmToTZDate(hhmm: string, timezone: string): TZDate | null;