/**
 * Time helpers for bundle first-week tasks: "day 2 at 09:00 in the
 * bundle's timezone" as a UTC instant, independent of the server's own
 * timezone (hosted servers run in UTC; owners mostly do not).
 *
 * @module services/bundle/bundle-time
 */
/** Calendar date and time in some timezone. */
interface ZonedParts {
    year: number;
    month: number;
    day: number;
    hour: number;
    minute: number;
}
/**
 * Whether a string is a valid IANA timezone.
 *
 * @param tz - Candidate
 * @returns True when Intl accepts it
 */
export declare function isValidTimezone(tz: string): boolean;
/**
 * Calendar parts of an instant in a timezone.
 *
 * @param date - Instant
 * @param tz - IANA timezone
 * @returns Year, month (1-12), day, hour, minute
 */
export declare function zonedParts(date: Date, tz: string): ZonedParts;
/**
 * The UTC instant of a wall-clock time in a timezone.
 *
 * Starts from the wall time read as UTC, then corrects by the zone's offset
 * at that instant (twice, which settles DST edges).
 *
 * @param wall - Calendar date and time in `tz`
 * @param tz - IANA timezone
 * @returns The instant
 */
export declare function zonedTimeToUtc(wall: ZonedParts, tz: string): Date;
/**
 * When a first-week task is due.
 *
 * Day 0 is due at `deployedAt`. Day n is due at `time` (default 09:00) on
 * the n-th calendar day after the deploy day, in `tz`.
 *
 * @param deployedAt - When the bundle was applied
 * @param day - 0-based day
 * @param time - `HH:MM` (optional)
 * @param tz - IANA timezone
 * @returns ISO timestamp
 *
 * @example
 * firstWeekDueAt(new Date('2026-09-25T02:00:00Z'), 1, '09:00', 'Asia/Shanghai') // '2026-09-26T01:00:00.000Z'
 */
export declare function firstWeekDueAt(deployedAt: Date, day: number, time: string | undefined, tz: string): string;
export {};
//# sourceMappingURL=bundle-time.d.ts.map