/**
 * v1.3.3 §C — friendly schedule input → node-cron expression.
 *
 * Referenced from OpenClaw (`--every "1h"`, `--cron`) and Hermes (`every 30m`,
 * `@daily`) cron UX: users shouldn't have to hand-write 5-field cron strings for
 * the common cases. `normalizeSchedule` accepts:
 *   - a raw cron expression (passthrough, validated)
 *   - `@hourly|@daily|@weekly|@monthly|@yearly` shortcuts
 *   - `every <n><unit>` / `<n><unit>` recurring intervals (m=minute, h=hour, d=day)
 * and returns the canonical cron string the rest of the system stores.
 *
 * One-shot schedules (a bare ISO timestamp / relative `20m` delay) are NOT
 * recurring crons and need a different execution path — deferred (see PRD §C
 * 비범위). They are rejected here with a clear message.
 */
export interface NormalizeResult {
    cron?: string;
    /** Human-readable readback of what was parsed (for preview). */
    describe?: string;
    error?: string;
}
/** Normalize a friendly schedule string into a node-cron expression. */
export declare function normalizeSchedule(input: string): NormalizeResult;
/**
 * v1.3.3 §C — parse a one-shot "when" into an absolute ISO timestamp.
 * Accepts an ISO 8601 timestamp or a relative delay `<n>s|m|h|d` (from now).
 * Rejects past times and unparseable input.
 */
export declare function parseWhen(input: string, now?: number): {
    at?: string;
    error?: string;
};
/**
 * v1.3.4 §A — parse a `<n>s|m|h` jitter/delay string into seconds.
 * Returns null for empty/invalid input (treated as "no jitter").
 */
export declare function parseDelaySeconds(input: string | undefined | null): number | null;
/**
 * v1.3.4 §B — the next N fire times for a recurring expression. Steps minute by
 * minute (tz/DST-aware) and collects matches. Empty array if invalid. For the
 * save-time preview; minute resolution (seconds field, if any, is ignored).
 */
export declare function nextRuns(expr: string, n?: number, timezone?: string, now?: number): Date[];
/** Best-effort human description of a 5-field cron expression. Falls back to
 *  the raw expression when the pattern isn't one of the common shapes. */
export declare function describeSchedule(expr: string): string;
/**
 * Estimate a cron's cadence in minutes for the common shapes `normalizeSchedule`
 * produces (interval / daily / weekly / monthly). Returns null when the shape
 * isn't recognised — callers treat null as "can't judge overdue".
 */
export declare function estimatePeriodMinutes(expr: string): number | null;
/**
 * Dead-man's-switch: is a cron overdue? True when its last successful run is
 * older than `graceFactor` × its estimated period. Returns false when the
 * period can't be estimated or there's no prior run (nothing to compare).
 */
export declare function isOverdue(lastSuccessIso: string | null, expr: string, now?: number, graceFactor?: number): boolean;
/** The next fire time for an expression (authoritative — uses node-cron's own
 *  scheduler). Returns null if the expression is invalid. */
export declare function nextRun(expr: string, timezone?: string): Date | null;