/**
 * Did the things that are supposed to run, run?
 *
 * `watch --once` is designed for a scheduler: it pulls, stores, evaluates and
 * saves state, so a cron entry is the whole daemon. Its state file records the
 * last cycle precisely so a restart is honest about the stretch it did not
 * watch — and that file is read by exactly one thing, which is the next cycle.
 *
 * **So nothing can tell you the watcher stopped, because the thing that would
 * tell you is the thing that stopped.** A dead cron produces silence, and
 * silence is what a watcher with nothing to report produces too. That is
 * `not-recorded is not not-happened` one layer up from where this repository
 * usually meets it: not a missing record, a missing *run*.
 *
 * This module is the arithmetic for saying so. The caller reads the state file
 * and the store; this turns instants into ages and ages into a verdict, which
 * is what makes the rule testable without waiting a week for a cron to die.
 *
 * **Three refusals shape it:**
 *
 * - **Something that never ran cannot be stale.** A repository where nobody
 *   has ever started a watcher is not a repository whose watcher is late; it
 *   has no cadence to be late against. `never-run` is its own verdict and it
 *   never gates, because a gate that fires on "you have not adopted this
 *   feature" is a tool nagging rather than measuring.
 * - **No limit, no verdict.** Without a stated threshold the ages are reported
 *   and nothing is judged. How stale is too stale is a policy, and this
 *   product does not write somebody's policy for them.
 * - **How far the measurements reach is not a run.** A store whose newest
 *   record covers up to yesterday is a provider reporting on its own schedule,
 *   not a job that failed. It is reported beside the runs and deliberately
 *   never judged by the same threshold: merging "nothing ran" with "the
 *   provider is a day behind" would produce a red build for somebody else's
 *   latency.
 */
export type HeartbeatKind = 
/** The last `watch` cycle, from its state file. */
'watch-cycle'
/** The last time a connector wrote a record into the store. */
 | 'store-pull'
/** How far the stored measurements reach — a fact, never a run. */
 | 'store-coverage';
export type HeartbeatVerdict = 
/** It has never happened here. Not late; there is no cadence to be late against. */
'never-run'
/** It happened, and no threshold was stated, so nothing is judged. */
 | 'not-judged'
/** Within the stated threshold. */
 | 'within'
/** Past the stated threshold. */
 | 'stale';
export interface Heartbeat {
    kind: HeartbeatKind;
    /** When it last happened, or null when it never has. */
    lastMs: number | null;
    /**
     * Whole hours since, or null when it never happened.
     *
     * Hours rather than days because the schedules this is about are hourly as
     * often as daily, and a cron that died twenty hours ago is zero days old.
     * Floored, so an age this reports as six hours is at least six hours.
     */
    ageHours: number | null;
    verdict: HeartbeatVerdict;
}
export interface HeartbeatReport {
    schemaVersion: 1;
    nowMs: number;
    /** The threshold the caller stated, or null when none was. */
    maxStaleHours: number | null;
    beats: Heartbeat[];
    /**
     * True when something that has run before is past the threshold.
     *
     * Never true for a `never-run` beat, and never true for `store-coverage`,
     * which is not a run.
     */
    stale: boolean;
}
/** What the caller found on disk. Nulls are absences, never zero. */
export interface HeartbeatInput {
    /** `lastCycleMs` from the watch state file, or null when there is none. */
    watchCycleMs: number | null;
    /** The newest `pulledAtMs` in the store, or null when the store is empty. */
    storePulledMs: number | null;
    /** The furthest `toMs` in the store, or null when the store is empty. */
    storeCoveredToMs: number | null;
}
export declare function heartbeats(input: HeartbeatInput, options: {
    nowMs: number;
    maxStaleHours?: number;
}): HeartbeatReport;
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