/**
 * Retention cap enforcement for the local analytics sink (events.ndjson).
 *
 * Policy (enforced on server boot and periodically afterwards):
 *   - Size cap: 50 MB — truncate to the newest events that fit.
 *   - Age cap: 30 days — drop events older than this by their `ts` field.
 *   The stricter of the two wins; oldest-first truncation always preserves
 *   the newest events.
 *
 * Atomicity: rewrites happen via a temp-file rename so a crash mid-write
 * never leaves a corrupt or empty events file. The write path must be in
 * the same directory (same filesystem partition) as the target so rename()
 * is atomic.
 *
 * Concurrency: callers MUST run sweepNdjson() through EventStore.runExclusive()
 * so the sweep's read→filter→rename window never races a concurrent append.
 * The store serializes all appends through a promise queue; runExclusive()
 * chains the sweep onto that same queue, guaranteeing mutual exclusion.
 * See store.ts and server/index.ts for the wiring.
 *
 * Corruption tolerance: lines that fail JSON.parse are silently kept rather
 * than aborting the sweep — a single bad line never blocks retention.
 */
/** 50 MB default size cap. */
export declare const DEFAULT_MAX_SIZE_BYTES: number;
/** 30 days default age cap. */
export declare const DEFAULT_MAX_AGE_MS: number;
export interface SweepOptions {
    maxSizeBytes?: number;
    maxAgeMs?: number;
}
export interface SweepResult {
    /** Number of lines in the file before the sweep. */
    linesBefore: number;
    /** Number of lines retained after the sweep. */
    linesAfter: number;
    /** True when the file was actually rewritten (something was trimmed). */
    rewritten: boolean;
}
/**
 * Enforces size and age caps on an ndjson file, retaining the newest events.
 *
 * Returns a SweepResult describing what happened. Never throws on ENOENT
 * (the file doesn't exist yet — that's fine). Propagates other I/O errors
 * to the caller.
 *
 * IMPORTANT: callers must run this through EventStore.runExclusive() to
 * prevent races with concurrent appends (see module-level docstring).
 */
export declare function sweepNdjson(filePath: string, options?: SweepOptions): Promise<SweepResult>;
//# sourceMappingURL=store-retention.d.ts.map