/**
 * Per-pattern `first_seen` discovery.
 *
 * For each of the top-N hashes, scan the engine's metric backwards in
 * time to find the earliest non-zero data point. That's the moment the
 * engine started observing the pattern — a load-bearing signal for the
 * Reader's "is this new or stable?" question.
 *
 * Implementation: a single batched PromQL range query per hash, covering
 * 30 days, at 1-hour step. Returns the earliest timestamp where the
 * metric was non-zero. Costs one round-trip per hash; in parallel.
 *
 * Formatting follows the locked rule:
 *   < 60 min     → "47m ago"
 *   60 min – 48h → "21h ago"
 *   ≥ 48h        → "7d ago"
 */
import type { EnvConfig } from './environments.js';
export interface FirstSeenResult {
    /** Seconds since the earliest non-zero timestamp. `null` if no data found. */
    ageSeconds: number | null;
    /** Unix-seconds timestamp of the first event, if found. */
    firstSeenUnix: number | null;
}
/**
 * Format an age (in seconds) per the locked time-bucket rule.
 * Returns "(unknown)" if `ageSeconds` is null.
 */
export declare function fmtAge(ageSeconds: number | null): string;
/**
 * Find `first_seen` for one hash. Returns `{ageSeconds: null}` on
 * any failure (network, malformed response, no series) — never throws,
 * so callers can safely await N of these in parallel without one
 * failure poisoning the whole batch.
 */
export declare function fetchFirstSeen(env: EnvConfig, hash: string, metric?: string, lookbackSeconds?: number): Promise<FirstSeenResult>;
/**
 * Batched parallel lookup — one Prom query per hash. The returned map
 * is keyed by hash. Missing entries (failures, no data) are simply
 * absent from the map; callers should treat absence as "(unknown)".
 */
export declare function fetchFirstSeenBatch(env: EnvConfig, hashes: string[], metric?: string, lookbackSeconds?: number): Promise<Map<string, FirstSeenResult>>;