/**
 * Query helpers that read the workflow visibility indexes laid down by
 * {@link buildWorkflowVisibilityIndexTransition} / backfill. Each helper
 * produces a `Set<string>` of candidate workflow ids; the caller
 * intersects sets across dimensions to narrow the slow-path scan.
 *
 * Every helper assumes the visibility-index watermark is `current` — the
 * caller checks {@link getWorkflowVisibilityWatermark} once per query and
 * uses the current full-scan correctness path when it is `stale`.
 *
 * @module core/engine/workflow-visibility-queries
 */
import { type Storage } from '../../storage/interface.ts';
import type { FailureCategory, WorkflowStatus } from '../types/identity.ts';
import type { TimeRange } from '../types/list-options.ts';
/**
 * Match every workflow whose `status` appears in `statuses`. Empty input
 * returns an empty set (intersection short-circuits to "no matches").
 */
export declare function queryWorkflowStatusIndex(storage: Storage, statuses: readonly WorkflowStatus[]): Promise<Set<string>>;
/** Match every workflow with the given `type`. */
export declare function queryWorkflowTypeIndex(storage: Storage, type: string): Promise<Set<string>>;
/**
 * Time-range scan over `wf-idx-{kind}:` (created, updated, or deadline).
 * Returns the candidate ids the engine post-filter will refine.
 */
export declare function queryWorkflowTimeRangeIndex(storage: Storage, kind: 'created' | 'updated' | 'deadline', range: TimeRange): Promise<Set<string>>;
/**
 * Enumerate candidate workflow ids whose raw id starts with `idPrefix`.
 * Uses the primary-key `wf:{enc(prefix)}` scan, which is sound because the
 * encoder is identity + concatenation-preserving on the validated safe
 * subset (see `src/storage/interface.test.ts`). The caller still re-checks
 * `state.id.startsWith(idPrefix)` as a defensive post-filter.
 */
export declare function queryWorkflowIdPrefixCandidates(storage: Storage, idPrefix: string): Promise<Set<string>>;
/**
 * Re-export for callers that only need the failure-category value type.
 * Keeps imports tidy at the call sites.
 */
export type { FailureCategory };