import type { Firestore } from "@google-cloud/firestore";
import type { LockBackend } from "../common/backend.js";
import type { FirestoreBackendOptions, FirestoreCapabilities } from "./types.js";
/**
 * Creates Firestore-based distributed lock backend using transactions.
 *
 * IMPORTANT: Requires composite index on lockId field for release()/extend() performance.
 * See firebase.json for index configuration.
 *
 * @param db - Firestore instance from @google-cloud/firestore
 * @param options - Backend configuration (collection, ttl, tolerance)
 * @returns LockBackend with client-side time authority
 * @see docs/specs/firestore-backend.md
 */
export declare function createFirestoreBackend(db: Firestore, options?: FirestoreBackendOptions): LockBackend<FirestoreCapabilities>;