import { Filter, FindOptions, ObjectId } from "mongodb";
import type { SavedLabel, UnsignedLabel } from "./util/types.js";
/**
 * Client for interacting with the MongoDB database where labels are stored.
 *
 * This class handles connecting to the database, creating necessary indexes,
 * and performing basic CRUD operations on labels.
 *
 * @param uri The URI to connect to the MongoDB instance.
 * @param databaseName The name of the database to use. Defaults to 'labeler'.
 * @param collectionName The name of the collection to use. Defaults to 'labels'.
 */
export declare class MongoDBClient {
    private _db?;
    private _client?;
    private _labels?;
    private readonly _url;
    /**
     * Create a new MongoDBClient instance.
     * @param uri The URI to connect to the MongoDB instance.
     */
    constructor(uri: string);
    /**
     * Connect to the MongoDB instance and initialize the collection.
     * If the collection doesn't exist, it will be created with the necessary indexes.
     *
     * This method should be called before any other method in this class.
     */
    connect(): Promise<void>;
    /**
     * Close the connection to MongoDB.
     */
    close(): Promise<void>;
    /**
     * Save a label to the MongoDB collection.
     *
     * @param label - The label to save, including a signature as an ArrayBuffer.
     * @returns A promise that resolves to the saved label.
     */
    saveLabel(label: UnsignedLabel & {
        sig: ArrayBuffer;
    }): Promise<SavedLabel>;
    /**
     * Find labels in the MongoDB collection matching the given query.
     *
     * @param query - The query object to filter labels.
     * @param options - Optional settings for the query, such as sort and limit.
     * @returns A promise that resolves to an array of labels matching the query.
     */
    findLabels(query?: Filter<SavedLabel> & {
        allowExpired?: boolean;
    }, options?: FindOptions<SavedLabel>): Promise<SavedLabel[]>;
    /**
     * Find a single label in the MongoDB collection matching the given query.
     *
     * @param query - The query object to filter labels.
     * @returns A promise that resolves to the matching label or null if not found.
     */
    findOne(query: Filter<SavedLabel>): Promise<SavedLabel | null>;
    /**
     * Retrieve a limited number of labels from the database that have an ID greater than the specified cursor.
     *
     * @param cursor - The ID after which labels should be retrieved.
     * @param limit - The maximum number of labels to return.
     * @returns A promise that resolves to an array of labels with IDs greater than the cursor.
     */
    getLabelsAfterCursor(cursor: ObjectId, limit: number): Promise<SavedLabel[]>;
    /**
     * Update an existing label in the MongoDB collection.
     *
     * @param id - The ID of the label to update.
     * @param label - The new label data.
     * @returns A promise that resolves to true if the update was successful, false if the label wasn't found.
     */
    updateLabel(id: ObjectId, label: UnsignedLabel & {
        sig: ArrayBuffer;
    }): Promise<boolean>;
}