import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import { DynamoDBDocumentClient } from '@aws-sdk/lib-dynamodb';
export { DataStoreNotFoundError, DataStoreServiceError, DataStoreUnavailableError } from './errors.js';
/**
 * Create the DynamoDB client used by the data store, configured for resilient reads under
 * throttling: adaptive retries, bounded attempts, and hard per-attempt timeouts.
 *
 * @returns A configured DynamoDB client
 */
export declare function createDalDynamoDBClient(): DynamoDBClient;
/**
 * A class for reading entries from the data store.
 *
 * This class uses a singleton pattern.
 * Use DataStore.getDataStore() to get the singleton instance.
 */
export declare class DataStore {
    private _tableName;
    private _ddb;
    private static _instance;
    /** @internal Test hook: inject a document client for unit tests */
    static _testDocumentClient: DynamoDBDocumentClient | null;
    /** @internal Test hook: inject logMRTError for unit tests */
    static _testLogMRTError: ((namespace: string, err: unknown, context?: Record<string, unknown>) => void) | null;
    /** @internal Test hook: inject a deterministic random source (returns [0, 1)) for unit tests */
    static _testRandom: (() => number) | null;
    private constructor();
    /**
     * Get or create a DynamoDB document client (for abstraction of attribute values).
     *
     * @private
     * @returns The DynamoDB document client
     * @throws {DataStoreUnavailableError} The data store is unavailable
     */
    private getClient;
    /**
     * Resolve the DynamoDB partition key for a read, applying shard selection.
     *
     * Reads the shard count from `MRT_NUM_SHARDS` (default 1) and picks a random
     * shard `i` in `[0, N)`. Shard 0 is the legacy unsuffixed partition key, so
     * when `MRT_NUM_SHARDS` is unset or 1 this is identical to today's behavior.
     * There is no runtime fallback: writers fan out to every shard, so every shard
     * a reader can pick is guaranteed to exist.
     *
     * @private
     * @returns The `projectEnvironment` partition key value to read
     */
    private resolveShardPartitionKey;
    /**
     * Get or create the singleton DataStore instance.
     *
     * @returns The singleton DataStore instance
     */
    static getDataStore(): DataStore;
    /**
     * Whether the data store can be used in the current environment.
     *
     * @returns true if the data store is available, false otherwise
     */
    isDataStoreAvailable(): boolean;
    /**
     * Fetch an entry from the data store.
     *
     * @param key The data store entry's key
     * @returns An object containing the entry's key and value
     * @throws {DataStoreUnavailableError} The data store is unavailable
     * @throws {DataStoreNotFoundError} An entry with the given key cannot be found
     * @throws {DataStoreServiceError} An internal error occurred
     */
    getEntry(key: string): Promise<Record<string, unknown> | undefined>;
}