import { ICacheClient } from "@gomomento/sdk-core";
import { BaseListChatMessageHistory } from "@langchain/core/chat_history";
import { BaseMessage } from "@langchain/core/messages";
/**
 * The settings to instantiate the Momento chat message history.
 */
export interface MomentoChatMessageHistoryProps {
    /**
     * The session ID to use to store the data.
     */
    sessionId: string;
    /**
     * The Momento cache client.
     */
    client: ICacheClient;
    /**
     * The name of the cache to use to store the data.
     */
    cacheName: string;
    /**
     * The time to live for the cache items in seconds.
     * If not specified, the cache client default is used.
     */
    sessionTtl?: number;
    /**
     * If true, ensure that the cache exists before returning.
     * If false, the cache is not checked for existence.
     * Defaults to true.
     */
    ensureCacheExists?: true;
}
/**
 * A class that stores chat message history using Momento Cache. It
 * interacts with a Momento cache client to perform operations like
 * fetching, adding, and deleting messages.
 * @example
 * ```typescript
 * const chatHistory = await MomentoChatMessageHistory.fromProps({
 *   client: new CacheClient({
 *     configuration: Configurations.Laptop.v1(),
 *     credentialProvider: CredentialProvider.fromEnvironmentVariable({
 *       environmentVariableName: "MOMENTO_API_KEY",
 *     }),
 *     defaultTtlSeconds: 60 * 60 * 24,
 *   }),
 *   cacheName: "langchain",
 *   sessionId: new Date().toISOString(),
 *   sessionTtl: 300,
 * });
 *
 * const messages = await chatHistory.getMessages();
 * console.log({ messages });
 * ```
 */
export declare class MomentoChatMessageHistory extends BaseListChatMessageHistory {
    lc_namespace: string[];
    private readonly sessionId;
    private readonly client;
    private readonly cacheName;
    private readonly sessionTtl;
    private constructor();
    /**
     * Create a new chat message history backed by Momento.
     *
     * @param {MomentoCacheProps} props The settings to instantiate the Momento chat message history.
     * @param {string} props.sessionId The session ID to use to store the data.
     * @param {ICacheClient} props.client The Momento cache client.
     * @param {string} props.cacheName The name of the cache to use to store the data.
     * @param {number} props.sessionTtl The time to live for the cache items in seconds.
     * If not specified, the cache client default is used.
     * @param {boolean} props.ensureCacheExists If true, ensure that the cache exists before returning.
     * If false, the cache is not checked for existence.
     * @throws {InvalidArgumentError} If {@link props.sessionTtl} is not strictly positive.
     * @returns A new chat message history backed by Momento.
     */
    static fromProps(props: MomentoChatMessageHistoryProps): Promise<MomentoChatMessageHistory>;
    /**
     * Validate the user-specified TTL, if provided, is strictly positive.
     * @param ttlSeconds The TTL to validate.
     */
    private validateTtlSeconds;
    /**
     * Fetches messages from the cache.
     * @returns A Promise that resolves to an array of BaseMessage instances.
     */
    getMessages(): Promise<BaseMessage[]>;
    /**
     * Adds a message to the cache.
     * @param message The BaseMessage instance to add to the cache.
     * @returns A Promise that resolves when the message has been added.
     */
    addMessage(message: BaseMessage): Promise<void>;
    /**
     * Deletes all messages from the cache.
     * @returns A Promise that resolves when all messages have been deleted.
     */
    clear(): Promise<void>;
}