/**
 * Copyright (c) Microsoft Corporation. All rights reserved.
 * Licensed under the MIT License.
 */
import { TurnContext, TurnState } from '@microsoft/agents-hosting';
import { TeamsApplication } from '../teamsApplication';
import { TaskModuleTaskInfo } from '../../task/taskModuleTaskInfo';
/**
 * Handles message-related operations for Teams applications.
 * Provides methods for handling message fetch operations.
 * @template TState Type extending TurnState to be used by the application
 */
export declare class Messages<TState extends TurnState> {
    private readonly _app;
    /**
     * Creates a new Messages instance.
     * @param app The TeamsApplication instance to associate with this Messages instance
     */
    constructor(app: TeamsApplication<TState>);
    /**
     * Handles fetch requests for messages in Teams, which typically occur when
     * a message action is invoked.
     *
     * @template TData Type of data expected in the message fetch request
     * @param handler Function to handle the message fetch request
     * @returns The TeamsApplication instance for chaining
     */
    fetch<TData extends Record<string, any> = Record<string, any>>(handler: (context: TurnContext, state: TState, data: TData) => Promise<TaskModuleTaskInfo | string>): TeamsApplication<TState>;
}