import { ConfigService } from '@nestjs/config';
import { EntityMap } from '../../../../classes';
import { Account, User } from '../../../../models';
import { AuthenticationModuleOptions } from '../../../authentication';
import { BaseHttpService } from '../../base-http.service';
import { FetchAccountOptionsDtoV1 } from './fetch-account-options.dto.v1.type';
/**
 * AccountsService
 *
 * Service client responsible for interacting with the Accounts microservice.
 * Extends `BaseHttpService` to inherit:
 * - Environment-sensitive URL resolution (internal vs. external).
 * - Secure inter-service authentication.
 * - Structured logging for traceability of outbound requests.
 *
 * Why this pattern?
 * - Ensures all outbound calls follow a unified configuration and logging structure.
 * - Promotes strong typing and maintainable HTTP logic.
 * - Makes service interactions predictable and debuggable across environments.
 */
export declare class AccountsService extends BaseHttpService {
    /**
     * Constructs an Accounts service client instance.
     *
     * @param {AuthenticationModuleOptions} authenticationOptions - Injected authentication configuration.
     * @param {ConfigService} configService - NestJS ConfigService for environment detection.
     */
    constructor(authenticationOptions: AuthenticationModuleOptions, configService: ConfigService);
    /**
     * Retrieves a single account entry by its MongoDB identifier.
     *
     * This method gracefully handles downstream failures by logging
     * and returning `undefined` instead of throwing.
     *
     * @param {string} accountId - Unique MongoDB identifier of the account.
     * @param {FetchAccountOptionsDtoV1} [options] - Optional query parameters for filtering or projection.
     * @returns {Promise<Account | undefined>} Resolves to an Account or `undefined` on failure.
     */
    fetchAccountV1(accountId: string, options?: FetchAccountOptionsDtoV1): Promise<Account | undefined>;
    /**
     * Retrieves a collection of account entries.
     *
     * Useful for batch lookups or paginated listings.
     * Returns an empty array if the downstream service call fails.
     *
     * @param {FetchAccountOptionsDtoV1} [options] - Optional filter options for narrowing results.
     * @returns {Promise<Account[]>} Resolves to a list of accounts, or an empty array if none found.
     */
    fetchAccountCollectionV1(options?: FetchAccountOptionsDtoV1): Promise<Account[]>;
    /**
     * Fetches accounts for multiple groups of account IDs and returns a mapped result.
     *
     * This is particularly useful when aggregating accounts related to different entities
     * (e.g., post authors, commenters, likedBy lists).
     *
     * The function ensures:
     * - Each unique account is fetched only once.
     * - The result is returned as an `EntityMap` for O(1) lookups.
     *
     * @param {string[][]} accountIdGroups - Nested arrays of account IDs.
     * @returns {Promise<EntityMap<Account>>} Map of accountId → Account entity.
     */
    fetchAccountMapV1(accountIdGroups: string[][]): Promise<EntityMap<Account>>;
    /**
     * Retrieves a single user entry by its MongoDB identifier.
     *
     * This method gracefully handles downstream failures by logging
     * and returning `undefined` instead of throwing.
     *
     * @param {string} userId - Unique MongoDB identifier of the user.
     * @param {FetchAccountOptionsDtoV1} [options] - Optional query parameters for filtering or projection.
     * @returns {Promise<User | undefined>} Resolves to an User or `undefined` on failure.
     */
    fetchUserV1(userId: string, options?: FetchAccountOptionsDtoV1): Promise<User | undefined>;
    /**
     * Retrieves a collection of user entries.
     *
     * Useful for batch lookups or paginated listings.
     * Returns an empty array if the downstream service call fails.
     *
     * @param {FetchAccountOptionsDtoV1} [options] - Optional filter options for narrowing results.
     * @returns {Promise<User[]>} Resolves to a list of users, or an empty array if none found.
     */
    fetchUserCollectionV1(options?: FetchAccountOptionsDtoV1): Promise<User[]>;
    /**
     * Fetches users for multiple groups of user IDs and returns a mapped result.
     *
     * This is particularly useful when aggregating users related to different entities
     * (e.g., post authors, commenters, likedBy lists).
     *
     * The function ensures:
     * - Each unique user is fetched only once.
     * - The result is returned as an `EntityMap` for O(1) lookups.
     *
     * @param {string[][]} userIdGroups - Nested arrays of user IDs.
     * @returns {Promise<EntityMap<User>>} Map of userId → User entity.
     */
    fetchUserMapV1(userIdGroups: string[][]): Promise<EntityMap<User>>;
}