import { HttpService } from "@nestjs/common";
import { FacebookUserInfo, IThirdPartyAuthPluginOptions } from "./interfaces";
export declare class FacebookAuthService {
    private httpService;
    private options;
    private endpoint;
    private version;
    private optionDetail;
    constructor(httpService: HttpService, options: Required<IThirdPartyAuthPluginOptions>);
    /**
     * The flow to verify a token will be:
     *
     *  1. Generate app_token using client_id, and client_secret
     *  2. Inspect the token below using app_token
     *  3. Call /me endpoint on behalf of user to get user's email
     *
     * @param token the token is retrieved from Facebook dialog in front-end
     */
    verify(token: string): Promise<FacebookUserInfo>;
    private getUserInfo;
    private inspectToken;
    private generateAppToken;
    private constructUrl;
}