type TClientId = `${string}.apps.googleusercontent.com`;
type TResponseType = "id_token" | "code";
type TLaunchWebAuthFlowParams = {
    clientId: TClientId;
    responseType: TResponseType | readonly TResponseType[];
    state?: string;
    nonce?: string;
    interactive?: boolean;
};
type TMapping = {
    id_token: {
        id_token: string;
    };
    code: {
        code: string;
    };
};
type TResult<T extends TResponseType | readonly TResponseType[]> = T extends TResponseType ? TMapping[T] : T extends readonly (infer Element)[] ? {
    [K in Element & keyof TMapping]: string;
} : never;
/**
 * 根据 responseType 推断返回类型
 * 例如: TResult<"code"> => { code: string }
 * TResult<["id_token", "code"]> => { id_token: string; code: string }
 * TResult<["code", "id_token"]> => { id_token: string; code: string }
 */
/**
 * 支持 Google OAuth2 登录的 client_id 类型（参数 clientId）
 * 需要 identity 权限
 * @param clientId - Google OAuth2 Web 应用 类型的 client_id，例如: "xxxxxx.apps.googleusercontent.com"
 * @param responseType - 响应类型，默认: "code"
 * @returns Promise<string> - 返回 id_token 或 code
 */
export declare function launchWebAuthFlow<P extends TLaunchWebAuthFlowParams>({ clientId, responseType, state, nonce, interactive, }: P): Promise<TResult<P["responseType"]> & (P extends {
    state: string;
} ? {
    state: string;
} : {})>;
/**
 * 解码 JWT
 * @param idToken - JWT
 * @returns 返回 JWT 的 payload
 */
export declare function decodeJWT(idToken: string): Record<string, any>;
export {};