import { Client as HttpClient, ILogger } from '@microsoft/teams.common';
import { NegotiateResult } from './types';
/**
 * Dependencies for {@link negotiate}. Kept explicit so the call is unit-testable
 * without a live Teams backend service endpoint.
 */
export type NegotiateDeps = {
    /** Fully-resolved negotiate URL (`{base}/v3/websockets/connect`). */
    readonly negotiateUrl: string;
    /** The app's shared HTTP client. */
    readonly client: HttpClient;
    /** Acquire the Bot Framework access token, reusing the app's credentials. */
    readonly getBotToken: () => Promise<string>;
    /**
     * Read the open, unexpired predecessor's exact ID after token acquisition.
     * Omit or return `undefined`/`""` to omit the planned-refresh replacement header.
     */
    readonly getConnectionIdToReplace?: () => string | undefined;
    /**
     * Abort the negotiate request after this many milliseconds so a hung endpoint
     * can't leave the caller pending forever. Defaults to
     * {@link DEFAULT_NEGOTIATE_TIMEOUT_MS}.
     */
    readonly timeoutMs?: number;
    readonly log?: ILogger;
};
/** Default negotiate request timeout — bounds a hung or misconfigured endpoint. */
export declare const DEFAULT_NEGOTIATE_TIMEOUT_MS = 15000;
/**
 * Reject a negotiate URL that isn't HTTPS. The negotiate request carries a Bot
 * Framework JWT in the `authorization` header; sending it over plaintext `http`
 * would leak that token. A narrow exception is made for loopback hosts
 * (`localhost`/`127.0.0.1`/`::1`) so local test endpoints still work.
 */
export declare function assertSecureNegotiateUrl(negotiateUrl: string): void;
/**
 * Error thrown by {@link negotiate} when the service returns a non-2xx status.
 * Carries the HTTP status and the parsed `Retry-After` (in milliseconds) when
 * the service asked the caller to back off — typically on `429` or `503` — so
 * the reconnect supervisor can honor it instead of using its own back-off.
 * Authentication and authorization failures (`401`/`403`) are not retried;
 * see {@link NegotiateError.isAuthError}.
 */
export declare class NegotiateError extends Error {
    /** Service-requested delay before retrying, when supplied. */
    readonly retryAfterMs?: number | undefined;
    /**
     * HTTP status returned by the Socket Mode negotiate endpoint. `undefined`
     * when the error was constructed without a status.
     */
    readonly statusCode?: number | undefined;
    constructor(message: string, 
    /** Service-requested delay before retrying, when supplied. */
    retryAfterMs?: number | undefined, 
    /**
     * HTTP status returned by the Socket Mode negotiate endpoint. `undefined`
     * when the error was constructed without a status.
     */
    statusCode?: number | undefined);
    /**
     * `true` when negotiate was rejected with HTTP `401` or `403`. Retrying
     * cannot fix these until the bot's credentials or Socket Mode access are
     * corrected, so the SDK stops retrying on startup and reconnect.
     */
    get isAuthError(): boolean;
}
/**
 * Perform the Teams backend service Socket Mode handshake: `POST {negotiateUrl}` authenticated
 * with a Bot Framework JWT minted from the bot's own credentials. Teams backend service returns
 * the Azure SignalR `url` + `accessToken` to open the socket against.
 *
 * @throws {NegotiateError} if Teams backend service returns a non-2xx response.
 * @throws if the bot token is missing (the app has no credentials configured).
 */
export declare function negotiate(deps: NegotiateDeps): Promise<NegotiateResult>;