import type { IncomingMessage } from 'http';
import type { Duplex } from 'stream';
import type { FastifyInstance } from 'fastify';
import type { WebSocketServer } from 'ws';
/**
 * Minimal structural type for an HTTP(S)/HTTP2 server that emits `upgrade`.
 * Avoids coupling to a concrete `http.Server` so it also accepts Vite's
 * `httpServer` (which may be an `Http2SecureServer`).
 */
type UpgradeableServer = {
    on(event: 'upgrade', listener: (request: IncomingMessage, socket: Duplex, head: Buffer) => void): unknown;
};
/**
 * Registers an HTTP `upgrade` handler for the Fastify (default) dev server that:
 *  - routes the reserved live-reload path to the internal dev websocket server, and
 *  - proxies every other websocket upgrade to the Dynatrace platform.
 *
 * Without this, the internal live-reload websocket server would answer *every*
 * upgrade, so the app's own websocket connections (e.g. to a backend service)
 * would be intercepted by the CLI instead of reaching the platform.
 *
 * @param server The Fastify instance whose underlying HTTP server emits `upgrade`
 * @param liveReloadWss The internal live-reload / error-reporting websocket server
 */
export declare function registerWebSocketUpgradeHandler({ server }: FastifyInstance, liveReloadWss: WebSocketServer): void;
/**
 * Registers an HTTP `upgrade` handler for the Vite (`--hmr`) dev server that
 * proxies app websocket connections to the Dynatrace platform.
 *
 * Vite attaches its own upgrade handler for live reload; it only claims upgrades
 * carrying a `vite-`-prefixed subprotocol and ignores the rest. This handler
 * mirrors that contract: it skips Vite's own connections (so HMR keeps working)
 * and proxies everything else - which Vite would otherwise leave unhandled - to
 * the platform.
 *
 * @param httpServer The underlying HTTP server of the Vite dev server
 */
export declare function registerViteWebSocketProxy(httpServer: UpgradeableServer | null): void;
/** Closes all proxied connections. Used during dev server shutdown. */
export declare function closeWebSocketProxy(): void;
export {};