import type { IncomingMessage } from 'node:http';
import type { Duplex } from 'node:stream';
/** Handle the HTTP upgrade for `GET /v1/nodes/{id}/attach`. A-9 matches the
 *  route, extracts `{id}`, and calls this with the raw upgrade triplet; this
 *  owns the WS handshake (its own noServer `wss` above) AND the spec §5.3
 *  attach-implies-revive semantics. Never throws — every failure path either
 *  refuses the upgrade (plain HTTP error + socket destroy) or, post-handshake,
 *  closes the WS with a code. So A-9's upgrade router needs no try/catch around
 *  this call beyond its own top-level safety net.
 *
 *  Flow:
 *   1. Guard `isSafeNodeId` (→ 400) and existence (→ 404) BEFORE building any
 *      fs path or reviving — an unsafe id must never reach `viewSocketPath`.
 *   2. Unless revive is opted out (`?revive=0` / `X-Crtr-Attach-Revive: 0`):
 *      `reviveNode(id, { resume:true })` then
 *      `waitForBrokerViewSocket` (bounded). Revive throw OR socket-not-listenable
 *      → refuse 409, WS never opens.
 *   3. Revive opted out: a single connect probe. Dormant (socket refuses) →
 *      refuse 409 (spec §5.3 asymmetry: a dead broker can't stream over WS).
 *   4. Only then upgrade and hand the live WS to {@link bridgeConnection}. */
export declare function handleAttachUpgrade(req: IncomingMessage, socket: Duplex, head: Buffer, nodeId: string): Promise<void>;