/**
 * Dependency-free contract for Node.js WebSocket server implementations.
 *
 * Core owns HTTP upgrade authorization and lifecycle. An extension owns the
 * protocol implementation used to complete an authorized upgrade on an
 * existing Node socket.
 */
export declare const NodeWebSocketServerProviderName = "NodeWebSocketServerProvider";
export declare const NODE_WEBSOCKET_SERVER_PROVIDER_PACKAGE = "@veryfront/ext-node-websocket-ws";
export declare const NODE_WEBSOCKET_SERVER_PROVIDER_MISSING_MESSAGE = "Node.js WebSocket upgrades require @veryfront/ext-node-websocket-ws; install it or remove the extension disable directive.";
export type NodeWebSocketMessageData = ArrayBuffer | ArrayBufferView | readonly ArrayBufferView[];
/** Minimal connection surface consumed by core's runtime-neutral adapter. */
export interface NodeWebSocketConnection extends EventTarget {
    on(event: "open", listener: () => void): this;
    on(event: "message", listener: (data: NodeWebSocketMessageData, isBinary: boolean) => void): this;
    on(event: "close", listener: (code?: number, reason?: ArrayBufferView | string) => void): this;
    on(event: "error", listener: (error: Error) => void): this;
    send(data: string | ArrayBuffer): void;
    close(code?: number, reason?: string): void;
    terminate?(): void;
}
/** Exact no-server options supplied by core for an existing HTTP listener. */
export interface NodeWebSocketServerOptions {
    readonly noServer: true;
    readonly handleProtocols: (protocols: ReadonlySet<string>, request: object) => string | false;
}
/** Minimal server surface used by upgrade and shutdown ownership. */
export interface NodeWebSocketServer {
    readonly clients?: Iterable<NodeWebSocketConnection>;
    on(event: "headers", listener: (headers: string[], request: unknown) => void): this;
    close(callback?: (error?: Error) => void): void;
    handleUpgrade(request: unknown, socket: unknown, head: unknown, callback: (socket: NodeWebSocketConnection) => void): void;
    emit(event: string, socket: NodeWebSocketConnection, request: unknown): void;
}
export interface NodeWebSocketServerProvider {
    readonly createServer: (options: NodeWebSocketServerOptions) => NodeWebSocketServer;
}
/**
 * Capture one server instance without retaining mutable method lookups. The
 * underlying implementation remains the receiver because protocol engines
 * legitimately keep mutable transport state on their instance.
 */
export declare function captureNodeWebSocketServer(value: unknown): Readonly<NodeWebSocketServer>;
/**
 * Capture a provider generation without retaining its mutable registration
 * object or invoking extension-owned accessors.
 */
export declare function snapshotNodeWebSocketServerProvider(value: unknown): Readonly<NodeWebSocketServerProvider>;
/** Create immutable registration metadata from a standalone factory. */
export declare function createNodeWebSocketServerProvider(createServer: (options: NodeWebSocketServerOptions) => NodeWebSocketServer): Readonly<NodeWebSocketServerProvider>;
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