import { DecafRequestContext } from "../request/index.d.cts";
import { DecafController } from "../controllers.d.cts";
import { DecafServerCtx } from "../constants.d.cts";
import type { ObserverEventsOptions } from "../types.d.cts";
import { ObserverSubscriptionRegistry } from "./ObserverSubscriptionRegistry.d.cts";
/**
 * @description REST payload for subscribing an SSE client to topics
 * @summary The request body accepted by the subscribe endpoint: an optional list
 * of webhook-style topic patterns.
 * @typedef {Object} SubscriptionPayload
 * @property {string[]} [topics] - The topics to subscribe the requester to
 * @memberOf module:for-nest.events
 */
type SubscriptionPayload = {
    topics?: string[];
};
/**
 * @description REST controller managing SSE topic subscriptions
 * @summary Exposes `POST subscribe` and `POST unsubscribe` endpoints that upsert or
 * remove the requester's topic subscriptions in the {@link ObserverSubscriptionRegistry}.
 * Both endpoints no-op with `{ enabled: false }` when subscription mode is disabled.
 * @class EventsSubscriptionController
 * @param {DecafRequestContext} clientContext - The active request context
 * @param {ObserverEventsOptions} options - Observer events configuration (injected via {@link OBSERVER_EVENTS_OPTIONS})
 * @param {ObserverSubscriptionRegistry} registry - The topic-subscription registry
 * @memberOf module:for-nest.events
 */
export declare class EventsSubscriptionController extends DecafController<DecafServerCtx> {
    private readonly options;
    private readonly registry;
    constructor(clientContext: DecafRequestContext, options: ObserverEventsOptions, registry: ObserverSubscriptionRegistry);
    /**
     * @description Resolves the request's requester fingerprint
     * @summary Delegates to {@link resolveRequesterFingerprint}, falling back to a
     * freshly generated id so every anonymous request still gets a stable key.
     * @returns {string} The resolved fingerprint value
     */
    private resolveFingerprint;
    /**
     * @description Subscribes the requester to a set of webhook topics
     * @summary Upserts the requester's topic subscriptions in the registry and returns
     * the stored (sanitized) topics plus a truncated fingerprint label. Returns
     * `{ enabled: false }` when subscription mode is disabled.
     * @param {SubscriptionPayload} body - The topics to subscribe to
     * @returns {Promise<Record<string, any>>} `{ enabled, fingerprint, topics }` or `{ enabled: false }`
     * @mermaid
     * sequenceDiagram
     *   participant Client
     *   participant Controller as EventsSubscriptionController
     *   participant Registry as ObserverSubscriptionRegistry
     *   Client->>Controller: POST subscribe { topics }
     *   alt subscription mode disabled
     *     Controller-->>Client: { enabled: false }
     *   else
     *     Controller->>Controller: resolveFingerprint()
     *     Controller->>Registry: upsert(fingerprint, topics)
     *     Registry-->>Controller: record
     *     Controller-->>Client: { fingerprint, topics }
     *   end
     */
    subscribe(body: SubscriptionPayload): Promise<Record<string, any>>;
    /**
     * @description Removes the requester's topic subscriptions
     * @summary Deletes the requester's record from the registry and reports whether a
     * subscription existed. Returns `{ enabled: false }` when subscription mode is
     * disabled.
     * @returns {Record<string, any>} `{ enabled, unsubscribed, fingerprint }` or `{ enabled: false }`
     */
    unsubscribe(): Record<string, any>;
}
export {};