/**
 * push/delivery.ts
 *
 * The single place a push message is actually encrypted and sent. Every send,
 * a `push.subscriptions.verify` test, or an approval/completion fan-out, flows
 * through `deliverToSubscription`, so the honesty rules live in one spot:
 *
 *  - A push service that answers 404/410 means the browser subscription is gone;
 *    the record is pruned and the receipt says `pruned`, never a fake success.
 *  - Any other non-2xx (or a transport error) is reported as `failed` with the
 *    status/reason, never swallowed into a success.
 *  - The request carries the RFC 8188 `Content-Encoding: aes128gcm` body plus
 *    the `TTL`, `Urgency`, and VAPID `Authorization` headers a push service
 *    requires.
 *
 * The endpoint is whatever the browser registered. In tests that is a local
 * HTTP sink; in production it is the browser vendor's push service. This module
 * never contacts a hard-coded external service of its own.
 */
import type { VapidManager } from './vapid.js';
import type { PushSubscriptionStore } from './subscription-store.js';
import type { PushDeliveryReceipt, PushMessage, StoredPushSubscription } from './types.js';
/** The `fetch` slice used to POST an encrypted payload. Injectable for tests. */
export type PushTransport = (url: string, init: {
    method: string;
    headers: Record<string, string>;
    body: Buffer;
}) => Promise<{
    status: number;
}>;
/**
 * Bounded retries before a dead endpoint that never answers 404/410 is pruned.
 * A push service that keeps returning 5xx/timeouts is treated as gone once the
 * consecutive-failure counter crosses this bound, reported as an honest `pruned`
 * receipt rather than an endless string of `failed`s.
 */
export declare const DELIVERY_FAILURE_PRUNE_THRESHOLD = 5;
export interface DeliveryDeps {
    readonly vapid: VapidManager;
    readonly store: PushSubscriptionStore;
    readonly transport?: PushTransport | undefined;
    /**
     * Consecutive refused deliveries after which the endpoint is treated as dead.
     * Absent ⇒ {@link DELIVERY_FAILURE_PRUNE_THRESHOLD}. The composition root
     * wires it to `push.subscriptions.failureThreshold`, the same key the
     * subscription sweep reads, so delivery and housekeeping cannot disagree
     * about when a push service has proved an endpoint gone.
     */
    readonly failureThreshold?: number | undefined;
}
/**
 * Encrypt and send one message to one subscription, prune-on-gone, and return
 * an honest receipt. The subscription's `lastOutcome` is stamped either way.
 */
export declare function deliverToSubscription(subscription: StoredPushSubscription, message: PushMessage, deps: DeliveryDeps): Promise<PushDeliveryReceipt>;
/**
 * Fan one message out to every stored subscription, delivering (and pruning) in
 * sequence. Returns one receipt per subscription, an empty array when there
 * are no subscriptions at all (the honest "nobody to notify" result, not a
 * silent success).
 */
export declare function deliverToAll(message: PushMessage, deps: DeliveryDeps): Promise<PushDeliveryReceipt[]>;
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