import type { AnyEvent } from "@uptimizr/schema";
/**
 * In-process live event bus + presence tracker (ADR 0032 §1, §2, §3a, §6).
 *
 * The collector is a single process (DuckDB single-writer, ADR 0020), so every
 * ingested event passes through one place. The ingest route publishes each
 * enriched, validated event here; live consumers (SSE endpoints, ADR §3) read
 * from it. This is the OSS fan-out source — a multi-instance scale tier
 * supplies its own shared-bus implementation behind the same interface
 * (ADR 0004/0020) without touching `oss/**`.
 *
 * Nothing here is persisted: presence is a rolling in-memory view and the
 * per-session backfill ring is bounded. Privacy: the roster exposed to clients
 * is non-identifying (no geo/UA/visitorId — ADR §3a); `visitorId` is used only
 * internally to count distinct active visitors.
 */
/** Coarse, non-identifying recency bucket for a live session (ADR §3a). */
export type ActivityLevel = "active" | "recent" | "idle";
/** A single non-identifying roster entry surfaced to clients (ADR §3a). */
export interface PresenceRosterItem {
    sessionId: string;
    sceneId: string;
    /** Server receive time of the session's first seen event (epoch ms). */
    startedAt: number;
    /** Server receive time of the session's most recent event (epoch ms). */
    lastSeen: number;
    /** Coarse recency bucket derived from `lastSeen`. */
    activity: ActivityLevel;
}
/** Aggregate live snapshot for a project (ADR §3). */
export interface PresenceSnapshot {
    /** Distinct live sessions within the window. */
    activeSessions: number;
    /** Distinct live visitors within the window. */
    activeVisitors: number;
    /** Non-identifying roster, most-recently-active first. */
    sessions: PresenceRosterItem[];
}
/** Options for a live subscription (used by the SSE endpoints — ADR §3). */
export interface LiveSubscribeOptions {
    projectId: string;
    /** Restrict to one session (live-follow tail); omit for the project firehose. */
    sessionId?: string;
    /** Optional event-type allow-list. */
    types?: ReadonlySet<string>;
    /** Per-subscriber bounded queue size; overrides the bus default. */
    queueLimit?: number;
}
/**
 * A bounded, drop-oldest async stream of events (ADR §6). A slow consumer loses
 * its oldest buffered events (counted in {@link dropped}); it never back-pressures
 * ingest or grows memory without bound.
 */
export interface LiveSubscriber extends AsyncIterable<AnyEvent> {
    /** Close the subscription and release it from the bus. Idempotent. */
    close(): void;
    /** Count of events dropped due to a full queue. */
    readonly dropped: number;
}
export interface LiveBus {
    /** Publish enriched, validated events (called from the ingest route). */
    publish(events: readonly AnyEvent[]): void;
    /** Current aggregate + roster snapshot for a project (ADR §3). */
    presence(projectId: string): PresenceSnapshot;
    /** Recent buffered events for one session, oldest first (connect-time backfill). */
    recentForSession(projectId: string, sessionId: string): AnyEvent[];
    /** Open a bounded live subscription (ADR §6). */
    subscribe(options: LiveSubscribeOptions): LiveSubscriber;
    /** Number of open subscriptions (for connection caps — ADR §6). */
    readonly subscriberCount: number;
    /** Release timers/subscribers. */
    stop(): void;
}
export interface CreateLiveBusOptions {
    /** Liveness window in ms (ADR §1, default 30_000). Must be ≥ SDK flush cadence. */
    windowMs?: number;
    /** Per-session backfill ring size (ADR §3, default 200). */
    backfillRingSize?: number;
    /** Default per-subscriber queue size (ADR §6, default 1_000). */
    subscriberQueueLimit?: number;
    /** Clock injection for tests; defaults to `Date.now`. */
    now?: () => number;
}
/** Create the default in-process live bus (ADR 0032 §2). */
export declare function createLiveBus(options?: CreateLiveBusOptions): LiveBus;
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