/**
 * Stats routes — GET /api/stats, GET /api/usage.
 *
 * Ports Python's viewer_routes/stats.py.
 */
import { type MemoryStore } from "@codemem/core";
import { Hono } from "hono";
type UsagePayload = Record<string, unknown>;
interface UsageCacheEntry {
    payload: UsagePayload;
    expiresAtMs: number;
}
/**
 * Sweep expired entries and enforce the size cap before inserting a new one.
 *
 * Mirrors the lazy-sweep approach in request-rate-limit.ts: eviction is
 * piggybacked on writes rather than run on a timer, so an idle viewer does no
 * background work. Expired entries (those past `expiresAtMs`) are always
 * dropped; if the map is still at capacity afterward — e.g. a burst of
 * distinct, still-live bypass keys — the oldest-expiring entries are evicted
 * to make room. This never changes hit/miss semantics for a live entry: the
 * caller still re-checks `expiresAtMs` on read, and only already-expired or
 * over-cap entries are removed here.
 */
declare function sweepUsagePayloadCache(cache: Map<string, UsageCacheEntry>, nowMs: number): void;
/**
 * Create stats routes. The store factory is called per-request to get a
 * fresh connection (matching the Python viewer pattern).
 */
export declare function statsRoutes(getStore: () => MemoryStore): Hono<import("hono/types").BlankEnv, import("hono/types").BlankSchema, "/">;
/**
 * Internals exposed for unit tests of the usage-cache eviction. Not part of the
 * route's public surface; consumers should go through the HTTP handlers.
 */
export declare const __usageCacheTestHooks: {
    cache: Map<string, UsageCacheEntry>;
    sweep: typeof sweepUsagePayloadCache;
    maxEntries: number;
    ttlMs: number;
};
export {};
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