export const DATA_MAX_AGE_MS: number;
export const FRESHNESS_FUTURE_SKEW_MS: number;

export interface Freshness {
  asOfMs: number | null;
  maxAgeMs: number | null;
  ageMs: number | null;
  stale: boolean;
  source: string | null;
}

export interface StampedFreshness extends Freshness {
  fetchedAt: string | null;
}

export function freshness(input?: {
  asOfMs?: unknown;
  maxAgeMs?: unknown;
  nowMs?: unknown;
  source?: string | null;
}): Freshness;

export function stampFreshness(result: unknown, options?: { nowMs?: number; maxAgeMs?: number; source?: string }): StampedFreshness;

export function freshnessBadge(f: Partial<Freshness> | null | undefined): string;