interface CacheEntry<T> {
  data: T;
  expiresAt: number; 
}

const cache = new Map<string, CacheEntry<unknown>>();


const DEFAULT_TTL_MS = 2 * 60 * 1000;


export function cacheSet<T>(key: string, data: T, ttlMs = DEFAULT_TTL_MS): void {
  const expiresAt = ttlMs > 0 ? Date.now() + ttlMs : 0;
  cache.set(key, { data, expiresAt });
}


export function cacheGet<T>(key: string): T | undefined {
  const entry = cache.get(key);
  if (!entry) return undefined;

  if (entry.expiresAt > 0 && Date.now() > entry.expiresAt) {
    cache.delete(key);
    return undefined;
  }

  return entry.data as T;
}


export function cacheHas(key: string): boolean {
  return cacheGet(key) !== undefined;
}


export function cacheDelete(key: string): void {
  cache.delete(key);
}


export function cacheClear(): void {
  cache.clear();
}


export function threadCacheKey(uri: string): string {
  return `thread:${uri}`;
}


export function timelineCacheKey(cursor?: string): string {
  return cursor ? `timeline:${cursor}` : 'timeline:first';
}


export function feedCacheKey(feedUri: string): string {
  return `feed:${feedUri}`;
}