type CacheEntry<T> = { data: T; expiresAt: number };
const store = new Map<string, CacheEntry<unknown>>();

export function cached<T>(
	key: string,
	ttlMs: number,
	fn: () => Promise<T>,
): Promise<T> {
	const existing = store.get(key);
	if (existing && existing.expiresAt > Date.now()) {
		return Promise.resolve(existing.data as T);
	}
	return fn().then((data) => {
		store.set(key, { data, expiresAt: Date.now() + ttlMs });
		return data;
	});
}