type CacheEntry<T> = {
  value: T;
  expiresAt: number;
};

export class MemoryCache {
  private readonly store = new Map<string, CacheEntry<unknown>>();

  public get<T>(key: string): T | undefined {
    const hit = this.store.get(key);
    if (!hit) {
      return undefined;
    }

    if (Date.now() >= hit.expiresAt) {
      this.store.delete(key);
      return undefined;
    }

    return hit.value as T;
  }

  public set<T>(key: string, value: T, ttlMs: number): void {
    this.store.set(key, {
      value,
      expiresAt: Date.now() + ttlMs
    });
  }
}