export class BoundedDedupMap {
  static readonly defaultCapN = 1000;
  static readonly defaultTtlMs = 60_000;

  private readonly entries = new Map<string, number>();

  constructor(
    private readonly capN: number = BoundedDedupMap.defaultCapN,
    private readonly ttlMs: number = BoundedDedupMap.defaultTtlMs,
  ) {}

  hasSeen(key: string): boolean {
    const now = Date.now();
    const expiredBefore = now - this.ttlMs;

    for (const [k, ts] of this.entries) {
      if (ts < expiredBefore) this.entries.delete(k);
    }

    if (this.entries.has(key)) return true;

    this.entries.set(key, now);

    if (this.entries.size > this.capN) {
      this.entries.delete(this.entries.keys().next().value!);
    }

    return false;
  }

  get size(): number {
    return this.entries.size;
  }
}