import { serviceDb, type ServiceDoc } from "./dbs";

export class ServiceSeqTracker {
  /**
   * @param _id
   * @constructor
   */
  static async Init(_id: string) {
    const serviceDoc = await serviceDb.get(_id).catch((error) => {
      if (error.name === "not_found") {
        return {
          _id,
          lastSeq: "0",
        };
      }
      throw error; // Re-throw other errors
    });
    return new ServiceSeqTracker(serviceDoc);
  }

  private constructor(private serviceDoc: ServiceDoc) {}

  get lastSeq() {
    return this.serviceDoc.lastSeq;
  }

  checkNextSeq(seq: number | string) {
    if (!this.serviceDoc) {
    }
    const next = parseInt(seq as string, 10);
    const current = parseInt(this.serviceDoc.lastSeq as string, 10);
    if (next < current) {
      throw new Error(
        `Sequence number is too old: ${seq} (${next} < ${current})`,
      );
    }
  }

  saveSeq(seq: number | string) {
    this.serviceDoc.lastSeq = seq;
    return serviceDb.put(this.serviceDoc);
  }
}