import { describe, expect, test } from "bun:test";

import { nextDueDate } from "../../web/src/server/services/recurring-invoices";

describe("recurring invoice scheduling", () => {
  test("advances weekly schedules from their scheduled occurrence", () => {
    const scheduledFor = new Date("2026-08-17T12:00:00.000Z");
    expect(nextDueDate("weekly", scheduledFor).toISOString()).toBe(
      "2026-08-24T12:00:00.000Z",
    );
  });

  test("does not mutate the source date", () => {
    const scheduledFor = new Date("2026-08-17T12:00:00.000Z");
    nextDueDate("monthly", scheduledFor);
    expect(scheduledFor.toISOString()).toBe("2026-08-17T12:00:00.000Z");
  });
});