import { windowStart, WINDOW_MS } from '../../src/intake/capacity';

const NOW = new Date('2026-09-01T12:00:00.000Z');
const DAY_AGO = new Date(NOW.getTime() - WINDOW_MS);

describe('windowStart', () => {
  it('is 24 hours ago when there has been no reset', () => {
    expect(windowStart(NOW, '').toISOString()).toBe(DAY_AGO.toISOString());
  });

  // A reset inside the window is the point of it: it forgives what came before
  // without deleting anything.
  it('is the reset when the reset is more recent', () => {
    const reset = '2026-09-01T09:00:00.000Z';
    expect(windowStart(NOW, reset).toISOString()).toBe(reset);
  });

  // An old reset must not widen the window beyond 24 hours, which would make
  // the ceiling stricter over time rather than rolling.
  it('ignores a reset older than the window', () => {
    expect(windowStart(NOW, '2026-08-01T00:00:00.000Z').toISOString()).toBe(DAY_AGO.toISOString());
  });

  // A malformed stored value must not produce an Invalid Date, which compares
  // false against everything and would silently disable the ceiling.
  it('falls back to 24 hours ago for an unparseable reset', () => {
    expect(windowStart(NOW, 'not-a-date').toISOString()).toBe(DAY_AGO.toISOString());
  });

  it('falls back for a reset in the future', () => {
    expect(windowStart(NOW, '2027-01-01T00:00:00.000Z').toISOString()).toBe(DAY_AGO.toISOString());
  });

  it('tolerates whitespace around an empty setting', () => {
    expect(windowStart(NOW, '   ').toISOString()).toBe(DAY_AGO.toISOString());
  });
});