import { describe, expect, it } from 'vitest';

import {
  nextOccurrence,
  nextOccurrenceFor,
  previewCron,
  previewTrigger,
  reconcileOccurrence,
} from './schedule-time.js';

describe('schedule time', () => {
  it('calculates future occurrences in Beijing time across the UTC day boundary', () => {
    expect(previewCron('0 9 * * *', 2, new Date('2026-07-30T00:30:00.000Z'))).toEqual([
      '2026-07-30T01:00:00.000Z',
      '2026-07-31T01:00:00.000Z',
    ]);
    expect(nextOccurrence('30 0 * * *', new Date('2026-07-30T15:59:00.000Z'))).toBe(
      '2026-07-30T16:30:00.000Z',
    );
  });

  it('rejects seconds fields and invalid cron grammar', () => {
    expect(() => previewCron('* * * * * *', 1)).toThrow(/five-field/i);
    expect(() => previewCron('99 99 * * *', 1)).toThrow(/cron/i);
  });

  it('reconciles a missed due time according to the per-task policy', () => {
    const common = {
      cronExpression: '*/10 * * * *',
      nextDueAt: '2026-07-30T01:00:00.000Z',
    };
    expect(
      reconcileOccurrence(
        { ...common, misfirePolicy: 'skip' },
        new Date('2026-07-30T01:25:00.000Z'),
      ),
    ).toEqual({
      action: 'skip',
      dueAt: '2026-07-30T01:20:00.000Z',
      nextDueAt: '2026-07-30T01:30:00.000Z',
    });
    expect(
      reconcileOccurrence(
        { ...common, misfirePolicy: 'catch-up-once' },
        new Date('2026-07-30T01:25:00.000Z'),
      ),
    ).toEqual({
      action: 'run',
      dueAt: '2026-07-30T01:20:00.000Z',
      nextDueAt: '2026-07-30T01:30:00.000Z',
    });
  });

  it('expands Hub fixed schedules over the Beijing weekday and time grid', () => {
    const weekdays = { kind: 'fixed' as const, weekdays: [4, 5], times: ['09:00', '21:30'] };
    // 2026-07-30 is a Thursday; 01:25Z is 09:25 in Beijing, so the same-day 21:30 slot is next.
    expect(previewTrigger(weekdays, 2, new Date('2026-07-30T01:25:00.000Z'))).toEqual([
      '2026-07-30T13:30:00.000Z',
      '2026-07-31T01:00:00.000Z',
    ]);
    expect(
      nextOccurrenceFor(
        { kind: 'fixed', weekdays: [6], times: ['00:30'] },
        new Date('2026-07-30T01:25:00.000Z'),
      ),
    ).toBe('2026-07-31T16:30:00.000Z');
  });

  it('keeps interval schedules anchored on the previous occurrence', () => {
    const interval = { kind: 'interval' as const, value: 90, unit: 'mins' as const };
    expect(nextOccurrenceFor(interval, new Date('2026-07-30T01:00:00.000Z'))).toBe(
      '2026-07-30T02:30:00.000Z',
    );
    expect(
      nextOccurrenceFor(
        interval,
        new Date('2026-07-30T05:00:00.000Z'),
        new Date('2026-07-30T01:00:00.000Z'),
      ),
    ).toBe('2026-07-30T05:30:00.000Z');
    expect(previewTrigger(interval, 3, new Date('2026-07-30T01:00:00.000Z'))).toEqual([
      '2026-07-30T02:30:00.000Z',
      '2026-07-30T04:00:00.000Z',
      '2026-07-30T05:30:00.000Z',
    ]);
  });

  it('reconciles fixed and interval misfires against the stored due time', () => {
    expect(
      reconcileOccurrence(
        {
          trigger: { kind: 'interval', value: 90, unit: 'mins' },
          nextDueAt: '2026-07-30T04:00:00.000Z',
          misfirePolicy: 'catch-up-once',
        },
        new Date('2026-07-30T05:00:00.000Z'),
      ),
    ).toEqual({
      action: 'run',
      dueAt: '2026-07-30T04:00:00.000Z',
      nextDueAt: '2026-07-30T05:30:00.000Z',
    });
    expect(
      reconcileOccurrence(
        {
          trigger: { kind: 'fixed', weekdays: [4, 5], times: ['09:00', '21:30'] },
          nextDueAt: '2026-07-30T01:00:00.000Z',
          misfirePolicy: 'skip',
        },
        new Date('2026-07-30T01:25:00.000Z'),
      ),
    ).toEqual({
      action: 'skip',
      dueAt: '2026-07-30T01:00:00.000Z',
      nextDueAt: '2026-07-30T13:30:00.000Z',
    });
  });
});