import { describe, expect, it } from 'vitest';
import { shiftAnchor, periodRange, isoWeekNumber } from '../src/domain/periodNav';

describe('shiftAnchor 周期导航', () => {
  it('周：±7 天', () => {
    expect(shiftAnchor('2026-07-21', 'weekly', 1)).toBe('2026-07-28');
    expect(shiftAnchor('2026-07-21', 'weekly', -1)).toBe('2026-07-14');
  });

  it('月：月末回退钳制（1月31日 → 2月28日）', () => {
    expect(shiftAnchor('2026-01-31', 'monthly', 1)).toBe('2026-02-28');
    expect(shiftAnchor('2026-03-31', 'monthly', -1)).toBe('2026-02-28');
  });

  it('月：跨年', () => {
    expect(shiftAnchor('2026-12-15', 'monthly', 1)).toBe('2027-01-15');
    expect(shiftAnchor('2026-01-15', 'monthly', -1)).toBe('2025-12-15');
  });

  it('年：±1 年', () => {
    expect(shiftAnchor('2026-07-21', 'annual', 1)).toBe('2027-07-21');
    expect(shiftAnchor('2026-07-21', 'annual', -1)).toBe('2025-07-21');
  });

  it('多步 delta', () => {
    expect(shiftAnchor('2026-07-21', 'monthly', 3)).toBe('2026-10-21');
    expect(shiftAnchor('2026-07-21', 'weekly', -2)).toBe('2026-07-07');
  });
});

describe('periodRange 周期范围', () => {
  it('周：周一起周日止（周二 anchor）', () => {
    expect(periodRange('2026-07-21', 'weekly')).toEqual({ start: '2026-07-20', end: '2026-07-26' });
  });

  it('周：周日 anchor 属于本周（周一开头）', () => {
    expect(periodRange('2026-07-26', 'weekly')).toEqual({ start: '2026-07-20', end: '2026-07-26' });
  });

  it('月：整月', () => {
    expect(periodRange('2026-02-10', 'monthly')).toEqual({ start: '2026-02-01', end: '2026-02-28' });
  });

  it('年：整年', () => {
    expect(periodRange('2026-07-21', 'annual')).toEqual({ start: '2026-01-01', end: '2026-12-31' });
  });
});

describe('isoWeekNumber ISO 周数', () => {
  it('2026-01-01 是第 1 周', () => {
    expect(isoWeekNumber('2026-01-01')).toBe(1);
  });

  it('2026-07-20 是第 30 周', () => {
    expect(isoWeekNumber('2026-07-20')).toBe(30);
  });
});