import { describe, it, expect } from 'vitest';
import {
  reportDayToDate,
  dateToReportDay,
  feedOrWeightDayToReportDay,
  formatLocalDate,
} from '../reportDay.ts';

/** Same instant PdfReportHeader tests use: 22 Mei 2026 00:00 WIB. */
const START = '2026-05-21T17:00:00.000Z';

describe('reportDayToDate', () => {
  it('maps day 0 to the cycle start date', () => {
    const date = reportDayToDate(START, 0);
    expect(formatLocalDate(date)).toBe('2026-05-22');
  });

  it('maps day 1 to the day after cycle start', () => {
    const date = reportDayToDate(START, 1);
    expect(formatLocalDate(date)).toBe('2026-05-23');
  });
});

describe('dateToReportDay', () => {
  it('maps cycle start calendar date to report day 0', () => {
    expect(dateToReportDay(START, reportDayToDate(START, 0))).toBe(0);
  });
});

describe('feedOrWeightDayToReportDay', () => {
  it('maps 1-based feed day 1 on cycle start to report day 0', () => {
    expect(feedOrWeightDayToReportDay(1)).toBe(0);
    const start = reportDayToDate(START, 0);
    expect(dateToReportDay(START, start)).toBe(0);
  });
});