dates.test.ts

import { describe, it, expect } from 'vitest';
import { timeAgo, isSameDay, formatCountdown, getCountdownAriaLabel } from './dates';

describe('timeAgo', () => {
  const NOW = new Date('2025-01-15T12:00:00Z');

  it('reports very recent times in seconds', () => {
    const tenSecondsAgo = new Date(NOW.getTime() - 10_000);
    expect(timeAgo(tenSecondsAgo, NOW)).toMatch(/second/);
  });

  it('reports minute-level differences in minutes', () => {
    const fiveMinutesAgo = new Date(NOW.getTime() - 5 * 60_000);
    expect(timeAgo(fiveMinutesAgo, NOW)).toMatch(/minute/);
  });

  it('reports day-level differences in days', () => {
    const threeDaysAgo = new Date(NOW.getTime() - 3 * 24 * 60 * 60_000);
    expect(timeAgo(threeDaysAgo, NOW)).toMatch(/day/);
  });

  it('handles future times', () => {
    const inOneHour = new Date(NOW.getTime() + 60 * 60_000);
    const result = timeAgo(inOneHour, NOW);
    expect(result).toMatch(/hour/);
  });
});

describe('isSameDay', () => {
  it('returns true for two times on the same calendar day', () => {
    const morning = new Date('2025-01-15T03:00:00');
    const evening = new Date('2025-01-15T22:00:00');
    expect(isSameDay(morning, evening)).toBe(true);
  });

  it('returns false for two times on different calendar days', () => {
    const day1 = new Date('2025-01-15T23:30:00');
    const day2 = new Date('2025-01-16T00:30:00');
    expect(isSameDay(day1, day2)).toBe(false);
  });
});

describe('formatCountdown', () => {
  const NOW = new Date('2025-02-20T12:00:00Z');

  it('returns "now" for past dates', () => {
    expect(formatCountdown('2025-02-19T00:00:00Z', NOW)).toBe('now');
  });

  it('formats minutes only', () => {
    expect(formatCountdown('2025-02-20T12:45:00Z', NOW)).toBe('45m');
  });

  it('formats hours and minutes', () => {
    expect(formatCountdown('2025-02-20T14:32:00Z', NOW)).toBe('2h 32m');
  });

  it('formats days only', () => {
    expect(formatCountdown('2025-02-23T12:00:00Z', NOW)).toBe('3d');
  });

  it('omits zero-valued units', () => {
    expect(formatCountdown('2025-02-20T13:00:00Z', NOW)).toBe('1h');
  });
});

describe('getCountdownAriaLabel', () => {
  const NOW = new Date('2025-02-20T12:00:00Z');

  it('returns a full sentence for hours and minutes', () => {
    expect(getCountdownAriaLabel('2025-02-20T14:14:00Z', NOW)).toBe('Next interest in 2 hours');
  });

  it('returns a full sentence for minutes', () => {
    expect(getCountdownAriaLabel('2025-02-20T12:14:00Z', NOW)).toBe('Next interest in 14 minutes');
  });

  it('returns a full sentence for days', () => {
    expect(getCountdownAriaLabel('2025-02-23T12:00:00Z', NOW)).toBe('Next interest in 3 days');
  });

  it('handles past dates gracefully', () => {
    expect(getCountdownAriaLabel('2025-02-19T00:00:00Z', NOW)).toBe('Interest is accruing now');
  });
});