/**
 * The two formatters the jobs tab and the chat lean on.
 *
 * Pure functions with an injectable `now`, so none of this needs fake timers —
 * which is also why they take one: a formatter that reads the clock itself is a
 * formatter you can only test by lying to the runtime.
 */
import { describe, expect, it } from 'vitest';
import { formatRelativeTime, formatWhen } from '../src/lib/utils';

const NOW = new Date('2026-08-21T12:00:00Z');
const ago = (ms: number) => new Date(NOW.getTime() - ms);

const SECOND = 1000;
const MINUTE = 60 * SECOND;
const HOUR = 60 * MINUTE;
const DAY = 24 * HOUR;

describe('formatRelativeTime', () => {
  it('collapses the first minute to "now"', () => {
    expect(formatRelativeTime(ago(0), NOW)).toBe('now');
    expect(formatRelativeTime(ago(59 * SECOND), NOW)).toBe('now');
  });

  it('reads a timestamp slightly in the future as "now" rather than negative', () => {
    // Clock skew between the server row and the browser, and optimistic rows.
    expect(formatRelativeTime(new Date(NOW.getTime() + 5 * SECOND), NOW)).toBe('now');
  });

  it('counts minutes, then hours', () => {
    expect(formatRelativeTime(ago(MINUTE), NOW)).toBe('1 min');
    expect(formatRelativeTime(ago(59 * MINUTE), NOW)).toBe('59 min');
    expect(formatRelativeTime(ago(HOUR), NOW)).toBe('1 h');
    expect(formatRelativeTime(ago(23 * HOUR), NOW)).toBe('23 h');
  });

  it('switches to a weekday inside the week and a date beyond it', () => {
    // Rounding down matters at the boundary: 24h ago is a day, not "24 h".
    expect(formatRelativeTime(ago(DAY), NOW)).not.toMatch(/h$/);
    expect(formatRelativeTime(ago(DAY), NOW)).toMatch(/^\w+/);

    const old = formatRelativeTime(ago(30 * DAY), NOW);
    expect(old).toMatch(/\d/);
  });
});

describe('formatWhen', () => {
  it('names today, tomorrow and yesterday', () => {
    const noon = new Date(2026, 7, 21, 12, 0);
    expect(formatWhen(new Date(2026, 7, 21, 14, 0), noon)).toMatch(/^Today /);
    expect(formatWhen(new Date(2026, 7, 22, 9, 0), noon)).toMatch(/^Tomorrow /);
    expect(formatWhen(new Date(2026, 7, 20, 9, 0), noon)).toMatch(/^Yesterday /);
  });

  it('compares calendar days, not elapsed hours', () => {
    // 23:00 tonight and 01:00 tomorrow are two hours apart. An elapsed-time
    // comparison calls both "Today"; only one of them is.
    const lateTonight = new Date(2026, 7, 21, 23, 0);
    const earlyTomorrow = new Date(2026, 7, 22, 1, 0);

    expect(formatWhen(lateTonight, lateTonight)).toMatch(/^Today /);
    expect(formatWhen(earlyTomorrow, lateTonight)).toMatch(/^Tomorrow /);
  });

  it('survives a daylight-saving boundary', () => {
    // Europe/Madrid springs forward on 29 March 2026: that day is 23 hours long,
    // so a naive divide-by-86400000 would call the next morning "Today".
    const beforeChange = new Date(2026, 2, 28, 12, 0);
    const afterChange = new Date(2026, 2, 29, 12, 0);
    expect(formatWhen(afterChange, beforeChange)).toMatch(/^Tomorrow /);
  });

  it('uses a weekday inside the week and a date beyond it', () => {
    const monday = new Date(2026, 7, 17, 12, 0);
    expect(formatWhen(new Date(2026, 7, 20, 14, 0), monday)).not.toMatch(/^(Today|Tomorrow)/);
    expect(formatWhen(new Date(2026, 8, 30, 14, 0), monday)).toMatch(/\d/);
  });
});