// @vitest-environment node
import { test, expect } from 'vitest';
import { cleanHistory, mergeHistory } from './readerHistory.js';

test('only well-formed chapters and days are kept', () => {
  const out = cleanHistory({
    chapters: { 'JHN.3': { n: 2, last: '2026-10-01' }, 'bad': { n: 1 }, 'GEN.1': { n: -5, last: 'yesterday' }, '1JN.2': null },
    days: ['2026-10-02', 'nope', '2026-10-01', '2026-10-01'],
  });
  expect(out.chapters).toEqual({ 'JHN.3': { n: 2, last: '2026-10-01' }, 'GEN.1': { n: 1, last: '' } });
  expect(out.days).toEqual(['2026-10-01', '2026-10-02']);
  expect(cleanHistory(null)).toEqual({ chapters: {}, days: [] });
});

test('merging keeps the larger count, the later date and every day', () => {
  const a = { chapters: { 'JHN.3': { n: 2, last: '2026-10-01' }, 'GEN.1': { n: 1, last: '2026-09-01' } }, days: ['2026-10-01'] };
  const b = { chapters: { 'JHN.3': { n: 1, last: '2026-10-05' }, 'ROM.8': { n: 1, last: '2026-10-04' } }, days: ['2026-10-04', '2026-10-05'] };
  const m = mergeHistory(a, b);
  expect(m.chapters['JHN.3']).toEqual({ n: 2, last: '2026-10-05' });
  expect(Object.keys(m.chapters).sort()).toEqual(['GEN.1', 'JHN.3', 'ROM.8']);
  expect(m.days).toEqual(['2026-10-01', '2026-10-04', '2026-10-05']);
  expect(mergeHistory(m, m)).toEqual(m); // merging again changes nothing
});