const { MARKER_REGEX, parseMarker, MAX_MARKER_LEN } = require('../src/citations/markers');
const { createMarkerStripper } = require('../src/citations/markerStripper');

function consume(chunks) {
  const stripper = createMarkerStripper();
  let text = '';
  const markers = [];
  let malformed = 0;
  for (const chunk of chunks) {
    const step = stripper.push(chunk);
    text += step.text;
    markers.push(...step.markers);
    malformed += step.malformed;
  }
  const tail = stripper.flush();
  text += tail.text;
  markers.push(...tail.markers);
  malformed += tail.malformed;
  return { text, markers, malformed };
}

function splitRandom(value, random) {
  const chunks = [];
  let index = 0;
  while (index < value.length) {
    const size = 1 + Math.floor(random() * 5);
    chunks.push(value.slice(index, index + size));
    index += size;
  }
  return chunks;
}

describe('marker grammar', () => {
  it('parses pages, ranges, and chapters', () => {
    expect(parseMarker('[[p:47]]')).toEqual({ kind: 'page', page: 47, pageEnd: 47 });
    expect(parseMarker('[[P: 47 - 49]]')).toEqual({ kind: 'page', page: 47, pageEnd: 49 });
    expect(parseMarker('[[ch:3]]')).toEqual({ kind: 'chapter', chapterNo: 3 });
    expect(parseMarker('[[p:abc]]')).toBeNull();
    expect(MAX_MARKER_LEN).toBe(24);
    expect('see [[p:47]][[ch:3]]'.match(MARKER_REGEX)).toHaveLength(2);
  });
});

describe('marker stripper', () => {
  it('keeps the same text and markers for any chunk split', () => {
    const source = 'Start [[p:47]] middle [[p:47-49]][[ch:3]] end.';
    const whole = consume([source]);
    let seed = 7;
    const random = () => {
      seed = (seed * 1103515245 + 12345) % 2147483648;
      return seed / 2147483648;
    };
    for (let trial = 0; trial < 30; trial += 1) {
      expect(consume(splitRandom(source, random))).toEqual(whole);
    }
    expect(whole.text).toBe('Start middle end.');
    expect(whole.markers).toEqual([
      { kind: 'page', page: 47, pageEnd: 47 },
      { kind: 'page', page: 47, pageEnd: 49 },
      { kind: 'chapter', chapterNo: 3 },
    ]);
  });

  it('handles markers at the start, middle, and end', () => {
    expect(consume(['[[ch:3]] Hello']).text).toBe('Hello');
    expect(consume(['Hello [[p:2]] there']).text).toBe('Hello there');
    expect(consume(['Hello [[p:2]].']).text).toBe('Hello.');
  });

  it('rejoins markers split across chunks', () => {
    expect(consume(['[[', 'p:', '47]]']).markers).toEqual([{ kind: 'page', page: 47, pageEnd: 47 }]);
    expect(consume(['[', '[p:47]]']).text).toBe('');
    expect(consume(['See [', '[p:1]] now']).text).toBe('See now');
  });

  it('strips malformed markers and keeps ordinary brackets', () => {
    const bad = consume(['Note [[p:abc]] next']);
    expect(bad.text).toBe('Note next');
    expect(bad.markers).toEqual([]);
    expect(bad.malformed).toBe(1);
    expect(consume(['[[p:4']).text).toBe('[[p:4');
    expect(consume(['Read [text](url) please']).text).toBe('Read [text](url) please');
    expect(consume(['Just [[ here']).text).toBe('Just [[ here');
    expect(consume(['[[ not a marker at all and much longer than the hold']).text).toContain('[[');
    expect(consume(['Café [[p:8]] résumé']).text).toBe('Café résumé');
  });
});