import { describe, expect, it } from 'vitest';
import { qrMatrix, qrShape } from './qr';

describe('qr', () => {
  const url = 'https://musicshare.app/u/alice';

  it('produces a square grid with the three finder patterns', () => {
    const m = qrMatrix(url);
    const n = m.length;
    expect(n).toBeGreaterThanOrEqual(21);
    expect(m.every((row) => row.length === n)).toBe(true);
    // Finder pattern corners: dark outer ring, light inner ring, dark 3x3 centre.
    for (const [r, c] of [
      [0, 0],
      [0, n - 7],
      [n - 7, 0],
    ] as const) {
      expect(m[r]![c]).toBe(true);
      expect(m[r + 1]![c + 1]).toBe(false);
      expect(m[r + 3]![c + 3]).toBe(true);
    }
  });

  it('is deterministic and draws every dark module', () => {
    const a = qrShape(url);
    expect(qrShape(url)).toEqual(a);
    const darkCount = qrMatrix(url).flat().filter(Boolean).length;
    const drawn = [...a.path.matchAll(/h(\d+)v1/g)].reduce((sum, m) => sum + Number(m[1]), 0);
    expect(drawn).toBe(darkCount);
  });

  it('grows for longer text', () => {
    expect(qrShape(`${url}?${'x'.repeat(200)}`).size).toBeGreaterThan(qrShape(url).size);
  });
});