import { test } from 'node:test';
import assert from 'node:assert/strict';
import { preprocess } from '../src/ocr.js';

/** Minimaler ImageData-Ersatz, damit der Test ohne Browser laeuft. */
function image(pixels) {
  const data = new Uint8ClampedArray(pixels.length * 4);
  pixels.forEach((value, i) => {
    data[i * 4] = value;
    data[i * 4 + 1] = value;
    data[i * 4 + 2] = value;
    data[i * 4 + 3] = 255;
  });
  return { width: pixels.length, height: 1, data };
}

test('preprocess erzeugt ein reines Schwarz-Weiss-Bild', () => {
  const result = preprocess(image([10, 40, 200, 250]));
  for (let i = 0; i < result.data.length; i += 4) {
    const value = result.data[i];
    assert.ok(value === 0 || value === 255, `Pixel ${i / 4} ist ${value}`);
    assert.equal(result.data[i + 1], value);
    assert.equal(result.data[i + 2], value);
    assert.equal(result.data[i + 3], 255);
  }
});

test('preprocess trennt dunkle von hellen Pixeln', () => {
  const result = preprocess(image([10, 40, 200, 250]));
  assert.equal(result.data[0], 0, 'dunkelstes Pixel wird schwarz');
  assert.equal(result.data[12], 255, 'hellstes Pixel wird weiss');
});

test('preprocess laesst Breite und Hoehe unveraendert', () => {
  const result = preprocess(image([0, 128, 255]));
  assert.equal(result.width, 3);
  assert.equal(result.height, 1);
});