import test from 'node:test';
import assert from 'node:assert/strict';
import { MpvSubtitleRenderMetrics } from '../../types';
import {
  applyMpvSubtitleRenderMetricsPatch,
  DEFAULT_MPV_SUBTITLE_RENDER_METRICS,
} from './mpv-render-metrics';

const BASE: MpvSubtitleRenderMetrics = {
  ...DEFAULT_MPV_SUBTITLE_RENDER_METRICS,
};

test('applyMpvSubtitleRenderMetricsPatch returns unchanged on empty patch', () => {
  const { next, changed } = applyMpvSubtitleRenderMetricsPatch(BASE, {});
  assert.equal(changed, false);
  assert.deepEqual(next, BASE);
});

test('applyMpvSubtitleRenderMetricsPatch reports changed when patch modifies value', () => {
  const { next, changed } = applyMpvSubtitleRenderMetricsPatch(BASE, {
    subPos: 95,
  });
  assert.equal(changed, true);
  assert.equal(next.subPos, 95);
});