// Smoke test for the render core: feeds the committed fixture (a real 35-move self-played
// Russian Scrabble game) through renderRequest and asserts a sane PNG comes back. Pixel
// goldens are deliberately avoided — font rasterization differs across hosts; the shared
// drawing logic itself is unit-tested in ui/ (gameimage.test.ts).
import test from 'node:test';
import assert from 'node:assert/strict';
import { readFileSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { renderRequest } from '../src/render.mjs';

const here = dirname(fileURLToPath(import.meta.url));
const fixture = () => JSON.parse(readFileSync(join(here, '../testdata/request.json'), 'utf8'));

function pngSize(buf) {
  // IHDR is the first chunk: width/height are big-endian u32 at offsets 16/20.
  return { w: buf.readUInt32BE(16), h: buf.readUInt32BE(20) };
}

test('renders the fixture game to a plausible PNG', async () => {
  const png = await renderRequest(fixture());
  assert.ok(png.length > 50_000, `png too small: ${png.length}`);
  assert.deepEqual([...png.subarray(0, 8)], [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a]);
  const { w, h } = pngSize(png);
  // scale 2 over a MIN_SIDE 620 board + two seat columns: sanity bounds, not a golden.
  assert.ok(w > 1600 && w < 3000, `unexpected width ${w}`);
  assert.ok(h > 1000 && h < 3000, `unexpected height ${h}`);
});

test('rejects a payload without a game', async () => {
  await assert.rejects(() => renderRequest({ moves: [] }), /bad payload/);
});

test('renders concurrently without cross-talk', async () => {
  const [a, b] = await Promise.all([renderRequest(fixture()), renderRequest(fixture())]);
  assert.equal(a.length, b.length);
});