// 取景公式的离线验证：不依赖浏览器，直接对 viewport-fitter.js 求值。
// 两条硬约束：① 16:9 下必须与作者设定完全一致；② 立绘层缩放比必须等于背景 cover 缩放比。
import { readFileSync } from "node:fs";

const src = readFileSync(new URL("../../dist/releases/collection-all/scripts/viewport-fitter.js", import.meta.url), "utf8").replace(/^export\s+/gm, "");
const mod = new Function(
  src + "\nreturn { contain, frameForAspect, coverScale, resolveViewport, toViewportConfig, REFERENCE_ASPECT };",
)();

const rect = (x, y, width, height) => ({ x, y, width, height });
const fmt = (r) =>
  `x=${r.x.toFixed(2)} y=${r.y.toFixed(2)} w=${r.width.toFixed(2)} h=${r.height.toFixed(2)} 比例=${(r.width / r.height).toFixed(4)}`;

const cases = [
  {
    name: "xilian（昔涟立绘）",
    R: rect(-2181.72, 1442.39, 4226.57, 3403.35),
    imgW: 2048,
    imgH: 1080,
  },
  {
    name: "kv37（「成为昨日的明天」）",
    R: rect(-1419.8, -512.4, 2457.6, 1228.8),
    imgW: 2560,
    imgH: 1440,
  },
];
const canvases = [
  [3440, 1440, "21:9"],
  [1920, 1080, "16:9"],
  [2560, 1600, "16:10"],
  [1080, 1920, "9:16"],
];

// 背景走 CSS background-size:cover，它在画布上真实的像素缩放就是这两个候选里的较大者。
const bgScale = (w, h, imgW, imgH) => Math.max(w / imgW, h / imgH);

let failures = 0;
for (const c of cases) {
  const imgAspect = c.imgW / c.imgH;
  const V0 = mod.contain(c.R, mod.REFERENCE_ASPECT);
  console.log(`\n=== ${c.name}   背景图 ${c.imgW}x${c.imgH}（比例 ${imgAspect.toFixed(4)}） ===`);
  console.log(`作者视口 R  : ${fmt(c.R)}`);
  console.log(`参考取景 V0 : ${fmt(V0)}`);

  // 基准取 16:9 1080p：立绘与背景都以此为准比较"被放大了多少倍"
  const refCanvas = [1920, 1080];
  const spinePx0 = refCanvas[1] / V0.height;
  const bgPx0 = bgScale(refCanvas[0], refCanvas[1], c.imgW, c.imgH);

  for (const [w, h, tag] of canvases) {
    const aspect = w / h;
    const V = mod.frameForAspect(V0, aspect, imgAspect);
    const spineRatio = h / V.height / spinePx0;
    const bgRatio = bgScale(w, h, c.imgW, c.imgH) / bgPx0;
    const synced = Math.abs(spineRatio - bgRatio) < 1e-6;
    if (!synced) failures++;
    console.log(
      `  ${tag.padEnd(5)} ${String(w).padStart(4)}x${String(h).padEnd(4)} ${fmt(V)}` +
        `  立绘 x${spineRatio.toFixed(4)}  背景 x${bgRatio.toFixed(4)}  ${synced ? "同步 ✓" : "不同步 ✗"}`,
    );
  }

  // 参考比例下必须与作者设定逐像素一致，且必须与拟合前的真实渲染值吻合
  const Vref = mod.frameForAspect(V0, mod.REFERENCE_ASPECT, imgAspect);
  const untouched = ["x", "y", "width", "height"].every((k) => Math.abs(Vref[k] - V0[k]) < 1e-9);
  if (!untouched) failures++;
  console.log(`  参考比例回归: ${untouched ? "与作者设定完全一致 ✓" : "被改动 ✗"}`);
}

console.log(`\n结论：${failures === 0 ? "全部通过 ✓" : `${failures} 项失败 ✗`}`);
process.exit(failures === 0 ? 0 : 1);