// 预览 `tools/downloader/_out/` 里的 staging：把一个**场景目录**组装成能跑的页面并起服务。
//
// 为什么需要它：`_cache/` 只是**文本**缓存（原始 bundle 文本，引用仍是线上绝对地址、贴图不在里面），
// 不可预览；`_out/` 是真实文件树，但 `serve.mjs` 只会按 URL 逐个取文件——没有索引、也不会画场景。
//
// staging 的形状是「一个场景 = 一个可直接搬走的壁纸目录」（见 tools/downloader/README.md），
// 所以预览的粒度也是场景，不是页面。
//
// 用法：
//   node tools/preview.mts                              # 列出 _out 里有哪些场景可预览
//   node tools/preview.mts ys/nico-tea                  # 页面 = 取它的推荐场景
//   node tools/preview.mts ys/nico-tea/scene_main       # 点名场景
//   node tools/preview.mts hsr/kv45/scene_ava --port 8199
//   node tools/preview.mts ys/nico-tea --no-serve       # 只组装到 tools/.cache/preview/
//
// 与 tools/checks/verify-scene-player.mts 的关系：那边也有一份「从 scene.json 生成预设」的代码，
// **故意不共用**——门必须独立于被验证对象，共用一份就变成"自己验自己"。
import { createServer } from "node:http";
import { createReadStream, existsSync } from "node:fs";
import { cp, mkdir, readFile, readdir, rm, stat, writeFile } from "node:fs/promises";
import { spawnSync } from "node:child_process";
import { dirname, extname, join, normalize, resolve } from "node:path";
import { fileURLToPath } from "node:url";

const ROOT = resolve(dirname(fileURLToPath(import.meta.url)), "..");
const OUT = join(ROOT, "tools", "downloader", "_out");
const PREVIEW = join(ROOT, "tools", ".cache", "preview");

const args = process.argv.slice(2);
const portFlag = args.indexOf("--port");
const port = portFlag >= 0 ? Number(args[portFlag + 1]) : 8196;
const noServe = args.includes("--no-serve");
const target = args.find((a) => !a.startsWith("--") && !/^\d+$/.test(a));

const MIME: Record<string, string> = {
  ".html": "text/html; charset=utf-8",
  ".js": "text/javascript; charset=utf-8",
  ".css": "text/css; charset=utf-8",
  ".json": "application/json; charset=utf-8",
  ".atlas": "text/plain; charset=utf-8",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".webp": "image/webp",
};

interface Part {
  kind: string;
  id: string;
  order: number;
  renderOrder?: number;
  position: number[];
  scale: number[];
  rotation?: number[];
  geometrySize?: number[];
  geometryCenter?: number[];
  animation?: string;
  skin?: string;
  timeScale?: number;
}

/** 场景目录的判据：有 `preset.template.json`（目录名是转义过的场景 id，不能靠名字认）。 */
const isSceneDir = (dir: string): boolean => existsSync(join(dir, "preset.template.json"));

/** 列出 _out 下所有「游戏/页面/场景」。 */
async function listScenes(): Promise<string[]> {
  if (!existsSync(OUT)) return [];
  const out: string[] = [];
  for (const game of await readdir(OUT, { withFileTypes: true })) {
    if (!game.isDirectory()) continue;
    for (const page of await readdir(join(OUT, game.name), { withFileTypes: true })) {
      if (!page.isDirectory()) continue;
      for (const scene of await readdir(join(OUT, game.name, page.name), { withFileTypes: true })) {
        if (!scene.isDirectory()) continue;
        if (isSceneDir(join(OUT, game.name, page.name, scene.name))) {
          out.push(`${game.name}/${page.name}/${scene.name}`);
        }
      }
    }
  }
  return out.sort();
}

/** 把「游戏/页面」或「游戏/页面/场景」解析成具体的场景目录路径。 */
async function resolveScene(rel: string): Promise<string | null> {
  const parts = rel.split("/").filter(Boolean);
  if (parts.length >= 3) {
    const dir = join(OUT, ...parts);
    return isSceneDir(dir) ? dir : null;
  }
  if (parts.length !== 2) return null;
  const pageDir = join(OUT, ...parts);
  if (!existsSync(pageDir)) return null;
  const scenes = (await readdir(pageDir, { withFileTypes: true }))
    .filter((entry) => entry.isDirectory() && isSceneDir(join(pageDir, entry.name)))
    .map((entry) => entry.name)
    .sort();
  if (scenes.length === 0) return null;
  let chosen = scenes[0]!;
  const pageFile = join(pageDir, "page.json");
  if (existsSync(pageFile)) {
    const page = JSON.parse(await readFile(pageFile, "utf8")) as { chosenDir?: string; chosenScene?: string };
    const wanted = page.chosenDir ?? page.chosenScene;
    if (wanted && scenes.includes(wanted)) chosen = wanted;
  }
  return join(pageDir, chosen);
}

if (!target) {
  const scenes = await listScenes();
  console.log(`_out 下有 ${scenes.length} 个场景可预览：\n`);
  for (const s of scenes) console.log(`  node tools/preview.mts ${s}`);
  console.log(`\n（「游戏/页面」会取该页的推荐场景；_cache/ 是文本调试缓存，不可预览）`);
  process.exit(0);
}

const staged = await resolveScene(target);
if (staged === null) {
  console.error(`没有这个场景目录：${target}（用 node tools/preview.mts 看有哪些）`);
  process.exit(2);
}
const rel = staged.slice(OUT.length + 1).replace(/\\/g, "/");

// 1) 运行时要有产物：缺了就编一次
if (!existsSync(join(ROOT, "build", "scripts", "scene-controller.js"))) {
  console.log("build/scripts/scene-controller.js 不存在，先编译运行时…");
  const build = spawnSync(process.execPath, ["node_modules/typescript/bin/tsc", "-p", "tsconfig.runtime.json"], {
    cwd: ROOT,
    encoding: "utf8",
  });
  if (build.status !== 0) {
    console.error("编译失败：", (build.stdout ?? "") + (build.stderr ?? ""));
    process.exit(1);
  }
}

// 2) 组装：运行时脚本 + 样式 + staging 资产 + 由 scene.json 生成的预设
const dir = join(PREVIEW, rel.replace(/\//g, "__"));
await rm(dir, { recursive: true, force: true });
await mkdir(join(dir, "scripts"), { recursive: true });
await mkdir(join(dir, "styles"), { recursive: true });
await cp(staged, join(dir, "assets"), { recursive: true });
for (const f of await readdir(join(ROOT, "build", "scripts"))) {
  if (f.endsWith(".js")) await cp(join(ROOT, "build", "scripts", f), join(dir, "scripts", f));
}
await cp(join(ROOT, "src", "vendor", "spine-player.js"), join(dir, "scripts", "spine-player.js"));
for (const f of await readdir(join(ROOT, "src", "styles"))) {
  await cp(join(ROOT, "src", "styles", f), join(dir, "styles", f));
}

const scene = JSON.parse(await readFile(join(staged, "scene.json"), "utf8")) as {
  id: string;
  ui?: number[];
  camera?: { camera?: { type?: number; fov?: number }; position?: number[] };
  parts: Part[];
};
const parts: string[] = [];
for (const part of scene.parts) {
  if (part.kind === "solid") continue; // 运行时画不了纯色平面（没有贴图），别写进预设
  const fields: string[] = [
    `kind: ${JSON.stringify(part.kind)}`,
    `id: ${JSON.stringify(part.id)}`,
    `order: ${JSON.stringify(part.order)}`,
    `position: ${JSON.stringify(part.position)}`,
    `scale: ${JSON.stringify(part.scale)}`,
  ];
  if (part.renderOrder) fields.push(`renderOrder: ${JSON.stringify(part.renderOrder)}`);
  if (part.rotation && part.rotation.some((v) => Math.abs(v) > 1e-9)) {
    fields.push(`rotation: ${JSON.stringify(part.rotation)}`);
  }
  if (part.geometrySize) {
    fields.push(`width: ${JSON.stringify(part.geometrySize[0])}`);
    fields.push(`height: ${JSON.stringify(part.geometrySize[1])}`);
  }
  if (part.geometryCenter) fields.push(`center: ${JSON.stringify(part.geometryCenter)}`);
  if (part.animation) fields.push(`animation: ${JSON.stringify(part.animation)}`);
  if (part.skin) fields.push(`skin: ${JSON.stringify(part.skin)}`);
  if (part.timeScale !== undefined) fields.push(`timeScale: ${JSON.stringify(part.timeScale)}`);
  if (part.kind === "spine") {
    fields.push(`jsonUrl: asset("../assets/spines/${part.id}/${part.id}.json")`);
    fields.push(`atlasUrl: asset("../assets/spines/${part.id}/${part.id}.atlas")`);
  } else {
    const files = existsSync(join(staged, "scene")) ? await readdir(join(staged, "scene")) : [];
    const hit = files.find((f) => f.startsWith(`${part.id}.`));
    if (!hit) continue;
    fields.push(`image: asset("../assets/scene/${hit}")`);
  }
  parts.push(`      { ${fields.join(", ")} },`);
}
const camera = scene.camera?.camera ?? {};
const cameraLine =
  camera.type === undefined
    ? ""
    : `    camera: ${JSON.stringify({ type: camera.type, fov: camera.fov, position: scene.camera?.position })},\n`;

await writeFile(
  join(dir, "scripts", "scene-preset.js"),
  [
    `const base = new URL("./", import.meta.url);`,
    `const asset = (path) => new URL(path, base).href;`,
    `export default {`,
    `  id: "preview",`,
    `  name: ${JSON.stringify(rel)},`,
    `  game: "preview",`,
    `  backgroundImage: "",`,
    `  sceneConfig: {`,
    `    ui: ${JSON.stringify(scene.ui ?? [2500, 1080])},`,
    cameraLine + `    parts: [`,
    ...parts,
    `    ],`,
    `  },`,
    `  audioChoices: [],`,
    `  audioOptions: { source: "" },`,
    `};`,
    ``,
  ].join("\n"),
  "utf8",
);
await writeFile(
  join(dir, "scripts", "presets.js"),
  `import preset from "./scene-preset.js";\nexport const defaultPresetId = "preview";\nexport default Object.fromEntries([["preview", preset]]);\n`,
  "utf8",
);
await writeFile(
  join(dir, "index.html"),
  [
    `<!DOCTYPE html>`,
    `<html lang="zh"><head><meta charset="UTF-8" /><title>preview ${rel}</title>`,
    `<link rel="icon" href="data:," />`,
    `<link rel="stylesheet" href="./styles/spine-player.css" />`,
    `<link rel="stylesheet" href="./styles/index.css" /></head>`,
    `<body><div id="spine-container"></div><audio id="background-music"></audio>`,
    `<script src="./scripts/spine-player.js"></script>`,
    `<script type="module" src="./scripts/index.js"></script></body></html>`,
    ``,
  ].join("\n"),
  "utf8",
);
console.log(
  `已组装 ${rel} → ${dir}\n  骨架 ${parts.filter((p) => p.includes('"spine"')).length} 件、` +
    `平面 ${parts.filter((p) => p.includes('"image"')).length} 件`,
);

if (noServe) process.exit(0);

// 3) 起服务（MIME 要认 .atlas，否则骨架读不到 atlas 文本）
const server = createServer(async (req, res) => {
  const pathname = decodeURIComponent(new URL(req.url ?? "/", "http://x").pathname);
  const path = normalize(pathname).replace(/^([/\\])+/, "");
  const file = resolve(join(dir, path === "" ? "index.html" : path));
  if (!file.startsWith(dir)) {
    res.writeHead(403).end();
    return;
  }
  try {
    const info = await stat(file);
    if (info.isDirectory()) {
      res.writeHead(404).end();
      return;
    }
    res.writeHead(200, { "content-type": MIME[extname(file).toLowerCase()] ?? "application/octet-stream" });
    createReadStream(file).pipe(res);
  } catch {
    res.writeHead(404).end();
  }
});
server.listen(port, "127.0.0.1", () => {
  console.log(`\n预览： http://127.0.0.1:${port}/`);
  console.log(`调试信息在页面里： window.__sceneDebug（parts / loaded / errors / framing / rotatedSkipped）`);
  console.log(`停止： Ctrl+C\n`);
});