// 零依赖静态服务器：把 dist/ 以正确的 MIME 暴露出来，供无头 Edge 与人工本地预览使用。
// 用法：node tools/serve.mjs [port] [--root <dir>]
//
// 它同时承担"测试台"的角色，且完全不改动 dist/：
//   ?nojs=1          剥掉所有 <script>，得到"只有 CSS 背景、没有 canvas"的对照组
//   ?__props={...}   模拟 Wallpaper Engine 下发用户属性，如 {"preset":"kv37","audio_volume":0.2}
//   ?__propsAt=load  默认在 window.load 之后下发（正常路径）
//                    =dom 则在 DOMContentLoaded 时下发，复现"WE 在 load 之前就推属性"的时序
//   ?__freeze=1      骨骼加载完成后暂停播放并把动画相位归零，使截图逐像素可复现
//   ?__hide=canvas   渲染正常但把 canvas 藏起来，得到"只有背景图"的同款参考帧
//
// 驱动脚本会把状态写进 document.title，配合 shot.mjs --dom 即可断言。

import { createServer } from "node:http";
import { createReadStream } from "node:fs";
import { readFile, stat } from "node:fs/promises";
import { extname, join, normalize, resolve, sep } from "node:path";

const args = process.argv.slice(2);
const portArg = args.find((a) => /^\d+$/.test(a));
const rootFlag = args.indexOf("--root");
const root = resolve(rootFlag >= 0 ? args[rootFlag + 1] : "dist");
const port = Number(portArg ?? 8181);

const MIME = {
  ".html": "text/html; charset=utf-8",
  ".js": "text/javascript; charset=utf-8",
  ".mjs": "text/javascript; charset=utf-8",
  ".css": "text/css; charset=utf-8",
  ".json": "application/json; charset=utf-8",
  ".atlas": "text/plain; charset=utf-8",
  ".txt": "text/plain; charset=utf-8",
  ".png": "image/png",
  ".jpg": "image/jpeg",
  ".jpeg": "image/jpeg",
  ".webp": "image/webp",
  ".gif": "image/gif",
  ".svg": "image/svg+xml",
  ".flac": "audio/flac",
  ".mp3": "audio/mpeg",
  ".ogg": "audio/ogg",
  ".opus": "audio/ogg",
  ".wav": "audio/wav",
  ".webm": "video/webm",
};

// 注入到 <script type="module" src="scripts/index.js"> 之前：
// 这是唯一能"在 spine-player.js 已加载、而 index.js 尚未执行"的插入点。
const DRIVER = (q) => `<script>
(function () {
  var q = new URLSearchParams(location.search);
  var props = {};
  try { props = JSON.parse(q.get("__props") || "{}"); } catch (e) { props = {}; }
  var freeze = q.get("__freeze") === "1";
  var propsAt = q.get("__propsAt") || "load";
  var state = { patched: false, presets: Object.keys(props), propsAt: null, successAt: null, frames: null, error: null };
  window.__test = state;

  if (!window.spine || !window.spine.SpinePlayer) {
    state.error = "spine.SpinePlayer missing";
  } else {
    // 注意：spine-player.js 用 __export 把导出定义成 getter-only，
    // 直接给 spine.SpinePlayer 赋值在非严格模式下会静默失败，所以只能补 prototype。
    var proto = window.spine.SpinePlayer.prototype;
    var origValidate = proto.validateConfig;
    proto.validateConfig = function (config) {
      var prevSuccess = config.success;
      var prevError = config.error;
      config.success = function (p) {
        window.__player = p;
        state.successAt = Math.round(performance.now());
        if (freeze) freezePlayer(p);
        if (prevSuccess) prevSuccess(p);
      };
      config.error = function (p, msg) { state.error = String(msg); if (prevError) prevError(p, msg); };
      state.patched = true;
      return origValidate.call(this, config);
    };
    var origInitialize = proto.initialize;
    proto.initialize = function () {
      window.__player = this;
      return origInitialize.apply(this, arguments);
    };
    var origDraw = proto.drawFrame;
    proto.drawFrame = function () {
      state.drawCalls = (state.drawCalls || 0) + 1;
      // 冻结只做一次是不够的：相位可能在成功回调前后被推进过一帧。这里每帧都强制归零，
      // 保证"同一份代码的任何两次截图"是同一相位，对拍才有意义。
      if (freeze) {
        try {
          var cur = this.animationState && this.animationState.getCurrent(0);
          if (cur) cur.trackTime = 0;
          if (this.skeleton) this.skeleton.updateWorldTransform(2);
          this.viewportTransitionStart = performance.now() - 1e6;
        } catch (e) { state.error = "freeze-frame: " + e; }
      }
      return origDraw.apply(this, arguments);
    };
  }

  function freezePlayer(p) {
    try {
      p.pause();
      var cur = p.animationState && p.animationState.getCurrent(0);
      if (cur) cur.trackTime = 0;
      if (p.skeleton) p.skeleton.updateWorldTransform(2);
      // 视口过渡（transitionTime 默认 0.25s）是时间相关的插值，会把"冻结"变得不彻底：
      // 把它推到足够久以前，transitionAlpha >= 1，直接使用 currentViewport。
      p.viewportTransitionStart = performance.now() - 1e6;
      state.info = {
        animations: p.skeleton ? p.skeleton.data.animations.map(function (a) { return a.name; }) : [],
        skin: p.skeleton ? p.skeleton.data.skins.map(function (s) { return s.name; }) : [],
        playerError: p.error ? String(p.error) : null,
      };
      if (q.get("__hide") === "canvas" && p.canvas) p.canvas.style.visibility = "hidden";
    } catch (e) { state.error = "freeze: " + e; }
  }

  function pushProps() {
    if (!Object.keys(props).length) return;
    var listener = window.wallpaperPropertyListener;
    if (!listener || !listener.applyUserProperties) { state.error = "wallpaperPropertyListener missing"; return; }
    var payload = {};
    Object.keys(props).forEach(function (k) { payload[k] = { value: props[k] }; });
    listener.applyUserProperties(payload);
    state.propsAt = Math.round(performance.now());
  }

  if (propsAt === "dom") {
    document.addEventListener("DOMContentLoaded", pushProps);
  } else {
    window.addEventListener("load", function () { setTimeout(pushProps, 0); });
  }

  var ticks = 0;
  var timer = setInterval(function () {
    ticks++;
    if (window.__player) state.frames = window.__player.time ? Math.round(window.__player.time.frames) : state.frames;
    document.title = "TESTSTATE " + JSON.stringify(state);
    if (ticks > 40) clearInterval(timer);
  }, 250);
})();
</script>`;

async function html(body, query) {
  let out = body;
  if (query.get("nojs") === "1") out = out.replace(/<script\b[^>]*><\/script>/g, "");
  else if (query.has("__props") || query.has("__freeze")) {
    out = out.replace(/(<script\b[^>]*type="module"[^>]*>)/, DRIVER(query) + "$1");
  }
  return out;
}

const server = createServer(async (req, res) => {
  try {
    const url = new URL(req.url, "http://127.0.0.1");
    let rel = decodeURIComponent(url.pathname);
    if (rel.endsWith("/")) rel += "index.html";
    const abs = normalize(join(root, rel));
    if (abs !== root && !abs.startsWith(root + sep)) {
      res.writeHead(403).end("forbidden");
      return;
    }
    const info = await stat(abs).catch(() => null);
    if (!info || !info.isFile()) {
      res.writeHead(404, { "content-type": "text/plain; charset=utf-8" }).end(`404 ${rel}`);
      console.log(`404 ${rel}`);
      return;
    }
    if (extname(abs).toLowerCase() === ".html") {
      const body = await html(await readFile(abs, "utf8"), url.searchParams);
      res.writeHead(200, {
        "content-type": "text/html; charset=utf-8",
        "content-length": Buffer.byteLength(body),
        "cache-control": "no-store",
      });
      res.end(body);
      return;
    }
    res.writeHead(200, {
      "content-type": MIME[extname(abs).toLowerCase()] ?? "application/octet-stream",
      "content-length": info.size,
      "cache-control": "no-store",
    });
    createReadStream(abs).pipe(res);
  } catch (err) {
    res.writeHead(500, { "content-type": "text/plain; charset=utf-8" }).end(String(err));
  }
});

server.listen(port, "127.0.0.1", () => {
  console.log(`serving ${root}`);
  console.log(`  http://127.0.0.1:${port}/`);
});