// 最小 CDP 客户端：用真实时间等待页面就绪，再截图 / 取状态。
// 为什么不用 msedge --screenshot：那个走的是"虚拟时间"，而贴图解码与 WebGL 初始化吃的是真实 CPU 时间，
// 虚拟时间预算会在骨骼真正加载完之前就耗尽，截出来的是还没画内容的帧（这个坑已经踩过一次）。

import { spawn } from "node:child_process";
import { existsSync } from "node:fs";
import { mkdir } from "node:fs/promises";
import { resolve } from "node:path";

const EDGE = [
  "C:\\Program Files (x86)\\Microsoft\\Edge\\Application\\msedge.exe",
  "C:\\Program Files\\Microsoft\\Edge\\Application\\msedge.exe",
].find((p) => existsSync(p));

const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

export async function withPage(opts, fn) {
  const { width = 1920, height = 1080, profile = "tools/.cache/edge-cdp", extraArgs = [] } = opts;
  if (!EDGE) throw new Error("找不到 msedge.exe");
  await mkdir(resolve(profile), { recursive: true });

  const child = spawn(
    EDGE,
    [
      "--headless=new",
      "--remote-debugging-port=0",
      `--user-data-dir=${resolve(profile)}`,
      "--no-first-run",
      "--no-default-browser-check",
      "--disable-extensions",
      "--hide-scrollbars",
      "--enable-unsafe-swiftshader",
      "--autoplay-policy=no-user-gesture-required",
      "--mute-audio",
      `--window-size=${width},${height}`,
      ...extraArgs,
      "about:blank",
    ],
    { stdio: ["ignore", "pipe", "pipe"] },
  );

  let stderr = "";
  const wsUrl = await new Promise((res, rej) => {
    const timer = setTimeout(() => rej(new Error("等待 DevTools 端点超时")), 20000);
    child.stderr.on("data", (d) => {
      stderr += d;
      const m = stderr.match(/DevTools listening on (ws:\/\/\S+)/);
      if (m) {
        clearTimeout(timer);
        res(m[1]);
      }
    });
    child.on("close", () => {
      clearTimeout(timer);
      rej(new Error("Edge 提前退出:\n" + stderr.slice(-800)));
    });
  });

  const port = new URL(wsUrl).port;
  const list = await (await fetch(`http://127.0.0.1:${port}/json/list`)).json();
  const page = list.find((t) => t.type === "page");
  if (!page) throw new Error("没有 page target");

  const ws = new WebSocket(page.webSocketDebuggerUrl);
  await new Promise((res, rej) => {
    ws.onopen = res;
    ws.onerror = (e) => rej(new Error("CDP WebSocket 连接失败: " + (e?.message ?? "")));
  });

  let nextId = 1;
  const pending = new Map();
  const consoleLines = [];
  const exceptions = [];
  ws.onmessage = (ev) => {
    const msg = JSON.parse(ev.data);
    if (msg.id && pending.has(msg.id)) {
      const { res, rej } = pending.get(msg.id);
      pending.delete(msg.id);
      msg.error ? rej(new Error(`${msg.error.message} (${JSON.stringify(msg.error.data ?? "")})`)) : res(msg.result);
      return;
    }
    if (msg.method === "Runtime.consoleAPICalled") {
      const text = (msg.params.args ?? []).map((a) => a.value ?? a.description ?? a.type).join(" ");
      consoleLines.push(`${msg.params.type}: ${text}`);
    }
    if (msg.method === "Runtime.exceptionThrown") {
      const d = msg.params.exceptionDetails;
      exceptions.push(d.exception?.description ?? d.text);
    }
    if (msg.method === "Log.entryAdded" && msg.params.entry.level === "error") {
      consoleLines.push(`log-error: ${msg.params.entry.text}`);
    }
  };

  const send = (method, params = {}) =>
    new Promise((res, rej) => {
      const id = nextId++;
      pending.set(id, { res, rej });
      ws.send(JSON.stringify({ id, method, params }));
    });

  const evaluate = async (expression) => {
    const r = await send("Runtime.evaluate", { expression, returnByValue: true, awaitPromise: true });
    if (r.exceptionDetails) throw new Error(r.exceptionDetails.exception?.description ?? "evaluate 失败");
    return r.result?.value;
  };

  try {
    await send("Page.enable");
    await send("Runtime.enable");
    await send("Log.enable");
    await send("Emulation.setDeviceMetricsOverride", {
      width,
      height,
      deviceScaleFactor: 1,
      mobile: false,
    });
    return await fn({ send, evaluate, consoleLines, exceptions, stderr: () => stderr });
  } finally {
    try { ws.close(); } catch {}
    child.kill();
    await sleep(120);
  }
}

export { sleep };