// Plumbing for driving a throwaway Theseus over CDP.
//
// This lives in the repo on purpose. It used to sit in scratchpad/, which is
// not tracked, and on 2026-10-22 a tidy-up deleted it along with the whole
// end-to-end suite — the only level of testing that catches breakage which
// exists solely in the browser. Rebuilding it cost an afternoon. Anything
// load-bearing belongs next to the code it tests.
//
// Two Windows lessons are baked in:
//
//   * Spawn electron.exe directly, never the .bin shim with shell:true. The
//     shim is a .cmd, so shell:true puts cmd.exe in between; killing the
//     child then kills cmd and orphans a dozen Electron processes that keep
//     the scratch profile locked, and the next run dies with EPERM.
//
//   * Kill by command line, not by pid tree. The developer very often has
//     their own Theseus running from this same checkout, and a blanket
//     Stop-Process -Name electron takes it down too. Every process we start
//     carries the scratch profile path in its command line, which is a
//     precise and safe filter.
import http from "node:http";
import fs from "node:fs";
import os from "node:os";
import path from "node:path";
import { spawn, execFileSync } from "node:child_process";
import { fileURLToPath } from "node:url";

export const HERE = path.dirname(fileURLToPath(import.meta.url));
export const ROOT = path.resolve(HERE, "../../..");          // TheseusNavigator/
export const PORT = 9333;
// The throwaway profile goes in the OS temp dir, NOT under this folder.
// addon-build/docx-editor/package.json declares "type": "module", and Node
// decides a file's module kind from the nearest package.json above it — so an
// add-on seeded into a profile under here is parsed as ESM and dies on its
// first require() with "require is not defined in ES module scope". The
// add-on is fine; the profile's location was not.
export const MARKER = "theseus-docx-e2e";
export const USER_DATA = path.join(os.tmpdir(), MARKER);

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

function electronExe() {
  const p = path.join(ROOT, "node_modules", "electron", "dist",
    process.platform === "win32" ? "electron.exe" : "electron");
  if (!fs.existsSync(p)) {
    throw new Error(`electron not installed at ${p}\nRun: cd ${ROOT} && npm install`);
  }
  return p;
}

/** Kill every Electron process started against our scratch profile. */
export function killStrays() {
  if (process.platform !== "win32") return;
  const needle = USER_DATA.replace(/\\/g, "\\\\");
  const ps = `1..8 | ForEach-Object {
    Get-CimInstance Win32_Process -Filter "Name='electron.exe'" |
      Where-Object { $_.CommandLine -like '*${needle}*' } |
      ForEach-Object { Stop-Process -Id $_.ProcessId -Force -ErrorAction SilentlyContinue }
    Start-Sleep -Milliseconds 400
  }`;
  try { execFileSync("powershell", ["-NoProfile", "-Command", ps], { stdio: "ignore" }); } catch {}
}

export function freshProfile() {
  killStrays();
  for (let i = 0; i < 12; i++) {
    try { fs.rmSync(USER_DATA, { recursive: true, force: true }); break; }
    catch { try { execFileSync("powershell", ["-NoProfile", "-Command", "Start-Sleep -Milliseconds 500"], { stdio: "ignore" }); } catch {} }
  }
  fs.mkdirSync(USER_DATA, { recursive: true });
}

export function boot({ onLine, keepProfile } = {}) {
  if (!keepProfile) freshProfile();
  const child = spawn(electronExe(), [ROOT, `--remote-debugging-port=${PORT}`], {
    cwd: ROOT,
    env: {
      ...process.env,
      THESEUS_USER_DATA: USER_DATA,
      // A throwaway instance running older code than the update channel
      // advertises will otherwise offer a real update, and one click
      // reinstalls over the developer's actual Theseus.
      THESEUS_NO_UPDATE_CHECK: "1",
    },
    stdio: ["ignore", "pipe", "pipe"],
  });
  const tail = [];
  const take = (b) => {
    const s = b.toString();
    tail.push(s); if (tail.length > 240) tail.shift();
    onLine?.(s);
  };
  child.stdout.on("data", take);
  child.stderr.on("data", take);
  return { child, tail, stop: () => { try { child.kill(); } catch {} killStrays(); } };
}

function getJson(p) {
  return new Promise((resolve, reject) => {
    http.get(`http://127.0.0.1:${PORT}${p}`, (res) => {
      let d = ""; res.on("data", (c) => (d += c));
      res.on("end", () => { try { resolve(JSON.parse(d)); } catch (e) { reject(e); } });
    }).on("error", reject);
  });
}

export async function waitForTarget(match, ms = 40000) {
  const stop = Date.now() + ms;
  while (Date.now() < stop) {
    try { const hit = (await getJson("/json")).find(match); if (hit) return hit; } catch {}
    await sleep(250);
  }
  throw new Error(`CDP target not found within ${ms}ms`);
}

export class Cdp {
  constructor(wsUrl) {
    this.id = 0; this.pending = new Map(); this.listeners = [];
    this.ws = new WebSocket(wsUrl);
    this.ready = new Promise((res, rej) => {
      this.ws.addEventListener("open", () => res());
      this.ws.addEventListener("error", () => rej(new Error("ws error")));
    });
    this.ws.addEventListener("message", (ev) => {
      const m = JSON.parse(typeof ev.data === "string" ? ev.data : Buffer.from(ev.data).toString("utf8"));
      if (m.id != null && this.pending.has(m.id)) {
        const { resolve, reject } = this.pending.get(m.id);
        this.pending.delete(m.id);
        m.error ? reject(new Error(m.error.message)) : resolve(m.result);
      } else for (const fn of this.listeners) fn(m);
    });
  }
  on(fn) { this.listeners.push(fn); }
  send(method, params = {}) {
    const id = ++this.id;
    return new Promise((resolve, reject) => {
      this.pending.set(id, { resolve, reject });
      this.ws.send(JSON.stringify({ id, method, params }));
    });
  }
  async ev(expression) {
    const r = await this.send("Runtime.evaluate", { expression, awaitPromise: true, returnByValue: true });
    if (r.exceptionDetails) {
      throw new Error("eval: " + (r.exceptionDetails.exception?.description || r.exceptionDetails.text));
    }
    return r.result?.value;
  }
  /** Collect console errors and uncaught exceptions into `sink`. */
  async watchErrors(sink) {
    await this.send("Runtime.enable");
    this.on((m) => {
      if (m.method === "Runtime.consoleAPICalled" && m.params.type === "error") {
        sink.push(m.params.args.map((a) => a.value ?? a.description).join(" "));
      } else if (m.method === "Runtime.exceptionThrown") {
        const d = m.params.exceptionDetails;
        sink.push("EXCEPTION " + (d.exception?.description || d.text));
      }
    });
  }
  close() { try { this.ws.close(); } catch {} }
}

export async function until(cdp, expr, ms = 20000, label = expr) {
  const stop = Date.now() + ms;
  let last;
  while (Date.now() < stop) {
    try { last = await cdp.ev(expr); if (last) return last; }
    catch (e) { last = e.message; }
    await sleep(200);
  }
  throw new Error(`timed out waiting for ${label} (last: ${JSON.stringify(last)?.slice(0, 200)})`);
}

export async function setFileInput(cdp, selector, absPath) {
  await cdp.send("DOM.enable");
  const { root } = await cdp.send("DOM.getDocument", { depth: -1 });
  const { nodeId } = await cdp.send("DOM.querySelector", { nodeId: root.nodeId, selector });
  if (!nodeId) throw new Error(`no node for ${selector}`);
  await cdp.send("DOM.setFileInputFiles", { files: [absPath], nodeId });
}