// lib.mjs — shared helpers for the lvmh cross-integration harness.
// Zero npm dependencies: Node >= 22 built-ins only (http, ws via global
// WebSocket, child_process, fs, net).

import { spawn, spawnSync } from "node:child_process";
import { randomUUID } from "node:crypto";
import * as fs from "node:fs";
import * as net from "node:net";
import * as path from "node:path";
import { fileURLToPath } from "node:url";

export const E2E_DIR = path.dirname(fileURLToPath(import.meta.url));
export const REPO_ROOT = path.resolve(E2E_DIR, "..");
export const DAEMON_DIR = path.join(REPO_ROOT, "daemon");
export const WEB_DIST = path.join(REPO_ROOT, "web", "dist");
export const TEST_TOKEN = "test-token";

// Bounded-wait deadlines (ms). All waits poll with a deadline, never fixed sleeps.
export const BOOT_TIMEOUT_MS = 120_000; // first `go run .` may need to compile
export const BUILD_TIMEOUT_MS = 300_000; // npm install + vite build
export const FRAME_WAIT_MS = 5_000; // one WS frame of interest
export const POLL_STEP_MS = 25;
export const KILL_WAIT_MS = 15_000; // daemon process-group teardown
export const CLOSE_WAIT_MS = 5_000;

export function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

// waitUntil polls fn (sync or async) until it returns truthy or the deadline
// passes. Always re-evaluates once after the deadline so a slow-but-successful
// predicate is not reported as a timeout.
export async function waitUntil(fn, timeoutMs = FRAME_WAIT_MS, stepMs = POLL_STEP_MS) {
  const deadline = Date.now() + timeoutMs;
  for (;;) {
    if (await fn()) return true;
    if (Date.now() >= deadline) return Boolean(await fn());
    await sleep(stepMs);
  }
}

export function sid(tag) {
  return `${tag}-${randomUUID().slice(0, 8)}`;
}

// Results collects check/xfail outcomes; printed live, one line per check.
export class Results {
  constructor() {
    this.entries = [];
    this.scenario = "";
  }
  group(name) {
    this.scenario = name;
    console.log(`\n── ${name} ──`);
  }
  record(status, name, detail, reason) {
    this.entries.push({ scenario: this.scenario, status, name, detail, reason });
    switch (status) {
      case "ok":
        console.log(`ok    ${name}`);
        break;
      case "fail":
        console.log(`FAIL  ${name}${detail ? " — " + detail : ""}`);
        break;
      case "xfail":
        console.log(`xfail ${name} [known: ${reason}]${detail ? " — " + detail : ""}`);
        break;
      case "xpass":
        console.log(`xpass ${name} [expected to fail, now passes — drop the xfail]`);
        break;
    }
  }
  check(name, ok, detail = "") {
    this.record(ok ? "ok" : "fail", name, detail);
  }
  // xfail: assertion documented as broken upstream. ok=true means the
  // underlying behavior unexpectedly works again (xpass), never a failure.
  xfail(name, ok, detail = "", reason = "") {
    this.record(ok ? "xpass" : "xfail", name, detail, reason);
  }
  summary() {
    const count = (s) => this.entries.filter((e) => e.status === s).length;
    return {
      ok: count("ok"),
      fail: count("fail"),
      xfail: count("xfail"),
      xpass: count("xpass"),
      total: this.entries.length,
    };
  }
}

// rest is a small fetch wrapper: token=null sends no Authorization header.
export async function rest(baseUrl, token, pathname, { method = "GET", body, headers = {} } = {}) {
  const h = { ...headers };
  if (token !== null) h.Authorization = `Bearer ${token}`;
  const opts = { method, headers: h };
  if (body !== undefined) {
    h["Content-Type"] = "application/json";
    opts.body = JSON.stringify(body);
  }
  const res = await fetch(baseUrl + pathname, opts);
  const text = await res.text();
  let json = null;
  try {
    json = JSON.parse(text);
  } catch {
    // non-JSON body (e.g. index.html) — text is still available
  }
  return { status: res.status, text, json, headers: res.headers };
}

// WSSock wraps the global (undici) WebSocket: buffers parsed frames and
// resolves deadline-bounded waiters.
export class WSSock {
  constructor(url, wsOptions) {
    this.url = url;
    this.frames = [];
    this.waiters = [];
    this.isOpen = false;
    this.failed = false;
    this.closed = false;
    this.ws = new WebSocket(url, wsOptions);
    this.ws.onopen = () => {
      this.isOpen = true;
    };
    this.ws.onerror = () => {
      this.failed = true;
    };
    this.ws.onclose = () => {
      this.closed = true;
      for (const w of this.waiters.splice(0)) {
        clearTimeout(w.timer);
        w.resolve(null);
      }
    };
    this.ws.onmessage = (ev) => {
      let f = null;
      try {
        f = JSON.parse(ev.data);
      } catch {
        return;
      }
      this.frames.push(f);
      for (const w of this.waiters.splice(0)) {
        if (w.pred(f)) {
          clearTimeout(w.timer);
          w.resolve(f);
        } else {
          this.waiters.push(w);
        }
      }
    };
  }
  send(obj) {
    this.ws.send(JSON.stringify(obj));
  }
  // opened resolves once the socket is open, failed or closed.
  async opened(timeoutMs = FRAME_WAIT_MS) {
    await waitUntil(() => this.isOpen || this.failed || this.closed, timeoutMs);
    return this.isOpen;
  }
  async waitForFrame(pred, timeoutMs = FRAME_WAIT_MS) {
    const hit = this.frames.find(pred);
    if (hit) return hit;
    return new Promise((resolve) => {
      const w = { pred, resolve, timer: null };
      w.timer = setTimeout(() => {
        const i = this.waiters.indexOf(w);
        if (i >= 0) this.waiters.splice(i, 1);
        resolve(null);
      }, timeoutMs);
      this.waiters.push(w);
    });
  }
  async waitForClose(timeoutMs = CLOSE_WAIT_MS) {
    return waitUntil(() => this.closed, timeoutMs);
  }
  close() {
    try {
      this.ws.close();
    } catch {
      // already dead
    }
  }
}

// agentClient connects exactly like the real plugin
// (plugin/lvmh-agent.ts: new WebSocket(url, { headers: { Authorization }})).
export async function agentClient(agentUrl, token) {
  const sock = new WSSock(agentUrl, { headers: { Authorization: `Bearer ${token}` } });
  if (!(await sock.opened())) {
    throw new Error(`agent WS failed to open: ${agentUrl}`);
  }
  return sock;
}

// webClient connects like the browser: token as query param on /ws.
export async function webClient(webUrl, token) {
  const sock = new WSSock(`${webUrl}?token=${encodeURIComponent(token)}`);
  if (!(await sock.opened())) {
    throw new Error(`web WS failed to open: ${webUrl}`);
  }
  return sock;
}

// hello/session snapshot per PROTOCOL.md.
export function sessionSnapshot(id, overrides = {}) {
  return {
    id,
    name: null,
    cwd: "/work/e2e",
    model: "glm-5.3",
    provider: "zai-renaud",
    agent: false,
    repo: null,
    startedAt: Date.now(),
    ...overrides,
  };
}

export function agentHello(sock, session) {
  sock.send({
    v: 1,
    type: "hello",
    sessionId: session.id,
    seq: 0,
    ts: Date.now(),
    session,
  });
  return sock.waitForFrame((f) => f.type === "welcome");
}

// agentEvent sends one agent→daemon frame; payload fields are flattened into
// the envelope (daemon README: "payload fields are flattened into the
// envelope object").
export function agentEvent(sock, sessionId, seq, type, payload = {}) {
  sock.send({ v: 1, sessionId, seq, ts: Date.now(), type, ...payload });
}

export async function freePort() {
  return new Promise((resolve) => {
    const srv = net.createServer();
    srv.listen(0, "127.0.0.1", () => {
      const port = srv.address().port;
      srv.close(() => resolve(port));
    });
  });
}

// startDaemon boots the REAL daemon via `go run .` (detached process group so
// the compiled child dies with it) and waits for /api/sessions readiness.
export async function startDaemon({ addr, dbPath, webdist, logPath, env }) {
  const logFd = fs.openSync(logPath, "a");
  const proc = spawn(
    "go",
    ["run", ".", "--addr", addr, "--db", dbPath, "--webdist", webdist],
    {
    cwd: DAEMON_DIR,
    env: { ...process.env, ...env },
    detached: true,
    stdio: ["ignore", logFd, logFd],
  });
  const ctl = {
    baseUrl: `http://${addr}`,
    agentUrl: `ws://${addr}/agent/ws`,
    webUrl: `ws://${addr}/ws`,
    pid: proc.pid,
    async stop(signal = "SIGTERM") {
      if (proc.exitCode === null) {
        try {
          process.kill(-proc.pid, signal); // whole group: go run + binary
        } catch {
          // already gone
        }
      }
      await new Promise((resolve) => {
        if (proc.exitCode !== null) return resolve();
        const t = setTimeout(resolve, KILL_WAIT_MS);
        proc.on("exit", () => {
          clearTimeout(t);
          resolve();
        });
      });
      try {
        fs.closeSync(logFd);
      } catch {
        // already closed
      }
    },
  };
  const ready = await waitUntil(async () => {
    try {
      const res = await fetch(`${ctl.baseUrl}/api/sessions`, {
        headers: { Authorization: `Bearer ${env.LVMH_TOKEN}` },
      });
      return res.status === 200;
    } catch {
      return false;
    }
  }, BOOT_TIMEOUT_MS, 100);
  if (!ready) {
    await ctl.stop("SIGKILL");
    throw new Error(`daemon not ready on ${addr} within ${BOOT_TIMEOUT_MS}ms — see ${logPath}`);
  }
  return ctl;
}

// ensureWebDist builds web/dist (npm install first when node_modules absent).
export function ensureWebDist() {
  if (fs.existsSync(path.join(WEB_DIST, "index.html"))) return false;
  const webDir = path.join(REPO_ROOT, "web");
  const run = (args) =>
    spawnSync(args[0], args.slice(1), { cwd: webDir, stdio: "inherit", timeout: BUILD_TIMEOUT_MS });
  if (!fs.existsSync(path.join(webDir, "node_modules"))) {
    const inst = run(["npm", "install", "--no-fund", "--no-audit"]);
    if (inst.status !== 0) throw new Error("npm install for web failed");
  }
  const build = run(["npm", "run", "build"]);
  if (build.status !== 0 || !fs.existsSync(path.join(WEB_DIST, "index.html"))) {
    throw new Error("web build failed");
  }
  return true;
}