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

const root = path.resolve(import.meta.dirname, "..");
const appPort = Number(process.env.E2E_PORT ?? 3100);
const fixturePort = Number(process.env.FIXTURE_PORT ?? 3101);
const baseUrl = `http://127.0.0.1:${appPort}`;
const children = [];

function run(command, args, options = {}) {
  return new Promise((resolve, reject) => {
    const child = spawn(command, args, { cwd: root, env: process.env, stdio: "inherit", ...options });
    child.once("error", reject);
    child.once("exit", (code) => code === 0
      ? resolve()
      : reject(new Error(`${command} ${args.join(" ")} exited with code ${code ?? "null"}`)));
  });
}

function start(command, args, env = {}) {
  const child = spawn(command, args, {
    cwd: root,
    env: { ...process.env, ...env },
    stdio: "inherit",
  });
  children.push(child);
  return child;
}

async function waitFor(url) {
  for (let attempt = 0; attempt < 60; attempt += 1) {
    try {
      const response = await fetch(url);
      if (response.ok) return;
    } catch {
      // The process is still starting.
    }
    await new Promise((resolve) => setTimeout(resolve, 250));
  }
  throw new Error(`Timed out waiting for ${url}`);
}

async function stopChildren() {
  await Promise.all(children.map((child) => new Promise((resolve) => {
    if (child.exitCode !== null) return resolve();
    child.once("exit", resolve);
    child.kill("SIGTERM");
    setTimeout(() => {
      if (child.exitCode === null) child.kill("SIGKILL");
    }, 3_000).unref();
  })));
}

async function prepareStandaloneServer() {
  const standaloneRoot = path.join(root, ".next", "standalone");
  await fs.rm(path.join(standaloneRoot, "public"), { recursive: true, force: true });
  await fs.rm(path.join(standaloneRoot, ".next", "static"), { recursive: true, force: true });
  await fs.cp(path.join(root, "public"), path.join(standaloneRoot, "public"), { recursive: true });
  await fs.cp(
    path.join(root, ".next", "static"),
    path.join(standaloneRoot, ".next", "static"),
    { recursive: true },
  );
}

const npm = process.platform === "win32" ? "npm.cmd" : "npm";

try {
  await run(npm, ["run", "build"]);
  await prepareStandaloneServer();
  start(process.execPath, ["e2e/fixture-server.mjs"], { FIXTURE_PORT: String(fixturePort) });
  start(process.execPath, [".next/standalone/server.js"], {
    CALENDAR_URL: `http://127.0.0.1:${fixturePort}/calendar.ics`,
    APP_URL: baseUrl,
    CORS_ORIGIN: baseUrl,
    PORT: String(appPort),
    HOSTNAME: "127.0.0.1",
  });
  await waitFor(`${baseUrl}/api/events`);
  await run(process.execPath, ["--test", "e2e/smoke.e2e.mjs"], {
    env: { ...process.env, E2E_BASE_URL: baseUrl },
  });
} finally {
  await stopChildren();
}