// Real-browser assertions for scripts/smoke-deploy.sh in the split topology (ADR 0045). Runs inside a
// disposable container on the deployment's `edge` network and drives a headless Chromium, itself a
// disposable container on the same network, over the Chrome DevTools Protocol, with Node.js's own
// fetch and WebSocket and no other dependency.
//
//   node deploy-smoke-browser.mjs
//
// What only a browser can prove: that a person signing in on the Dashboard's hostname gets a session
// cookie on the API's hostname alone, that the Dashboard then imports a module's UI from the API's
// origin and the module's credentialed requests succeed under CORS, that the module's display page
// mounts on the API's origin with that same session, and that sign-out ends it. Output is one line
// per check; nothing printed carries a credential, cookie value, or response body.

function required(name) {
  const value = process.env[name];
  if (!value) {
    throw new Error(`${name} is required.`);
  }
  return value;
}

const apiOrigin = `https://${required("SMOKE_HOSTNAME")}`;
const dashboardOrigin = `https://${required("SMOKE_DASHBOARD_HOSTNAME")}`;
const apiHostname = new URL(apiOrigin).hostname;
const devtools = required("SMOKE_CDP_ADDRESS");
const timeoutMs = 30_000;

let failures = 0;
function check(condition, description) {
  console.log(`${condition ? "ok  " : "FAIL"} ${description}`);
  if (!condition) {
    failures += 1;
  }
}

/** The smallest Chrome DevTools Protocol client: numbered commands, flat sessions, and events. */
async function connect() {
  // The browser container was started moments ago; give it time to listen.
  // One overall deadline, with every attempt bounded, so a browser that never comes up fails the
  // run in seconds rather than waiting out TCP timeouts.
  const deadline = Date.now() + 30_000;
  let version;
  while (version === undefined) {
    try {
      const response = await fetch(`http://${devtools}/json/version`, {
        signal: AbortSignal.timeout(2_000),
      });
      version = await response.json();
    } catch {
      if (Date.now() > deadline) {
        throw new Error("The headless browser never answered.");
      }
      await new Promise((resolve) => setTimeout(resolve, 500));
    }
  }
  // Chromium names its WebSocket after the Host it was asked on; ask on the same address.
  const socketUrl = version.webSocketDebuggerUrl.replace(/^ws:\/\/[^/]+/u, `ws://${devtools}`);
  const socket = new WebSocket(socketUrl);
  await new Promise((resolve, reject) => {
    socket.addEventListener("open", resolve, { once: true });
    socket.addEventListener("error", () => reject(new Error("DevTools connection failed.")), {
      once: true,
    });
  });
  let nextId = 1;
  const pending = new Map();
  const listeners = [];
  socket.addEventListener("message", (event) => {
    const message = JSON.parse(String(event.data));
    if (message.id !== undefined) {
      const waiter = pending.get(message.id);
      pending.delete(message.id);
      if (message.error) {
        waiter?.reject(new Error(`DevTools ${waiter.method} failed.`));
      } else {
        waiter?.resolve(message.result);
      }
      return;
    }
    for (const listener of listeners) {
      listener(message);
    }
  });
  return {
    close: () => socket.close(),
    on: (listener) => listeners.push(listener),
    send(method, params = {}, sessionId = undefined) {
      const id = nextId;
      nextId += 1;
      socket.send(JSON.stringify({ id, method, params, ...(sessionId ? { sessionId } : {}) }));
      return new Promise((resolve, reject) => pending.set(id, { method, reject, resolve }));
    },
  };
}

const cdp = await connect();
const { targetId } = await cdp.send("Target.createTarget", { url: "about:blank" });
const { sessionId } = await cdp.send("Target.attachToTarget", { flatten: true, targetId });
const send = (method, params) => cdp.send(method, params, sessionId);

/** Every response and failure the page sees, for the API's origin. A CORS refusal is a
 * `loadingFailed` here, never a response. */
const responses = [];
const failed = [];
cdp.on((message) => {
  if (message.sessionId !== sessionId) {
    return;
  }
  if (message.method === "Network.responseReceived") {
    const { response, type } = message.params;
    responses.push({ status: response.status, type, url: response.url });
  } else if (message.method === "Network.loadingFailed") {
    failed.push(message.params);
  }
});
await send("Network.enable");
await send("Page.enable");
await send("Runtime.enable");
// A desktop-sized window: a module may reasonably decline to render its management UI on a small one.
await send("Emulation.setDeviceMetricsOverride", {
  deviceScaleFactor: 1,
  height: 1080,
  mobile: false,
  width: 1920,
});

async function evaluate(expression) {
  const result = await send("Runtime.evaluate", {
    awaitPromise: true,
    expression,
    returnByValue: true,
  });
  if (result.exceptionDetails) {
    throw new Error("A page expression threw.");
  }
  return result.result.value;
}

async function waitFor(expression, description) {
  const deadline = Date.now() + timeoutMs;
  while (Date.now() < deadline) {
    if (await evaluate(`Boolean(${expression})`).catch(() => false)) {
      return true;
    }
    await new Promise((resolve) => setTimeout(resolve, 250));
  }
  console.log(`FAIL timed out waiting for ${description}`);
  failures += 1;
  return false;
}

async function navigate(url) {
  await send("Page.navigate", { url });
}

const selector = (testId) => `document.querySelector('[data-testid="${testId}"]')`;

async function cookiesFor(origin) {
  const { cookies } = await send("Network.getCookies", { urls: [`${origin}/`] });
  return cookies;
}

// --- Sign in on the Dashboard's hostname -------------------------------------------------------
await navigate(`${dashboardOrigin}/`);
await waitFor(selector("login-email"), "the sign-in form on the Dashboard hostname");
await evaluate(`(() => {
  // React tracks input values through the native setter; assigning .value alone is invisible to it.
  const setValue = (element, value) => {
    Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, "value").set.call(element, value);
    element.dispatchEvent(new Event("input", { bubbles: true }));
  };
  setValue(${selector("login-email")}, ${JSON.stringify(required("SMOKE_OWNER_EMAIL"))});
  setValue(${selector("login-password")}, ${JSON.stringify(required("SMOKE_OWNER_PASSWORD"))});
  ${selector("login-email")}.form.requestSubmit();
})()`);
check(
  await waitFor(selector("host-shell"), "the signed-in Dashboard"),
  "a person signs in through the real form on the Dashboard hostname",
);

const apiCookies = await cookiesFor(apiOrigin);
const dashboardCookies = await cookiesFor(dashboardOrigin);
check(
  apiCookies.some((cookie) => cookie.httpOnly && cookie.secure && cookie.domain === apiHostname) &&
    dashboardCookies.length === 0,
  "the session cookie is host-only on the API hostname, and the Dashboard hostname holds none",
);

// --- A module UI, imported from the API's origin -------------------------------------------------
const moduleButton = "document.querySelector('[data-testid^=\"select-\"]')";
const hasModule = await waitFor(moduleButton, "a module in the Dashboard navigation");
if (hasModule) {
  const moduleId = await evaluate(`${moduleButton}.dataset.testid.slice("select-".length)`);
  await evaluate(`${moduleButton}.click()`);
  const mounted = await waitFor(
    `${selector("module-container")}?.childElementCount > 0 && !${selector("module-loading")} && !${selector("module-error")}`,
    "the module UI to mount",
  );
  check(
    mounted && !(await evaluate(`Boolean(${selector("module-error")})`)),
    `the ${moduleId} module UI mounts`,
  );
  // Give the module's first requests a moment to settle before judging them.
  await new Promise((resolve) => setTimeout(resolve, 1_000));
  check(
    responses.some(
      (response) =>
        response.url.startsWith(`${apiOrigin}/api/v1/module-ui/${moduleId}/`) &&
        response.status === 200,
    ),
    "its UI artifact was imported from the API's origin",
  );
  check(
    responses.some(
      (response) =>
        response.url.startsWith(`${apiOrigin}/api/v1/modules/${moduleId}`) &&
        response.status >= 200 &&
        response.status < 300,
    ),
    "its own credentialed API request to the API's origin succeeded under CORS",
  );
  const streams = responses.filter((response) => response.type === "EventSource");
  check(
    streams.every((response) => response.status === 200),
    `every realtime stream it opened was accepted (${streams.length} opened)`,
  );
}
// A CORS refusal or a blocked request is always a failure. A request the page itself cancelled (a
// module unmounting, a navigation) is not.
const refused = failed.filter(
  (failure) =>
    failure.corsErrorStatus !== undefined ||
    failure.blockedReason !== undefined ||
    !(failure.canceled || failure.errorText === "net::ERR_ABORTED"),
);
check(
  refused.length === 0,
  `no request from the Dashboard failed or was refused by CORS (${refused.length} refused)`,
);

// --- The display host, on the API's origin, with the same session --------------------------------
const displayPath =
  await evaluate(`fetch(${JSON.stringify(`${apiOrigin}/api/v1/dashboard/navigation`)}, {
  credentials: "include",
}).then((response) => response.json()).then((navigation) => {
  const entries = [...navigation.ungrouped, ...navigation.groups.flatMap((group) => group.modules)];
  return entries.find((entry) => entry.module.display !== null)?.module.display.url ?? null;
})`);
if (displayPath === null) {
  console.log("skip no installed module publishes a display");
} else {
  await navigate(`${apiOrigin}${displayPath}`);
  check(
    await waitFor(
      `${selector("display-module-container")}?.childElementCount > 0 && !${selector("display-error")}`,
      "the display to mount",
    ),
    "the module's display page mounts on the API hostname with the same session",
  );
  check(
    await waitFor(
      "navigator.serviceWorker.getRegistrations().then((registrations) => registrations.length > 0)",
      "the display's service worker",
    ),
    "the display's offline service worker registers on the API's origin",
  );
}

// --- Sign out on the Dashboard -------------------------------------------------------------------
await navigate(`${dashboardOrigin}/`);
await waitFor(selector("host-logout"), "the sign-out control");
await evaluate(`${selector("host-logout")}.click()`);
check(
  await waitFor(selector("login-email"), "the sign-in form after sign-out"),
  "sign-out returns the Dashboard to the sign-in form",
);
const principal = await evaluate(`fetch(${JSON.stringify(`${apiOrigin}/api/v1/principal`)}, {
  credentials: "include",
}).then((response) => response.json()).then((body) => body.kind)`);
check(principal === "anonymous", "after sign-out, the API answers anonymous to the same browser");

await cdp.send("Target.closeTarget", { targetId });
cdp.close();
if (failures > 0) {
  console.error(`${failures} check(s) failed`);
  process.exit(1);
}