import assert from "node:assert/strict";
import { chromium } from "playwright-core";

const password = process.env.E2E_PASSWORD;
assert.ok(password, "E2E_PASSWORD must be set");

async function completeKeycloakLogin(page) {
  for (let attempt = 1; attempt <= 2; attempt += 1) {
    await page.locator("#username").fill(
      process.env.E2E_USERNAME ?? "regular-user",
    );
    await page.locator("#password").fill(password);
    await page.locator("#kc-login").click();
    await page.waitForLoadState("domcontentloaded");

    if (page.url() === "http://localhost:8083/") {
      return;
    }
    if (attempt === 1) {
      await page.goto(
        "http://localhost:8083/oauth2/authorization/keycloak",
      );
      await page.waitForURL(/localhost:8080/u);
    }
  }
  throw new Error(`Keycloak login did not return to AP3: ${page.url()}`);
}

const browser = await chromium.launch({
  executablePath: process.env.CHROME_BIN ?? "/usr/bin/google-chrome",
  headless: true,
  args: ["--no-sandbox"],
});

try {
  const context = await browser.newContext();
  const page = await context.newPage();
  const browserRequests = [];
  page.on("request", (request) =>
    browserRequests.push({ method: request.method(), url: request.url() }),
  );

  await page.goto("http://localhost:8083");
  const authorizationRequestPromise = page.waitForRequest((request) =>
    request.url().includes(
      "/protocol/openid-connect/auth?response_type=code",
    ),
  );
  await page.locator("#login").click();
  const authorizationRequest = await authorizationRequestPromise;
  const authorizationUrl = new URL(authorizationRequest.url());
  assert.equal(authorizationUrl.searchParams.get("client_id"), "bff-confidential");
  assert.equal(authorizationUrl.searchParams.get("code_challenge_method"), "S256");
  assert.ok(authorizationUrl.searchParams.get("code_challenge"));

  await page.waitForURL(/localhost:8080/u);
  await completeKeycloakLogin(page);
  const callbackRequest = browserRequests.find(({ url }) =>
    url.startsWith("http://localhost:8083/login/oauth2/code/keycloak?"),
  );
  assert.ok(callbackRequest, "authorization response must use the BFF callback");
  assert.equal(callbackRequest.method, "GET");

  const boundaryResponsePromise = page.waitForResponse((response) =>
    response.url().endsWith("/bff/token-boundary"),
  );
  await page.locator("#inspect").click();
  const boundaryResponse = await boundaryResponsePromise;
  assert.equal(boundaryResponse.status(), 200);
  const boundary = await boundaryResponse.json();
  assert.equal(boundary.accessTokenStoredOnServer, true);
  assert.equal(boundary.refreshTokenStoredOnServer, true);
  assert.equal(boundary.browserTokenCount, 0);
  assert.equal(boundary.csrfProtectionEnabled, true);
  assert.equal(JSON.stringify(boundary).includes("access_token"), false);
  assert.equal(JSON.stringify(boundary).includes("refresh_token"), false);

  const proxyResponsePromise = page.waitForResponse((response) =>
    response.url().endsWith("/bff/api/me"),
  );
  await page.locator("#call-bff").click();
  const proxyResponse = await proxyResponsePromise;
  assert.equal(proxyResponse.status(), 200);
  const resource = await proxyResponse.json();
  assert.equal(resource.username, "regular-user");
  assert.ok(resource.audience.includes("keycloak-pattern-api"));

  assert.equal(
    browserRequests.some(({ url }) =>
      url.startsWith("http://localhost:8081/"),
    ),
    false,
    "the browser must not bypass the BFF",
  );
  assert.equal(
    browserRequests.some(({ url }) =>
      url.includes("/protocol/openid-connect/token"),
    ),
    false,
    "the token exchange must be server-to-server",
  );

  const cookies = await context.cookies("http://localhost:8083/");
  const sessionCookie = cookies.find((cookie) => cookie.name === "AP3_SESSION");
  assert.ok(sessionCookie);
  assert.equal(sessionCookie.httpOnly, true);
  assert.equal(sessionCookie.sameSite, "Lax");

  const storage = await page.evaluate(() => ({
    localStorage: Object.values(localStorage),
    sessionStorage: Object.values(sessionStorage),
    readableCookies: document.cookie,
  }));
  assert.deepEqual(storage.localStorage, []);
  assert.deepEqual(storage.sessionStorage, []);
  assert.equal(storage.readableCookies.includes("AP3_SESSION"), false);

  const missingCsrfResponse = await page.evaluate(async () => {
    const response = await fetch("/bff/api/preferences", {
      method: "POST",
      body: new URLSearchParams({ theme: "missing-csrf" }),
      headers: { "Content-Type": "application/x-www-form-urlencoded" },
    });
    return response.status;
  });
  assert.equal(missingCsrfResponse, 403);

  const csrfResponsePromise = page.waitForResponse((response) =>
    response.url().endsWith("/bff/csrf"),
  );
  const validChangeResponsePromise = page.waitForResponse(
    (response) =>
      response.url().endsWith("/bff/api/preferences") &&
      response.request().method() === "POST" &&
      response.status() === 200,
  );
  await page.locator("#change-with-csrf").click();
  const csrfResponse = await csrfResponsePromise;
  const validChangeResponse = await validChangeResponsePromise;
  assert.equal(csrfResponse.status(), 200);
  assert.equal(validChangeResponse.status(), 200);
  const validChange = await validChangeResponse.json();
  assert.equal(validChange.theme, "dark");

  const csrfCookies = await context.cookies("http://localhost:8083/");
  const csrfCookie = csrfCookies.find((cookie) => cookie.name === "XSRF-TOKEN");
  assert.ok(csrfCookie);
  assert.equal(csrfCookie.httpOnly, false);

  await page.goto("http://localhost:8088");
  const [forgedResponse] = await Promise.all([
    page.waitForNavigation(),
    page.evaluate(() => {
      const form = document.createElement("form");
      form.method = "POST";
      form.action = "http://localhost:8083/bff/api/preferences";
      const input = document.createElement("input");
      input.name = "theme";
      input.value = "attacker";
      form.append(input);
      document.body.append(form);
      form.submit();
    }),
  ]);
  assert.ok(forgedResponse);
  assert.equal(forgedResponse.status(), 403);

  await page.goto("http://127.0.0.1:8088");
  const crossSiteRequestPromise = page.waitForRequest(
    (request) =>
      request.url() === "http://localhost:8083/bff/api/preferences" &&
      request.method() === "POST",
  );
  await page.evaluate(() => {
    const form = document.createElement("form");
    form.method = "POST";
    form.action = "http://localhost:8083/bff/api/preferences";
    const input = document.createElement("input");
    input.name = "theme";
    input.value = "cross-site-attacker";
    form.append(input);
    document.body.append(form);
    form.submit();
  });
  const crossSiteRequest = await crossSiteRequestPromise;
  const crossSiteHeaders = await crossSiteRequest.allHeaders();
  assert.equal(
    (crossSiteHeaders.cookie ?? "").includes("AP3_SESSION="),
    false,
    "SameSite=Lax must omit the session cookie on a cross-site POST",
  );

  console.log(
    "pattern3 BFF verified: tokenless POST 403, CSRF header 200, SameSite=Lax session",
  );
} finally {
  await browser.close();
}