/**
 * AI Software Factory — E2E: Performance (Phase 15)
 *
 * Browser-side performance budgets, asserted against a real dev stack. These
 * are the E2E complements to the k6 suite in tests/performance (which
 * measures server-side latency under load). Budgets are soft here (logged +
 * failed only on gross violations) because a shared dev machine is noisy;
 * the CI k6 suite owns the hard numbers.
 *
 * Budgets (PRODUCT-SPEC §Performance):
 *   - First contentful paint of a workspace page < 3s (dev), < 2s (prod target)
 *   - Time to interactive (editor ready) < 4s
 *   - Block keystroke → paint < 100ms (editor interaction < 50ms target)
 *   - Search keystroke → first result < 1s
 */
import { test, expect } from "../fixtures";
import { createPage } from "../utils/api";

const DEV_FCP_BUDGET_MS = 3_000;
const DEV_TTI_BUDGET_MS = 4_000;
const KEYSROKE_PAINT_BUDGET_MS = 100;
const SEARCH_RESULT_BUDGET_MS = 1_000;

test.describe("Performance — Phase 15 (E2E budgets)", () => {
  test("workspace page first contentful paint under budget", async ({
    authPage,
    freshWorkspace,
  }) => {
    const ws = await freshWorkspace("Perf Space");
    const metrics = await authPage.goto(`/w/${ws.id}`, { waitUntil: "networkidle" });
    void metrics;
    // Rely on PerformanceNavigationTiming captured via CDP for the FCP proxy.
    const fcp = await authPage.evaluate(async () => {
      // FCP via PerformanceObserver (falls back to load-event timing).
      return new Promise<number>((resolve) => {
        const observer = new PerformanceObserver((list) => {
          const entry = list.getEntries().find((e) => e.name === "first-contentful-paint");
          if (entry) {
            observer.disconnect();
            resolve(entry.startTime);
          }
        });
        observer.observe({ type: "paint", buffered: true });
        // Fallback: resolve with load timing if no paint event arrives.
        setTimeout(() => {
          const nav = performance.getEntriesByType("navigation")[0] as PerformanceNavigationTiming;
          observer.disconnect();
          resolve(nav ? nav.loadEventEnd : performance.now());
        }, 5_000);
      });
    });
    console.log(`[perf] FCP = ${Math.round(fcp)}ms (budget ${DEV_FCP_BUDGET_MS}ms)`);
    expect(fcp, `FCP ${fcp}ms exceeded budget ${DEV_FCP_BUDGET_MS}ms`).toBeLessThan(
      DEV_FCP_BUDGET_MS * 1.5,
    ); // 50% slack on dev; hard budget enforced in CI k6 suite.
  });

  test("editor becomes interactive under budget", async ({
    authPage,
    api,
    freshWorkspace,
  }) => {
    const ws = await freshWorkspace("Perf TTI Space");
    const page = await createPage(api, ws.id, { title: "TTI Page" });
    const started = Date.now();
    await authPage.goto(`/w/${ws.id}/page/${page.id}`, { waitUntil: "networkidle" });
    // Interactive = the first block is focusable/clickable.
    const firstBlock = authPage.locator('[data-testid^="block-"]').first();
    await expect(firstBlock).toBeVisible({ timeout: DEV_TTI_BUDGET_MS });
    const tti = Date.now() - started;
    console.log(`[perf] TTI (editor ready) = ${tti}ms (budget ${DEV_TTI_BUDGET_MS}ms)`);
    expect(tti).toBeLessThan(DEV_TTI_BUDGET_MS * 1.5);
  });

  test("keystroke-to-paint under budget in the editor", async ({
    authPage,
    api,
    freshWorkspace,
  }) => {
    const ws = await freshWorkspace("Perf Typing Space");
    const page = await createPage(api, ws.id, { title: "Typing Page" });
    await authPage.goto(`/w/${ws.id}/page/${page.id}`, { waitUntil: "networkidle" });
    const block = authPage.locator('[data-testid^="block-"]').first();
    await block.click();

    // Time a single keystroke → text visible in the DOM.
    const t0 = Date.now();
    await authPage.keyboard.type("x");
    await expect(block).toContainText("x");
    const dt = Date.now() - t0;
    console.log(`[perf] keystroke→paint = ${dt}ms (budget ${KEYSROKE_PAINT_BUDGET_MS}ms)`);
    // Dev machine slack: fail only on gross regression (3× budget).
    expect(dt, `keystroke→paint ${dt}ms`).toBeLessThan(KEYSROKE_PAINT_BUDGET_MS * 3);
  });

  test("search first result under budget", async ({
    authPage,
    api,
    freshWorkspace,
  }) => {
    const ws = await freshWorkspace("Perf Search Space");
    const token = `PERF-${Date.now()}-${Math.random().toString(36).slice(2, 8)}`;
    await createPage(api, ws.id, { title: `${token} fast lookup` });

    await authPage.goto(`/w/${ws.id}`, { waitUntil: "networkidle" });
    await authPage.getByTestId("search-button").click();
    const input = authPage.getByTestId("search-input");

    const t0 = Date.now();
    await input.fill(token);
    await expect(authPage.getByTestId("search-result").first()).toBeVisible({
      timeout: 5_000,
    });
    const dt = Date.now() - t0;
    console.log(`[perf] search→result = ${dt}ms (budget ${SEARCH_RESULT_BUDGET_MS}ms)`);
    // Indexing may lag the write on a fresh dev stack; allow 2× on first pass.
    expect(dt, `search→result ${dt}ms`).toBeLessThan(SEARCH_RESULT_BUDGET_MS * 2);
  });
});