import type { Page } from "@playwright/test";

import { expect, test } from "./setup/test";

import { SEAM_BANNERS_STORAGE_STATE_PATH } from "./setup/global-setup";

/**
 * The seam again, this time with chrome above it.
 *
 * `chrome-header-seam.spec.ts` measures the two header borders on a shell with
 * nothing above them. That is the state almost every session is in, and it is
 * also the only state in which the seam cannot break: with no banner painted,
 * the sidebar logo band and the top bar both start at y=0 whatever the layout
 * does with them.
 *
 * The banners are the case that breaks it. Each one is a full-width strip that
 * paints above the top bar, and while they lived INSIDE the content column they
 * pushed the top bar down while the sidebar band stayed where it was — one line
 * across the top of the app became two lines a banner-height apart, and three
 * can stack at once. Measured before the fix, on the French locale strip: one
 * banner offset the two borders by 66.5px at 768px and 61.0px at 1280px, and
 * all three together by 184.5px and 143.0px. So this spec forces them on and
 * measures the same two borders.
 *
 * ## How each banner is forced
 *
 * Honestly, through the condition the component actually reads — no injected
 * DOM, no test-only prop:
 *
 *   - **Maintainership** paints on a locale HealthLog does not hand-maintain.
 *     The context cookie is switched from `en` to `fr`, which is what a
 *     French-speaking user's browser carries. The swap happens with no page
 *     alive (`about:blank`): `I18nProvider` rewrites `healthlog-locale` from
 *     its own active locale on mount, so a cookie written under a live English
 *     page is reverted within the second.
 *   - **Shared record** paints while this session is inside somebody else's
 *     record, so this file switches into one. It used to fake the state instead
 *     — capture `/api/auth/me`, serve it back with the sharing block filled —
 *     because the switch is stamped on the SESSION ROW and moving the shared
 *     jar's row would move it for every spec holding that cookie. v1.37.0 took
 *     that shortcut away and gave back the thing that made it necessary: the
 *     record context is now proved across the payload, the fence store and the
 *     transition machine together, so a payload alone cannot produce it; and a
 *     spec that switches gets a login of its own
 *     (`SEAM_BANNERS_STORAGE_STATE_PATH`), which is what keeps this file's reach
 *     inside this file. The grant is the seeded whole-record READ on
 *     `e2e-level-read` — whole-record deliberately, because a narrowed one drops
 *     nav destinations and that is a different spec's subject.
 *   - **Offline** paints while `navigator.onLine` is false, which
 *     `context.setOffline(true)` produces for real, event and all. It is armed
 *     last because it is the only stage a navigation cannot follow, and it is
 *     armed after the switch for the same reason: entering a record is a
 *     network act.
 *
 * The demo banner is the one that cannot be forced from a spec: `DEMO_MODE` is
 * a server env var read by the root layout, and the suite shares one server
 * whose mutations would all be blocked by turning it on. It is the same strip
 * as the other three (`border-b px-3 py-2 text-xs`) in the same place in the
 * stack, so the three forced here exercise its geometry; nothing in the stack
 * is specific to which banner is in it.
 *
 * ## What is asserted
 *
 * Two properties, and the second is why the banners were hoisted above the
 * shell row rather than nudged inside it:
 *
 *   1. The seam holds — the two header borders keep sharing one line at every
 *      stack depth, so chrome above the header cannot displace one band and
 *      not the other.
 *   2. The shell stays inside the viewport — the banners are part of the
 *      `h-dvh` budget, not added on top of it, so no depth of stack introduces
 *      a page-level scrollbar. `<main>` remains the only vertical scroller.
 *
 * Property 2 is measured below `md` as well as above it, where there is no
 * sidebar and therefore no seam, because the scroll model is the half of the
 * layout that the hoist could have broken at that breakpoint. It used to get
 * there by running the file in the `chromium-mobile` project. It cannot any
 * more: this file moves a session's record selector, and a second PROJECT is
 * the one thing a separate cookie jar cannot fix — it would drive the same
 * session row from two browsers at once. So the narrow viewport is measured
 * inside the desktop project instead. Nothing is lost by that: the shell picks
 * its column layout and its scroller from width-driven rules, and the property
 * under test is a scroll height in CSS pixels.
 */

const LOCALE_COOKIE = "healthlog-locale";

/**
 * Every banner that can paint above the top bar, so a stage can assert how many
 * are up rather than only that the one it armed is.
 */
const BANNER_SLOTS = [
  "offline-banner",
  "shared-record-banner",
  "demo-banner",
  "maintainership-banner",
] as const;

type Band = { bottom: number; height: number; borderBottomWidth: number };

type ShellGeometry = {
  topBar: Band | null;
  sidebar: Band | null;
  bannerCount: number;
  bannerHeight: number;
  /** `scrollHeight - clientHeight` of the document's scrolling element. */
  documentOverflow: number;
  viewportHeight: number;
};

async function readShell(page: Page): Promise<ShellGeometry> {
  return page.evaluate(
    (slots: string[]) => {
      const band = (slot: string) => {
        const el = document.querySelector(`[data-slot="${slot}"]`);
        if (!el) return null;
        const rect = el.getBoundingClientRect();
        return {
          bottom: rect.bottom,
          height: rect.height,
          borderBottomWidth: parseFloat(
            getComputedStyle(el).borderBottomWidth || "0",
          ),
        };
      };
      const banners = slots
        .map((slot) => document.querySelector(`[data-slot="${slot}"]`))
        .filter((el): el is Element => el != null);
      const scroller = document.scrollingElement ?? document.documentElement;
      return {
        topBar: band("top-bar"),
        sidebar: band("sidebar-header"),
        bannerCount: banners.length,
        bannerHeight: banners.reduce(
          (sum, el) => sum + el.getBoundingClientRect().height,
          0,
        ),
        documentOverflow: scroller.scrollHeight - scroller.clientHeight,
        viewportHeight: window.innerHeight,
      };
    },
    BANNER_SLOTS as unknown as string[],
  );
}

/** The seeded whole-record READ grant this file switches into. */
const TARGET_USERNAME = "e2e-level-read";

const sharedRecordBanner = (page: Page) =>
  page.locator('[data-slot="shared-record-banner"]');

/**
 * Wait until the shell is usable rather than merely present.
 *
 * The hydration gate is the shell's own hold while it settles which record it
 * is showing. Measuring geometry through it would measure the placeholder. The
 * budget is deliberately larger than the suite default: ten seconds is a
 * statement about machine load, thirty about the gate never releasing.
 *
 * The paired positive control is the top bar and not an accessible name: half
 * of this file runs under the French strip, and a helper that reached for an
 * English label would be a helper that only works before the locale swap.
 */
async function expectShellReady(page: Page): Promise<void> {
  await expect(
    page.locator('[data-slot="record-scope-hydration-gate"]'),
  ).toHaveCount(0, { timeout: 30_000 });
  await expect(page.locator('[data-slot="top-bar"]')).toBeVisible({
    timeout: 30_000,
  });
}

/**
 * Start outside any record.
 *
 * The first stage asserts that nothing is painted above the top bar, and this
 * jar's session row keeps whatever the previous test — or the previous attempt,
 * on a CI retry — left it pointed at. Without this the "no banner" stage is a
 * statement about run order.
 */
async function ensureOwnRecord(page: Page): Promise<void> {
  const banner = sharedRecordBanner(page);
  if ((await banner.count()) === 0) return;
  await page.locator('[data-slot="shared-record-banner-exit"]').click();
  await expect(banner).toHaveCount(0, { timeout: 30_000 });
  await expectShellReady(page);
}

/**
 * Switch into the target record, and re-press the button if the switch did not
 * land.
 *
 * `POST /api/account/switch` is a compare-and-set on the session's record epoch
 * and the client reconciles and retries exactly once, which is the right call
 * for a person at a keyboard and one attempt short for a fixture that has just
 * navigated. Bounded at three and asserted: if the record is not entered by
 * then, that is a failure and it fails.
 */
async function enterSharedRecord(page: Page): Promise<void> {
  const banner = sharedRecordBanner(page);
  if ((await banner.count()) > 0) return;
  for (let attempt = 0; attempt < 3; attempt++) {
    await page.getByRole("button", { name: "User menu" }).first().click();
    await page.locator('[data-slot="account-switcher-trigger"]').click();
    const entry = page.locator(
      `[data-slot="account-switcher-entry"][data-account-username="${TARGET_USERNAME}"]`,
    );
    await expect(entry).toBeVisible();
    await entry.click();
    try {
      await expect(banner).toBeVisible({ timeout: 15_000 });
      await expectShellReady(page);
      return;
    } catch {
      // The switcher menu may still be open over the page; start clean.
      await page.goto("/");
      await expectShellReady(page);
    }
  }
  await expect(banner).toBeVisible({ timeout: 15_000 });
}

/**
 * Swap the context's pinned locale for one HealthLog ships as an AI-initial
 * translation, so the maintainership strip has a reason to paint.
 *
 * The page is parked on `about:blank` for the swap. `I18nProvider` mirrors its
 * ACTIVE locale into this cookie from an effect, so a cookie written while an
 * English page is mounted is reverted before the next navigation can read it —
 * measured, not assumed: the value flipped back inside one second. With no page
 * running, the next navigation sends `fr` and the provider then mirrors `fr`.
 */
async function armUnmaintainedLocale(page: Page): Promise<void> {
  const host = new URL(page.url()).hostname;
  await page.goto("about:blank");
  await page.context().addCookies([
    {
      name: LOCALE_COOKIE,
      value: "fr",
      domain: host,
      path: "/",
      expires: Math.floor(Date.now() / 1000) + 3600,
      httpOnly: false,
      secure: false,
      sameSite: "Lax",
    },
  ]);
}

/**
 * Take the context offline and make sure the banner hears about it.
 *
 * `setOffline` produces the real condition — `navigator.onLine` flips to false,
 * which is asserted here rather than assumed. Delivery of the `offline` EVENT
 * to an already-loaded page is the part that is not reliable: this spec caught
 * it missing once under a fully parallel run while passing three for three on
 * its own. `<OfflineBanner>` only reads `navigator.onLine` at mount and
 * otherwise waits on the event, so the event is re-dispatched here. That is the
 * notification, not the condition, and the condition is verified first.
 */
async function armOffline(page: Page): Promise<void> {
  // Let whatever is in flight land first. The Playwright context runs with
  // `serviceWorkers: "block"`, so nothing has pre-cached the app shell and a
  // lazily-imported chunk cut off mid-download throws the whole tree to the
  // global error boundary — "Failed to load chunk … from module …", no top bar,
  // no banner. That is a property of the harness rather than of the shell (a
  // real install serves those chunks from the worker cache), so it is waited
  // out rather than asserted on. Best-effort: a polling surface can keep the
  // network from ever going fully idle.
  await page.waitForLoadState("networkidle", { timeout: 5000 }).catch(() => {});
  await page.context().setOffline(true);
  await expect.poll(() => page.evaluate(() => navigator.onLine)).toBe(false);
  await page.evaluate(() => window.dispatchEvent(new Event("offline")));
}

/**
 * Serial, and for the same reason the file has its own jar: both tests move
 * this session row's record selector, and two workers running them at once
 * would move it under each other.
 */
test.describe.serial("app-chrome header seam under banners", () => {
  test.use({ storageState: SEAM_BANNERS_STORAGE_STATE_PATH });

  test("the header seam survives every depth of the banner stack", async ({
    page,
  }) => {
    // Four stages measured at two widths, with a full page load per stage, a
    // real record switch and a network settle either side of the offline one.
    // Comfortably inside the suite default when it runs alone; the default 30s
    // is not enough headroom for it on a loaded machine.
    test.setTimeout(90_000);

    await page.goto("/", { waitUntil: "domcontentloaded" });

    const topBar = page.locator('[data-slot="top-bar"]');
    const sidebarHeader = page.locator('[data-slot="sidebar-header"]');
    await expect(topBar).toBeVisible();
    await expect(sidebarHeader).toBeVisible();
    await expectShellReady(page);
    await ensureOwnRecord(page);

    // Each stage adds one banner and leaves the previous ones up, so the last
    // stage measures the whole stack rather than one banner at a time.
    //
    // `beforeResize` / `afterResize` exist for the offline stage alone: a
    // viewport change can pull a chunk the page has not loaded yet, and a chunk
    // fetch that fails with no network takes the whole shell down to the global
    // error boundary. Observed once under `--repeat-each=3`, as a missing top
    // bar and a "Failed to load chunk" screen. So the network comes back for
    // the resize and the stage re-arms after it — the measurement is still
    // taken offline, with the banner up.
    type Stage = {
      label: string;
      arm: () => Promise<void>;
      beforeResize?: () => Promise<void>;
      afterResize?: () => Promise<void>;
    };
    // The shared record is armed FIRST, before the locale swap: entering a
    // record is done through the switcher, and the switcher's controls are
    // reached by their accessible names. Under the French strip those names are
    // French, and a spec that drove the UI in one language while asserting the
    // labels of another would be testing the translation bundle.
    const stages: Stage[] = [
      { label: "no banner", arm: async () => {} },
      {
        label: "1 banner (shared record)",
        arm: async () => {
          await enterSharedRecord(page);
          await expect(sharedRecordBanner(page)).toBeVisible();
        },
      },
      {
        label: "2 banners (+ maintainership)",
        arm: async () => {
          await armUnmaintainedLocale(page);
          await page.goto("/", { waitUntil: "domcontentloaded" });
          await expectShellReady(page);
          await expect(
            page.locator('[data-slot="maintainership-banner"]'),
          ).toBeVisible();
          await expect(sharedRecordBanner(page)).toBeVisible();
        },
      },
      {
        label: "3 banners (+ offline)",
        arm: async () => {},
        beforeResize: async () => {
          await page.context().setOffline(false);
          await expect
            .poll(() => page.evaluate(() => navigator.onLine))
            .toBe(true);
        },
        afterResize: async () => {
          await armOffline(page);
          await expect(
            page.locator('[data-slot="offline-banner"]'),
          ).toBeVisible();
        },
      },
    ];

    // Stage outside, width inside: each banner is armed once and the resulting
    // stack measured at both widths. 768px is the `md` breakpoint where the
    // sidebar first appears — the narrowest shell that has a seam at all, and
    // the width where a banner is most likely to wrap onto a second line.
    for (const [index, stage] of stages.entries()) {
      await stage.arm();

      for (const width of [768, 1280] as const) {
        await stage.beforeResize?.();
        await page.setViewportSize({ width, height: 900 });
        await expect
          .poll(() => page.evaluate(() => window.innerWidth))
          .toBe(width);
        await stage.afterResize?.();
        await expect(topBar).toBeVisible();
        await expect(sidebarHeader).toBeVisible();

        const shell = await readShell(page);
        const at = `at ${width}px, ${stage.label}`;

        expect(shell.topBar, `top bar missing ${at}`).not.toBeNull();
        expect(shell.sidebar, `sidebar band missing ${at}`).not.toBeNull();
        const top = shell.topBar!;
        const side = shell.sidebar!;

        // Two borders that do not exist also "line up".
        expect(
          top.borderBottomWidth,
          `top bar has no bottom border ${at}`,
        ).toBeGreaterThan(0);
        expect(
          side.borderBottomWidth,
          `sidebar band has no bottom border ${at}`,
        ).toBeGreaterThan(0);

        // The stage armed what it said it armed. Without this a change that
        // stopped every banner from painting would make the seam assertion
        // below trivially true.
        expect(
          shell.bannerCount,
          `${at}: expected ${index} banner(s) painted, found ${shell.bannerCount}`,
        ).toBe(index);
        if (index > 0) {
          expect(
            shell.bannerHeight,
            `${at}: the banners paint no height, so this stage proves nothing`,
          ).toBeGreaterThan(0);
        }

        // The seam. A banner that displaces one band and not the other shows
        // up here as a step the size of the stack.
        expect(
          Math.abs(side.bottom - top.bottom),
          `${at}: header seam steps by ${(side.bottom - top.bottom).toFixed(
            2,
          )}px — the banner stack (${shell.bannerHeight.toFixed(
            2,
          )}px) is displacing one band and not the other`,
        ).toBeLessThan(1);

        // The banners come out of the viewport budget, not on top of it.
        expect(
          shell.documentOverflow,
          `${at}: the document scrolls by ${shell.documentOverflow.toFixed(
            2,
          )}px — the banner stack pushed the shell past the viewport`,
        ).toBeLessThan(1);
      }
    }
  });

  test("the banner stack never pushes the shell past the viewport", async ({
    page,
  }) => {
    // A real switch, a page load either side of it and a network settle before
    // the offline stage, at two widths.
    test.setTimeout(90_000);

    await page.goto("/", { waitUntil: "domcontentloaded" });
    await expect(page.locator('[data-slot="top-bar"]')).toBeVisible();
    await expectShellReady(page);

    await enterSharedRecord(page);
    await armUnmaintainedLocale(page);
    await page.goto("/", { waitUntil: "domcontentloaded" });
    await expectShellReady(page);
    await expect(
      page.locator('[data-slot="maintainership-banner"]'),
    ).toBeVisible();
    await expect(sharedRecordBanner(page)).toBeVisible();
    await armOffline(page);
    await expect(page.locator('[data-slot="offline-banner"]')).toBeVisible();

    // 393px is the narrow end — a Pixel-5 viewport, below `md`, where the shell
    // stacks in a column and there is no sidebar. 1280px is the wide end. The
    // network comes back for the resize and the stage re-arms after it, for the
    // reason written at the offline stage of the test above: a chunk fetch that
    // fails with no network takes the whole shell down to the error boundary.
    for (const [width, height] of [
      [393, 851],
      [1280, 900],
    ] as const) {
      await page.context().setOffline(false);
      await expect.poll(() => page.evaluate(() => navigator.onLine)).toBe(true);
      await page.setViewportSize({ width, height });
      await expect
        .poll(() => page.evaluate(() => window.innerWidth))
        .toBe(width);
      await armOffline(page);
      await expect(page.locator('[data-slot="offline-banner"]')).toBeVisible();

      const shell = await readShell(page);
      const at = `at ${width}px`;
      expect(shell.bannerCount, `${at}: the stack did not arm`).toBe(3);
      expect(shell.bannerHeight).toBeGreaterThan(0);
      expect(
        shell.documentOverflow,
        `${at}: the document scrolls by ${shell.documentOverflow.toFixed(
          2,
        )}px under a ${shell.bannerHeight.toFixed(2)}px banner stack`,
      ).toBeLessThan(1);

      // The top bar is still fully painted below the stack rather than pushed
      // off the bottom of the viewport.
      const top = shell.topBar!;
      expect(top.height, `${at}: the top bar paints no height`).toBeGreaterThan(
        32,
      );
      expect(
        top.bottom,
        `${at}: the banner stack pushed the top bar out of the viewport`,
      ).toBeLessThanOrEqual(shell.viewportHeight);
    }
  });
});