/**
 * The access gate's identity resolution.
 *
 * This is the piece whose failure is SILENT: get the order wrong and the broker iframe
 * reads an empty identity, provisions a second virtual user, and the returning user
 * lands in an empty space with no error anywhere. So the order is pinned, not trusted.
 */
import { getCurrentUser } from "../src/shared-wallet/bootstrap";
import { test, expect, afterEach } from "bun:test";
import { configure } from "../src/index";
import { init } from "../src/surface/lifecycle";
import { configureStoreRegistry, setCurrentUser } from "../src/shared-wallet/bootstrap";
import { resetConfig, resetStoreRegistry } from "../src/shared-wallet/bootstrap";
import { ensureIdentity } from "../src/shared-wallet/access-gate";

const KEY = "ng-eventually:identity";

/** A localStorage double — the real one is absent in `bun test`. */
function fakeStorage(initial: Record<string, string> = {}) {
  const map = new Map(Object.entries(initial));
  return {
    getItem: (k: string) => map.get(k) ?? null,
    setItem: (k: string, v: string) => void map.set(k, v),
    removeItem: (k: string) => void map.delete(k),
    get size() { return map.size; },
  };
}

/**
 * Which side of the broker frontier a page is on — the thing that decides whether the
 * barrier shows at all, so no page double may leave it unsaid.
 */
type Side = "top-level" | "in the broker iframe";

/**
 * The `window` a page of that side presents.
 *
 * `window.self !== window.top` is the signal the gate reads, and it is the one
 * `@ng-org/web`'s `init()` reads to decide whether to hand the page over. A double that
 * omitted `window` would silently be a top-level page — and every framed assertion here
 * would be quietly testing the other context.
 */
function fakeWindow(side: Side, onEvent?: (type: string, fn: (e: unknown) => void) => void) {
  const self = {};
  return {
    self,
    top: side === "top-level" ? self : {},
    addEventListener: (type: string, fn: (e: unknown) => void): void => onEvent?.(type, fn),
  };
}

/** Put the page in a given URL + storage state, on a given side, as the browser would. */
function inPage(search: string, storage: ReturnType<typeof fakeStorage>, side: Side) {
  const location = { search, href: "https://app.example" + search };
  Object.assign(globalThis, {
    location,
    localStorage: storage,
    history: { replaceState: (): void => {} },
    window: fakeWindow(side),
  });
  return { location };
}

/** Everything a page installs on the global object, so nothing leaks into the next test. */
const PAGE_GLOBALS = ["location", "localStorage", "history", "document", "window"] as const;

afterEach(() => {
  setCurrentUser(null);
  resetConfig();
  resetStoreRegistry();
  for (const name of PAGE_GLOBALS) Reflect.deleteProperty(globalThis, name);
});

/**
 * A broker over an EMPTY wallet: every read answers zero bindings, every write lands
 * nowhere, and `doc_create` mints a distinct NURI.
 *
 * These tests are about the gate, not about storage — but `ensureIdentity()` goes on to
 * connect the identity it settled, and connecting reaches the broker. It was handed `{}`
 * here, which no real platform ever presents: `sparql_query` was simply missing, and the
 * `TypeError` that produced was swallowed by the connection work. Now that a failed
 * connection is reported (`emulated-verifier/connect.ts`), a fake that cannot answer would
 * fail every test in this file for a reason none of them is about. An empty wallet — a page
 * where nobody has signed in yet — is a state the real system produces constantly, and it
 * changes nothing this file asserts: connecting finds no account and returns.
 */
function emptyWallet() {
  let created = 0;
  return {
    sparql_query: async (): Promise<unknown> => ({ results: { bindings: [] } }),
    sparql_update: async (): Promise<void> => undefined,
    doc_create: async (): Promise<string> => `did:ng:o:gate${++created}`,
  };
}

function configured(injectedInit?: (...args: unknown[]) => unknown) {
  configure({
    ng: emptyWallet() as never,
    useShape: (() => {}) as never,
    sharedWallet: { fileUrl: "/w.ngw", password: "pw" },
    // Only where a test needs a hand-over to come back FROM: the delegation is what the
    // polyfill's `init()` registers, and a page that never delegated was never handed over.
    ...(injectedInit ? { init: injectedInit } : {}),
  });
  // AFTER `configure`, which wires the registry onto the package's own session — a session
  // that only `init()` can open, and no page here calls it. The substitution is what lets
  // these tests reach the gate without a broker, and it must be the last word.
  configureStoreRegistry({
    getSession: async () => ({ sessionId: "s", privateStoreId: "did:ng:o:p" }),
    normalizeId: (id: string) => id.trim().replace(/^@/, "").toLowerCase(),
  });
}

test("an identity already set is left alone — the gate never re-asks", async () => {
  // The escape hatch: a caller that took charge of the identity itself is not a person
  // arriving at a page, so there is nobody to show a barrier to — top-level or not.
  configured();
  inPage("", fakeStorage(), "top-level");
  setCurrentUser("alice");
  await ensureIdentity();
  expect(getCurrentUser()).toBe("alice");
});

test("the URL parameter WINS over storage — it is the only thing that crosses the frontier", async () => {
  // The top-level page and the broker iframe have separate localStorage partitions, so a
  // value written on one side is not the value the other reads. The URL survives the
  // round-trip; storage does not. If storage won here, a user entering a second
  // identifier would keep being sent back to the first one's space.
  configured();
  inPage("?ng-id=fromurl", fakeStorage({ [KEY]: "fromstorage" }), "in the broker iframe");
  await ensureIdentity();
  expect(getCurrentUser()).toBe("fromurl");
});

test("the URL parameter is copied into THIS partition, so a plain reload still knows", async () => {
  configured();
  const storage = fakeStorage();
  inPage("?ng-id=carol", storage, "in the broker iframe");
  await ensureIdentity();
  expect(storage.getItem(KEY)).toBe("carol");
});

test("inside the iframe, with no parameter, storage answers — the barrier stays away", async () => {
  // The round-trip is behind us here, so a known identifier settles the question outright.
  // Top-level it does not, and the pair below says so.
  configured();
  inPage("", fakeStorage({ [KEY]: "dana" }), "in the broker iframe");
  await ensureIdentity();
  expect(getCurrentUser()).toBe("dana");
});

test("nothing known and no DOM to ask on → it refuses loudly", async () => {
  // Continuing silently would provision an anonymous virtual space, which is the failure
  // this module exists to prevent. The error names what the caller must do.
  configured();
  inPage("", fakeStorage(), "top-level");
  await expect(ensureIdentity()).rejects.toThrow(/no DOM to ask on/i);
});

test("no shared wallet configured → it refuses, rather than inventing a space", async () => {
  configure({ ng: {} as never, useShape: (() => {}) as never });
  inPage("", fakeStorage(), "top-level");
  await expect(ensureIdentity()).rejects.toThrow(/no shared wallet configured/i);
});

test("the URL value is NORMALIZED on the way in — `@Erin` and `erin` are one space", async () => {
  // Ported from the consumer's `identifiant-resolution` feature, and it caught a real
  // defect here: the gate normalized what a user TYPED but not what the URL carried, so
  // a link with `?ng-id=@Erin` keyed onto a different virtual user than the same person
  // typing `erin`. One normalizer — the injected one — for all three entry paths.
  configured();
  inPage("?ng-id=@Erin", fakeStorage(), "in the broker iframe");
  await ensureIdentity();
  expect(getCurrentUser()).toBe("erin");
});

test("a stored value is normalized too — an old entry cannot key onto a second space", async () => {
  configured();
  inPage("", fakeStorage({ [KEY]: "@Frank" }), "in the broker iframe");
  await ensureIdentity();
  expect(getCurrentUser()).toBe("frank");
});


// ── The parameter must be in the address bar before `init()` reads it ──────
//
// The round-trip to the broker is `ng.init()`'s job and stays there: it navigates to
// NextGraph's login with `window.location.href` AS IT FINDS IT. It knows nothing of
// `ng-id`, so the one thing the gate owes the round-trip is that the parameter is already
// in the address bar when `init()` runs — whatever settled the identity. Miss one path and
// the iframe reads no identity, provisions a second virtual user, and the returning user
// lands in an empty space with no error anywhere.
//
// So every test below asserts on `location.href`: that IS what `init()` would hand over.

const APP = "https://app.example/";

/** Let pending microtasks and timers run — the gate resolves on a click, then continues. */
function flush(): Promise<void> {
  return new Promise((r) => setTimeout(r, 0));
}

/** One element of the gate, holding the listeners the gate attaches to it. */
function fakeElement() {
  const handlers = new Map<string, ((e: unknown) => void)[]>();
  return {
    value: "",
    disabled: false,
    textContent: "",
    addEventListener(type: string, fn: (e: unknown) => void): void {
      handlers.set(type, [...(handlers.get(type) ?? []), fn]);
    },
    focus(): void {},
    fire(type: string, event: unknown = {}): void {
      for (const fn of handlers.get(type) ?? []) fn(event);
    },
  };
}

/**
 * A DOM for the gate, honest about its one limitation: it does not parse markup, so
 * `querySelector` hands back the input and the button it was built with rather than ones
 * found in the HTML. What that markup contains is the e2e's job; what these tests assert
 * is what happens AFTER a user submits. Everything else is a real element's behaviour: a
 * value, a disabled flag, listeners that fire.
 */
function fakeDom() {
  const input = fakeElement();
  const go = fakeElement();
  let mounted = 0;
  const root = {
    innerHTML: "",
    querySelector: (sel: string) => (sel === "input" ? input : sel === "button.go" ? go : null),
  };
  const host = {
    setAttribute: (): void => {},
    attachShadow: () => root,
    remove: (): void => void (mounted -= 1),
  };
  return {
    document: {
      createElement: () => host,
      body: { appendChild: (): void => void (mounted += 1) },
    },
    /** Is the barrier on screen? */
    get shown(): boolean {
      return mounted > 0;
    },
    /** What the field holds before anyone touches it — the prefill, seen as a user sees it. */
    get prefilled(): string {
      return input.value;
    },
    /** The button's label and whether it can be pressed — the frozen state, once entered. */
    get button(): { label: string; disabled: boolean } {
      return { label: go.textContent, disabled: go.disabled };
    },
    /** What a user does at the gate: type an identifier, then press Entrer. */
    submit(id: string): void {
      input.value = id;
      input.fire("input");
      go.fire("click");
    },
    /** What a returning user does: press Entrer on the field as they found it. */
    confirm(): void {
      go.fire("click");
    },
    /** A press of Enter in the field — which a real one still takes once the button is dead. */
    pressEnter(): void {
      input.fire("keydown", { key: "Enter" });
    },
  };
}

/**
 * Put the code in a real browser page.
 *
 * Faithful in the ways these assertions depend on, because a double that got them wrong
 * would prove nothing: `location.search` tracks `href`, and `history.replaceState` MOVES
 * `href` — as a real browser does, and as `init()` relies on when it reads the address bar
 * afterwards. A fake whose `replaceState` did nothing would let a broken gate pass.
 */
function inBrowser(opts: { url: string; storage?: ReturnType<typeof fakeStorage>; side?: Side }) {
  const storage = opts.storage ?? fakeStorage();
  const dom = fakeDom();
  const side = opts.side ?? "top-level";

  let href = opts.url;
  let reloads = 0;
  const location = {
    get href(): string { return href; },
    set href(next: string) { href = next; },
    get search(): string { return new URL(href).search; },
    reload: (): void => void (reloads += 1),
  };
  const history = {
    replaceState: (_state: unknown, _title: string, next: string): void => void (href = next),
  };
  // The page-level listeners the gate installs, kept so a test can play the browser event
  // that fires them. `pageshow` is the only one, and it cannot be simulated any other way.
  const listeners = new Map<string, ((e: unknown) => void)[]>();
  Object.assign(globalThis, {
    location,
    history,
    localStorage: storage,
    document: dom.document,
    window: fakeWindow(side, (type, fn) => listeners.set(type, [...(listeners.get(type) ?? []), fn])),
  });
  return {
    location,
    storage,
    dom,
    /**
     * How many times the page asked the browser to reload it — which must stay at zero.
     * A reload throws away everything the application holds in memory, and it cannot opt
     * out, observe it, or clean up first; the barrier is this package's screen, so putting
     * it back is this package's business and nothing else on the page may be disturbed.
     */
    get reloads(): number { return reloads; },
    /** Is anything listening for the browser restoring this page from its cache? */
    get armed(): boolean { return (listeners.get("pageshow") ?? []).length > 0; },
    /** How many such listeners — one hand-over or ten, the page needs exactly one. */
    get armings(): number { return (listeners.get("pageshow") ?? []).length; },
    /**
     * The browser restoring this page — from its back/forward cache (`persisted`) or
     * loading it afresh. Only the first is a return from a hand-over that did not complete.
     */
    pageshow(persisted: boolean): void {
      for (const fn of listeners.get("pageshow") ?? []) fn({ persisted });
    },
  };
}

test("settled at the GATE: the address bar carries the identifier `init()` will hand over", async () => {
  configured();
  const page = inBrowser({ url: APP });
  const settled = ensureIdentity();

  expect(page.dom.shown).toBe(true);
  // A first access knows nothing, so the field is bare — the prefill below has to be able
  // to fail, and it cannot if the field is filled whatever happened.
  expect(page.dom.prefilled).toBe("");
  page.dom.submit("Gina");

  expect(await settled).toBe("gina");
  expect(page.storage.getItem(KEY)).toBe("gina");
  expect(page.location.href).toBe(APP + "?ng-id=gina");
});

test("settled from STORAGE: the address bar gains the identifier — the silent case", async () => {
  // The one that bites. Storage does not cross the frontier: the top-level page and the
  // broker iframe read different localStorage partitions. A returning user is recognised
  // from storage and the URL stays bare, so unless the parameter is written HERE the
  // round-trip leaves without it and the user lands in a second, empty virtual space.
  //
  // Top-level, being recognised is not the same as being let through: the barrier shows,
  // with the field already filled, and the identifier reaches the address bar when the
  // person confirms it.
  configured();
  const page = inBrowser({ url: APP, storage: fakeStorage({ [KEY]: "dana" }) });
  const settled = ensureIdentity();
  expect(page.dom.prefilled).toBe("dana");
  page.dom.confirm();
  expect(await settled).toBe("dana");
  expect(page.location.href).toBe(APP + "?ng-id=dana");
});

test("settled from the URL: the parameter is rewritten NORMALIZED, not as the link spelled it", async () => {
  // `@Erin` and `erin` must be one virtual space, and it is the address bar that survives
  // the round-trip — so it is the normalized form that has to be in it, not the raw one.
  // The field shows the normalized form too: it is the identifier, not the spelling of the
  // link, that names the space they are about to enter.
  configured();
  const page = inBrowser({ url: APP + "?ng-id=@Erin" });
  const settled = ensureIdentity();
  expect(page.dom.prefilled).toBe("erin");
  page.dom.confirm();
  expect(await settled).toBe("erin");
  expect(page.location.href).toBe(APP + "?ng-id=erin");
});

test("settled by the CALLER: an identity set before the call still reaches the address bar", async () => {
  configured();
  const page = inBrowser({ url: APP });
  setCurrentUser("alice");
  expect(await ensureIdentity()).toBe("alice");
  expect(page.location.href).toBe(APP + "?ng-id=alice");
});

// ── Which side of the frontier decides whether the barrier shows ───────────
//
// Not whether the identity is known. A top-level page is one redirect away from the
// broker, and someone whose browser has lost the wallet — or never had it, the identifier
// having reached them by link — lands there on a static dead end with no way back but the
// browser's own Back button. The barrier is the only screen that hands the wallet out, so
// it shows on every top-level load and stands aside only past the round-trip, inside the
// iframe. Keying it on identity presence is what made it skip itself, silently, for
// exactly the people who needed it.

test("TOP-LEVEL, a known identifier fills the field — it does not skip the barrier", async () => {
  // The regression this pair exists for. `dana` is known from storage, and the barrier
  // shows anyway, prefilled: one click, no typing, and the wallet still on offer above it.
  configured();
  const page = inBrowser({ url: APP, storage: fakeStorage({ [KEY]: "dana" }) });
  const settled = ensureIdentity();

  expect(page.dom.shown).toBe(true);
  expect(page.dom.prefilled).toBe("dana");

  page.dom.confirm();
  expect(await settled).toBe("dana");
});

test("INSIDE THE IFRAME, the same known identifier stands the barrier down", async () => {
  // The other half, and what makes the one above an assertion rather than a tautology:
  // same identity, same storage, a DOM perfectly able to show a barrier — and no barrier,
  // because the round-trip is behind us. A returning user asked to confirm again on the
  // far side would be answering the same question twice for nothing.
  configured();
  const page = inBrowser({
    url: APP + "?ng-id=dana",
    storage: fakeStorage({ [KEY]: "dana" }),
    side: "in the broker iframe",
  });
  expect(await ensureIdentity()).toBe("dana");
  expect(page.dom.shown).toBe(false);
});

test("inside the iframe, a page that knows NOBODY still asks — the safe failure", async () => {
  // The last resort, and it must stay: an iframe reached without the parameter has no
  // identity to act as, and continuing would provision an anonymous virtual space that
  // looks like a working application. Asking is the honest outcome.
  configured();
  const page = inBrowser({ url: APP, side: "in the broker iframe" });
  const settled = ensureIdentity();
  expect(page.dom.shown).toBe(true);
  page.dom.submit("Hana");
  expect(await settled).toBe("hana");
});

// ── Coming BACK from a hand-over that dead-ended ──────────────────────────
//
// The broker sends a walletless visitor to a static page with no return path. Back is
// their only way out, and it restores this document from the browser's cache exactly as
// it left — barrier frozen, button dead, `init()` already delegated and never redirecting
// again. Without a reset there is nothing on that page left to press.
//
// The reset used to be `location.reload()`, and it was this package charging its own
// scaffolding to the application: a reload destroys whatever the application held in
// memory, and the application cannot opt out of it, observe it, or clean up first. So the
// barrier — which is entirely ours — is what comes back, and the page is left alone.
//
// Every test below therefore goes through the polyfill's `init()`: the hand-over IS that
// delegation, so a page that never delegated has nothing to come back from, and a fixture
// that played `pageshow` at it would be replaying a state no browser produces.

/**
 * A page wired the way an application wires one, with the injected `init` recording what
 * the address bar said each time it was handed over — which is what the broker would carry.
 *
 * It records rather than navigates: a delegation that really navigated would end the test
 * (and the document), and what is being judged here is that the SECOND one happens at all.
 */
function handingOverFrom(opts: { url: string; storage?: ReturnType<typeof fakeStorage>; side?: Side }) {
  const handOvers: string[] = [];
  configured((..._args: unknown[]) => {
    handOvers.push(String((globalThis as { location?: { href: string } }).location?.href));
    return Promise.resolve();
  });
  const page = inBrowser(opts);
  return { page, handOvers };
}

test("a top-level page that has been handed over holds its barrier, frozen", async () => {
  const { page, handOvers } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Gina");
  await delegated;

  expect(handOvers.length).toBe(1);
  // Not removed: the hand-over is a navigation, and a bare page is what the person would
  // come back to. This is also the state the revival below un-sticks.
  expect(page.dom.shown).toBe(true);
  expect(page.dom.button).toEqual({ label: "Accès en cours…", disabled: true });
  expect(page.armed).toBe(true);
});

test("restored from the browser's cache, the BARRIER comes back to life — the page is not reloaded", async () => {
  const { page, handOvers } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Gina");
  await delegated;
  expect(handOvers.length).toBe(1);

  page.pageshow(true);

  // Nothing outside the barrier is touched: no reload, so whatever the application held in
  // memory is still there, and it never had to be told to hold nothing.
  expect(page.reloads).toBe(0);
  // And the barrier is usable again — the same screen, the field as they left it, the
  // button live and labelled to be pressed rather than frozen on what already failed.
  expect(page.dom.shown).toBe(true);
  expect(page.dom.prefilled).toBe("Gina");
  expect(page.dom.button).toEqual({ label: "Entrer", disabled: false });
});

test("confirming the revived barrier hands the page over AGAIN — which is the way out", async () => {
  // The point of reviving it. A live button that led nowhere would be the same dead end
  // with a friendlier face: what the person needs is the hand-over to happen again, and
  // `init()` cannot do it — it delegated once and its promise is long answered.
  const { page, handOvers } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Gina");
  await delegated;

  page.pageshow(true);
  page.dom.confirm();

  expect(handOvers).toEqual([APP + "?ng-id=gina", APP + "?ng-id=gina"]);
  expect(page.reloads).toBe(0);
  // Handing over again freezes it again — a second round-trip is in flight, and the same
  // listener is still there for a second return.
  expect(page.dom.button).toEqual({ label: "Accès en cours…", disabled: true });
});

test("someone who comes back to change their identifier leaves with the NEW one", async () => {
  // Not a hypothetical: the dead end they came back from is exactly where a person
  // discovers they entered the wrong identifier. So the second confirmation is a full
  // settling — normalized, in the address bar, and the identity the page now acts as —
  // and not a replay of the value that left.
  const { page, handOvers } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Gina");
  await delegated;

  page.pageshow(true);
  page.dom.submit("Hank");

  expect(page.location.href).toBe(APP + "?ng-id=hank");
  expect(page.storage.getItem(KEY)).toBe("hank");
  expect(getCurrentUser()).toBe("hank");
  expect(handOvers[1]).toBe(APP + "?ng-id=hank");
  expect(page.reloads).toBe(0);
});

test("a barrier handing over ignores a second Enter — one listener, one hand-over", async () => {
  // The button is dead by then, and a dead button dispatches no click — but the field
  // still takes the key. Twice acted on would be twice handed over, and twice armed would
  // leave a listener behind on every round-trip.
  const { page, handOvers } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Gina");
  await delegated;

  page.dom.pressEnter();

  expect(handOvers.length).toBe(1);
  expect(page.armings).toBe(1);
});

test("an ordinary load is not a return — the barrier is left frozen", async () => {
  // `pageshow` fires on every load, cached or not. Reviving on the plain one would arm the
  // button of a page whose hand-over is still on its way out, and offer a second one.
  const { page, handOvers } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Gina");
  await delegated;

  page.pageshow(false);

  expect(page.reloads).toBe(0);
  expect(page.dom.button).toEqual({ label: "Accès en cours…", disabled: true });
  page.dom.confirm();
  expect(handOvers.length).toBe(1);
});

test("someone still AT the barrier is not reset — what they typed survives", async () => {
  // Armed on the way OUT, not at load: a person who wandered off before confirming comes
  // back to the page they left, with the field as they left it and the button still live.
  // So the arming has to straddle the confirmation, and this pins both sides of it.
  const { page } = handingOverFrom({ url: APP });
  const delegated = init(() => {}, true, []);
  expect(page.armed).toBe(false);

  // A barrier left unanswered would hold the settling in flight and every later test would
  // JOIN it instead of raising its own — so answer it, always.
  page.dom.submit("Gina");
  await delegated;
  expect(page.armed).toBe(true);
});

test("inside the iframe nothing is armed — there was no hand-over to come back from", async () => {
  const { page } = handingOverFrom({ url: APP, side: "in the broker iframe" });
  const delegated = init(() => {}, true, []);
  page.dom.submit("Hana");
  await delegated;

  // And the barrier IS removed here: the application renders behind it.
  expect(page.dom.shown).toBe(false);
  expect(page.armed).toBe(false);
});

test("a storage that refuses writes does not cost the round-trip its parameter", async () => {
  // Private mode, quota, a sandboxed document: `setItem` throws. Storage is only
  // same-partition convenience — the address bar is what crosses the frontier — so the two
  // writes must fail independently. Sharing one `try` would let the lesser failure take
  // the greater one down, silently.
  configured();
  const refuses = {
    getItem: () => null,
    setItem: (): never => {
      throw new Error("QuotaExceededError: the storage is full or write-protected");
    },
    removeItem: (): void => {},
  };
  const page = inBrowser({ url: APP });
  Object.assign(globalThis, { localStorage: refuses });
  setCurrentUser("alice");
  expect(await ensureIdentity()).toBe("alice");
  expect(page.location.href).toBe(APP + "?ng-id=alice");
});

test("an address bar that cannot be rewritten fails safely — the gate asks again", async () => {
  // A sandboxed document without `allow-same-origin` throws on `replaceState`. Nothing
  // here can substitute for it: the URL `init()` hands over is the browser's, not ours. So
  // signing in must still succeed locally, and the identity must still be remembered —
  // the round-trip loses it and the gate asks again, which is the safe failure.
  configured();
  const page = inBrowser({ url: APP, storage: fakeStorage({ [KEY]: "dana" }) });
  Object.assign(globalThis, {
    history: {
      replaceState: (): never => {
        throw new Error("SecurityError: the document is sandboxed and lacks allow-same-origin");
      },
    },
  });
  const settled = ensureIdentity();
  page.dom.confirm();
  expect(await settled).toBe("dana");
  expect(page.storage.getItem(KEY)).toBe("dana");
  expect(page.location.href).toBe(APP);
});