/**
 * public-store.test.ts — the emulated *"downloaded from the outerOverlay"*, in isolation.
 *
 * `cross-user-access.test.ts` proves the consequence end to end (Bob reads Alice's
 * public document from a bare reference). This file pins the primitive itself: what it
 * asks, what it refuses, and when it says nothing at all.
 */
import { test, expect, mock, afterEach } from "bun:test";
import { exposeReadCap, fetchReadCap, resetPublicStoreFetches } from "../src/emulated-verifier/public-store";
import { mintCap } from "../src/emulated-verifier/caps";
import { getCaps } from "../src/shared-wallet/bootstrap";
import { configure } from "../src/index";
import { configureStoreRegistry, setCurrentUser } from "../src/shared-wallet/bootstrap";
import { resetCaps, resetConfig, resetStoreRegistry } from "../src/shared-wallet/bootstrap";
import type { Nuri } from "../src/model/types";

const SHIM = "urn:ng-eventually:shim";
const SESSION = { sessionId: "sid-ps", privateStoreId: "PRIV-PS" };

interface Quad { g: string; s: string; p: string; o: string }

/** A fake `ng` holding just enough to answer the Header-branch `exposedReadCap` query. */
function inject() {
  const quads: Quad[] = [];
  const sparql_update = mock(async (...a: unknown[]) => {
    const query = a[1] as string;
    const anchor = a[2] as string;
    if (/^\s*DELETE WHERE/.test(query)) {
      for (let i = quads.length - 1; i >= 0; i--) if (quads[i]!.g === anchor) quads.splice(i, 1);
      return undefined;
    }
    const m = query.match(/<([^>]+)>\s+<([^>]+)>\s+"([^"]*)"/);
    if (m) quads.push({ g: anchor, s: m[1]!, p: m[2]!, o: m[3]! });
    return undefined;
  });
  // Documents the emulated broker cannot be asked about right now — an outage, a repo
  // this session has not synced, a rejected read. Scoped to ONE anchor on purpose: the
  // connection work `setCurrentUser` fires reads on its own account, and an outage that
  // took those down would be testing something else.
  const unreachable = new Set<string>();
  const sparql_query = mock(async (...a: unknown[]) => {
    if (unreachable.has(a[3] as string)) throw new Error("emulated broker: cannot serve that overlay");
    return {
      results: {
        bindings: quads
          .filter((q) => q.g === (a[3] as string) && q.p === `${SHIM}:exposedReadCap`)
          .map((q) => ({ c: { value: q.o } })),
      },
    };
  });
  configure({ ng: { doc_create: mock(async () => "did:ng:o:x"), sparql_update, sparql_query } as any, useShape: (() => {}) as any });
  configureStoreRegistry({ getSession: async () => SESSION });
  resetCaps();
  resetPublicStoreFetches();
  setCurrentUser(null);
  return { sparql_query, quads, unreachable };
}

afterEach(() => {
  resetConfig();
  resetStoreRegistry();
  resetCaps();
  setCurrentUser(null);
});

/**
 * Alice creates her note and exposes its cap — the two halves of what `createEntityDoc`
 * does for a `public` scope, in that order.
 *
 * The `mint` is not decoration: exposing writes to the document, and writing needs to
 * reach it. Without it this file only passed while the emulation happened to be
 * DISARMED, which made its results depend on which test file ran first — it went red in
 * `bun test <other-file> test/public-store.test.ts`. A fixture that exposes a cap for a
 * document nobody holds describes a state the library never produces.
 */
async function aliceExposesHerNote(): Promise<void> {
  getCaps().mint(PUB);
  await exposeReadCap(PUB, mintCap(PUB));
}

/** Arm the emulation without giving the current holder anything: some OTHER document. */
function armEmulation(): void {
  setCurrentUser("someone-else");
  getCaps().mint("did:ng:o:unrelated");
}

const PUB = "did:ng:o:pub" as Nuri;

test("a cap exposed on a document is downloaded by a holder that has nothing", async () => {
  inject();
  setCurrentUser("alice");
  await aliceExposesHerNote();

  setCurrentUser("bob");
  armEmulation();
  setCurrentUser("bob");
  expect(getCaps().capFor(PUB)).toBeUndefined();

  expect(await fetchReadCap(PUB)).toBe(true);
  expect(getCaps().capFor(PUB)).toBe(mintCap(PUB));
  expect(getCaps().isInPublicStore(PUB)).toBe(true);
});

test("a document that exposes nothing yields nothing — that is the normal case, not an error", async () => {
  inject();
  armEmulation();
  setCurrentUser("bob");
  expect(await fetchReadCap("did:ng:o:protected" as Nuri)).toBe(false);
  expect(getCaps().capFor("did:ng:o:protected" as Nuri)).toBeUndefined();
});

// A document speaks for itself and for nothing else. Without this, whoever can write
// into one public document could file caps for every document they care to name.
test("a cap naming ANOTHER document is refused, not filed", async () => {
  const { quads } = inject();
  setCurrentUser("alice");
  await aliceExposesHerNote();
  // Forge the exposed value so it names a different document.
  quads[0]!.o = mintCap("did:ng:o:someone-elses" as Nuri);

  armEmulation();
  setCurrentUser("bob");
  expect(await fetchReadCap(PUB)).toBe(false);
  expect(getCaps().capFor(PUB)).toBeUndefined();
  expect(getCaps().capFor("did:ng:o:someone-elses" as Nuri)).toBeUndefined();
});

test("inert while no cap has been issued at all — nothing to obtain, nothing asked", async () => {
  const { sparql_query } = inject();
  setCurrentUser("bob");
  expect(await fetchReadCap(PUB)).toBe(false);
  expect(sparql_query).toHaveBeenCalledTimes(0);
});

// REGRESSION (2026-08-07, found adversarially). The memo used to cache a BOOLEAN, so the
// first holder to ask triggered the download, the cap was filed for THEM, and every later
// holder got `true` while holding nothing — their next read was refused. Upstream a broker
// serving a pinned outer overlay answers EVERY asker.
test("a public store serves every asker, not only the first", async () => {
  inject();
  setCurrentUser("alice");
  await aliceExposesHerNote();
  armEmulation();

  setCurrentUser("bob");
  expect(await fetchReadCap(PUB)).toBe(true);
  expect(getCaps().capFor(PUB)).toBe(mintCap(PUB));

  setCurrentUser("carol");
  expect(await fetchReadCap(PUB)).toBe(true);
  expect(getCaps().capFor(PUB)).toBe(mintCap(PUB)); // …and she HOLDS it, not just "true"
});

test("asked once per document: the outcome is memoised, in both directions", async () => {
  const { sparql_query } = inject();
  // Counted PER DOCUMENT (the read is anchored on the one being asked about), not over
  // every read the process makes. `setCurrentUser` fires the connection work, which reads
  // on its own account in the background — none of it about this document — so a total
  // makes the memo's arithmetic depend on whatever else happens to be in flight. This is
  // the same assertion, about the read it is actually about.
  const asks = (nuri: string): number =>
    sparql_query.mock.calls.filter((c) => c[3] === nuri).length;

  setCurrentUser("alice");
  await aliceExposesHerNote();
  armEmulation();
  setCurrentUser("bob");

  await fetchReadCap(PUB);
  const afterHit = asks(PUB);
  await fetchReadCap(PUB); // held now → not even the memo is consulted
  expect(asks(PUB)).toBe(afterHit);

  const absent = "did:ng:o:nothing-here" as Nuri;
  await fetchReadCap(absent);
  const afterMiss = asks(absent);
  expect(afterMiss).toBe(1); // it WAS asked once — a memo over nothing proves nothing
  await fetchReadCap(absent); // a miss is remembered too
  expect(asks(absent)).toBe(afterMiss);
});

test("resetting the caps forgets the memo — a stale yes would hand back what is no longer held", async () => {
  const { sparql_query } = inject();
  setCurrentUser("alice");
  await aliceExposesHerNote();
  armEmulation();
  setCurrentUser("bob");
  await fetchReadCap(PUB);

  resetCaps(); // also calls resetPublicStoreFetches
  armEmulation();
  setCurrentUser("bob");
  const before = sparql_query.mock.calls.length;
  expect(await fetchReadCap(PUB)).toBe(true);
  expect(sparql_query.mock.calls.length).toBeGreaterThan(before); // asked again
});

// ── A failure is not an answer ───────────────────────────────────────────────
// REGRESSION (2026-09-15). `downloadReadCap` caught its own errors and returned the same
// `null` as a genuine absence, which the memo then held for the whole session: ONE
// transient outage recorded "no capability" for that document until the session ended.
// Deposits being consumed, the deposit was retired before its arm read anything — and
// every re-deposit sent to repair it met the same memoised `null` and was destroyed too.
//
// SECOND HALF (`1.0.0-dev.9`). That repair kept the two negatives apart in the MEMO and
// still handed the caller one value for both: a failure and an absence were both `false`.
// The tests below said so, and what they were really asserting was the memo's arithmetic
// - which is why every `asksAbout` count here is unchanged. What moved is the ANSWER: a
// download that could not happen now rejects, because three call sites read `false` as
// "this document exposes no cap" and turned a breakdown into a statement about the
// document. A genuine absence still answers `false`, and still only asks once.

/** How many times the network was asked ABOUT `nuri` — anchored reads only, so the
 *  connection work happening in the background on other documents does not count. */
function asksAbout(sparql_query: { mock: { calls: unknown[][] } }, nuri: string): number {
  return sparql_query.mock.calls.filter((c) => c[3] === nuri).length;
}

test("a fetch that FAILED is asked again, and the cap arrives once the broker recovers", async () => {
  const { sparql_query, unreachable } = inject();
  setCurrentUser("alice");
  await aliceExposesHerNote();
  armEmulation();
  setCurrentUser("bob");

  unreachable.add(PUB); // the broker cannot answer for this document
  // NOT `false`: "the store could not be asked" is not "the document exposes no cap".
  await expect(fetchReadCap(PUB)).rejects.toThrow(/UNKNOWN/);
  expect(asksAbout(sparql_query, PUB)).toBe(1);
  expect(getCaps().capFor(PUB)).toBeUndefined();

  unreachable.delete(PUB); // …and recovers
  expect(await fetchReadCap(PUB)).toBe(true);
  expect(asksAbout(sparql_query, PUB)).toBe(2); // asked AGAIN — the outage was not an answer
  expect(getCaps().capFor(PUB)).toBe(mintCap(PUB));
});

// The two negatives in one test, so neither half can be "fixed" by sacrificing the other:
// an absence was READ off the Header branch and is kept; a failure was never read at all.
test("an absence is remembered, a failure is not — the two negatives are not the same", async () => {
  const { sparql_query, unreachable } = inject();
  armEmulation();
  setCurrentUser("bob");

  const absent = "did:ng:o:exposes-nothing" as Nuri;
  expect(await fetchReadCap(absent)).toBe(false); // an ANSWER, and `false` is what it is
  expect(await fetchReadCap(absent)).toBe(false);
  expect(asksAbout(sparql_query, absent)).toBe(1); // read once, and the answer stands

  const unreached = "did:ng:o:cannot-ask" as Nuri;
  unreachable.add(unreached);
  // Not an answer at all, so it does not get to look like one. The two negatives now
  // differ in what the caller SEES, not only in what the memo keeps.
  await expect(fetchReadCap(unreached)).rejects.toThrow(/UNKNOWN/);
  await expect(fetchReadCap(unreached)).rejects.toThrow(/UNKNOWN/);
  expect(asksAbout(sparql_query, unreached)).toBe(2); // never answered, so asked every time
});

// The memo's OTHER job. Losing it would turn one cold read by N holders into N round-trips.
test("concurrent askers share ONE failing round-trip, and exactly one re-ask follows", async () => {
  const { sparql_query, unreachable } = inject();
  armEmulation();
  setCurrentUser("bob");

  unreachable.add(PUB);
  // `allSettled`, so all three outcomes are asserted rather than only the first: a
  // failure reaching one asker and not the others would be a worse bug than the one this
  // test was written for.
  const answers = await Promise.allSettled([
    fetchReadCap(PUB),
    fetchReadCap(PUB),
    fetchReadCap(PUB),
  ]);
  expect(answers.map((a) => a.status)).toEqual(["rejected", "rejected", "rejected"]);
  expect(asksAbout(sparql_query, PUB)).toBe(1); // one in-flight fetch served all three

  await expect(fetchReadCap(PUB)).rejects.toThrow(/UNKNOWN/);
  expect(asksAbout(sparql_query, PUB)).toBe(2); // and the failure left nothing behind
});

// `fetchReadCap` files for whoever is connected NOW, on EVERY call — the memo spares the
// round-trip, not the filing. A re-attempt after a failure must obey that too, or the
// recovered cap would land in the ring of whoever happened to hit the outage.
test("a cap obtained after a failure is filed for whoever is connected THEN", async () => {
  const { unreachable } = inject();
  setCurrentUser("alice");
  await aliceExposesHerNote();
  armEmulation();

  setCurrentUser("bob");
  unreachable.add(PUB);
  await expect(fetchReadCap(PUB)).rejects.toThrow(/UNKNOWN/);

  unreachable.delete(PUB);
  setCurrentUser("carol");
  expect(await fetchReadCap(PUB)).toBe(true);
  expect(getCaps().capFor(PUB)).toBe(mintCap(PUB)); // carol asked, carol holds it

  setCurrentUser("bob");
  expect(getCaps().capFor(PUB)).toBeUndefined(); // bob only ever met the outage
});

// The rejection has to be USABLE, or a caller meeting it learns no more than it did from
// `false`: it must name the document it is about, and it must not lose what actually went
// wrong underneath. `cause` is where the broker's own words survive.
test("the rejection names the document and keeps the original failure on `cause`", async () => {
  const { unreachable } = inject();
  armEmulation();
  setCurrentUser("bob");

  const doc = "did:ng:o:outage" as Nuri;
  unreachable.add(doc);
  const error = await fetchReadCap(doc).then(
    () => null,
    (e: unknown) => e,
  );
  expect(error).toBeInstanceOf(Error);
  expect((error as Error).message).toContain(doc);
  expect(String((error as Error).cause)).toContain("cannot serve that overlay");
});