import { expect, test } from "bun:test";
import { indexing, type Indexing } from "../src/indexing";
import type { Nuri } from "../src/port";
import { ENTRY_VALUE, INDEX_FIELD } from "../src/vocabulary";
import { FakeNextGraph, publishObject } from "./fake-nextgraph";

/**
 * Each actor gets their own handle, and they share no variable carrying business
 * data. The ONE value that crosses between them is the index's NURI — and that
 * crossing is the mechanism this design names: an application references the
 * index's NURI in its own source. `hardcodedInAppSource` marks every such
 * crossing, so anything else moving between actors would stand out.
 */
const PUBLISHED_AT = "http://schema.org/datePublished";
const NAME = "http://schema.org/name";

function hardcodedInAppSource(nuri: Nuri): Nuri {
  return nuri;
}

type Port = ReturnType<FakeNextGraph["portFor"]>;

function world(): {
  network: FakeNextGraph;
  alice: Indexing;
  bob: Indexing;
  carol: Indexing;
  ports: { alice: Port; bob: Port; carol: Port };
} {
  const network = new FakeNextGraph();
  const ports = {
    alice: network.portFor("alice"),
    bob: network.portFor("bob"),
    carol: network.portFor("carol"),
  };
  return {
    network,
    alice: indexing(ports.alice),
    bob: indexing(ports.bob),
    carol: indexing(ports.carol),
    ports,
  };
}

// --- creating an index ----------------------------------------------------

test("any user creates an index in their public store, and it declares its field", async () => {
  const { alice, ports } = world();

  const index = await alice.createIndex(PUBLISHED_AT);

  // An ordinary document: what makes it an index is the field it declares, which
  // a reader going straight to `readUnion` sees on the index's own subject.
  const subjects = await ports.alice.readDocument(index);
  const self = subjects.find((s) => s.subject === index);
  expect(self?.props[INDEX_FIELD]).toEqual([PUBLISHED_AT]);

  expect(await alice.read(index)).toEqual([]);
});

test("reading a document that declares no index field is refused, not answered empty", async () => {
  const { alice, ports } = world();
  const ordinary = await ports.alice.createPublicDocument();
  await expect(alice.read(ordinary)).rejects.toThrow(/declares no index field/);
});

// --- the whole loop, across three people ----------------------------------

test("a stranger refers an object, the owner curates, and anyone reads the result", async () => {
  const { alice, bob, carol, ports } = world();

  // Alice creates the index and its NURI goes into the application's source.
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));

  // Bob, who owns nothing of Alice's, creates his own public object and hands the
  // index a reference to it. He needs no permission and gets no write.
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  await bob.refer(indexNuri, article);

  // Nothing is in the index until its owner acts.
  expect(await carol.read(indexNuri)).toEqual([]);

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toEqual([{ result: "indexed", object: article, value: "2026-03-04" }]);

  // Carol knows only the NURI from the application's source, and gets the entry.
  const entries = await carol.read(indexNuri);
  expect(entries).toEqual([{ object: article, value: "2026-03-04" }]);

  // The entry is a usable reference: Carol opens the object straight from it,
  // holding nothing but what she read out of the index.
  const first = entries[0];
  expect(first).toBeDefined();
  const opened = await ports.carol.readDocument(first!.object);
  expect(opened[0]?.props[PUBLISHED_AT]).toEqual(["2026-03-04"]);
});

test("an entry is a subject keyed by the object's NURI, so reading needs nothing new", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  await bob.refer(indexNuri, article);
  await alice.curate(indexNuri);

  // What `readUnion([indexNuri])` hands an application that never loaded this
  // package: the index's own subject, plus one subject per indexed object.
  const subjects = await ports.bob.readDocument(indexNuri);
  const entry = subjects.find((s) => s.subject === article);
  expect(entry?.props[ENTRY_VALUE]).toEqual(["2026-03-04"]);
  expect(subjects.map((s) => s.subject).sort()).toEqual([article, indexNuri].sort());
});

// --- only the owner curates ----------------------------------------------

test("nobody but the index's owner can curate it: the inbox is refused to others", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  await bob.refer(indexNuri, article);

  await expect(bob.curate(indexNuri)).rejects.toThrow(/may only READ your own/);
  expect(await alice.read(indexNuri)).toEqual([]);
});

test("nobody but the owner writes an index, whatever they know about it", async () => {
  const { alice, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));

  await expect(
    ports.bob.addLiteralProperty(indexNuri, "did:ng:o:forged", ENTRY_VALUE, "2999-01-01"),
  ).rejects.toThrow(/only a document's owner writes to it/);
  await expect(ports.bob.openInbox(indexNuri)).rejects.toThrow(/may not open an inbox/);
});

test("an index whose owner never opened an inbox refuses a deposit rather than losing it", async () => {
  const { bob, ports } = world();
  // A public document that was never made into an index: no inbox was opened.
  const notAnIndex = hardcodedInAppSource(await ports.alice.createPublicDocument());
  await expect(bob.refer(notAnIndex, "did:ng:o:doc-9")).rejects.toThrow(/has no inbox/);
});

// --- adding is idempotent -------------------------------------------------

test("the same reference deposited twice produces one entry", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");

  await bob.refer(indexNuri, article);
  await bob.refer(indexNuri, article);

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toEqual([
    { result: "indexed", object: article, value: "2026-03-04" },
    { result: "unchanged", object: article },
  ]);
  expect(await alice.read(indexNuri)).toEqual([{ object: article, value: "2026-03-04" }]);
});

test("curating twice changes nothing the second time — deposits are not consumed", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  await bob.refer(indexNuri, article);

  await alice.curate(indexNuri);
  const before = await alice.read(indexNuri);

  const second = await alice.curate(indexNuri);
  expect(second.outcomes).toEqual([{ result: "unchanged", object: article }]);
  expect(await alice.read(indexNuri)).toEqual(before);
});

// --- a read that cannot answer must never cost the index anything ---------

test("a reference the broker cannot resolve is reported, and adds nothing", async () => {
  const { network, alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));

  const first = await publishObject(ports.bob, PUBLISHED_AT, "2026-01-01");
  await bob.refer(indexNuri, first);
  await alice.curate(indexNuri);

  const second = await publishObject(ports.bob, PUBLISHED_AT, "2026-02-02");
  await bob.refer(indexNuri, second);
  network.breakReadsOf(second, "broker unreachable");

  const report = await alice.curate(indexNuri);
  const unresolved = report.outcomes.filter((o) => o.result === "unresolved");
  expect(unresolved).toHaveLength(1);
  expect(unresolved[0]).toMatchObject({ object: second });

  // THE POINT: the entry that was already there is untouched.
  expect(await alice.read(indexNuri)).toEqual([{ object: first, value: "2026-01-01" }]);
});

test("an already-indexed object survives its own reads failing, and is not even re-read", async () => {
  const { network, alice, bob, carol, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-01-01");
  await bob.refer(indexNuri, article);
  await alice.curate(indexNuri);

  // A passer-by nudges the index about an entry she found IN IT. Carol obtains
  // the reference the only way she could in a real application — by reading the
  // index whose NURI her app hardcodes — rather than being handed it by the test.
  const seen = await carol.read(indexNuri);
  const noticed = seen[0];
  expect(noticed).toBeDefined();

  // …and only then does the object become unreachable.
  network.breakReadsOf(article, "broker unreachable");
  await carol.refer(indexNuri, noticed!.object);

  const report = await alice.curate(indexNuri);
  expect(report.outcomes.every((o) => o.result === "unchanged")).toBe(true);
  expect(await alice.read(indexNuri)).toEqual([{ object: article, value: "2026-01-01" }]);
});

test("a failed resolve is self-correcting: the next curation adds what it could not", async () => {
  const { network, alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-05-06");
  await bob.refer(indexNuri, article);

  network.breakReadsOf(article, "broker unreachable");
  expect((await alice.curate(indexNuri)).outcomes[0]?.result).toBe("unresolved");
  expect(await alice.read(indexNuri)).toEqual([]);

  // The deposit is still there, so nothing has to be re-deposited.
  network.healReadsOf(article);
  expect((await alice.curate(indexNuri)).outcomes[0]).toEqual({
    result: "indexed",
    object: article,
    value: "2026-05-06",
  });
  expect(await alice.read(indexNuri)).toEqual([{ object: article, value: "2026-05-06" }]);
});

test("a reference to something that was never created is reported, not silently dropped", async () => {
  const { network, alice, bob } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  await bob.refer(indexNuri, network.neverCreatedNuri());

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toHaveLength(1);
  expect(report.outcomes[0]?.result).toBe("unresolved");
  expect(await alice.read(indexNuri)).toEqual([]);
});

// --- an object that does not fit the index --------------------------------

test("an object carrying nothing for the index's field is not added", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  // Exists, is public, is readable — but says nothing about the field this index
  // is built on. OPEN QUESTION: this is the narrow behaviour, not a settled policy.
  const object = await publishObject(ports.bob, NAME, "an object with no date");
  await bob.refer(indexNuri, object);

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toEqual([{ result: "skipped", object, reason: "no-field" }]);
  expect(await alice.read(indexNuri)).toEqual([]);
});

test("an object carrying several values for the field is not added", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const object = await publishObject(ports.bob, PUBLISHED_AT, "2026-01-01");
  await ports.bob.addLiteralProperty(object, object, PUBLISHED_AT, "2026-09-09");
  await bob.refer(indexNuri, object);

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toEqual([{ result: "skipped", object, reason: "several-values" }]);
  expect(await alice.read(indexNuri)).toEqual([]);
});

test("a payload that is not a reference is reported as foreign and changes nothing", async () => {
  const { alice, bob, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const article = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  await bob.refer(indexNuri, article);
  // Anyone may deposit anything into an inbox, so untrusted payloads do arrive.
  await ports.bob.depositTo(indexNuri, { drop: "everything" });

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toEqual([
    { result: "indexed", object: article, value: "2026-03-04" },
    { result: "foreign", reason: "payload is not a reference" },
  ]);
  expect(await alice.read(indexNuri)).toEqual([{ object: article, value: "2026-03-04" }]);
});

test("an index referred to itself is skipped, so its declaration cannot become an entry", async () => {
  const { alice, bob } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  await bob.refer(indexNuri, indexNuri);

  const report = await alice.curate(indexNuri);
  expect(report.outcomes).toEqual([
    { result: "skipped", object: indexNuri, reason: "self-reference" },
  ]);
  expect(await alice.read(indexNuri)).toEqual([]);
});

// --- indexing by a date is an instance of indexing by a field -------------

test("an index whose field is a date reads back in chronological order", async () => {
  const { alice, bob, carol, ports } = world();
  const indexNuri = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));

  const march = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  const january = await publishObject(ports.bob, PUBLISHED_AT, "2026-01-31");
  const december = await publishObject(ports.bob, PUBLISHED_AT, "2025-12-25");

  // Referred out of order, on purpose.
  await bob.refer(indexNuri, march);
  await bob.refer(indexNuri, december);
  await bob.refer(indexNuri, january);
  await alice.curate(indexNuri);

  expect((await carol.read(indexNuri)).map((e) => e.value)).toEqual([
    "2025-12-25",
    "2026-01-31",
    "2026-03-04",
  ]);
});

test("two indexes over the same objects, on different fields, do not interfere", async () => {
  const { alice, bob, ports } = world();
  const byDate = hardcodedInAppSource(await alice.createIndex(PUBLISHED_AT));
  const byName = hardcodedInAppSource(await alice.createIndex(NAME));

  const object = await publishObject(ports.bob, PUBLISHED_AT, "2026-03-04");
  await ports.bob.addLiteralProperty(object, object, NAME, "Anemone");

  await bob.refer(byDate, object);
  await bob.refer(byName, object);
  await alice.curate(byDate);
  await alice.curate(byName);

  expect(await alice.read(byDate)).toEqual([{ object, value: "2026-03-04" }]);
  expect(await alice.read(byName)).toEqual([{ object, value: "Anemone" }]);
});