/**
 * anti-fork.test.ts — behavioral tests for the reconnection fix in the
 * polyfill-era shim (src/store-registry.ts). Two guards, one file:
 *
 *  (1) DETERMINISTIC RESOLUTION — a shim whose account subject carries DUPLICATE
 *      scope-doc values (fork residue: several `shim:docPublic`) must resolve to
 *      the SAME canonical doc every time (lexicographically-smallest NURI), so the
 *      session that WROTE an entity and a fresh page that RESOLVES the doc never
 *      disagree. This is the root-cause fix for the reconnection bug.
 *
 *  (2) ANTI-FORK BOUNDED RETRY — a fresh page over a persistent wallet may read
 *      the shim as 0 rows while the private store is still syncing. A BOUNDED retry
 *      (capped backoff, from the injected `provisionRetry` budget) bridges that
 *      window before concluding "account genuinely new" and provisioning —
 *      preventing new fork residue. A genuinely-new account (always 0) is still
 *      provisioned exactly once. The budget defaults to `attempts: 1` (no retry)
 *      when unset, so the synchronous unit fakes stay single-read and unchanged.
 */

import { describe, it, expect, mock, beforeEach, afterAll } from "bun:test";
import {
  ensureAccount,
  resolveAccount,
  loadShim,
  resetRegistryCache,
} from "../src/store-registry";
import type { RegistrySession } from "../src/store-registry";
import {
  configure,
  configureStoreRegistry,
  resetStoreRegistry,
  resetConfig,
} from "../src/polyfill";
import { resetOpenedRepos } from "../src/open-repo";

afterAll(() => {
  resetConfig();
  resetStoreRegistry();
  resetRegistryCache();
  resetOpenedRepos();
});

const SESSION: RegistrySession = { sessionId: "sid-af", privateStoreId: "PRIV-AF" };

// ---------------------------------------------------------------------------
// Fake ng — in-memory quad store. Two variants:
//   - makeFakeNg(): NO doc_subscribe → non-reactive path (no sync lag, no retry).
//   - makeLaggyFakeNg({lag}): HAS doc_subscribe (so the anti-fork retry path
//     fires) and can simulate a sync lag: the account SELECT returns 0 rows for the
//     first `lag` reads, then the seeded data — modelling a shim not yet synced.
// ---------------------------------------------------------------------------

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

function unescapeLiteral(s: string): string {
  let out = "";
  for (let i = 0; i < s.length; i++) {
    if (s[i] === "\\" && i + 1 < s.length) {
      const next = s[++i];
      out += next === "n" ? "\n" : next === "r" ? "\r" : next === "t" ? "\t" : next;
    } else {
      out += s[i];
    }
  }
  return out;
}

function makeSparqlUpdate(quads: Quad[]) {
  return mock(async (...a: unknown[]) => {
    const query = a[1] as string;
    const anchor = a[2] as string | undefined;
    const gm = query.match(/GRAPH <([^>]+)>\s*\{([\s\S]*)\}/);
    let g: string;
    let body: string;
    if (gm) {
      g = gm[1]!;
      body = gm[2]!;
    } else {
      if (!anchor) return undefined;
      g = anchor;
      body = query.replace(/^\s*INSERT DATA\s*\{/, "").replace(/\}\s*$/, "");
    }
    const sm = body.match(/<([^>]+)>/);
    if (!sm) return undefined;
    const s = sm[1]!;
    const pairRe = /(?:a|<([^>]+)>)\s+(?:"((?:[^"\\]|\\.)*)"|<([^>]+)>)/g;
    let m: RegExpExecArray | null;
    const after = body.slice(body.indexOf(sm[0]) + sm[0].length);
    while ((m = pairRe.exec(after)) !== null) {
      const p = m[1] ?? "urn:ng-eventually:shim:Account";
      const o = m[2] !== undefined ? unescapeLiteral(m[2]) : (m[3] ?? "");
      quads.push({ g, s, p, o });
    }
    return undefined;
  });
}

/** Build the account-SELECT bindings from the quads (grouped per subject). Each
 *  (subject × docPublic × docProtected × docPrivate) combination is a binding, so
 *  a subject with DUPLICATE scope docs yields a cross-product of bindings — exactly
 *  what a corrupted shim returns. */
function accountBindings(quads: Quad[], anchor: string | undefined, onlySubject: string | null) {
  const bySubject = new Map<string, { id: string; pub: string[]; prot: string[]; priv: string[] }>();
  for (const q of quads) {
    if (q.g !== anchor) continue;
    if (onlySubject !== null && q.s !== onlySubject) continue;
    const rec = bySubject.get(q.s) ?? { id: "", pub: [], prot: [], priv: [] };
    if (q.p === "urn:ng-eventually:shim:id") rec.id = q.o;
    if (q.p === "urn:ng-eventually:shim:docPublic") rec.pub.push(q.o);
    if (q.p === "urn:ng-eventually:shim:docProtected") rec.prot.push(q.o);
    if (q.p === "urn:ng-eventually:shim:docPrivate") rec.priv.push(q.o);
    bySubject.set(q.s, rec);
  }
  const bindings: Array<Record<string, { value: string }>> = [];
  for (const rec of bySubject.values()) {
    if (!rec.id) continue;
    const pubs = rec.pub.length ? rec.pub : [""];
    const prots = rec.prot.length ? rec.prot : [""];
    const privs = rec.priv.length ? rec.priv : [""];
    for (const pub of pubs)
      for (const prot of prots)
        for (const priv of privs)
          bindings.push({
            id: { value: rec.id },
            docPublic: { value: pub },
            docProtected: { value: prot },
            docPrivate: { value: priv },
          });
  }
  return bindings;
}

/** Non-reactive fake ng (no doc_subscribe → no sync lag, no retry). */
function makeFakeNg() {
  const quads: Quad[] = [];
  let docCounter = 0;
  let accountQueryCount = 0;
  const doc_create = mock(async (..._a: unknown[]) => `did:ng:o:doc${++docCounter}`);
  const sparql_update = makeSparqlUpdate(quads);
  const sparql_query = mock(async (...a: unknown[]) => {
    const query = a[1] as string;
    const anchor = a[3] as string | undefined;
    if (query.includes("<urn:ng-eventually:shim:id>")) {
      accountQueryCount++;
      const subjM = query.match(/GRAPH <[^>]+>\s*\{\s*<([^>]+)>\s+a\s+<urn:ng-eventually:shim:Account>/);
      return { results: { bindings: accountBindings(quads, anchor, subjM ? subjM[1]! : null) } };
    }
    const bindings = quads
      .filter((q) => q.g === anchor && q.p === "urn:ng-eventually:shim:contains")
      .map((q) => ({ e: { value: q.o } }));
    return { results: { bindings } };
  });
  return { doc_create, sparql_update, sparql_query, _quads: quads, getAccountQueryCount: () => accountQueryCount };
}

/** Fake ng with a SYNC-LAG simulation: the first `lag` account reads return 0 rows
 *  (shim not synced yet), then the seeded data appears — modelling a fresh page over
 *  a persistent wallet. Used with a fast `provisionRetry` budget to exercise the
 *  anti-fork retry. (Carries a `doc_subscribe` so it also passes as a reactive ng.) */
function makeLaggyFakeNg(opts: { lag?: number } = {}) {
  const quads: Quad[] = [];
  let docCounter = 0;
  let accountQueryCount = 0;
  let lag = opts.lag ?? 0;
  const doc_create = mock(async (..._a: unknown[]) => `did:ng:o:doc${++docCounter}`);
  const sparql_update = makeSparqlUpdate(quads);
  const sparql_query = mock(async (...a: unknown[]) => {
    const query = a[1] as string;
    const anchor = a[3] as string | undefined;
    if (query.includes("<urn:ng-eventually:shim:id>")) {
      accountQueryCount++;
      if (lag > 0) { lag--; return { results: { bindings: [] } }; } // sync not landed yet
      const subjM = query.match(/GRAPH <[^>]+>\s*\{\s*<([^>]+)>\s+a\s+<urn:ng-eventually:shim:Account>/);
      return { results: { bindings: accountBindings(quads, anchor, subjM ? subjM[1]! : null) } };
    }
    const bindings = quads
      .filter((q) => q.g === anchor && q.p === "urn:ng-eventually:shim:contains")
      .map((q) => ({ e: { value: q.o } }));
    return { results: { bindings } };
  });
  // doc_subscribe: immediately push a State (the sync barrier) so `ensureRepoOpen`
  // resolves at once. `resolveAccount`/`ensureAccount` now open the anchor repo
  // (open-repo.ts) before reading/writing the shim (the cold-start heal); the real
  // broker pushes `TabInfo` then a first `State` on subscribe, and open-repo awaits
  // that `State`. Model it: invoke the callback with a `State` AppResponse so the
  // barrier is reached synchronously (no 8s fallback → the retry tests stay fast).
  const doc_subscribe = mock(async (_repo: unknown, _sid: unknown, cb: Function) => {
    if (typeof cb === "function") cb({ V0: { State: {} } });
    return () => {};
  });
  return {
    doc_create, sparql_update, sparql_query, doc_subscribe,
    _quads: quads,
    getAccountQueryCount: () => accountQueryCount,
  };
}

function inject(
  fakeNg: unknown,
  provisionRetry?: { attempts?: number; baseMs?: number; maxStepMs?: number },
) {
  configure({ ng: fakeNg as any, useShape: (() => {}) as any });
  configureStoreRegistry({
    getSession: async () => SESSION,
    normalizeId: (u) => u.trim().toLowerCase(),
    // Default (unset) → attempts:1 (no retry). The retry tests pass a fast budget.
    provisionRetry,
  });
  resetRegistryCache();
  resetOpenedRepos();
}

// ---------------------------------------------------------------------------
// (1) Deterministic resolution
// ---------------------------------------------------------------------------

describe("deterministic resolution over a shim corrupted by fork residue", () => {
  beforeEach(() => { resetRegistryCache(); resetOpenedRepos(); });

  it("(1a) a subject with MULTIPLE docPublic values always resolves the SAME canonical (lexicographically-smallest)", async () => {
    const fakeNg = makeFakeNg();
    inject(fakeNg);
    const anchor = "did:ng:PRIV-AF";
    // Same account subject with 5 duplicate docPublic values (fork residue), out of
    // lexicographic order, plus one docProtected/docPrivate each.
    const subj = "urn:ng-eventually:shim:account:dupuser";
    const dupPublics = [
      "did:ng:o:pub-m", "did:ng:o:pub-a", "did:ng:o:pub-z", "did:ng:o:pub-c", "did:ng:o:pub-a",
    ];
    fakeNg._quads.push({ g: anchor, s: subj, p: "urn:ng-eventually:shim:id", o: "dupuser" });
    for (const p of dupPublics)
      fakeNg._quads.push({ g: anchor, s: subj, p: "urn:ng-eventually:shim:docPublic", o: p });
    fakeNg._quads.push({ g: anchor, s: subj, p: "urn:ng-eventually:shim:docProtected", o: "did:ng:o:prot-1" });
    fakeNg._quads.push({ g: anchor, s: subj, p: "urn:ng-eventually:shim:docPrivate", o: "did:ng:o:priv-1" });

    const r1 = await resolveAccount("dupuser");
    resetRegistryCache();
    const r2 = await resolveAccount("dupuser");
    const viaShim = (await loadShim()).get("dupuser");

    // Canonical = lexicographically smallest → "did:ng:o:pub-a".
    expect(r1?.docPublic).toBe("did:ng:o:pub-a");
    // Stable across independent resolves...
    expect(r2?.docPublic).toBe(r1?.docPublic);
    // ...and loadShim (full scan) agrees with resolveAccount (targeted).
    expect(viaShim?.docPublic).toBe(r1?.docPublic);
    expect(viaShim?.docProtected).toBe("did:ng:o:prot-1");
    expect(viaShim?.docPrivate).toBe("did:ng:o:priv-1");
  });
});

// ---------------------------------------------------------------------------
// (2) Anti-fork bounded retry
// ---------------------------------------------------------------------------

describe("ensureAccount: anti-fork bounded retry", () => {
  beforeEach(() => { resetRegistryCache(); resetOpenedRepos(); });

  it("(2a) NO-FORK: account already in shim → reused, 0 new doc_create (non-reactive fake, single read)", async () => {
    const fakeNg = makeFakeNg();
    inject(fakeNg);
    const first = await ensureAccount("LauraBarrier");
    expect(fakeNg.doc_create).toHaveBeenCalledTimes(3);

    resetRegistryCache();
    resetOpenedRepos();
    const second = await ensureAccount("LauraBarrier");

    expect(second.docPublic).toBe(first.docPublic);
    expect(second.docProtected).toBe(first.docProtected);
    expect(second.docPrivate).toBe(first.docPrivate);
    expect(fakeNg.doc_create).toHaveBeenCalledTimes(3); // still 3, not 6
  });

  it("(2b) SYNC LAG: shim reads 0 K times then the data → RETRY reuses, no fork", async () => {
    // Seed an account into an initial (non-reactive) fake, capture its NURIs.
    const seed = makeFakeNg();
    inject(seed);
    const orig = await ensureAccount("LaggyUser");
    expect(seed.doc_create).toHaveBeenCalledTimes(3);

    // Fresh reactive session over the SAME quads, with a 3-read sync lag: the first
    // 3 account reads return 0 rows (shim not synced), then the seeded data appears.
    const reactive = makeLaggyFakeNg({ lag: 3 });
    reactive._quads.push(...seed._quads);
    inject(reactive, { attempts: 8, baseMs: 1, maxStepMs: 2 }); // fast budget

    const resolved = await ensureAccount("LaggyUser");

    // Reused the SAME account — NO fork provisioning despite the initial 0 rows.
    expect(resolved.docPublic).toBe(orig.docPublic);
    expect(resolved.docProtected).toBe(orig.docProtected);
    expect(resolved.docPrivate).toBe(orig.docPrivate);
    expect(reactive.doc_create).toHaveBeenCalledTimes(0); // no new docs → no fork
    // It DID retry: more than one account read (1 initial + retries until data).
    expect(reactive.getAccountQueryCount()).toBeGreaterThan(1);
  });

  it("(2c) GENUINELY NEW: shim always reads 0 → provisioned exactly once after the budget", async () => {
    const reactive = makeLaggyFakeNg({ lag: 999 }); // never resolves → genuinely new
    inject(reactive, { attempts: 5, baseMs: 1, maxStepMs: 2 });

    const rec = await ensureAccount("BrandNewUser");

    // Provisioned exactly ONE set of scope docs.
    expect(reactive.doc_create).toHaveBeenCalledTimes(3);
    expect(rec.docPublic).toMatch(/^did:ng:o:doc/);
    expect(rec.docProtected).not.toBe(rec.docPublic);
    // Retry was BOUNDED: exactly `attempts` account reads, then it gave up and provisioned.
    expect(reactive.getAccountQueryCount()).toBe(5);
  });

  it("(2d) default budget (unset → attempts:1): genuinely-new account → single read, no retry", async () => {
    const fakeNg = makeFakeNg();
    inject(fakeNg); // provisionRetry unset → attempts:1 (synchronous default)

    const rec = await ensureAccount("SyncUser");

    expect(fakeNg.doc_create).toHaveBeenCalledTimes(3);
    // Exactly ONE account read — the default budget does not retry.
    expect(fakeNg.getAccountQueryCount()).toBe(1);
    expect(rec.docPublic).toMatch(/^did:ng:o:doc/);
  });

  it("(2e) idempotence within a session: ensureAccount twice never creates 2 sets", async () => {
    const fakeNg = makeFakeNg();
    inject(fakeNg);
    const a = await ensureAccount("SameUser");
    const b = await ensureAccount("SameUser");
    expect(b).toEqual(a);
    expect(fakeNg.doc_create).toHaveBeenCalledTimes(3);
  });
});