// Isolationsnachweis der Backup-/Restore-Engine (destruktive Lane).
//
// Beweisziel: Export → Wipe → Restore von Mandant `demo` lässt JEDE Tabelle des
// zweiten Mandanten `demo2` (inkl. der Join-Tabellen UserRole/RolePermission)
// BIT-genau unberührt. Gemessen wird per Owner-Rowcount (BYPASSRLS) über die aus
// dem DMMF abgeleitete Traversierungs-Topologie — also über GENAU die Tabellen,
// die die Engine anfasst.
//
// Lauf: npx tsx scripts/test-backup-isolation.ts
// Nutzt die lokale isms-DB (geseedet: demo + demo2). Nach Erfolg ist `demo`
// wiederhergestellt; bei Fehlschlag ggf. `npx tsx prisma/seed.ts` nachziehen.

import "dotenv/config";
import { prisma } from "../src/server/db";
import { buildTenantTopology, assertTopologyMatchesDatabase } from "../src/server/backup/topology";
import { exportTenant } from "../src/server/backup/export";
import { restoreTenant } from "../src/server/backup/restore";

let failures = 0;
const ok = (cond: boolean, msg: string) => {
  console.log(`${cond ? "✓" : "✗ FEHLER"} ${msg}`);
  if (!cond) failures++;
};

type Fingerprint = Map<string, number>;

/** Owner-Rowcount je Modell für genau einen Mandanten (Join-Tabellen via id-Menge). */
async function fingerprint(tenantId: string): Promise<Fingerprint> {
  const topo = buildTenantTopology();
  const fp: Fingerprint = new Map();
  // id-Mengen der scopenden Elternteile (User/Role) einmal bestimmen.
  const idSets = new Map<string, string[]>();
  for (const node of topo.insertOrder) {
    const delegate = (prisma as unknown as Record<string, {
      count: (a: unknown) => Promise<number>;
      findMany: (a: unknown) => Promise<Record<string, unknown>[]>;
    }>)[node.delegate];

    let count: number;
    if (node.scope.by === "tenantColumn") {
      count = await delegate.count({ where: { tenantId } });
      if (node.pk.length === 1) {
        const rows = await delegate.findMany({ where: { tenantId }, select: { [node.pk[0]]: true } });
        idSets.set(node.model, rows.map((r) => String(r[node.pk[0]])));
      }
    } else {
      const via = node.scope.via;
      const ids = idSets.get(via.parent) ?? [];
      count = ids.length
        ? await delegate.count({ where: { [via.fromFields[0]]: { in: ids } } })
        : 0;
    }
    fp.set(node.model, count);
  }
  return fp;
}

function compare(before: Fingerprint, after: Fingerprint, adjust: Record<string, number> = {}): string[] {
  const diffs: string[] = [];
  for (const [model, b] of before) {
    const expected = b + (adjust[model] ?? 0);
    const a = after.get(model) ?? -1;
    if (a !== expected) diffs.push(`${model}: erwartet ${expected}, ist ${a}`);
  }
  return diffs;
}

/** Destruktiver Wipe eines Mandanten (nur DB-Zeilen; Identities unangetastet). */
async function wipeTenant(tenantId: string): Promise<void> {
  const topo = buildTenantTopology();
  await prisma.$transaction(async (tx) => {
    await tx.$executeRawUnsafe(`SET LOCAL session_replication_role = replica`);
    for (const node of topo.deleteOrder) {
      const del = (tx as unknown as Record<string, {
        deleteMany: (a: unknown) => Promise<{ count: number }>;
        findMany: (a: unknown) => Promise<Record<string, unknown>[]>;
      }>)[node.delegate];
      if (node.scope.by === "tenantColumn") {
        await del.deleteMany({ where: { tenantId } });
      } else {
        const via = node.scope.via;
        const parentNode = topo.nodes.get(via.parent)!;
        const parentPk = parentNode.pk[0];
        const parentDelegate = (tx as unknown as Record<string, {
          findMany: (a: unknown) => Promise<Record<string, unknown>[]>;
        }>)[parentNode.delegate];
        const parents = await parentDelegate.findMany({ where: { tenantId }, select: { [parentPk]: true } });
        const ids = parents.map((p) => String(p[parentPk]));
        if (ids.length) await del.deleteMany({ where: { [via.fromFields[0]]: { in: ids } } });
      }
    }
  });
}

async function main() {
  // 0. Topologie-Selbstnachweis: abgeleitete FK-Ordnung == reale DB-Constraints.
  await assertTopologyMatchesDatabase(prisma);
  ok(true, "Topologie deckt sich mit den DB-FK-Constraints (fail-closed-Prüfung bestanden)");

  const demo = await prisma.tenant.findUnique({ where: { slug: "demo" }, select: { id: true } });
  const demo2 = await prisma.tenant.findUnique({ where: { slug: "demo2" }, select: { id: true } });
  if (!demo || !demo2) {
    console.error("demo/demo2 nicht gefunden — bitte seeden (npx tsx prisma/seed.ts).");
    process.exit(1);
  }

  // 1. Ausgangs-Fingerprints.
  const demoBefore = await fingerprint(demo.id);
  const demo2Before = await fingerprint(demo2.id);
  const demoTotal = [...demoBefore.values()].reduce((a, b) => a + b, 0);
  const demo2Total = [...demo2Before.values()].reduce((a, b) => a + b, 0);
  ok(demoTotal > 0, `demo hat Daten (${demoTotal} Zeilen über ${demoBefore.size} Tabellen)`);
  ok(demo2Total > 0, `demo2 hat Daten (${demo2Total} Zeilen über ${demo2Before.size} Tabellen)`);
  // Join-Tabellen explizit sichtbar machen (Prompt-Fokus).
  ok((demo2Before.get("UserRole") ?? 0) > 0, `demo2 UserRole-Zuweisungen vorhanden (${demo2Before.get("UserRole")})`);
  ok((demo2Before.get("RolePermission") ?? 0) > 0, `demo2 RolePermission-Zuordnungen vorhanden (${demo2Before.get("RolePermission")})`);

  // 2. Export demo (in-memory, kein Upload nötig).
  const snap = await exportTenant(demo.id, { persist: false, reason: "isolation-test" });
  ok(snap.manifest.totalRows === demoTotal, `Export demo erfasst alle Zeilen (${snap.manifest.totalRows}/${demoTotal})`);

  // 3. Wipe demo (destruktiv).
  await wipeTenant(demo.id);
  const demoWiped = await fingerprint(demo.id);
  ok([...demoWiped.values()].every((c) => c === 0), "demo nach Wipe leer (alle Tabellen 0)");

  // 3a. BEWEIS: demo2 nach dem demo-Wipe unverändert.
  const demo2AfterWipe = await fingerprint(demo2.id);
  const wipeDiffs = compare(demo2Before, demo2AfterWipe);
  ok(wipeDiffs.length === 0, `demo2 nach demo-Wipe UNVERÄNDERT${wipeDiffs.length ? " — " + wipeDiffs.join("; ") : ""}`);

  // 4. Restore demo aus dem Artefakt.
  const res = await restoreTenant(
    demo.id,
    { artifact: snap.artifact, manifest: snap.manifest },
    { skipPreRestore: true, actorId: undefined },
  );
  ok(res.restoredRows === demoTotal, `Restore demo reinsertet alle Zeilen (${res.restoredRows}/${demoTotal})`);
  ok(res.stubIdentities.length === 0, "Restore demo ohne Identity-Stubs (Identities waren intakt)");

  // 4a. demo exakt wiederhergestellt (AuditLog +1 durch den Restore-Audit-Eintrag).
  const demoAfter = await fingerprint(demo.id);
  const demoDiffs = compare(demoBefore, demoAfter, { AuditLog: 1 });
  ok(demoDiffs.length === 0, `demo exakt wiederhergestellt${demoDiffs.length ? " — " + demoDiffs.join("; ") : " (AuditLog +1 = Restore-Audit)"}`);

  // 4b. BEWEIS (Hauptziel): demo2 über den gesamten Restore unverändert.
  const demo2After = await fingerprint(demo2.id);
  const restoreDiffs = compare(demo2Before, demo2After);
  ok(restoreDiffs.length === 0, `demo2 nach demo-Restore UNVERÄNDERT — JEDE Tabelle${restoreDiffs.length ? " — " + restoreDiffs.join("; ") : " (inkl. UserRole/RolePermission)"}`);
}

main()
  .then(async () => {
    await prisma.$disconnect();
    if (failures > 0) {
      console.error(`\n✗ ${failures} Testfall/-fälle fehlgeschlagen.`);
      process.exit(1);
    }
    console.log("\nOK");
  })
  .catch(async (e) => {
    console.error(e);
    await prisma.$disconnect();
    process.exit(1);
  });