Microfrontends + BFF en banca regulada

// packages/shared-types/src/mep-simulation.ts
export interface SimulationRequest {
  mortgageId: string;
  amount: number;
  currency: "USD" | "ARS";
}

export interface SimulationResponse {
  rate: number;
  totalCost: number;
  breakdown: { label: string; value: number }[];
  expiresAt: string; // ISO — el BFF normaliza timezone
}

// El MFE solo consume SimulationResponse.
// El BFF traduce SOAP/Oracle → este shape.

// bff/src/routes/simulation.ts
export async function getSimulation(req: Request, res: Response) {
  try {
    const [rate, limits, customer] = await Promise.all([
      oracleClient.getRate(req.body.mortgageId),
      oracleClient.getLimits(req.body.mortgageId),
      oracleClient.getCustomer(req.user.id),
    ]);

    const response: SimulationResponse = mapOracleToSimulation({
      rate, limits, customer, amount: req.body.amount,
    });

    return res.json(response);
  } catch (error) {
    // Error normalizado — el MFE nunca ve stack Oracle
    return res.status(mapOracleError(error)).json({
      code: "SIMULATION_FAILED",
      message: getUserFacingMessage(error),
    });
  }
}

// shell/src/App.tsx
const OnboardingMFE = lazy(() => import("mfe_onboarding/App"));
const SimulationMFE = lazy(() => import("mfe_simulation/App"));
const ConfirmationMFE = lazy(() => import("mfe_confirmation/App"));

export function App() {
  return (
    <AuthProvider>
      <ShellLayout>
        <Routes>
          <Route path="/onboarding/*" element={<OnboardingMFE />} />
          <Route path="/simulation/*" element={<SimulationMFE />} />
          <Route path="/confirm/*" element={<ConfirmationMFE />} />
        </Routes>
      </ShellLayout>
    </AuthProvider>
  );
}