feat: add two factor auth (#643)

Add two factor authentication for users who wish to enhance the security of their accounts.

packages/lib/server-only/2fa/validate-2fa.ts

@@ -0,0 +1,35 @@
+import { User } from '@documenso/prisma/client';
+
+import { ErrorCode } from '../../next-auth/error-codes';
+import { verifyTwoFactorAuthenticationToken } from './verify-2fa-token';
+import { verifyBackupCode } from './verify-backup-code';
+
+type ValidateTwoFactorAuthenticationOptions = {
+  totpCode?: string;
+  backupCode?: string;
+  user: User;
+};
+
+export const validateTwoFactorAuthentication = async ({
+  backupCode,
+  totpCode,
+  user,
+}: ValidateTwoFactorAuthenticationOptions) => {
+  if (!user.twoFactorEnabled) {
+    throw new Error(ErrorCode.TWO_FACTOR_SETUP_REQUIRED);
+  }
+
+  if (!user.twoFactorSecret) {
+    throw new Error(ErrorCode.TWO_FACTOR_MISSING_SECRET);
+  }
+
+  if (totpCode) {
+    return await verifyTwoFactorAuthenticationToken({ user, totpCode });
+  }
+
+  if (backupCode) {
+    return await verifyBackupCode({ user, backupCode });
+  }
+
+  throw new Error(ErrorCode.TWO_FACTOR_MISSING_CREDENTIALS);
+};