public async Task VerifyActiveDirectoryConnectivity()

in wwauth/Google.Solutions.WWAuth/Adapters/Adfs/AdfsAdapterBase.cs [84:146]
51 lines of code
4 McCabe index (conditional complexity)

        public async Task VerifyActiveDirectoryConnectivity()
        {
            await Task.Run(() =>
            {
                //
                // Check if computer is domain joined at all
                // (irrespective of the user we're running as).
                //
                Domain domain;
                string domainContainer;
                try
                {
                    domain = Domain.GetComputerDomain();
                    domainContainer = domain
                        .GetDirectoryEntry()
                        .Properties["distinguishedName"]
                        .Value as string;

                    this.Logger.Info(
                        "Computer joined to domain '{0}', ({1})",
                        domain.Name,
                        domainContainer);
                }
                catch (Exception e)
                {
                    throw new TokenAcquisitionException(
                        "The current computer is not domain-joined and can't use " +
                        "integrated windows authentication", e);
                }

                //
                // Check if we can lookup the server's SPN. If that fails, we
                // know that obtaining a Kerberos ticket will fail (causing a
                // fallback to NTLM).
                //
                var spn = this.ServicePrincipalName;
                try
                {
                    using (var root = new DirectoryEntry())
                    using (var searcher = new DirectorySearcher(root)
                    {
                        Filter = $"(servicePrincipalName={spn})"
                    })
                    {
                        var result = searcher.FindOne();
                        if (result == null)
                        {
                            throw new ActiveDirectoryObjectNotFoundException(
                                $"SPN '{spn}' not found in directory");
                        }

                        this.Logger.Info("SPN '{0}' resolved to '{1}'", spn, result.Path);
                    }
                }
                catch (Exception e)
                {
                    throw new TokenAcquisitionException(
                        $"The Kerberos SPN '{spn}' does not exist in Active Directory. " +
                        $"Add the SPN to the service account used by AD FS to enable " +
                        $"Kerberos authentication.", e);
                }
            });
        }