protected X509Certificate ContextLocalCertificateSelect()

in src/NMS.AMQP/Transport/SecureTransportContext.cs [253:330]
69 lines of code
13 McCabe index (conditional complexity)

        protected X509Certificate ContextLocalCertificateSelect(object sender, string targetHost, X509CertificateCollection localCertificates, X509Certificate remoteCertificate, string[] acceptableIssuers)
        {
            if (Tracer.IsDebugEnabled)
            {
                string subjects = "{";
                string issuers = "{";
                string acceptedIssuers = "{";

                foreach (X509Certificate cert in localCertificates)
                {
                    subjects += cert.Subject + ", ";
                    issuers += cert.Issuer + ", ";
                }

                subjects += "}";
                issuers += "}";

                for (int i = 0; i < acceptableIssuers.Length; i++)
                {
                    acceptedIssuers += acceptableIssuers[i] + ", ";
                }

                Tracer.DebugFormat("Local Certificate Selection.\n" +
                    "Sender {0}, Target Host {1}, Remote Cert Subject {2}, Remote Cert Issuer {3}" +
                    "\nlocal Cert Subjects {4}, " +
                    "\nlocal Cert Issuers {5}",
                    sender.ToString(),
                    targetHost,
                    remoteCertificate?.Subject,
                    remoteCertificate?.Issuer,
                    subjects,
                    issuers);
            }
            X509Certificate localCertificate = null;
            if (ClientCertificateSelectCallback != null)
            {
                try
                {
                    if (Tracer.IsDebugEnabled) Tracer.DebugFormat("Calling application callback for Local certificate selection.");
                    localCertificate = ClientCertificateSelectCallback(sender, targetHost, localCertificates, remoteCertificate, acceptableIssuers);
                }
                catch (Exception ex)
                {
                    Tracer.InfoFormat("Caught Exception from application callback for local certificate selction. Exception : {0}", ex);
                    throw ex;
                }
            }
            else if (localCertificates.Count >= 1)
            {
                // when there is only one certificate select that certificate.
                localCertificate = localCertificates[0];
                if (!String.IsNullOrWhiteSpace(this.ClientCertSubject))
                {
                    // should the application identify a specific certificate to use search for that certificate.
                    localCertificate = null;
                    foreach (X509Certificate cert in localCertificates)
                    {
                        if (String.Compare(cert.Subject, this.ClientCertSubject, true) == 0)
                        {
                            localCertificate = cert;
                            break;
                        }
                    }
                    
                }
            }

            if (localCertificate == null)
            {
                Tracer.InfoFormat("Could not select Local Certificate for target host {0}", targetHost);
            }
            else if (Tracer.IsDebugEnabled)
            {
                Tracer.DebugFormat("Selected Local Certificate {0}", localCertificate.ToString());
            }

            return localCertificate;
        }