feat(notifications): EmailTransport enum + parser for the EWS transport discriminator

2026-08-10 06:07:14 -04:00
parent 9f4d7d4bcb
commit d21b7a5a48
2 changed files with 90 additions and 0 deletions
@@ -0,0 +1,50 @@
+namespace ZB.MOM.WW.ScadaBridge.NotificationService;
+
+/// <summary>
+/// The email delivery transports the service supports. The configured
+/// <c>SmtpConfiguration.Transport</c> string is parsed into this enum to choose
+/// which client actually submits the message.
+/// </summary>
+public enum EmailTransport
+{
+    /// <summary>Direct SMTP submission via MailKit (the original path).</summary>
+    Smtp,
+
+    /// <summary>On-prem Exchange Web Services — one CreateItem SOAP call over HTTPS.</summary>
+    Ews,
+}
+
+/// <summary>
+/// Parses the free-text <c>SmtpConfiguration.Transport</c> value into an
+/// <see cref="EmailTransport"/>, rejecting unknown values rather than silently
+/// falling back to SMTP.
+/// </summary>
+public static class EmailTransportParser
+{
+    /// <summary>
+    /// Parses a configured transport string. A null or empty value defaults to
+    /// <see cref="EmailTransport.Smtp"/> — every pre-EWS configuration row stores no
+    /// transport and is an SMTP row. An unknown value is a configuration error that
+    /// retrying cannot fix, so it throws and the delivery adapter surfaces it as a
+    /// permanent failure (mirrors <see cref="SmtpTlsModeParser"/>).
+    /// </summary>
+    /// <param name="transport">The transport string to parse (Smtp or Ews); null/empty defaults to Smtp.</param>
+    /// <exception cref="ArgumentException">The value is not one of Smtp/Ews.</exception>
+    /// <returns>The corresponding <see cref="EmailTransport"/> enum value.</returns>
+    public static EmailTransport Parse(string? transport)
+    {
+        if (string.IsNullOrWhiteSpace(transport))
+        {
+            return EmailTransport.Smtp;
+        }
+
+        return transport.Trim().ToLowerInvariant() switch
+        {
+            "smtp" => EmailTransport.Smtp,
+            "ews" => EmailTransport.Ews,
+            _ => throw new ArgumentException(
+                $"Unknown email transport '{transport}'. Expected one of: Smtp, Ews.",
+                nameof(transport)),
+        };
+    }
+}