worker(alarms): synthetic GUID + degraded/source_provider on emitted transitions

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAccessAlarmEventSink.cs

@@ -86,6 +86,12 @@ public sealed class MxAccessAlarmEventSink : IMxAccessEventSink
     /// <param name="operatorComment">The operator's comment, if any.</param>
     /// <param name="category">The alarm category.</param>
     /// <param name="description">The alarm description.</param>
+    /// <param name="degraded">
+    ///     <see langword="true"/> when the transition was synthesized by the
+    ///     subtag-provider fallback rather than the native alarmmgr path.
+    ///     Defaults to <see langword="false"/> so existing alarmmgr callers
+    ///     compile unchanged and stay on the parity (alarmmgr) path.
+    /// </param>
     internal void EnqueueTransition(
         string alarmFullReference,
         string sourceObjectReference,
@@ -97,10 +103,16 @@ public sealed class MxAccessAlarmEventSink : IMxAccessEventSink
         string operatorUser,
         string operatorComment,
         string category,
-        string description)
+        string description,
+        bool degraded = false)
     {
         try
         {
+            // Degraded transitions come from the subtag fallback; the native
+            // alarmmgr (wnwrap) path stays degraded=false / ALARMMGR for parity.
+            AlarmProviderMode sourceProvider = degraded
+                ? AlarmProviderMode.Subtag
+                : AlarmProviderMode.Alarmmgr;
             MxEvent mxEvent = eventMapper.CreateOnAlarmTransition(
                 sessionId,
                 alarmFullReference,
@@ -114,7 +126,9 @@ public sealed class MxAccessAlarmEventSink : IMxAccessEventSink
                 operatorComment,
                 category,
                 description,
-                statuses: null);
+                statuses: null,
+                degraded: degraded,
+                sourceProvider: sourceProvider);
             eventQueue.Enqueue(mxEvent);
         }
         catch (Exception exception)

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAccessEventMapper.cs

@@ -124,6 +124,15 @@ public sealed class MxAccessEventMapper
     /// <param name="category">Alarm taxonomy bucket from the Galaxy template.</param>
     /// <param name="description">Human-readable alarm description.</param>
     /// <param name="statuses">Array of MxStatusProxy values from MXAccess.</param>
+    /// <param name="degraded">
+    ///     <see langword="true"/> when this transition was synthesized by the
+    ///     subtag-provider fallback rather than the native alarmmgr path.
+    ///     Defaults to <see langword="false"/> to preserve alarmmgr parity.
+    /// </param>
+    /// <param name="sourceProvider">
+    ///     The alarm provider that sourced this transition. Defaults to
+    ///     <see cref="AlarmProviderMode.Alarmmgr"/> for the native path.
+    /// </param>
     public MxEvent CreateOnAlarmTransition(
         string sessionId,
         string alarmFullReference,
@@ -137,7 +146,9 @@ public sealed class MxAccessEventMapper
         string operatorComment,
         string category,
         string description,
-        Array? statuses)
+        Array? statuses,
+        bool degraded = false,
+        AlarmProviderMode sourceProvider = AlarmProviderMode.Alarmmgr)
     {
         MxEvent mxEvent = CreateBaseEvent(
             MxEventFamily.OnAlarmTransition,
@@ -159,6 +170,8 @@ public sealed class MxAccessEventMapper
             OperatorComment = operatorComment ?? string.Empty,
             Category = category ?? string.Empty,
             Description = description ?? string.Empty,
+            Degraded = degraded,
+            SourceProvider = sourceProvider,
         };
         if (originalRaiseTimestampUtc is { } orts)
         {

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/MxAlarmSnapshot.cs

@@ -37,4 +37,12 @@ public sealed class MxAlarmSnapshotRecord
     public string OperatorName { get; set; } = string.Empty;
     /// <summary>Gets or sets the alarm comment.</summary>
     public string AlarmComment { get; set; } = string.Empty;
+    /// <summary>
+    ///     Gets or sets a value indicating whether this record was synthesized
+    ///     by the subtag-provider fallback rather than emitted by the native
+    ///     alarmmgr (wnwrap) path. Default <see langword="false"/> preserves
+    ///     parity for the alarmmgr path; the subtag fallback sets it to
+    ///     <see langword="true"/>.
+    /// </summary>
+    public bool Degraded { get; set; }
 }

src/ZB.MOM.WW.MxGateway.Worker/MxAccess/SyntheticAlarmGuid.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace ZB.MOM.WW.MxGateway.Worker.MxAccess;
+
+/// <summary>
+///     Derives a deterministic synthetic <see cref="Guid"/> from an alarm
+///     reference for the subtag-provider fallback path, which has no native
+///     MxAccess alarm GUID. Hashing the reference yields a stable identity so
+///     repeated transitions for the same alarm reference correlate downstream
+///     (acknowledge, snapshot, OPC UA mapping) without an alarmmgr-supplied GUID.
+/// </summary>
+public static class SyntheticAlarmGuid
+{
+    /// <summary>
+    ///     Produces a stable <see cref="Guid"/> for the given alarm reference.
+    ///     The same reference always maps to the same GUID; distinct references
+    ///     map to distinct GUIDs with overwhelming probability.
+    /// </summary>
+    /// <param name="reference">
+    ///     The fully-qualified alarm reference (for example
+    ///     <c>"Galaxy!Area.Tag.HiHi"</c>). Treated as UTF-8 bytes.
+    /// </param>
+    /// <returns>A deterministic, non-empty GUID derived from the reference.</returns>
+    /// <exception cref="ArgumentNullException">
+    ///     Thrown when <paramref name="reference"/> is <see langword="null"/>.
+    /// </exception>
+    public static Guid ForReference(string reference)
+    {
+        if (reference is null) throw new ArgumentNullException(nameof(reference));
+
+        byte[] bytes = Encoding.UTF8.GetBytes(reference);
+
+        // MD5 is used purely for a stable, non-cryptographic identity mapping
+        // (reference -> 16-byte GUID), never for security. Its 128-bit output
+        // fits a GUID exactly, which is why it is preferred here.
+        using MD5 md5 = MD5.Create();
+        byte[] hash = md5.ComputeHash(bytes);
+        return new Guid(hash);
+    }
+}