feat(alarms): NativeAlarmProjector maps transitions to condition snapshots (Phase B WS-4a)

2026-06-14 03:16:44 -04:00
parent e1ccd99ea2
commit c1aeafaaf3
2 changed files with 218 additions and 0 deletions
@@ -0,0 +1,52 @@
+using ZB.MOM.WW.OtOpcUa.Commons.OpcUa;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Drivers;
+
+/// <summary>
+///     Derives a full Part 9 <see cref="AlarmConditionSnapshot"/> from each native
+///     <see cref="AlarmEventArgs"/> delta, tracking per-condition-NodeId prior state. Owned by the
+///     single-threaded <c>DriverHostActor</c> (no locking). Native alarms carry only a transition
+///     <see cref="AlarmTransitionKind"/>, not a full state machine, so this is the translation the
+///     scripted-alarm engine does internally.
+/// </summary>
+public sealed class NativeAlarmProjector
+{
+    private readonly Dictionary<string, (bool Active, bool Acked, ushort Severity, string Message)> _prior =
+        new(StringComparer.Ordinal);
+
+    /// <summary>Project an alarm transition onto the full condition snapshot for <paramref name="nodeId"/>.</summary>
+    /// <param name="nodeId">The materialised condition node's id (the projection's state key).</param>
+    /// <param name="e">The native alarm transition.</param>
+    /// <returns>The full Part 9 condition snapshot to write to the node.</returns>
+    public AlarmConditionSnapshot Project(string nodeId, AlarmEventArgs e)
+    {
+        var prev = _prior.TryGetValue(nodeId, out var p)
+            ? p
+            : (Active: false, Acked: true, Severity: (ushort)0, Message: string.Empty);
+        var sev = MapSeverity(e.Severity);
+        var (active, acked) = e.Kind switch
+        {
+            AlarmTransitionKind.Raise or AlarmTransitionKind.Retrigger => (true, false),
+            AlarmTransitionKind.Acknowledge => (prev.Active, true),
+            AlarmTransitionKind.Clear => (false, prev.Acked),
+            _ => (prev.Active, prev.Acked),
+        };
+        _prior[nodeId] = (active, acked, sev, e.Message);
+        return new AlarmConditionSnapshot(
+            Active: active, Acknowledged: acked, Confirmed: true, Enabled: true,
+            Shelving: AlarmShelvingKind.Unshelved, Severity: sev, Message: e.Message);
+    }
+
+    /// <summary>Clears all tracked per-node state (call on address-space rebuild).</summary>
+    public void Clear() => _prior.Clear();
+
+    private static ushort MapSeverity(AlarmSeverity s) => s switch
+    {
+        AlarmSeverity.Low => 200,
+        AlarmSeverity.Medium => 500,
+        AlarmSeverity.High => 700,
+        AlarmSeverity.Critical => 900,
+        _ => 500,
+    };
+}