From a73cbf8c0cfb525814e9d971f5153e34166f3f67 Mon Sep 17 00:00:00 2001
From: Ari Sulistiono <ari.sulistiono@gmail.com>
Date: Sat, 19 Sep 2026 08:34:02 +0700
Subject: [PATCH] perf(scl): reuse short-lived save enrichment snapshot

---
 .../NativeIec61850Client.CanonicalModel.cs    | 23 +++++++++++++++++++
 .../CanonicalLiveSclExportRegressionTests.cs  | 19 +++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/Services/NativeIec61850Client.CanonicalModel.cs b/Services/NativeIec61850Client.CanonicalModel.cs
index ffb53e4e1..6d9ea6498 100644
--- a/Services/NativeIec61850Client.CanonicalModel.cs
+++ b/Services/NativeIec61850Client.CanonicalModel.cs
@@ -7,6 +7,11 @@ public sealed partial class NativeIec61850Client
 {
     private LiveIedCanonicalModel? _liveCanonicalModel;
     private ArMms.InitialFcReadExecutionResult? _liveInitialFcRead;
+    private LiveIedModelDiscoveryDocument? _saveSclEnrichmentModel;
+    private DateTimeOffset _saveSclEnrichmentCapturedAtUtc = DateTimeOffset.MinValue;
+    private static readonly TimeSpan SaveSclEnrichmentReuseWindow = TimeSpan.FromSeconds(15);
+
+    public bool LastSaveSclEnrichmentReused { get; private set; }
 
     /// <summary>
     /// Canonical live snapshot bound to the accepted MMS association that produced
@@ -56,6 +61,19 @@ public async Task<LiveIedCanonicalModel> EnrichCanonicalForSclSaveAsync(
         if (_liveModel is null)
             throw new InvalidOperationException("Save-SCL enrichment requires a successful live discovery model.");
 
+        var now = DateTimeOffset.UtcNow;
+        if (_liveCanonicalModel is not null &&
+            _liveInitialFcRead is not null &&
+            ReferenceEquals(_saveSclEnrichmentModel, _liveModel) &&
+            _saveSclEnrichmentCapturedAtUtc != DateTimeOffset.MinValue &&
+            now - _saveSclEnrichmentCapturedAtUtc <= SaveSclEnrichmentReuseWindow)
+        {
+            LastSaveSclEnrichmentReused = true;
+            return _liveCanonicalModel;
+        }
+
+        LastSaveSclEnrichmentReused = false;
+
         var sourcePlan = ArMms.InitialFcReadPlanner.FromSclModel(_liveModel);
         var safeTargets = sourcePlan.Targets
             .Where(target => SaveSclEnrichmentFunctionalConstraints.Contains(
@@ -92,6 +110,8 @@ or ArMms.InitialFcReadExecutionStatus.TimedOut
         }
 
         PublishCanonicalModel(_liveModel, initialRead);
+        _saveSclEnrichmentModel = _liveModel;
+        _saveSclEnrichmentCapturedAtUtc = DateTimeOffset.UtcNow;
         return _liveCanonicalModel
             ?? throw new InvalidOperationException("Save-SCL enrichment did not publish a canonical model.");
     }
@@ -100,5 +120,8 @@ private void ClearCanonicalModel()
     {
         _liveInitialFcRead = null;
         _liveCanonicalModel = null;
+        _saveSclEnrichmentModel = null;
+        _saveSclEnrichmentCapturedAtUtc = DateTimeOffset.MinValue;
+        LastSaveSclEnrichmentReused = false;
     }
 }
diff --git a/tests/ARSAS.Tests/CanonicalLiveSclExportRegressionTests.cs b/tests/ARSAS.Tests/CanonicalLiveSclExportRegressionTests.cs
index 67364653b..502c82c9d 100644
--- a/tests/ARSAS.Tests/CanonicalLiveSclExportRegressionTests.cs
+++ b/tests/ARSAS.Tests/CanonicalLiveSclExportRegressionTests.cs
@@ -15,6 +15,25 @@ public void NativeClient_RetainsAcceptedAssociationCanonicalSnapshot()
         Assert.Contains("ClearCanonicalModel();", lifecycle, StringComparison.Ordinal);
     }
 
+    [Fact]
+    public void SaveSclEnrichment_ReusesOnlyShortLivedSameModelSnapshot()
+    {
+        var canonical = File.ReadAllText(FindRepoFile("Services/NativeIec61850Client.CanonicalModel.cs"));
+        var lifecycle = File.ReadAllText(FindRepoFile("Services/NativeIec61850Client.SmartDiscoveryLifecycle.cs"));
+        var client = File.ReadAllText(FindRepoFile("Services/NativeIec61850Client.cs"));
+
+        Assert.Contains("SaveSclEnrichmentReuseWindow = TimeSpan.FromSeconds(15)", canonical, StringComparison.Ordinal);
+        Assert.Contains("ReferenceEquals(_saveSclEnrichmentModel, _liveModel)", canonical, StringComparison.Ordinal);
+        Assert.Contains("now - _saveSclEnrichmentCapturedAtUtc <= SaveSclEnrichmentReuseWindow", canonical, StringComparison.Ordinal);
+        Assert.Contains("LastSaveSclEnrichmentReused = true", canonical, StringComparison.Ordinal);
+        Assert.Contains("_saveSclEnrichmentModel = _liveModel", canonical, StringComparison.Ordinal);
+        Assert.Contains("_saveSclEnrichmentCapturedAtUtc = DateTimeOffset.UtcNow", canonical, StringComparison.Ordinal);
+        Assert.Contains("_saveSclEnrichmentModel = null", canonical, StringComparison.Ordinal);
+        Assert.Contains("_saveSclEnrichmentCapturedAtUtc = DateTimeOffset.MinValue", canonical, StringComparison.Ordinal);
+        Assert.Contains("ClearCanonicalModel();", lifecycle, StringComparison.Ordinal);
+        Assert.Contains("ClearCanonicalModel();", client, StringComparison.Ordinal);
+    }
+
     [Fact]
     public void SmartDiscovery_DefersEagerFcValueReadsFromStructuralScan()
     {