refactor(kpi): K13/K15 trend review fixups — per-metric isolation, disable-during-load + logging, loading-flag finally, test coverage

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Audit/AuditLogPage.razor

@@ -31,12 +31,12 @@
                 <div class="btn-group btn-group-sm" role="group" aria-label="Trend window">
                     <button type="button"
                             class="btn @(_windowHours == 24 ? "btn-secondary" : "btn-outline-secondary")"
-                            @onclick="() => SetWindowAsync(24)">
+                            @onclick="() => SetWindowAsync(24)" disabled="@_trendsLoading">
                         24h
                     </button>
                     <button type="button"
                             class="btn @(_windowHours == 168 ? "btn-secondary" : "btn-outline-secondary")"
-                            @onclick="() => SetWindowAsync(168)">
+                            @onclick="() => SetWindowAsync(168)" disabled="@_trendsLoading">
                         7d
                     </button>
                 </div>

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Audit/AuditLogPage.razor.cs

@@ -2,6 +2,7 @@ using System.Globalization;
 using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Routing;
 using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.Extensions.Logging;
 using ZB.MOM.WW.ScadaBridge.CentralUI.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Audit;
 using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
@@ -56,6 +57,10 @@ public partial class AuditLogPage : IDisposable
     /// </summary>
     [Inject] private IKpiHistoryQueryService KpiHistory { get; set; } = null!;
 
+    /// <summary>Logger for the best-effort Trends panel — a degraded series fetch
+    /// is logged at warning level so the silent fallback is still observable.</summary>
+    [Inject] private ILogger<AuditLogPage> Logger { get; set; } = null!;
+
     private AuditLogQueryFilter? _currentFilter;
     private AuditEventView? _selectedEvent;
     private bool _drawerOpen;
@@ -271,6 +276,13 @@ public partial class AuditLogPage : IDisposable
     /// <summary>Whether the Trends panel is expanded (open by default).</summary>
     private bool _trendsOpen = true;
 
+    /// <summary>
+    /// True while a window's series are being (re)fetched — disables the 24h/7d
+    /// window toggle buttons so a mid-flight click cannot stack overlapping loads
+    /// (mirrors the K13/K14 trend pages).
+    /// </summary>
+    private bool _trendsLoading;
+
     /// <summary>Active window in hours — 24 (default) or 168 (7 days).</summary>
     private int _windowHours = 24;
 
@@ -297,25 +309,35 @@ public partial class AuditLogPage : IDisposable
     /// </summary>
     private async Task LoadTrendsAsync()
     {
-        var toUtc = DateTime.UtcNow;
-        var fromUtc = toUtc - TimeSpan.FromHours(_windowHours);
-
-        foreach (var (metric, _, _) in TrendMetrics)
+        _trendsLoading = true;
+        try
         {
-            try
+            var toUtc = DateTime.UtcNow;
+            var fromUtc = toUtc - TimeSpan.FromHours(_windowHours);
+
+            foreach (var (metric, _, _) in TrendMetrics)
             {
-                var points = await KpiHistory.GetSeriesAsync(
-                    KpiSources.AuditLog, metric, KpiScopes.Global, scopeKey: null,
-                    fromUtc, toUtc);
-                _trendSeries[metric] = new TrendSeries(points, IsAvailable: true, ErrorMessage: null);
-            }
-            catch (Exception)
-            {
-                // Best-effort: degrade this chart only, keep the rest of the page alive.
-                _trendSeries[metric] = new TrendSeries(
-                    Points: null, IsAvailable: false, ErrorMessage: "Trend data unavailable.");
+                try
+                {
+                    var points = await KpiHistory.GetSeriesAsync(
+                        KpiSources.AuditLog, metric, KpiScopes.Global, scopeKey: null,
+                        fromUtc, toUtc);
+                    _trendSeries[metric] = new TrendSeries(points, IsAvailable: true, ErrorMessage: null);
+                }
+                catch (Exception ex)
+                {
+                    // Best-effort: degrade this chart only, keep the rest of the page
+                    // alive — but log the failure so the silent fallback is observable.
+                    Logger.LogWarning(ex, "Failed to load Audit Log KPI trend series for metric {Metric}.", metric);
+                    _trendSeries[metric] = new TrendSeries(
+                        Points: null, IsAvailable: false, ErrorMessage: "Trend data unavailable.");
+                }
             }
         }
+        finally
+        {
+            _trendsLoading = false;
+        }
     }
 
     /// <summary>Returns the rendered state for a metric, defaulting to available-empty.</summary>