feat(flex): read path anchors on the FlexChainComputedThrough cursor

eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn.Test/PlanRegistrationHelperTests.cs

@@ -1703,4 +1703,46 @@ public void GetDeclaredPayCodes_EmptyRuleSet_ReturnsEmpty()
     {
         Assert.That(TimePlanningWorkingHoursService.GetDeclaredPayCodes(new PayRuleSet()), Is.Empty);
     }
+
+    [Test]
+    public void Anchor_SkipsRowsBeyondTheCursor_AndSeedsFromTheLastComputedRow()
+    {
+        // A site whose chain is computed through 2026-06-10. The 06-11 row was
+        // created ahead of time and never filled in -- SumFlexEnd 0 -- so anchoring
+        // on it would discard the balance. The anchor must be the 06-10 row.
+        var site = new AssignedSite
+        {
+            SiteId = 1,
+            FlexChainComputedThrough = new DateTime(2026, 6, 10)
+        };
+        var computed = new PlanRegistration
+        {
+            SdkSitId = 1, Date = new DateTime(2026, 6, 10), SumFlexEnd = 42.5
+        };
+        var uncomputed = new PlanRegistration
+        {
+            SdkSitId = 1, Date = new DateTime(2026, 6, 11), SumFlexEnd = 0
+        };
+
+        var anchor = PlanRegistrationHelper.ResolveChainAnchor(
+            new[] { computed, uncomputed }, site, new DateTime(2026, 6, 12));
+
+        Assert.That(anchor, Is.SameAs(computed));
+    }
+
+    [Test]
+    public void Anchor_WithNullCursor_FallsBackToTheImmediatelyPrecedingRow()
+    {
+        var site = new AssignedSite { SiteId = 1, FlexChainComputedThrough = null };
+        var previous = new PlanRegistration
+        {
+            SdkSitId = 1, Date = new DateTime(2026, 6, 11), SumFlexEnd = 7.0
+        };
+
+        var anchor = PlanRegistrationHelper.ResolveChainAnchor(
+            new[] { previous }, site, new DateTime(2026, 6, 12));
+
+        Assert.That(anchor, Is.SameAs(previous),
+            "a null cursor means nothing is known -- behave exactly as before");
+    }
 }

eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Infrastructure/Helpers/PlanRegistrationHelper.cs

@@ -364,6 +364,26 @@ public static void RecalculatePlanHoursFromShifts(PlanRegistration pr, bool useO
         RecalculatePlanHoursFromShifts(pr);
     }
 
+    /// <summary>
+    /// The row a chain recompute should seed from: the latest candidate strictly
+    /// before <paramref name="windowStart"/> that the site's cursor vouches for.
+    /// A row after the cursor may be one created ahead of time and never filled
+    /// in, whose zero would silently discard the accumulated balance.
+    /// A null cursor means nothing is known, so behave exactly as before.
+    /// </summary>
+    public static PlanRegistration? ResolveChainAnchor(
+        IEnumerable<PlanRegistration> candidates, AssignedSite site, DateTime windowStart)
+    {
+        var eligible = candidates.Where(x => x.Date < windowStart);
+
+        if (site.FlexChainComputedThrough is { } cursor)
+        {
+            eligible = eligible.Where(x => x.Date <= cursor);
+        }
+
+        return eligible.OrderByDescending(x => x.Date).FirstOrDefault();
+    }
+
     public static async Task<TimePlanningPlanningModel> UpdatePlanRegistrationsInPeriod(
         List<PlanRegistration> planningsInPeriod,
         TimePlanningPlanningModel siteModel,
@@ -495,6 +515,7 @@ await dbContext.PlanRegistrations.AsNoTracking()
                                 .Where(x => x.WorkflowState != Constants.WorkflowStates.Removed)
                                 .Where(x => x.Date < planRegistration.Date
                                             && x.SdkSitId == dbAssignedSite.SiteId)
+                                .Where(x => dbAssignedSite.FlexChainComputedThrough == null || x.Date <= dbAssignedSite.FlexChainComputedThrough)
                                 .OrderByDescending(x => x.Date)
                                 .FirstOrDefaultAsync();
 
@@ -787,6 +808,7 @@ await dbContext.PlanRegistrations.AsNoTracking()
                                 .Where(x => x.WorkflowState != Constants.WorkflowStates.Removed)
                                 .Where(x => x.Date < planRegistration.Date
                                             && x.SdkSitId == dbAssignedSite.SiteId)
+                                .Where(x => dbAssignedSite.FlexChainComputedThrough == null || x.Date <= dbAssignedSite.FlexChainComputedThrough)
                                 .OrderByDescending(x => x.Date)
                                 .FirstOrDefaultAsync();
 
@@ -1180,6 +1202,7 @@ await dbContext.PlanRegistrations.AsNoTracking()
                             .Where(x => x.WorkflowState != Constants.WorkflowStates.Removed)
                             .Where(x => x.Date < planRegistration.Date
                                         && x.SdkSitId == dbAssignedSite.SiteId)
+                            .Where(x => dbAssignedSite.FlexChainComputedThrough == null || x.Date <= dbAssignedSite.FlexChainComputedThrough)
                             .OrderByDescending(x => x.Date)
                             .FirstOrDefaultAsync();
 
@@ -1460,6 +1483,7 @@ await dbContext.PlanRegistrations.AsNoTracking()
                             .Where(x => x.WorkflowState != Constants.WorkflowStates.Removed)
                             .Where(x => x.Date < planRegistration.Date
                                         && x.SdkSitId == dbAssignedSite.SiteId)
+                            .Where(x => dbAssignedSite.FlexChainComputedThrough == null || x.Date <= dbAssignedSite.FlexChainComputedThrough)
                             .OrderByDescending(x => x.Date)
                             .FirstOrDefaultAsync();
 

eFormAPI/Plugins/TimePlanning.Pn/TimePlanning.Pn/Services/TimePlanningPlanningService/TimePlanningPlanningService.cs

@@ -381,6 +381,7 @@ await innerDbContext.PlanRegistrations.AsNoTracking()
                                 .Where(x => x.WorkflowState != Constants.WorkflowStates.Removed)
                                 .Where(x => x.Date < missingDate
                                             && x.SdkSitId == dbAssignedSite.SiteId)
+                                .Where(x => dbAssignedSite.FlexChainComputedThrough == null || x.Date <= dbAssignedSite.FlexChainComputedThrough)
                                 .OrderByDescending(x => x.Date)
                                 .FirstOrDefaultAsync();
 
@@ -595,6 +596,7 @@ await dbContext.PlanRegistrations.AsNoTracking()
                         .Where(x => x.WorkflowState != Constants.WorkflowStates.Removed)
                         .Where(x => x.Date < missingDate
                                     && x.SdkSitId == dbAssignedSite.SiteId)
+                        .Where(x => dbAssignedSite.FlexChainComputedThrough == null || x.Date <= dbAssignedSite.FlexChainComputedThrough)
                         .OrderByDescending(x => x.Date)
                         .FirstOrDefaultAsync();