From d9ae3e00f6ee7d7dc7db267a23d7a215496b9f91 Mon Sep 17 00:00:00 2001
From: Oliver Kieselbach <oliver.kieselbach@outlook.com>
Date: Thu, 12 Feb 2026 18:28:59 +0100
Subject: [PATCH] fix duration - startedAt now correct

---
 .../Functions/IngestEventsFunction.cs            | 16 +++++++++++++---
 .../Services/TableStorageService.cs              | 12 +++++++++++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs b/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs
index 6c5989ea..e64bedff 100644
--- a/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs
+++ b/src/Backend/AutopilotMonitor.Functions/Functions/IngestEventsFunction.cs
@@ -119,12 +119,19 @@ namespace AutopilotMonitor.Functions.Functions
                 EnrollmentEvent? lastPhaseChangeEvent = null;
                 EnrollmentEvent? completionEvent = null;
                 EnrollmentEvent? failureEvent = null;
+                DateTime? earliestEventTimestamp = null;
 
                 // Track app install events for AppInstallSummary aggregation
                 var appInstallUpdates = new Dictionary<string, AppInstallSummary>(StringComparer.OrdinalIgnoreCase);
 
                 foreach (var evt in storedEvents)
                 {
+                    // Track earliest event timestamp for accurate session StartedAt
+                    if (!earliestEventTimestamp.HasValue || evt.Timestamp < earliestEventTimestamp.Value)
+                    {
+                        earliestEventTimestamp = evt.Timestamp;
+                    }
+
                     // Track special events for session status updates
                     if (evt.EventType == "phase_changed" || evt.EventType == "esp_phase_changed")
                     {
@@ -158,7 +165,8 @@ namespace AutopilotMonitor.Functions.Functions
                         request.SessionId,
                         SessionStatus.Succeeded,
                         completionEvent.Phase,
-                        completedAt: completionEvent.Timestamp
+                        completedAt: completionEvent.Timestamp,
+                        earliestEventTimestamp: earliestEventTimestamp
                     );
                     _logger.LogInformation($"{sessionPrefix} Status: Succeeded");
                 }
@@ -175,7 +183,8 @@ namespace AutopilotMonitor.Functions.Functions
                         SessionStatus.Failed,
                         failureEvent.Phase,
                         failureReason,
-                        completedAt: failureEvent.Timestamp
+                        completedAt: failureEvent.Timestamp,
+                        earliestEventTimestamp: earliestEventTimestamp
                     );
                     _logger.LogWarning($"{sessionPrefix} Status: Failed - {failureReason}");
                 }
@@ -186,7 +195,8 @@ namespace AutopilotMonitor.Functions.Functions
                         request.TenantId,
                         request.SessionId,
                         SessionStatus.InProgress,
-                        lastPhaseChangeEvent.Phase
+                        lastPhaseChangeEvent.Phase,
+                        earliestEventTimestamp: earliestEventTimestamp
                     );
                 }
                 else if (processedCount > 0)
diff --git a/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs b/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs
index 7acaecdb..d8dce317 100644
--- a/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs
+++ b/src/Backend/AutopilotMonitor.Functions/Services/TableStorageService.cs
@@ -340,7 +340,7 @@ namespace AutopilotMonitor.Functions.Services
         /// <summary>
         /// Updates the session status and current phase
         /// </summary>
-        public async Task<bool> UpdateSessionStatusAsync(string tenantId, string sessionId, SessionStatus status, EnrollmentPhase? currentPhase = null, string? failureReason = null, DateTime? completedAt = null)
+        public async Task<bool> UpdateSessionStatusAsync(string tenantId, string sessionId, SessionStatus status, EnrollmentPhase? currentPhase = null, string? failureReason = null, DateTime? completedAt = null, DateTime? earliestEventTimestamp = null)
         {
             SecurityValidator.EnsureValidGuid(tenantId, nameof(tenantId));
             SecurityValidator.EnsureValidGuid(sessionId, nameof(sessionId));
@@ -367,6 +367,16 @@ namespace AutopilotMonitor.Functions.Services
                         session["CurrentPhase"] = (int)currentPhase.Value;
                     }
 
+                    // Update StartedAt if an earlier event timestamp is provided
+                    if (earliestEventTimestamp.HasValue)
+                    {
+                        var currentStartedAt = session.GetDateTimeOffset("StartedAt")?.UtcDateTime ?? DateTime.MaxValue;
+                        if (earliestEventTimestamp.Value < currentStartedAt)
+                        {
+                            session["StartedAt"] = earliestEventTimestamp.Value;
+                        }
+                    }
+
                     // Set completion time if succeeded or failed
                     if (status == SessionStatus.Succeeded || status == SessionStatus.Failed)
                     {