Adjust activatedAt (expiresAt) on responses to account for clock drift

OmniKit/MessageTransport/MessageBlocks/ConfigureAlertsCommand.swift

@@ -116,8 +116,9 @@ extension AlertConfiguration {
         case .unitsRemaining(let volume):
             let ticks = UInt16(volume / Pod.pulseSize / 2)
             data.appendBigEndian(ticks)
-        case .timeUntilAlert(let duration):
-            let minutes = UInt16(duration.minutes)
+        case .timeUntilAlert(let secondsUntilAlert):
+            // round the time to alert to the nearest minute
+            let minutes = UInt16((secondsUntilAlert + 30).minutes)
             data.appendBigEndian(minutes)
         }
         data.append(beepRepeat.rawValue)

OmniKit/PumpManager/PodState.swift

@@ -42,7 +42,7 @@ public struct PodState: RawRepresentable, Equatable, CustomDebugStringConvertibl
 
     public let address: UInt32
     fileprivate var nonceState: NonceState
-    public var activatedAt: Date?
+    public var activatedAt: Date? // set based on StatusResponse timeActive and can change due to Pod clock drift and/or a system time change
 
     public var expiresAt: Date? {
         return activatedAt?.addingTimeInterval(Pod.serviceDuration - Pod.endOfServiceImminentWindow - Pod.expirationAdvisoryWindow)
@@ -144,11 +144,19 @@ public struct PodState: RawRepresentable, Equatable, CustomDebugStringConvertibl
     }
 
     public mutating func updateFromStatusResponse(_ response: StatusResponse) {
+        let now = Date()
+        let activatedAtComputed = now - response.timeActive
         if activatedAt == nil {
-            self.activatedAt = Date() - response.timeActive
+            self.activatedAt = activatedAtComputed
+        } else if let currActivatedAt = self.activatedAt,
+          (activatedAtComputed < currActivatedAt || activatedAtComputed > currActivatedAt + TimeInterval(minutes: 1)) {
+            // The computed activatedAt time is earlier than or more than a minute later than the current activatedAt time,
+            // so use the computed activatedAt time instead to handle Pod clock drift and/or system time changes issues.
+            // The more than a minute later test prevents oscillation of activatedAt based on the timing of the responses.
+            self.activatedAt = activatedAtComputed
         }
         updateDeliveryStatus(deliveryStatus: response.deliveryStatus)
-        lastInsulinMeasurements = PodInsulinMeasurements(statusResponse: response, validTime: Date())
+        lastInsulinMeasurements = PodInsulinMeasurements(statusResponse: response, validTime: now)
         activeAlertSlots = response.alerts
     }