loopandlearn · bjorkert · Sep 27, 2026
@@ -218,6 +218,14 @@ struct Alarm: Identifiable, Codable, Equatable {
     /// CGM sensor lifetime in days (e.g. 10 for Dexcom G6, 15 for G7 15-day)
     var sensorLifetimeDays: Int?
 
+    /// Extra notification text: the CGM state behind a gap in readings.
+    private var notificationBody: String? {
+        guard type == .missedReading || type == .notLooping,
+              let state = Observable.shared.cgmSensorState.value
+        else { return nil }
+        return "CGM reported: \(state.summary)"
+    }
+
     /// Function for when the alarm is triggered.
     /// If this alarm, all alarms is disabled or snoozed, then should not be called. This or all alarmd could be muted, then this function will just generate a notification.
     func trigger(config: AlarmConfiguration, now: Date) {
@@ -277,7 +285,7 @@ struct Alarm: Identifiable, Codable, Equatable {
             }
         }()
 
-        AlarmManager.shared.sendNotification(title: type.rawValue, actionTitle: snoozeDuration == 0 ? "Acknowledge" : "Snooze")
+        AlarmManager.shared.sendNotification(title: type.rawValue, body: notificationBody, actionTitle: snoozeDuration == 0 ? "Acknowledge" : "Snooze")
 
         if playSound {
             AlarmSound.setSoundFile(soundFile)

@@ -186,14 +186,17 @@ class AlarmManager {
         UNUserNotificationCenter.current().removeAllPendingNotificationRequests()
     }
 
-    func sendNotification(title: String, actionTitle: String? = nil) {
+    func sendNotification(title: String, body: String? = nil, actionTitle: String? = nil) {
         UNUserNotificationCenter.current().removeAllPendingNotificationRequests()
 
         let content = UNMutableNotificationContent()
         content.title = title
         content.subtitle += Observable.shared.bgText.value + " "
         content.subtitle += Observable.shared.directionText.value + " "
         content.subtitle += Observable.shared.deltaText.value
+        if let body {
+            content.body = body
+        }
         content.categoryIdentifier = "category"
         content.sound = .default
 

@@ -140,6 +140,7 @@ final class BGChartModel: ObservableObject {
     @Published var resumes: [TreatmentPoint] = []
     @Published var sensorStarts: [TreatmentPoint] = []
     @Published var notes: [TreatmentPoint] = []
+    @Published var sensorStates: [TreatmentPoint] = []
 
     @Published var overrides: [BandRect] = []
     @Published var tempTargets: [BandRect] = []
@@ -517,6 +518,17 @@ final class BGChartModel: ObservableObject {
             )
         }
 
+        sensorStates = (showOtherTreatments ? vc.cgmSensorStates : []).compactMap { state in
+            guard let sgv = CGMSensorState.anchorSGV(at: state.date.timeIntervalSince1970, readings: vc.bgData) else { return nil }
+            return TreatmentPoint(
+                date: state.date,
+                value: Double(sgv),
+                sgv: Double(sgv),
+                label: state.name,
+                pillText: "CGM: \(state.displayName)\n\(pillTimeString(for: state.date))"
+            )
+        }
+
         basalScheduled = (showBasal ? vc.basalScheduleData : []).map {
             ScheduledBasalPoint(date: Date(timeIntervalSince1970: $0.date), rate: $0.basalRate)
         }

@@ -682,7 +682,7 @@ private struct MainBGChart: View {
     /// lookup and the tap hit test.
     private func forEachTreatmentAnchor(_ body: (BGChartModel.TreatmentPoint) -> Void) {
         for group in [model.boluses, model.carbs, model.smbs, model.bgChecks,
-                      model.notes, model.suspends, model.resumes, model.sensorStarts]
+                      model.notes, model.sensorStates, model.suspends, model.resumes, model.sensorStarts]
         {
             for t in group {
                 body(t)
@@ -1422,6 +1422,16 @@ private struct BGChartCanvas: View, Equatable {
             .symbolSize(isSmall ? 22 : 54)
             .foregroundStyle(Color.gray.opacity(0.75))
         }
+
+        ForEach(windowed(model.sensorStates) { $0.drawnDate }) { pt in
+            PointMark(
+                x: .value("time", pt.drawnDate),
+                y: .value("sgv", pt.sgv)
+            )
+            .symbol(.triangle)
+            .symbolSize(isSmall ? 22 : 54)
+            .foregroundStyle(Color.orange.opacity(0.85))
+        }
     }
 
     @ChartContentBuilder

@@ -101,6 +101,8 @@ extension MainViewController {
 
     func clearOldNotes() {
         noteGraphData.removeAll()
+        cgmSensorStates.removeAll()
         updateNotes()
+        updateCGMSensorState()
     }
 }
@@ -279,6 +279,7 @@ extension MainViewController {
 
             self.updateBGGraph()
             self.updateStats()
+            self.updateCGMSensorState()
 
             let latestEntryIndex = entries.count - 1
             let latestBG = entries[latestEntryIndex].sgv

@@ -214,7 +214,7 @@ extension MainViewController {
         if note.count > 0 {
             processNotes(entries: note)
         } else {
-            if noteGraphData.count > 0 {
+            if noteGraphData.count > 0 || cgmSensorStates.count > 0 {
                 clearOldNotes()
             }
         }

@@ -8,6 +8,7 @@ extension MainViewController {
     func processNotes(entries: [[String: AnyObject]]) {
         // because it's a small array, we're going to destroy and reload every time.
         noteGraphData.removeAll()
+        cgmSensorStates.removeAll()
         var lastFoundIndex = 0
 
         for currentEntry in entries.reversed() {
@@ -24,15 +25,21 @@ extension MainViewController {
 
             if let parsedDate = NightscoutUtils.parseDate(date) {
                 let dateTimeStamp = parsedDate.timeIntervalSince1970
-                let sgv = findNearestBGbyTime(needle: dateTimeStamp, haystack: bgData, startingIndex: lastFoundIndex)
-                lastFoundIndex = sgv.foundIndex
 
-                guard let thisNote = currentEntry["notes"] as? String else { continue }
+                guard let thisNote = currentEntry["notes"] as? String,
+                      dateTimeStamp < (dateTimeUtils.getNowTimeIntervalUTC() + (60 * 60))
+                else { continue }
 
-                if dateTimeStamp < (dateTimeUtils.getNowTimeIntervalUTC() + (60 * 60)) {
-                    let dot = DataStructs.noteStruct(date: Double(dateTimeStamp), sgv: Int(sgv.sgv), note: thisNote)
-                    noteGraphData.append(dot)
+                if let state = CGMSensorState(note: thisNote, date: parsedDate) {
+                    cgmSensorStates.append(state)
+                    continue
                 }
+
+                let sgv = findNearestBGbyTime(needle: dateTimeStamp, haystack: bgData, startingIndex: lastFoundIndex)
+                lastFoundIndex = sgv.foundIndex
+
+                let dot = DataStructs.noteStruct(date: Double(dateTimeStamp), sgv: Int(sgv.sgv), note: thisNote)
+                noteGraphData.append(dot)
             } else {
                 print("Failed to parse date")
             }
@@ -41,5 +48,23 @@ extension MainViewController {
         if Storage.shared.graphOtherTreatments.value {
             updateNotes()
         }
+        updateCGMSensorState()
+    }
+
+    /// Publishes the CGM state reported after the newest reading, if any.
+    func updateCGMSensorState() {
+        let latestBGDate = bgData.last.map { Date(timeIntervalSince1970: $0.date) }
+        let active = CGMSensorState.active(in: cgmSensorStates, latestBGDate: latestBGDate)
+        guard active != Observable.shared.cgmSensorState.value else { return }
+
+        Observable.shared.cgmSensorState.value = active
+        if let active {
+            LogManager.shared.log(category: .nightscout, message: "CGM sensor state: \(active.name) at \(active.date)")
+        } else {
+            LogManager.shared.log(category: .nightscout, message: "CGM sensor state cleared")
+        }
+        #if !targetEnvironment(macCatalyst)
+            LiveActivityManager.shared.refreshFromCurrentState(reason: "cgmSensorState")
+        #endif
     }
 }
@@ -0,0 +1,93 @@
+// LoopFollow
+// CGMSensorState.swift
+
+import Foundation
+
+/// A CGM state without reliable glucose, as uploaded by Loop or Trio in a
+/// Nightscout note of the form "CGM: <state>". The state is the CGM kit's own
+/// name, for example "temporarySensorIssue", "warmup" or ".unknown(23)".
+struct CGMSensorState: Equatable {
+    /// The kit's name for the state.
+    let name: String
+    let date: Date
+
+    init(name: String, date: Date) {
+        self.name = name
+        self.date = date
+    }
+
+    /// Parses a note text; nil when the note is not a sensor-state note.
+    init?(note: String, date: Date) {
+        let prefix = "CGM: "
+        guard note.hasPrefix(prefix) else { return nil }
+        let name = String(note.dropFirst(prefix.count))
+        guard !name.isEmpty, !name.contains(where: \.isWhitespace) else { return nil }
+        self.init(name: name, date: date)
+    }
+
+    /// The state in plain words, e.g. "Temporary sensor issue".
+    var displayName: String {
+        Self.displayName(for: name)
+    }
+
+    /// The state and its time, e.g. "Temporary sensor issue at 22:33".
+    var summary: String {
+        "\(displayName) at \(date.formatted(date: .omitted, time: .shortened))"
+    }
+
+    /// The newest state reported after the newest reading. A reading after a
+    /// state means the CGM delivers glucose again, so that state is over.
+    static func active(in states: [CGMSensorState], latestBGDate: Date?) -> CGMSensorState? {
+        guard let newest = states.max(by: { $0.date < $1.date }) else { return nil }
+        if let latestBGDate, newest.date <= latestBGDate {
+            return nil
+        }
+        return newest
+    }
+
+    /// Glucose to draw a state's marker at: the last reading at or before the
+    /// state, else the first reading after it. `readings` are sorted by date.
+    static func anchorSGV(at date: TimeInterval, readings: [ShareGlucoseData]) -> Int? {
+        if let before = readings.last(where: { $0.date <= date }) {
+            return before.sgv
+        }
+        return readings.first?.sgv
+    }
+
+    static func displayName(for name: String) -> String {
+        if name.hasPrefix(".unknown("), name.hasSuffix(")") {
+            let code = name.dropFirst(".unknown(".count).dropLast()
+            return "Unknown state (\(code))"
+        }
+        if name == "questionMarks" {
+            return "Question marks (???)"
+        }
+
+        // G7SensorKit spells some names "Dueto".
+        let identifier = name.replacingOccurrences(of: "Dueto", with: "DueTo")
+
+        var words: [String] = []
+        var current = ""
+        var previous: Character?
+        for character in identifier {
+            if let previous {
+                let startsWord = (character.isUppercase && (previous.isLowercase || previous.isNumber))
+                    || (character.isNumber && previous.isLetter)
+                if startsWord {
+                    words.append(current)
+                    current = ""
+                }
+            }
+            current.append(character)
+            previous = character
+        }
+        words.append(current)
+
+        // Acronyms such as "BGs" keep their case.
+        let normalized = words.map { word -> String in
+            word.dropFirst().contains(where: \.isUppercase) ? word : word.lowercased()
+        }
+        guard let first = normalized.first, !first.isEmpty else { return name }
+        return ([first.prefix(1).uppercased() + first.dropFirst()] + normalized.dropFirst()).joined(separator: " ")
+    }
+}
@@ -241,6 +241,7 @@ class APNSClient {
         ]
 
         snapshotDict["isNotLooping"] = snapshot.isNotLooping
+        if let cgmSensorState = snapshot.cgmSensorState { snapshotDict["cgmSensorState"] = cgmSensorState }
         snapshotDict["showRenewalOverlay"] = snapshot.showRenewalOverlay
         if let iob = snapshot.iob { snapshotDict["iob"] = iob }
         if let cob = snapshot.cob { snapshotDict["cob"] = cob }

@@ -101,6 +101,9 @@ protocol CurrentGlucoseStateProviding {
     /// True when LoopFollow detects the loop has not reported in 15+ minutes.
     var isNotLooping: Bool { get }
 
+    /// CGM state reported after the newest reading, as display text.
+    var cgmSensorState: String? { get }
+
     // MARK: - Renewal
 
     /// True when the Live Activity is within renewalWarning seconds of its deadline.
@@ -173,6 +176,7 @@ enum GlucoseSnapshotBuilder {
             maxBgMgdl: provider.maxBgMgdl,
             unit: preferredUnit,
             isNotLooping: provider.isNotLooping,
+            cgmSensorState: provider.cgmSensorState,
             showRenewalOverlay: provider.showRenewalOverlay,
         )
     }

@@ -141,6 +141,10 @@ struct StorageCurrentGlucoseStateProvider: CurrentGlucoseStateProviding {
         return Date().timeIntervalSince1970 - lastLoopTime >= 15 * 60
     }
 
+    var cgmSensorState: String? {
+        Observable.shared.cgmSensorState.value?.summary
+    }
+
     // MARK: - Renewal
 
     var showRenewalOverlay: Bool {

@@ -13,6 +13,7 @@ struct SnoozerView: View {
     @ObservedObject var directionText = Observable.shared.directionText
     @ObservedObject var deltaText = Observable.shared.deltaText
     @ObservedObject var bgStale = Observable.shared.bgStale
+    @ObservedObject var cgmSensorState = Observable.shared.cgmSensorState
     @ObservedObject var bg = Observable.shared.bg
     @ObservedObject var snoozerEmoji = Storage.shared.snoozerEmoji
 
@@ -209,6 +210,16 @@ struct SnoozerView: View {
                 .minimumScaleFactor(0.5)
                 .foregroundColor(.white.opacity(0.6))
                 .frame(maxWidth: .infinity, maxHeight: ageMaxH)
+
+            if let state = cgmSensorState.value {
+                Text("CGM: \(state.summary)")
+                    .font(.system(size: 30, weight: .semibold))
+                    .minimumScaleFactor(0.5)
+                    .lineLimit(2)
+                    .multilineTextAlignment(.center)
+                    .foregroundColor(.orange)
+                    .frame(maxWidth: .infinity)
+            }
         }
         .padding(.top, topPad)
         .padding(.horizontal, 16)

@@ -57,6 +57,9 @@ class Observable {
 
     var isNotLooping = ObservableValue<Bool>(default: false)
 
+    /// CGM state reported after the newest reading; nil while readings flow.
+    var cgmSensorState = ObservableValue<CGMSensorState?>(default: nil)
+
     /// Selected tab index used by SwiftUI TabView — set from MainViewController to switch tabs
     var selectedTabIndex = ObservableValue<Int>(default: 0)
 

@@ -15,6 +15,10 @@ extension MainViewController {
     func treatmentsTaskAction() {
         // If Nightscout not enabled, wait 60s and try again
         guard IsNightscoutEnabled(), Storage.shared.downloadTreatments.value else {
+            if !cgmSensorStates.isEmpty {
+                cgmSensorStates.removeAll()
+                updateCGMSensorState()
+            }
             TaskScheduler.shared.rescheduleTask(id: .treatments, to: Date().addingTimeInterval(60))
             return
         }

@@ -16,6 +16,7 @@ struct BGDisplayView: View {
     @ObservedObject var predictionText = Observable.shared.predictionText
     @ObservedObject var predictionColor = Observable.shared.predictionColor
     @ObservedObject var isNotLooping = Observable.shared.isNotLooping
+    @ObservedObject var cgmSensorState = Observable.shared.cgmSensorState
 
     var onRefresh: (() -> Void)?
 
@@ -49,6 +50,14 @@ struct BGDisplayView: View {
                 Text(minAgoText.value)
                     .font(.system(size: 17))
 
+                if let state = cgmSensorState.value {
+                    Text("CGM: \(state.summary)")
+                        .font(.system(size: 17, weight: .semibold))
+                        .foregroundColor(.orange)
+                        .multilineTextAlignment(.center)
+                        .frame(maxWidth: .infinity)
+                }
+
                 if isNotLooping.value {
                     Text(loopStatusText.value)
                         .font(.system(size: 18, weight: .bold))

@@ -98,6 +98,7 @@ class MainViewController: UIViewController, UNUserNotificationCenterDelegate {
     var resumeGraphData: [DataStructs.timestampOnlyStruct] = []
     var sensorStartGraphData: [DataStructs.timestampOnlyStruct] = []
     var noteGraphData: [DataStructs.noteStruct] = []
+    var cgmSensorStates: [CGMSensorState] = []
     var deviceBatteryData: [DataStructs.batteryStruct] = []
     var lastCalDate: Double = 0
     var latestLoopStatusString = ""