Use maxBolus to set automaticDosingIOBLimit

Loop/Managers/DoseMath.swift

@@ -234,7 +234,9 @@ extension Collection where Element: GlucoseValue {
         at date: Date,
         suspendThreshold: HKQuantity,
         sensitivity: HKQuantity,
-        model: InsulinModel
+        model: InsulinModel,
+        insulinOnBoard: Double?,
+        automaticDosingIOBLimit: Double?
     ) -> InsulinCorrection? {
         var minGlucose: GlucoseValue?
         var eventualGlucose: GlucoseValue?
@@ -327,9 +329,19 @@ extension Collection where Element: GlucoseValue {
                 minTarget: minGlucoseTargets.lowerBound,
                 units: units
             )
-        } else if eventual.quantity > eventualGlucoseTargets.upperBound,
-            let minCorrectionUnits = minCorrectionUnits, let correctingGlucose = correctingGlucose
-        {
+        } else if eventual.quantity > eventualGlucoseTargets.upperBound, var minCorrectionUnits = minCorrectionUnits, let correctingGlucose = correctingGlucose {
+            /// Don't allow the correction units + current `insulinOnBoard` to go over `automaticDosingIOBLimit`
+            if
+                let automaticDosingIOBLimit,
+                let insulinOnBoard,
+                minCorrectionUnits > 0,
+                insulinOnBoard + minCorrectionUnits > automaticDosingIOBLimit
+            {
+                let unitsOverAutomaticDosingLimit = (insulinOnBoard + minCorrectionUnits) - automaticDosingIOBLimit
+                // TO DO - nice to have logging but not required
+                minCorrectionUnits = Swift.max(minCorrectionUnits - unitsOverAutomaticDosingLimit, 0)
+            }
+
             return .aboveRange(
                 min: min,
                 correcting: correctingGlucose,
@@ -371,14 +383,18 @@ extension Collection where Element: GlucoseValue {
         rateRounder: ((Double) -> Double)? = nil,
         isBasalRateScheduleOverrideActive: Bool = false,
         duration: TimeInterval = .minutes(30),
-        continuationInterval: TimeInterval = .minutes(11)
+        continuationInterval: TimeInterval = .minutes(11),
+        insulinOnBoard: Double?,
+        automaticDosingIOBLimit: Double?
     ) -> TempBasalRecommendation? {
         let correction = self.insulinCorrection(
             to: correctionRange,
             at: date,
             suspendThreshold: suspendThreshold ?? correctionRange.quantityRange(at: date).lowerBound,
             sensitivity: sensitivity.quantity(at: date),
-            model: model
+            model: model,
+            insulinOnBoard: insulinOnBoard,
+            automaticDosingIOBLimit: automaticDosingIOBLimit
         )
 
         let scheduledBasalRate = basalRates.value(at: date)
@@ -439,14 +455,18 @@ extension Collection where Element: GlucoseValue {
         rateRounder: ((Double) -> Double)? = nil,
         isBasalRateScheduleOverrideActive: Bool = false,
         duration: TimeInterval = .minutes(30),
-        continuationInterval: TimeInterval = .minutes(11)
+        continuationInterval: TimeInterval = .minutes(11),
+        insulinOnBoard: Double?,
+        automaticDosingIOBLimit: Double?
     ) -> AutomaticDoseRecommendation? {
         guard let correction = self.insulinCorrection(
             to: correctionRange,
             at: date,
             suspendThreshold: suspendThreshold ?? correctionRange.quantityRange(at: date).lowerBound,
             sensitivity: sensitivity.quantity(at: date),
-            model: model
+            model: model,
+            insulinOnBoard: insulinOnBoard,
+            automaticDosingIOBLimit: automaticDosingIOBLimit
         ) else {
             return nil
         }
@@ -516,7 +536,9 @@ extension Collection where Element: GlucoseValue {
             at: date,
             suspendThreshold: suspendThreshold ?? correctionRange.quantityRange(at: date).lowerBound,
             sensitivity: sensitivity.quantity(at: date),
-            model: model
+            model: model,
+            insulinOnBoard: nil,
+            automaticDosingIOBLimit: nil
         ) else {
             return ManualBolusRecommendation(amount: 0, pendingInsulin: pendingInsulin)
         }

Loop/Managers/LoopDataManager.swift

@@ -63,6 +63,8 @@ final class LoopDataManager {
 
     private var timeBasedDoseApplicationFactor: Double = 1.0
 
+    private var insulinOnBoard: InsulinValue?
+
     deinit {
         for observer in notificationObservers {
             NotificationCenter.default.removeObserver(observer)
@@ -1034,16 +1036,13 @@ extension LoopDataManager {
                 updateGroup.leave()
             }
         }
-
-        var insulinOnBoard: InsulinValue?
-
         updateGroup.enter()
         doseStore.insulinOnBoard(at: now()) { result in
             switch result {
             case .failure(let error):
                 warnings.append(.fetchDataWarning(.insulinOnBoard(error: error)))
             case .success(let insulinValue):
-                insulinOnBoard = insulinValue
+                self.insulinOnBoard = insulinValue
             }
             updateGroup.leave()
         }
@@ -1064,7 +1063,7 @@ extension LoopDataManager {
         dosingDecision.date = now()
         dosingDecision.historicalGlucose = historicalGlucose
         dosingDecision.carbsOnBoard = carbsOnBoard
-        dosingDecision.insulinOnBoard = insulinOnBoard
+        dosingDecision.insulinOnBoard = self.insulinOnBoard
         dosingDecision.glucoseTargetRangeSchedule = settings.effectiveGlucoseTargetRangeSchedule()
 
         // These will be updated by updatePredictedGlucoseAndRecommendedDose, if possible
@@ -1629,6 +1628,9 @@ extension LoopDataManager {
 
             let dosingRecommendation: AutomaticDoseRecommendation?
 
+            // automaticDosingIOBLimit calculated from the user entered maxBolus
+            let automaticDosingIOBLimit = maxBolus! * 2.0
+
             switch settings.automaticDosingStrategy {
             case .automaticBolus:
                 let volumeRounder = { (_ units: Double) in
@@ -1647,7 +1649,9 @@ extension LoopDataManager {
                     lastTempBasal: lastTempBasal,
                     volumeRounder: volumeRounder,
                     rateRounder: rateRounder,
-                    isBasalRateScheduleOverrideActive: settings.scheduleOverride?.isBasalRateScheduleOverriden(at: startDate) == true
+                    isBasalRateScheduleOverrideActive: settings.scheduleOverride?.isBasalRateScheduleOverriden(at: startDate) == true,
+                    insulinOnBoard: self.insulinOnBoard?.value,
+                    automaticDosingIOBLimit: automaticDosingIOBLimit
                 )
             case .tempBasalOnly:
                 let temp = predictedGlucose.recommendedTempBasal(
@@ -1660,7 +1664,9 @@ extension LoopDataManager {
                     maxBasalRate: maxBasal!,
                     lastTempBasal: lastTempBasal,
                     rateRounder: rateRounder,
-                    isBasalRateScheduleOverrideActive: settings.scheduleOverride?.isBasalRateScheduleOverriden(at: startDate) == true
+                    isBasalRateScheduleOverrideActive: settings.scheduleOverride?.isBasalRateScheduleOverriden(at: startDate) == true,
+                    insulinOnBoard: self.insulinOnBoard?.value,
+                    automaticDosingIOBLimit: automaticDosingIOBLimit
                 )
                 dosingRecommendation = AutomaticDoseRecommendation(basalAdjustment: temp)
             }
@@ -1745,6 +1751,9 @@ extension LoopDataManager {
 protocol LoopState {
     /// The last-calculated carbs on board
     var carbsOnBoard: CarbValue? { get }
+
+    /// The last-calculated insulin on board
+    var insulinOnBoard: InsulinValue? { get }
 
     /// An error in the current state of the loop, or one that happened during the last attempt to loop.
     var error: LoopError? { get }
@@ -1847,6 +1856,11 @@ extension LoopDataManager {
             dispatchPrecondition(condition: .onQueue(loopDataManager.dataAccessQueue))
             return loopDataManager.carbsOnBoard
         }
+
+        var insulinOnBoard: InsulinValue? {
+            dispatchPrecondition(condition: .onQueue(loopDataManager.dataAccessQueue))
+            return loopDataManager.insulinOnBoard
+        }
 
         var error: LoopError? {
             dispatchPrecondition(condition: .onQueue(loopDataManager.dataAccessQueue))
@@ -2051,6 +2065,7 @@ extension LoopDataManager {
                 "lastLoopCompleted: \(String(describing: manager.lastLoopCompleted))",
                 "basalDeliveryState: \(String(describing: manager.basalDeliveryState))",
                 "carbsOnBoard: \(String(describing: state.carbsOnBoard))",
+                "insulinOnBoard: \(String(describing: manager.insulinOnBoard))",
                 "error: \(String(describing: state.error))",
                 "overrideInUserDefaults: \(String(describing: UserDefaults.appGroup?.intentExtensionOverrideToSet))",
                 "",

LoopTests/Managers/LoopDataManagerTests.swift

@@ -21,6 +21,28 @@ enum DataManagerTestType {
     case lowAndFallingWithCOB
     case lowWithLowTreatment
     case highAndFalling
+    /// uses fixtures for .highAndRisingWithCOB with a low max bolus and dosing set to autobolus
+    case autoBolusIOBClamping
+}
+
+extension DataManagerTestType {
+    var dosingStrategy: AutomaticDosingStrategy {
+        switch self {
+        case .autoBolusIOBClamping:
+            return .automaticBolus
+        default:
+            return .tempBasalOnly
+        }
+    }
+
+    var maxBolus: Double {
+        switch self {
+        case .autoBolusIOBClamping:
+            return 5
+        default:
+            return LoopDataManagerDosingTests.defaultMaxBolus
+        }
+    }
 }
 
 extension TimeZone {
@@ -56,7 +78,7 @@ class LoopDataManagerDosingTests: XCTestCase {
 
     // MARK: Settings
     let maxBasalRate = 5.0
-    let maxBolus = 10.0
+    static let defaultMaxBolus = 10.0
 
     var suspendThreshold: GlucoseThreshold {
         return GlucoseThreshold(unit: HKUnit.milligramsPerDeciliter, value: 75)
@@ -85,8 +107,9 @@ class LoopDataManagerDosingTests: XCTestCase {
             glucoseTargetRangeSchedule: glucoseTargetRangeSchedule,
             basalRateSchedule: basalRateSchedule,
             maximumBasalRatePerHour: maxBasalRate,
-            maximumBolus: maxBolus,
-            suspendThreshold: suspendThreshold
+            maximumBolus: test.maxBolus,
+            suspendThreshold: suspendThreshold,
+            automaticDosingStrategy: test.dosingStrategy
         )
 
         let doseStore = MockDoseStore(for: test)
@@ -507,7 +530,7 @@ class LoopDataManagerDosingTests: XCTestCase {
             dosingEnabled: false,
             glucoseTargetRangeSchedule: glucoseTargetRangeSchedule,
             maximumBasalRatePerHour: maxBasalRate,
-            maximumBolus: maxBolus,
+            maximumBolus: Self.defaultMaxBolus,
             suspendThreshold: suspendThreshold
         )
 
@@ -558,6 +581,40 @@ class LoopDataManagerDosingTests: XCTestCase {
         XCTAssertNil(mockDelegate.recommendation)
     }
 
+
+    func testAutoBolusMaxIOBClamping() {
+        /// `maximumBolus` is set to clamp the automatic dose
+        /// Autobolus without clamping: 0.65 U. Clamped recommendation: 0.2 U.
+        setUp(for: .autoBolusIOBClamping)
+
+        let updateGroup = DispatchGroup()
+        updateGroup.enter()
+
+        var insulinOnBoard: InsulinValue?
+        var recommendedBolus: Double?
+        self.loopDataManager.getLoopState { _, state in
+            insulinOnBoard = state.insulinOnBoard
+            recommendedBolus = state.recommendedAutomaticDose?.recommendation.bolusUnits
+            updateGroup.leave()
+        }
+        updateGroup.wait()
+
+        XCTAssertEqual(recommendedBolus!, 0.2, accuracy: 0.01)
+        XCTAssertEqual(insulinOnBoard?.value, 9.5)
+
+        /// Set the `maximumBolus` so there's no clamping
+        updateGroup.enter()
+        self.loopDataManager.mutateSettings { settings in settings.maximumBolus = Self.defaultMaxBolus }
+        self.loopDataManager.getLoopState { _, state in
+            insulinOnBoard = state.insulinOnBoard
+            recommendedBolus = state.recommendedAutomaticDose?.recommendation.bolusUnits
+            updateGroup.leave()
+        }
+        updateGroup.wait()
+
+        XCTAssertEqual(recommendedBolus!, 0.65, accuracy: 0.01)
+        XCTAssertEqual(insulinOnBoard?.value, 9.5)
+    }
 }
 
 extension LoopDataManagerDosingTests {

LoopTests/Mock Stores/MockCarbStore.swift

@@ -124,7 +124,7 @@ extension MockCarbStore {
             return "flat_and_stable_carb_effect"
         case .highAndStable:
             return "high_and_stable_carb_effect"
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return "high_and_rising_with_cob_carb_effect"
         case .lowAndFallingWithCOB:
             return "low_and_falling_carb_effect"

LoopTests/Mock Stores/MockDoseStore.swift

@@ -60,7 +60,12 @@ class MockDoseStore: DoseStoreProtocol {
     }
 
     func insulinOnBoard(at date: Date, completion: @escaping (DoseStoreResult<InsulinValue>) -> Void) {
-        completion(.failure(.configurationError))
+        switch testType {
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
+            completion(.success(.init(startDate: MockDoseStore.currentDate(for: testType), value: 9.5)))
+        default:
+            completion(.failure(.configurationError))
+        }
     }
 
     func generateDiagnosticReport(_ completion: @escaping (String) -> Void) {
@@ -112,7 +117,7 @@ class MockDoseStore: DoseStoreProtocol {
             return dateFormatter.date(from: "2020-08-11T20:45:02")!
         case .highAndStable:
             return dateFormatter.date(from: "2020-08-12T12:39:22")!
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return dateFormatter.date(from: "2020-08-11T21:48:17")!
         case .lowAndFallingWithCOB:
             return dateFormatter.date(from: "2020-08-11T22:06:06")!
@@ -140,7 +145,7 @@ extension MockDoseStore {
             return "flat_and_stable_insulin_effect"
         case .highAndStable:
             return "high_and_stable_insulin_effect"
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return "high_and_rising_with_cob_insulin_effect"
         case .lowAndFallingWithCOB:
             return "low_and_falling_insulin_effect"

LoopTests/Mock Stores/MockGlucoseStore.swift

@@ -112,7 +112,7 @@ extension MockGlucoseStore {
             return "flat_and_stable_counteraction_effect"
         case .highAndStable:
             return "high_and_stable_counteraction_effect"
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return "high_and_rising_with_cob_counteraction_effect"
         case .lowAndFallingWithCOB:
             return "low_and_falling_counteraction_effect"
@@ -129,7 +129,7 @@ extension MockGlucoseStore {
             return "flat_and_stable_momentum_effect"
         case .highAndStable:
             return "high_and_stable_momentum_effect"
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return "high_and_rising_with_cob_momentum_effect"
         case .lowAndFallingWithCOB:
             return "low_and_falling_momentum_effect"
@@ -146,7 +146,7 @@ extension MockGlucoseStore {
             return dateFormatter.date(from: "2020-08-11T20:45:02")!
         case .highAndStable:
             return dateFormatter.date(from: "2020-08-12T12:39:22")!
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return dateFormatter.date(from: "2020-08-11T21:48:17")!
         case .lowAndFallingWithCOB:
             return dateFormatter.date(from: "2020-08-11T22:06:06")!
@@ -163,7 +163,7 @@ extension MockGlucoseStore {
             return 123.42849966275706
         case .highAndStable:
             return 200.0
-        case .highAndRisingWithCOB:
+        case .highAndRisingWithCOB, .autoBolusIOBClamping:
             return 129.93174411197853
         case .lowAndFallingWithCOB:
             return 75.10768374646841

LoopTests/ViewModels/BolusEntryViewModelTests.swift

@@ -764,6 +764,8 @@ fileprivate class MockLoopState: LoopState {
 
     var carbsOnBoard: CarbValue?
 
+    var insulinOnBoard: InsulinValue?
+
     var error: LoopError?
 
     var insulinCounteractionEffects: [GlucoseEffectVelocity] = []