[LOOP-4470] refactoring bolus handling in bolus entry view (#548)

Author: nhamming

Loop/View Models/BolusEntryViewModel.swift

@@ -103,7 +103,13 @@ final class BolusEntryViewModel: ObservableObject {
     private var manualGlucoseSample: NewGlucoseSample? // derived from `enteredManualGlucose`, but stored to ensure timestamp consistency
 
     @Published var recommendedBolus: HKQuantity?
+    var recommendedBolusAmount: Double? {
+        recommendedBolus?.doubleValue(for: .internationalUnit())
+    }
     @Published var enteredBolus = HKQuantity(unit: .internationalUnit(), doubleValue: 0)
+    var enteredBolusAmount: Double {
+        enteredBolus.doubleValue(for: .internationalUnit())
+    }
     private var userChangedBolusAmount = false
     @Published var isInitiatingSaveOrBolus = false
 
@@ -307,11 +313,11 @@ final class BolusEntryViewModel: ObservableObject {
     // MARK: - View API
 
     var isBolusRecommended: Bool {
-        guard let recommendedBolus = recommendedBolus else {
+        guard let recommendedBolusAmount = recommendedBolusAmount else {
             return false
         }
 
-        return recommendedBolus.doubleValue(for: .internationalUnit()) > 0
+        return recommendedBolusAmount > 0
     }
 
     func saveAndDeliver(onSuccess completion: @escaping () -> Void) {
@@ -325,15 +331,13 @@ final class BolusEntryViewModel: ObservableObject {
             return
         }
 
-        let amountEntered = enteredBolus.doubleValue(for: .internationalUnit())
-
-        let amountToDeliver = delegate.roundBolusVolume(units: amountEntered)
-        guard amountEntered == 0 || amountToDeliver > 0 else {
+        let amountToDeliver = delegate.roundBolusVolume(units: enteredBolusAmount)
+        guard enteredBolusAmount == 0 || amountToDeliver > 0 else {
             presentAlert(.bolusTooSmall)
             return
         }
 
-        let amountToDeliverString = bolusVolumeFormatter.numberFormatter.string(from: amountToDeliver) ?? String(amountToDeliver)
+        let amountToDeliverString = formatBolusAmount(amountToDeliver)
 
         // Capture state as is during initial action, to prevent race conditions
         // caused by later updates to member variables while async operations are
@@ -403,7 +407,7 @@ final class BolusEntryViewModel: ObservableObject {
     }
 
     private func saveCarbsAndDeliverBolus(amountToDeliver: Double, potentialCarbEntry: NewCarbEntry?, onSuccess completion: @escaping () -> Void) {
-        let activationType = BolusActivationType.activationTypeFor(recommendedAmount: recommendedBolus?.doubleValue(for: .internationalUnit()), bolusAmount: amountToDeliver)
+        let activationType = BolusActivationType.activationTypeFor(recommendedAmount: recommendedBolusAmount, bolusAmount: amountToDeliver)
 
         guard let carbEntry = potentialCarbEntry else {
             dosingDecision.carbEntry = nil
@@ -465,7 +469,12 @@ final class BolusEntryViewModel: ObservableObject {
         activeAlert = alert
     }
 
-    private lazy var bolusVolumeFormatter = QuantityFormatter(for: .internationalUnit())
+    private lazy var bolusAmountFormatter: NumberFormatter = {
+        let formatter = QuantityFormatter()
+        formatter.setPreferredNumberFormatter(for: .internationalUnit())
+        formatter.numberFormatter.roundingMode = .down
+        return formatter.numberFormatter
+    }()
 
     private lazy var absorptionTimeFormatter: DateComponentsFormatter = {
         let formatter = DateComponentsFormatter()
@@ -477,15 +486,15 @@ final class BolusEntryViewModel: ObservableObject {
     }()
 
     var enteredBolusAmountString: String {
-        let bolusVolume = enteredBolus.doubleValue(for: .internationalUnit())
-        return bolusVolumeFormatter.numberFormatter.string(from: bolusVolume) ?? String(bolusVolume)
+        let bolusAmount = enteredBolusAmount
+        return formatBolusAmount(bolusAmount)
     }
 
     var maximumBolusAmountString: String? {
-        guard let maxBolusVolume = maximumBolus?.doubleValue(for: .internationalUnit()) else {
+        guard let maxBolusAmount = maximumBolus?.doubleValue(for: .internationalUnit()) else {
             return nil
         }
-        return bolusVolumeFormatter.numberFormatter.string(from: maxBolusVolume) ?? String(maxBolusVolume)
+        return formatBolusAmount(maxBolusAmount)
     }
 
     var carbEntryAmountAndEmojiString: String? {
@@ -698,9 +707,11 @@ final class BolusEntryViewModel: ObservableObject {
         let notice: Notice?
         do {
             recommendation = try computeBolusRecommendation(from: state)
+
             if let recommendation = recommendation {
                 recommendedBolus = HKQuantity(unit: .internationalUnit(), doubleValue: delegate.roundBolusVolume(units: recommendation.amount))
-
+                //recommendedBolus = HKQuantity(unit: .internationalUnit(), doubleValue: recommendation.amount)
+                
                 switch recommendation.notice {
                 case .glucoseBelowSuspendThreshold:
                     if let suspendThreshold = delegate.settings.suspendThreshold {
@@ -822,6 +833,25 @@ final class BolusEntryViewModel: ObservableObject {
 
         chartDateInterval = DateInterval(start: chartStartDate, duration: .hours(totalHours))
     }
+
+    func formatBolusAmount(_ bolusAmount: Double) -> String {
+        bolusAmountFormatter.string(from: bolusAmount) ?? String(bolusAmount)
+    }
+
+    var recommendedBolusString: String {
+        guard let amount = recommendedBolusAmount else {
+            return "–"
+        }
+        return formatBolusAmount(amount)
+    }
+
+    func updateEnteredBolus(_ enteredBolusString: String) {
+        updateEnteredBolus(bolusAmountFormatter.number(from: enteredBolusString)?.doubleValue)
+    }
+
+    func updateEnteredBolus(_ enteredBolusAmount: Double?) {
+        enteredBolus = HKQuantity(unit: .internationalUnit(), doubleValue: enteredBolusAmount ?? 0)
+    }
 }
 
 extension BolusEntryViewModel.Alert: Identifiable {

Loop/Views/BolusEntryView.swift

@@ -63,17 +63,17 @@ struct BolusEntryView: View {
                 .supportedInterfaceOrientations(.portrait)
                 .alert(item: self.$viewModel.activeAlert, content: self.alert(for:))
                 .onReceive(self.viewModel.$recommendedBolus) { recommendation in
-                    // If the recommendation changes, and the user has not edited the bolus amount, update the bolus amount
-                    let amount = recommendation?.doubleValue(for: .internationalUnit()) ?? 0
-                    if !editedBolusAmount {
-                        var newEnteredBolusString: String
-                        if amount == 0 {
-                            newEnteredBolusString = ""
-                        } else {
-                            newEnteredBolusString = Self.doseAmountFormatter.string(from: amount) ?? String(amount)
-                        }
-                        enteredBolusStringBinding.wrappedValue = newEnteredBolusString
+                    // If the user has not edited the bolus amount and there are recommendation changes, then update the bolus amount
+                    guard !editedBolusAmount else { return }
+
+                    guard let amount = recommendation?.doubleValue(for: .internationalUnit()),
+                          amount != 0
+                    else {
+                        enteredBolusStringBinding.wrappedValue = ""
+                        return
                     }
+
+                    enteredBolusStringBinding.wrappedValue = viewModel.formatBolusAmount(amount)
                 }
                 .onReceive(self.viewModel.$isManualGlucoseEntryEnabled) { isManualGlucoseEntryEnabled in
                     // The view model can disable manual glucose entry if CGM data returns.
@@ -270,19 +270,12 @@ struct BolusEntryView: View {
         }
     }
 
-    private static let doseAmountFormatter: NumberFormatter = {
-        let quantityFormatter = QuantityFormatter()
-        quantityFormatter.setPreferredNumberFormatter(for: .internationalUnit())
-        quantityFormatter.numberFormatter.roundingMode = .down
-        return quantityFormatter.numberFormatter
-    }()
-
     private var recommendedBolusRow: some View {
         HStack {
             Text("Recommended Bolus", comment: "Label for recommended bolus row on bolus screen")
             Spacer()
             HStack(alignment: .firstTextBaseline) {
-                Text(recommendedBolusString)
+                Text(viewModel.recommendedBolusString)
                     .font(.title)
                     .foregroundColor(Color(.label))
                 bolusUnitsLabel
@@ -291,19 +284,9 @@ struct BolusEntryView: View {
         .accessibilityElement(children: .combine)
     }
 
-    private var recommendedBolusString: String {
-        guard let amount = viewModel.recommendedBolus?.doubleValue(for: .internationalUnit()) else {
-            return "–"
-        }
-        return Self.doseAmountFormatter.string(from: amount) ?? String(amount)
-    }
-
     private func didBeginEditing() {
         if !editedBolusAmount {
-            enteredBolusString = ""
-            DispatchQueue.main.async {
-                self.viewModel.enteredBolus = HKQuantity(unit: .internationalUnit(), doubleValue: 0)
-            }
+            enteredBolusStringBinding.wrappedValue = ""
             editedBolusAmount = true
         }
     }
@@ -315,7 +298,7 @@ struct BolusEntryView: View {
             HStack(alignment: .firstTextBaseline) {
                 DismissibleKeyboardTextField(
                     text: enteredBolusStringBinding,
-                    placeholder: Self.doseAmountFormatter.string(from: 0.0)!,
+                    placeholder: viewModel.formatBolusAmount(0.0),
                     font: .preferredFont(forTextStyle: .title1),
                     textColor: .loopAccent,
                     textAlignment: .right,
@@ -338,10 +321,10 @@ struct BolusEntryView: View {
 
     private var enteredBolusStringBinding: Binding<String> {
         Binding(
-            get: { self.enteredBolusString },
+            get: { enteredBolusString },
             set: { newValue in
-                self.viewModel.enteredBolus = HKQuantity(unit: .internationalUnit(), doubleValue: Self.doseAmountFormatter.number(from: newValue)?.doubleValue ?? 0)
-                self.enteredBolusString = newValue
+                viewModel.updateEnteredBolus(newValue)
+                enteredBolusString = newValue
             }
         )
     }