Seed UserPreferences at launch instead of during view rendering

Bedtime/Bedtime/BedtimeApp.swift

@@ -41,6 +41,32 @@ struct BedtimeApp: App {
         }
     }()
 
+    init() {
+        Self.seedDefaultPreferencesIfNeeded(in: sharedModelContainer)
+    }
+
+    /// Creates the single `UserPreferences` record when the store is empty.
+    ///
+    /// SwiftData persists the schema but never creates instances, so a fresh install —
+    /// or a launch right after the store reset above — starts with nothing to read.
+    /// Seeding here, before the view tree exists, keeps the insert out of `ContentView`'s
+    /// body evaluation: SwiftUI reads a view's properties an unspecified number of times
+    /// per update, so inserting from there can write several default records and mutates
+    /// persistent state in the middle of a render.
+    @MainActor
+    private static func seedDefaultPreferencesIfNeeded(in container: ModelContainer) {
+        let context = container.mainContext
+
+        var descriptor = FetchDescriptor<UserPreferences>()
+        descriptor.fetchLimit = 1
+
+        // A failed fetch is not a reason to insert; ContentView still seeds defensively.
+        guard let existing = try? context.fetch(descriptor), existing.isEmpty else { return }
+
+        context.insert(UserPreferences())
+        try? context.save()
+    }
+
     var body: some Scene {
         WindowGroup {
             ContentView()

Bedtime/Bedtime/ContentView.swift

@@ -41,17 +41,7 @@ struct ContentView: View {
         return ViewModel.recentSourceAppLinks(sleepSessions: healthKitManager.allSleepSessions)
     }
 
-    private var userPreferences: UserPreferences {
-        if let existing = preferences.first {
-            return existing
-        } else {
-            let new = UserPreferences()
-            modelContext.insert(new)
-            return new
-        }
-    }
-
-    private var sleepBank: SleepBank {
+    private func sleepBank(for userPreferences: UserPreferences) -> SleepBank {
         ViewModel.calculateSleepBank(
             sleepSessions: healthKitManager.sleepSessions,
             goalHours: userPreferences.sleepGoalHours,
@@ -61,22 +51,25 @@ struct ContentView: View {
 
     /// Balance over the widest selectable lookback, independent of the current range, so the
     /// balance chart can show every night the range start can be moved to.
-    private var fullWindowSleepBank: SleepBank {
+    private func fullWindowSleepBank(for userPreferences: UserPreferences) -> SleepBank {
         ViewModel.calculateSleepBank(
             sleepSessions: healthKitManager.sleepSessions,
             goalHours: userPreferences.sleepGoalHours,
             recentDays: Constants.sleepBankDaysRange.upperBound
         )
     }
 
-    private var sleepBankDaysBinding: Binding<Int> {
+    private func sleepBankDaysBinding(for userPreferences: UserPreferences) -> Binding<Int> {
         Binding(
             get: { userPreferences.sleepBankDays },
             set: { userPreferences.sleepBankDays = $0 }
         )
     }
 
-    private var bedtimeRecommendation: BedtimeRecommendation {
+    private func bedtimeRecommendation(
+        for userPreferences: UserPreferences,
+        sleepBank: SleepBank
+    ) -> BedtimeRecommendation {
         ViewModel.generateBedtimeRecommendation(
             wakeTime: userPreferences.wakeTime,
             earliestBedtime: userPreferences.earliestReasonableBedtime,
@@ -86,14 +79,14 @@ struct ContentView: View {
         )
     }
 
-    private var wakeTimeBinding: Binding<Date> {
+    private func wakeTimeBinding(for userPreferences: UserPreferences) -> Binding<Date> {
         Binding(
             get: { userPreferences.wakeTime },
             set: { userPreferences.wakeTime = $0 }
         )
     }
 
-    private var sleepBankInsight: SleepBankInsight? {
+    private func sleepBankInsight(for userPreferences: UserPreferences) -> SleepBankInsight? {
         SleepInsightsEngine.generateInsight(
             sleepSessions: healthKitManager.sleepSessions,
             goalHours: userPreferences.sleepGoalHours,
@@ -104,8 +97,32 @@ struct ContentView: View {
         )
     }
 
+    /// `BedtimeApp` seeds the record before the view tree is built, so the placeholder
+    /// below is only reachable if that seed failed — or in previews and tests, which
+    /// start from an empty in-memory container.
     var body: some View {
+        if let userPreferences = preferences.first {
+            dashboard(for: userPreferences)
+        } else {
+            ProgressView()
+                .task { seedDefaultPreferencesIfNeeded() }
+        }
+    }
+
+    private func seedDefaultPreferencesIfNeeded() {
+        guard preferences.isEmpty else { return }
+        modelContext.insert(UserPreferences())
+    }
+
+    @ViewBuilder
+    private func dashboard(for userPreferences: UserPreferences) -> some View {
         let isBeforeEvening = Calendar.current.component(.hour, from: Date()) < 18
+        let currentSleepBank = sleepBank(for: userPreferences)
+        let recommendation = bedtimeRecommendation(for: userPreferences, sleepBank: currentSleepBank)
+        let insight = sleepBankInsight(for: userPreferences)
+        let daysBinding = sleepBankDaysBinding(for: userPreferences)
+        let wakeBinding = wakeTimeBinding(for: userPreferences)
+
         NavigationStack {
             ScrollView {
                 VStack(spacing: 20) {
@@ -124,20 +141,20 @@ struct ContentView: View {
                                           sourceAppLinks: recentSourceAppLinks)
                         } else {
                             BedtimeRecommendationCard(
-                                recommendation: bedtimeRecommendation,
-                                wakeTime: wakeTimeBinding
+                                recommendation: recommendation,
+                                wakeTime: wakeBinding
                             )
                         }
 
                         SleepBankCard(
-                            sleepBank: sleepBank,
-                            fullWindowBank: fullWindowSleepBank,
-                            sleepBankDays: sleepBankDaysBinding
+                            sleepBank: currentSleepBank,
+                            fullWindowBank: fullWindowSleepBank(for: userPreferences),
+                            sleepBankDays: daysBinding
                         )
 
-                        if let sleepBankInsight {
+                        if let insight {
                             SleepInsightsCard(
-                                insight: sleepBankInsight,
+                                insight: insight,
                                 currentSleepBankDays: userPreferences.sleepBankDays,
                                 onApplyDays: { days in
                                     withAnimation(.easeInOut(duration: 0.2)) {
@@ -149,8 +166,8 @@ struct ContentView: View {
 
                         if isBeforeEvening {
                             BedtimeRecommendationCard(
-                                recommendation: bedtimeRecommendation,
-                                wakeTime: wakeTimeBinding
+                                recommendation: recommendation,
+                                wakeTime: wakeBinding
                             )
                         } else {
                             LastNightCard(sleepSessions: lastNightData,
@@ -165,7 +182,7 @@ struct ContentView: View {
                                 allSessions: healthKitManager.allSleepSessions,
                                 excludedSourceIDs: sourcePreferences.excludedBundleIdentifiers,
                                 sleepGoal: userPreferences.sleepGoalHours,
-                                sleepBankDays: sleepBankDaysBinding
+                                sleepBankDays: daysBinding
                             )
                         }
                     }