Add sleep bank insights with auto-selected windows

Bedtime/Bedtime/BedtimeApp.swift

@@ -20,7 +20,24 @@ struct BedtimeApp: App {
         do {
             return try ModelContainer(for: schema, configurations: [modelConfiguration])
         } catch {
-            fatalError("Could not create ModelContainer: \(error)")
+            // The store on disk can be incompatible with the current schema after a
+            // model change that SwiftData can't lightweight-migrate (e.g. the max-hours
+            // → earliestReasonableBedtime refactor). Rather than crash on open for
+            // anyone upgrading, discard the stale store and rebuild it. UserPreferences
+            // only holds user settings, which fall back to sensible defaults.
+            if let storeURL = modelConfiguration.url as URL? {
+                let fileManager = FileManager.default
+                for suffix in ["", "-shm", "-wal"] {
+                    let url = URL(fileURLWithPath: storeURL.path + suffix)
+                    try? fileManager.removeItem(at: url)
+                }
+            }
+
+            do {
+                return try ModelContainer(for: schema, configurations: [modelConfiguration])
+            } catch {
+                fatalError("Could not create ModelContainer after resetting the store: \(error)")
+            }
         }
     }()
 

Bedtime/Bedtime/ContentView.swift

@@ -11,6 +11,7 @@ import SwiftData
 struct ContentView: View {
     @Environment(\.modelContext) private var modelContext
     @Environment(\.horizontalSizeClass) private var horizontalSizeClass
+    @Environment(\.scenePhase) private var scenePhase
     @Query private var preferences: [UserPreferences]
     @StateObject private var sourcePreferences: SourcePreferences
     @StateObject private var healthKitManager: HealthKitManager
@@ -57,6 +58,17 @@ struct ContentView: View {
         )
     }
 
+    private var sleepBankInsight: SleepBankInsight? {
+        SleepInsightsEngine.generateInsight(
+            sleepSessions: healthKitManager.sleepSessions,
+            goalHours: userPreferences.sleepGoalHours,
+            maxSleepHours: SleepWindow.maxSleepHours(
+                earliestBedtime: userPreferences.earliestReasonableBedtime,
+                wakeTime: userPreferences.wakeTime
+            )
+        )
+    }
+
     var body: some View {
         let isBeforeEvening = Calendar.current.component(.hour, from: Date()) < 18
         NavigationStack {
@@ -80,6 +92,10 @@ struct ContentView: View {
 
                         SleepBankCard(sleepBank: sleepBank)
 
+                        if let sleepBankInsight {
+                            SleepInsightsCard(insight: sleepBankInsight)
+                        }
+
                         if isBeforeEvening {
                             BedtimeRecommendationCard(recommendation: bedtimeRecommendation)
                         } else {
@@ -131,6 +147,13 @@ struct ContentView: View {
         .task {
             try? await healthKitManager.fetchSleepData()
         }
+        .onChange(of: scenePhase) { _, newPhase in
+            // Refresh on return from background: the observer query's background
+            // delivery is throttled, and `.task` doesn't re-run on resume, so this
+            // covers data added in the Health app while we were suspended.
+            guard newPhase == .active else { return }
+            Task { try? await healthKitManager.fetchSleepData() }
+        }
     }
 }
 

Bedtime/Bedtime/Models/HealthKitManager.swift

@@ -31,6 +31,9 @@ class HealthKitManager: ObservableObject {
     private let sourcePreferences: SourcePreferences
     private var rawSleepSamples: [HKCategorySample] = []
     private var cancellables = Set<AnyCancellable>()
+    /// Long-lived query that re-loads data whenever HealthKit sleep samples change.
+    /// Registered once, after the first successful fetch; torn down in `deinit`.
+    private var observerQuery: HKObserverQuery?
 
     @Published private(set) var permissionsRequestState: PermissionsRequestState = .loading
     @Published var sleepSessions: [Date: [SleepSession]] = [:]
@@ -56,6 +59,12 @@ class HealthKitManager: ObservableObject {
             .store(in: &cancellables)
     }
 
+    deinit {
+        if let observerQuery {
+            healthStore.stop(observerQuery)
+        }
+    }
+
     private func checkHealthKitAvailability() throws {
         guard HKHealthStore.isHealthDataAvailable() else {
             throw NSError(domain: "HealthKitManager", code: 1, userInfo: [NSLocalizedDescriptionKey: "HealthKit is not available on this device"])
@@ -90,6 +99,7 @@ class HealthKitManager: ObservableObject {
         do {
             try await requestAuthorization()
             try await loadSleepData()
+            startObservingSleepChanges()
         } catch {
             errorMessage = error.localizedDescription
             throw error
@@ -100,6 +110,57 @@ class HealthKitManager: ObservableObject {
         _ = try await [fetchSleepDataForDisplay(), discoverAvailableSources()]
     }
 
+    /// Registers an `HKObserverQuery` so the app re-loads sleep data whenever
+    /// HealthKit gains new samples — no manual pull-to-refresh needed — and enables
+    /// background delivery so those updates arrive even while the app is suspended.
+    /// Idempotent: safe to call from every `fetchSleepData()`; only registers once.
+    private func startObservingSleepChanges() {
+        guard observerQuery == nil else { return }
+
+        let query = HKObserverQuery(
+            sampleType: HKCategoryType.sleepAnalysis,
+            predicate: nil
+        ) { [weak self] _, completionHandler, error in
+            // HealthKit invokes this handler off the main thread, so hop to the main
+            // actor to touch `errorMessage`/`loadSleepData`. Always call
+            // `completionHandler()` so HealthKit releases its background assertion and
+            // stops retrying the notification.
+            Task { @MainActor in
+                defer { completionHandler() }
+                guard let self else { return }
+                if let error {
+                    self.errorMessage = "Sleep data observer error: \(error.localizedDescription)"
+                    return
+                }
+                do {
+                    try await self.loadSleepData()
+                } catch {
+                    self.errorMessage = "Failed to refresh sleep data: \(error.localizedDescription)"
+                }
+            }
+        }
+
+        observerQuery = query
+        healthStore.execute(query)
+        enableBackgroundDelivery()
+    }
+
+    /// Asks HealthKit to wake the app (subject to system throttling) whenever new
+    /// sleep samples land, so the observer query fires while backgrounded. Requires
+    /// the `com.apple.developer.healthkit.background-delivery` entitlement.
+    private func enableBackgroundDelivery() {
+        healthStore.enableBackgroundDelivery(
+            for: HKCategoryType.sleepAnalysis,
+            frequency: .immediate
+        ) { [weak self] _, error in
+            guard let error else { return }
+            let message = "Failed to enable background updates: \(error.localizedDescription)"
+            Task { @MainActor [weak self] in
+                self?.errorMessage = message
+            }
+        }
+    }
+
     private func fetchSleepDataForDisplay() async throws {
         let calendar = Calendar.current
         let endDate = Date()

Bedtime/Bedtime/Models/SleepData.swift

@@ -85,7 +85,7 @@ extension HKCategoryValueSleepAnalysis {
     }
 }
 
-struct SleepBank {
+struct SleepBank: Equatable {
     let currentBalance: Double // in hours
     let goalHours: Double
     let averageHours: Double?
@@ -118,5 +118,5 @@ struct BedtimeRecommendation {
     let recommendedBedtime: Date
     let wakeTime: Date
     let targetSleepDuration: Double // in hours
-    let reason: String
+    let reason: String?
 }