Add WatchConnectivity for bidirectional iOS-Watch sync

Implement real-time sync between iOS and Apple Watch apps using
WatchConnectivity framework. This replaces reliance on CloudKit
which doesn't work reliably in simulators.

- Add WatchConnectivityManager to both iOS and Watch targets
- Sync workouts, splits, exercises, and logs between devices
- Update iOS views to trigger sync on data changes
- Add onChange observer to ExerciseView for live progress updates
- Configure App Groups for shared container storage
- Add Watch app views: WorkoutLogsView, WorkoutLogListView, ExerciseProgressView

Workouts Watch App/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -1,13 +1,14 @@
 {
-  "images" : [
+  "images": [
     {
-      "idiom" : "universal",
-      "platform" : "watchos",
-      "size" : "1024x1024"
+      "filename": "icon-1024.png",
+      "idiom": "universal",
+      "platform": "watchos",
+      "size": "1024x1024"
     }
   ],
-  "info" : {
-    "author" : "xcode",
-    "version" : 1
+  "info": {
+    "author": "xcode",
+    "version": 1
   }
-}
+}

Workouts Watch App/Connectivity/WatchConnectivityManager.swift

@@ -0,0 +1,455 @@
+//
+// WatchConnectivityManager.swift
+// Workouts Watch App
+//
+// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
+//
+
+import Foundation
+import WatchConnectivity
+import CoreData
+
+class WatchConnectivityManager: NSObject, ObservableObject {
+    static let shared = WatchConnectivityManager()
+
+    private var session: WCSession?
+    private var viewContext: NSManagedObjectContext?
+
+    @Published var lastSyncDate: Date?
+
+    override init() {
+        super.init()
+
+        if WCSession.isSupported() {
+            session = WCSession.default
+            session?.delegate = self
+            session?.activate()
+        }
+    }
+
+    func setViewContext(_ context: NSManagedObjectContext) {
+        self.viewContext = context
+
+        // Process any pending application context
+        if let session = session, !session.receivedApplicationContext.isEmpty {
+            processApplicationContext(session.receivedApplicationContext)
+        }
+    }
+
+    // MARK: - Send Data to iOS
+
+    func syncToiOS() {
+        guard let session = session else {
+            print("[WC-Watch] No WCSession")
+            return
+        }
+
+        print("[WC-Watch] Syncing to iOS - state: \(session.activationState.rawValue), reachable: \(session.isReachable)")
+
+        guard session.activationState == .activated else {
+            print("[WC-Watch] Session not activated")
+            return
+        }
+
+        guard let context = viewContext else {
+            print("[WC-Watch] No view context")
+            return
+        }
+
+        context.perform {
+            do {
+                let workoutsData = try self.encodeAllWorkouts(context: context)
+
+                let payload: [String: Any] = [
+                    "type": "syncFromWatch",
+                    "workouts": workoutsData,
+                    "timestamp": Date().timeIntervalSince1970
+                ]
+
+                if session.isReachable {
+                    session.sendMessage(payload, replyHandler: nil) { error in
+                        print("[WC-Watch] Failed to send sync: \(error)")
+                    }
+                    print("[WC-Watch] Sent \(workoutsData.count) workouts to iOS via message")
+                } else {
+                    // Use transferUserInfo for background delivery
+                    session.transferUserInfo(payload)
+                    print("[WC-Watch] Queued \(workoutsData.count) workouts to iOS via transferUserInfo")
+                }
+
+            } catch {
+                print("[WC-Watch] Failed to encode data: \(error)")
+            }
+        }
+    }
+
+    private func encodeAllWorkouts(context: NSManagedObjectContext) throws -> [[String: Any]] {
+        let request = Workout.fetchRequest()
+        request.sortDescriptors = [NSSortDescriptor(keyPath: \Workout.start, ascending: false)]
+        let workouts = try context.fetch(request)
+        return workouts.map { encodeWorkout($0) }
+    }
+
+    private func encodeWorkout(_ workout: Workout) -> [String: Any] {
+        var data: [String: Any] = [
+            "start": workout.start.timeIntervalSince1970,
+            "status": workout.status.rawValue
+        ]
+
+        if let end = workout.end {
+            data["end"] = end.timeIntervalSince1970
+        }
+
+        if let split = workout.split {
+            data["splitName"] = split.name
+        }
+
+        data["logs"] = workout.logsArray.map { encodeWorkoutLog($0) }
+
+        return data
+    }
+
+    private func encodeWorkoutLog(_ log: WorkoutLog) -> [String: Any] {
+        var data: [String: Any] = [
+            "exerciseName": log.exerciseName,
+            "order": log.order,
+            "sets": log.sets,
+            "reps": log.reps,
+            "weight": log.weight,
+            "status": log.status.rawValue,
+            "currentStateIndex": log.currentStateIndex,
+            "completed": log.completed,
+            "loadType": log.loadType
+        ]
+
+        if let duration = log.duration {
+            data["duration"] = duration.timeIntervalSince1970
+        }
+
+        if let notes = log.notes {
+            data["notes"] = notes
+        }
+
+        return data
+    }
+
+    // MARK: - Request Sync from iOS
+
+    func requestSync() {
+        guard let session = session else {
+            print("[WC-Watch] No WCSession")
+            return
+        }
+
+        print("[WC-Watch] Session state: \(session.activationState.rawValue), reachable: \(session.isReachable)")
+
+        guard session.isReachable else {
+            print("[WC-Watch] iPhone not reachable, checking pending context...")
+            // Try to process any pending application context
+            if !session.receivedApplicationContext.isEmpty {
+                print("[WC-Watch] Found pending context, processing...")
+                processApplicationContext(session.receivedApplicationContext)
+            } else {
+                print("[WC-Watch] No pending context")
+            }
+            return
+        }
+
+        session.sendMessage(["type": "requestSync"], replyHandler: nil) { error in
+            print("[WC-Watch] Failed to request sync: \(error)")
+        }
+    }
+
+    // MARK: - Process Incoming Data
+
+    private func processApplicationContext(_ context: [String: Any]) {
+        guard let viewContext = viewContext else {
+            print("View context not set")
+            return
+        }
+
+        viewContext.perform {
+            do {
+                // Process splits first (workouts reference them)
+                if let splitsData = context["splits"] as? [[String: Any]] {
+                    // Get all split names from iOS
+                    let iosSplitNames = Set(splitsData.compactMap { $0["name"] as? String })
+
+                    // Delete splits not on iOS
+                    let existingSplits = (try? viewContext.fetch(Split.fetchRequest())) ?? []
+                    for split in existingSplits {
+                        if !iosSplitNames.contains(split.name) {
+                            viewContext.delete(split)
+                        }
+                    }
+
+                    for splitData in splitsData {
+                        self.importSplit(splitData, context: viewContext)
+                    }
+                }
+
+                // Process workouts
+                if let workoutsData = context["workouts"] as? [[String: Any]] {
+                    // Get all workout start dates from iOS
+                    let iosStartDates = Set(workoutsData.compactMap { $0["start"] as? TimeInterval })
+
+                    // Delete workouts not on iOS
+                    let existingWorkouts = (try? viewContext.fetch(Workout.fetchRequest())) ?? []
+                    for workout in existingWorkouts {
+                        let startInterval = workout.start.timeIntervalSince1970
+                        // Check if this workout exists on iOS (within 1 second tolerance)
+                        let existsOnIOS = iosStartDates.contains { abs($0 - startInterval) < 1 }
+                        if !existsOnIOS {
+                            viewContext.delete(workout)
+                        }
+                    }
+
+                    for workoutData in workoutsData {
+                        self.importWorkout(workoutData, context: viewContext)
+                    }
+                }
+
+                try viewContext.save()
+
+                DispatchQueue.main.async {
+                    self.lastSyncDate = Date()
+                }
+
+                print("Successfully imported data from iPhone")
+
+            } catch {
+                print("Failed to import data: \(error)")
+            }
+        }
+    }
+
+    // MARK: - Import Methods
+
+    private func importSplit(_ data: [String: Any], context: NSManagedObjectContext) {
+        guard let idString = data["id"] as? String,
+              let name = data["name"] as? String else { return }
+
+        // Find existing or create new
+        let split = findOrCreateSplit(idString: idString, name: name, context: context)
+
+        split.name = name
+        split.color = data["color"] as? String ?? "blue"
+        split.systemImage = data["systemImage"] as? String ?? "dumbbell.fill"
+        split.order = Int32(data["order"] as? Int ?? 0)
+
+        // Import exercises
+        if let exercisesData = data["exercises"] as? [[String: Any]] {
+            // Get all exercise names from iOS
+            let iosExerciseNames = Set(exercisesData.compactMap { $0["name"] as? String })
+
+            // Delete exercises not on iOS
+            for exercise in split.exercisesArray {
+                if !iosExerciseNames.contains(exercise.name) {
+                    context.delete(exercise)
+                }
+            }
+
+            // Import/update exercises from iOS
+            for exerciseData in exercisesData {
+                importExercise(exerciseData, split: split, context: context)
+            }
+        }
+    }
+
+    private func importExercise(_ data: [String: Any], split: Split, context: NSManagedObjectContext) {
+        guard let idString = data["id"] as? String,
+              let name = data["name"] as? String else { return }
+
+        let exercise = findOrCreateExercise(idString: idString, name: name, split: split, context: context)
+
+        exercise.name = name
+        exercise.order = Int32(data["order"] as? Int ?? 0)
+        exercise.sets = Int32(data["sets"] as? Int ?? 3)
+        exercise.reps = Int32(data["reps"] as? Int ?? 10)
+        exercise.weight = Int32(data["weight"] as? Int ?? 0)
+        exercise.loadType = Int32(data["loadType"] as? Int ?? 1)
+
+        if let durationInterval = data["duration"] as? TimeInterval {
+            exercise.duration = Date(timeIntervalSince1970: durationInterval)
+        }
+
+        exercise.split = split
+    }
+
+    private func importWorkout(_ data: [String: Any], context: NSManagedObjectContext) {
+        guard let idString = data["id"] as? String,
+              let startInterval = data["start"] as? TimeInterval else { return }
+
+        let startDate = Date(timeIntervalSince1970: startInterval)
+        let workout = findOrCreateWorkout(idString: idString, startDate: startDate, context: context)
+
+        workout.start = startDate
+
+        if let endInterval = data["end"] as? TimeInterval {
+            workout.end = Date(timeIntervalSince1970: endInterval)
+        }
+
+        if let statusRaw = data["status"] as? String,
+           let status = WorkoutStatus(rawValue: statusRaw) {
+            workout.status = status
+        }
+
+        // Link to split
+        if let splitName = data["splitName"] as? String {
+            workout.split = findSplitByName(splitName, context: context)
+        }
+
+        // Import logs
+        if let logsData = data["logs"] as? [[String: Any]] {
+            // Get all exercise names from iOS
+            let iosExerciseNames = Set(logsData.compactMap { $0["exerciseName"] as? String })
+
+            // Delete logs not on iOS
+            for log in workout.logsArray {
+                if !iosExerciseNames.contains(log.exerciseName) {
+                    context.delete(log)
+                }
+            }
+
+            // Import/update logs from iOS
+            for logData in logsData {
+                importWorkoutLog(logData, workout: workout, context: context)
+            }
+        }
+    }
+
+    private func importWorkoutLog(_ data: [String: Any], workout: Workout, context: NSManagedObjectContext) {
+        guard let idString = data["id"] as? String,
+              let exerciseName = data["exerciseName"] as? String else { return }
+
+        let log = findOrCreateWorkoutLog(idString: idString, exerciseName: exerciseName, workout: workout, context: context)
+
+        log.exerciseName = exerciseName
+        log.date = Date(timeIntervalSince1970: data["date"] as? TimeInterval ?? Date().timeIntervalSince1970)
+        log.order = Int32(data["order"] as? Int ?? 0)
+        log.sets = Int32(data["sets"] as? Int ?? 3)
+        log.reps = Int32(data["reps"] as? Int ?? 10)
+        log.weight = Int32(data["weight"] as? Int ?? 0)
+        log.currentStateIndex = Int32(data["currentStateIndex"] as? Int ?? 0)
+        log.completed = data["completed"] as? Bool ?? false
+        log.loadType = Int32(data["loadType"] as? Int ?? 1)
+
+        if let statusRaw = data["status"] as? String,
+           let status = WorkoutStatus(rawValue: statusRaw) {
+            log.status = status
+        }
+
+        if let durationInterval = data["duration"] as? TimeInterval {
+            log.duration = Date(timeIntervalSince1970: durationInterval)
+        }
+
+        log.notes = data["notes"] as? String
+        log.workout = workout
+    }
+
+    // MARK: - Find or Create Helpers
+
+    private func findOrCreateSplit(idString: String, name: String, context: NSManagedObjectContext) -> Split {
+        // Try to find by name first (more reliable than object ID across devices)
+        let request = Split.fetchRequest()
+        request.predicate = NSPredicate(format: "name == %@", name)
+        request.fetchLimit = 1
+
+        if let existing = try? context.fetch(request).first {
+            return existing
+        }
+
+        return Split(context: context)
+    }
+
+    private func findOrCreateExercise(idString: String, name: String, split: Split, context: NSManagedObjectContext) -> Exercise {
+        // Find by name within split
+        if let existing = split.exercisesArray.first(where: { $0.name == name }) {
+            return existing
+        }
+
+        return Exercise(context: context)
+    }
+
+    private func findOrCreateWorkout(idString: String, startDate: Date, context: NSManagedObjectContext) -> Workout {
+        // Find by start date (should be unique per workout)
+        let request = Workout.fetchRequest()
+        // Match within 1 second to account for any floating point differences
+        let startInterval = startDate.timeIntervalSince1970
+        request.predicate = NSPredicate(
+            format: "start >= %@ AND start <= %@",
+            Date(timeIntervalSince1970: startInterval - 1) as NSDate,
+            Date(timeIntervalSince1970: startInterval + 1) as NSDate
+        )
+        request.fetchLimit = 1
+
+        if let existing = try? context.fetch(request).first {
+            return existing
+        }
+
+        return Workout(context: context)
+    }
+
+    private func findOrCreateWorkoutLog(idString: String, exerciseName: String, workout: Workout, context: NSManagedObjectContext) -> WorkoutLog {
+        // Find existing log in this workout with same exercise name
+        if let existing = workout.logsArray.first(where: { $0.exerciseName == exerciseName }) {
+            return existing
+        }
+
+        return WorkoutLog(context: context)
+    }
+
+    private func findSplitByName(_ name: String, context: NSManagedObjectContext) -> Split? {
+        let request = Split.fetchRequest()
+        request.predicate = NSPredicate(format: "name == %@", name)
+        request.fetchLimit = 1
+        return try? context.fetch(request).first
+    }
+}
+
+// MARK: - WCSessionDelegate
+
+extension WatchConnectivityManager: WCSessionDelegate {
+    func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
+        if let error = error {
+            print("[WC-Watch] Activation failed: \(error)")
+        } else {
+            print("[WC-Watch] Activated with state: \(activationState.rawValue)")
+
+            // Check for any pending context
+            let context = session.receivedApplicationContext
+            print("[WC-Watch] Pending context keys: \(context.keys)")
+            if !context.isEmpty {
+                print("[WC-Watch] Processing pending context...")
+                processApplicationContext(context)
+            }
+        }
+    }
+
+    // Receive application context updates
+    func session(_ session: WCSession, didReceiveApplicationContext applicationContext: [String: Any]) {
+        print("[WC-Watch] Received application context with keys: \(applicationContext.keys)")
+        if let workouts = applicationContext["workouts"] as? [[String: Any]] {
+            print("[WC-Watch] Contains \(workouts.count) workouts")
+        }
+        processApplicationContext(applicationContext)
+    }
+
+    // Receive immediate messages
+    func session(_ session: WCSession, didReceiveMessage message: [String: Any]) {
+        if let type = message["type"] as? String {
+            switch type {
+            case "workoutUpdate":
+                if let workoutData = message["workout"] as? [String: Any],
+                   let context = viewContext {
+                    context.perform {
+                        self.importWorkout(workoutData, context: context)
+                        try? context.save()
+                    }
+                }
+            default:
+                break
+            }
+        }
+    }
+}

Workouts Watch App/ContentView.swift

@@ -15,13 +15,7 @@ struct ContentView: View {
     @Environment(\.managedObjectContext) private var viewContext
 
     var body: some View {
-        VStack {
-            Image(systemName: "dumbbell.fill")
-                .imageScale(.large)
-                .foregroundStyle(.tint)
-            Text("Workouts")
-        }
-        .padding()
+        WorkoutLogsView()
     }
 }
 

Workouts Watch App/Models/Workout.swift

@@ -5,7 +5,6 @@ import CoreData
 public class Workout: NSManagedObject, Identifiable {
     @NSManaged public var start: Date
     @NSManaged public var end: Date?
-    @NSManaged private var statusRaw: String
 
     @NSManaged public var split: Split?
     @NSManaged public var logs: NSSet?
@@ -13,13 +12,26 @@ public class Workout: NSManagedObject, Identifiable {
     public var id: NSManagedObjectID { objectID }
 
     var status: WorkoutStatus {
-        get { WorkoutStatus(rawValue: statusRaw) ?? .notStarted }
-        set { statusRaw = newValue.rawValue }
+        get {
+            willAccessValue(forKey: "status")
+            let raw = primitiveValue(forKey: "status") as? String ?? "notStarted"
+            didAccessValue(forKey: "status")
+            return WorkoutStatus(rawValue: raw) ?? .notStarted
+        }
+        set {
+            willChangeValue(forKey: "status")
+            setPrimitiveValue(newValue.rawValue, forKey: "status")
+            didChangeValue(forKey: "status")
+        }
     }
 
     var label: String {
         if status == .completed, let endDate = end {
-            return "\(start.formattedDate())—\(endDate.formattedDate())"
+            if start.isSameDay(as: endDate) {
+                return "\(start.formattedDate())—\(endDate.formattedTime())"
+            } else {
+                return "\(start.formattedDate())—\(endDate.formattedDate())"
+            }
         } else {
             return start.formattedDate()
         }

Workouts Watch App/Persistence/PersistenceController.swift

@@ -9,6 +9,9 @@ struct PersistenceController {
     // CloudKit container identifier - same as iOS app for sync
     static let cloudKitContainerIdentifier = "iCloud.dev.rzen.indie.Workouts"
 
+    // App Group identifier for shared storage between iOS and Watch
+    static let appGroupIdentifier = "group.dev.rzen.indie.Workouts"
+
     var viewContext: NSManagedObjectContext {
         container.viewContext
     }
@@ -57,28 +60,37 @@ struct PersistenceController {
         if inMemory {
             description.url = URL(fileURLWithPath: "/dev/null")
             description.cloudKitContainerOptions = nil
-        } else if cloudKitEnabled {
-            // Check if CloudKit is available before enabling
-            let cloudKitAvailable = FileManager.default.ubiquityIdentityToken != nil
-
-            if cloudKitAvailable {
-                // Set CloudKit container options
-                let cloudKitOptions = NSPersistentCloudKitContainerOptions(
-                    containerIdentifier: Self.cloudKitContainerIdentifier
-                )
-                description.cloudKitContainerOptions = cloudKitOptions
-            } else {
-                // CloudKit not available (not signed in, etc.)
-                description.cloudKitContainerOptions = nil
-                print("CloudKit not available - using local storage only")
+        } else {
+            // Use App Group container for shared storage between iOS and Watch
+            if let appGroupURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: Self.appGroupIdentifier) {
+                let storeURL = appGroupURL.appendingPathComponent("Workouts.sqlite")
+                description.url = storeURL
+                print("Using shared App Group store at: \(storeURL)")
             }
 
-            // Enable persistent history tracking (useful even without CloudKit)
-            description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
-            description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
-        } else {
-            // CloudKit explicitly disabled
-            description.cloudKitContainerOptions = nil
+            if cloudKitEnabled {
+                // Check if CloudKit is available before enabling
+                let cloudKitAvailable = FileManager.default.ubiquityIdentityToken != nil
+
+                if cloudKitAvailable {
+                    // Set CloudKit container options
+                    let cloudKitOptions = NSPersistentCloudKitContainerOptions(
+                        containerIdentifier: Self.cloudKitContainerIdentifier
+                    )
+                    description.cloudKitContainerOptions = cloudKitOptions
+                } else {
+                    // CloudKit not available (not signed in, etc.)
+                    description.cloudKitContainerOptions = nil
+                    print("CloudKit not available - using local storage only")
+                }
+
+                // Enable persistent history tracking (useful even without CloudKit)
+                description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
+                description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
+            } else {
+                // CloudKit explicitly disabled
+                description.cloudKitContainerOptions = nil
+            }
         }
 
         container.loadPersistentStores { storeDescription, error in

Workouts Watch App/Views/ExerciseProgressView.swift

@@ -0,0 +1,309 @@
+//
+// ExerciseProgressView.swift
+// Workouts Watch App
+//
+// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
+//
+
+import SwiftUI
+import WatchKit
+
+struct ExerciseProgressView: View {
+    @Environment(\.managedObjectContext) private var viewContext
+    @Environment(\.dismiss) private var dismiss
+
+    @ObservedObject var workoutLog: WorkoutLog
+
+    @State private var currentPage: Int = 0
+    @State private var showingCancelConfirm = false
+
+    private var totalSets: Int {
+        max(1, Int(workoutLog.sets))
+    }
+
+    private var totalPages: Int {
+        // Set 1, Rest 1, Set 2, Rest 2, ..., Set N, Done
+        // = N sets + (N-1) rests + 1 done = 2N
+        totalSets * 2
+    }
+
+    private var firstUnfinishedSetPage: Int {
+        // currentStateIndex is the number of completed sets
+        let completedSets = Int(workoutLog.currentStateIndex)
+        if completedSets >= totalSets {
+            // All done, go to done page
+            return totalPages - 1
+        }
+        // Each set is at page index * 2 (Set1=0, Set2=2, Set3=4...)
+        return completedSets * 2
+    }
+
+    var body: some View {
+        TabView(selection: $currentPage) {
+            ForEach(0..<totalPages, id: \.self) { index in
+                pageView(for: index)
+                    .tag(index)
+            }
+        }
+        .tabViewStyle(.page)
+        .toolbar {
+            ToolbarItem(placement: .cancellationAction) {
+                Button {
+                    showingCancelConfirm = true
+                } label: {
+                    Image(systemName: "xmark")
+                }
+            }
+        }
+        .confirmationDialog("Cancel Exercise?", isPresented: $showingCancelConfirm, titleVisibility: .visible) {
+            Button("Cancel Exercise", role: .destructive) {
+                dismiss()
+            }
+            Button("Continue", role: .cancel) { }
+        }
+        .onAppear {
+            // Skip to first unfinished set
+            currentPage = firstUnfinishedSetPage
+        }
+        .onChange(of: currentPage) { _, newPage in
+            updateProgress(for: newPage)
+        }
+    }
+
+    @ViewBuilder
+    private func pageView(for index: Int) -> some View {
+        let lastPageIndex = totalPages - 1
+
+        if index == lastPageIndex {
+            // Done page
+            DonePageView {
+                completeExercise()
+                dismiss()
+            }
+        } else if index % 2 == 0 {
+            // Set page (0, 2, 4, ...)
+            let setNumber = (index / 2) + 1
+            SetPageView(
+                setNumber: setNumber,
+                totalSets: totalSets,
+                reps: Int(workoutLog.reps),
+                isTimeBased: workoutLog.loadTypeEnum == .duration,
+                durationMinutes: workoutLog.durationMinutes,
+                durationSeconds: workoutLog.durationSeconds
+            )
+        } else {
+            // Rest page (1, 3, 5, ...)
+            let restNumber = (index / 2) + 1
+            RestPageView(restNumber: restNumber)
+        }
+    }
+
+    private func updateProgress(for pageIndex: Int) {
+        // Calculate which set we're on based on page index
+        // Pages: Set1(0), Rest1(1), Set2(2), Rest2(3), Set3(4), Done(5)
+        // After completing Set 1 and moving to Rest 1, progress should be 1
+        let setIndex = (pageIndex + 1) / 2
+        let clampedProgress = min(setIndex, totalSets)
+
+        if clampedProgress != Int(workoutLog.currentStateIndex) {
+            workoutLog.currentStateIndex = Int32(clampedProgress)
+
+            if clampedProgress >= totalSets {
+                workoutLog.status = .completed
+                workoutLog.completed = true
+            } else if clampedProgress > 0 {
+                workoutLog.status = .inProgress
+                workoutLog.completed = false
+            }
+
+            updateWorkoutStatus()
+            try? viewContext.save()
+
+            // Sync to iOS
+            WatchConnectivityManager.shared.syncToiOS()
+        }
+    }
+
+    private func completeExercise() {
+        workoutLog.currentStateIndex = Int32(totalSets)
+        workoutLog.status = .completed
+        workoutLog.completed = true
+        updateWorkoutStatus()
+        try? viewContext.save()
+
+        // Sync to iOS
+        WatchConnectivityManager.shared.syncToiOS()
+    }
+
+    private func updateWorkoutStatus() {
+        guard let workout = workoutLog.workout else { return }
+        let logs = workout.logsArray
+        let allCompleted = logs.allSatisfy { $0.status == .completed }
+        let anyInProgress = logs.contains { $0.status == .inProgress }
+        let allNotStarted = logs.allSatisfy { $0.status == .notStarted }
+
+        if allCompleted {
+            workout.status = .completed
+            workout.end = Date()
+        } else if anyInProgress || !allNotStarted {
+            workout.status = .inProgress
+        } else {
+            workout.status = .notStarted
+        }
+    }
+}
+
+// MARK: - Set Page View
+
+struct SetPageView: View {
+    let setNumber: Int
+    let totalSets: Int
+    let reps: Int
+    let isTimeBased: Bool
+    let durationMinutes: Int
+    let durationSeconds: Int
+
+    var body: some View {
+        VStack(spacing: 8) {
+            Text("Set \(setNumber) of \(totalSets)")
+                .font(.headline)
+                .foregroundColor(.secondary)
+
+            Text("\(setNumber)")
+                .font(.system(size: 72, weight: .bold, design: .rounded))
+                .foregroundColor(.green)
+
+            if isTimeBased {
+                Text(formattedDuration)
+                    .font(.title3)
+                    .foregroundColor(.secondary)
+            } else {
+                Text("\(reps) reps")
+                    .font(.title3)
+                    .foregroundColor(.secondary)
+            }
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .onAppear {
+            WKInterfaceDevice.current().play(.start)
+        }
+    }
+
+    private var formattedDuration: String {
+        if durationMinutes > 0 && durationSeconds > 0 {
+            return "\(durationMinutes)m \(durationSeconds)s"
+        } else if durationMinutes > 0 {
+            return "\(durationMinutes) min"
+        } else {
+            return "\(durationSeconds) sec"
+        }
+    }
+}
+
+// MARK: - Rest Page View
+
+struct RestPageView: View {
+    let restNumber: Int
+
+    @State private var elapsedSeconds: Int = 0
+    @State private var timer: Timer?
+
+    var body: some View {
+        VStack(spacing: 8) {
+            Text("Rest")
+                .font(.headline)
+                .foregroundColor(.secondary)
+
+            Text(formattedTime)
+                .font(.system(size: 56, weight: .bold, design: .monospaced))
+                .foregroundColor(.orange)
+
+            Text("Swipe to continue")
+                .font(.caption2)
+                .foregroundColor(.secondary)
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .onAppear {
+            startTimer()
+            WKInterfaceDevice.current().play(.start)
+        }
+        .onDisappear {
+            stopTimer()
+        }
+    }
+
+    private var formattedTime: String {
+        let minutes = elapsedSeconds / 60
+        let seconds = elapsedSeconds % 60
+        return String(format: "%d:%02d", minutes, seconds)
+    }
+
+    private func startTimer() {
+        elapsedSeconds = 0
+        timer = Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) { _ in
+            elapsedSeconds += 1
+            checkHapticPing()
+        }
+    }
+
+    private func stopTimer() {
+        timer?.invalidate()
+        timer = nil
+    }
+
+    private func checkHapticPing() {
+        // Haptic ping every 10 seconds with pattern:
+        // 10s: single, 20s: double, 30s: triple, 40s: single, 50s: double, etc.
+        guard elapsedSeconds > 0 && elapsedSeconds % 10 == 0 else { return }
+
+        let cyclePosition = (elapsedSeconds / 10) % 3
+        let pingCount: Int
+        switch cyclePosition {
+        case 1: pingCount = 1  // 10s, 40s, 70s...
+        case 2: pingCount = 2  // 20s, 50s, 80s...
+        case 0: pingCount = 3  // 30s, 60s, 90s...
+        default: pingCount = 1
+        }
+
+        playHapticPings(count: pingCount)
+    }
+
+    private func playHapticPings(count: Int) {
+        for i in 0..<count {
+            DispatchQueue.main.asyncAfter(deadline: .now() + Double(i) * 0.2) {
+                WKInterfaceDevice.current().play(.click)
+            }
+        }
+    }
+}
+
+// MARK: - Done Page View
+
+struct DonePageView: View {
+    let onDone: () -> Void
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Image(systemName: "checkmark.circle.fill")
+                .font(.system(size: 60))
+                .foregroundColor(.green)
+
+            Text("Done!")
+                .font(.title2)
+                .fontWeight(.bold)
+
+            Text("Tap to finish")
+                .font(.caption)
+                .foregroundColor(.secondary)
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .contentShape(Rectangle())
+        .onTapGesture {
+            WKInterfaceDevice.current().play(.success)
+            onDone()
+        }
+        .onAppear {
+            WKInterfaceDevice.current().play(.success)
+        }
+    }
+}

Workouts Watch App/Views/WorkoutLogListView.swift

@@ -0,0 +1,229 @@
+//
+// WorkoutLogListView.swift
+// Workouts Watch App
+//
+// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
+//
+
+import SwiftUI
+import CoreData
+
+struct WorkoutLogListView: View {
+    @Environment(\.managedObjectContext) private var viewContext
+
+    @ObservedObject var workout: Workout
+
+    @State private var showingExercisePicker = false
+    @State private var selectedLog: WorkoutLog?
+
+    var sortedWorkoutLogs: [WorkoutLog] {
+        workout.logsArray
+    }
+
+    var body: some View {
+        List {
+            Section(header: Text(workout.label)) {
+                ForEach(sortedWorkoutLogs, id: \.objectID) { log in
+                    Button {
+                        selectedLog = log
+                    } label: {
+                        WorkoutLogRowLabel(log: log)
+                    }
+                    .buttonStyle(.plain)
+                }
+            }
+
+            Section {
+                Button {
+                    showingExercisePicker = true
+                } label: {
+                    HStack {
+                        Image(systemName: "plus.circle.fill")
+                            .foregroundColor(.green)
+                        Text("Add Exercise")
+                    }
+                }
+            }
+        }
+        .overlay {
+            if sortedWorkoutLogs.isEmpty {
+                ContentUnavailableView(
+                    "No Exercises",
+                    systemImage: "figure.strengthtraining.traditional",
+                    description: Text("Tap + to add exercises.")
+                )
+            }
+        }
+        .navigationTitle(workout.split?.name ?? Split.unnamed)
+        .navigationDestination(item: $selectedLog) { log in
+            ExerciseProgressView(workoutLog: log)
+        }
+        .sheet(isPresented: $showingExercisePicker) {
+            ExercisePickerView(workout: workout)
+        }
+    }
+
+}
+
+// MARK: - Workout Log Row Label
+
+struct WorkoutLogRowLabel: View {
+    @ObservedObject var log: WorkoutLog
+
+    var body: some View {
+        HStack {
+            statusIcon
+                .foregroundColor(statusColor)
+
+            VStack(alignment: .leading, spacing: 2) {
+                Text(log.exerciseName)
+                    .font(.headline)
+                    .lineLimit(1)
+
+                Text(subtitle)
+                    .font(.caption2)
+                    .foregroundColor(.secondary)
+            }
+
+            Spacer()
+        }
+    }
+
+    private var statusIcon: Image {
+        switch log.status {
+        case .completed:
+            Image(systemName: "checkmark.circle.fill")
+        case .inProgress:
+            Image(systemName: "circle.dotted")
+        case .notStarted:
+            Image(systemName: "circle")
+        case .skipped:
+            Image(systemName: "xmark.circle")
+        }
+    }
+
+    private var statusColor: Color {
+        switch log.status {
+        case .completed:
+            .green
+        case .inProgress:
+            .orange
+        case .notStarted:
+            .secondary
+        case .skipped:
+            .secondary
+        }
+    }
+
+    private var subtitle: String {
+        if log.loadTypeEnum == .duration {
+            let mins = log.durationMinutes
+            let secs = log.durationSeconds
+            if mins > 0 && secs > 0 {
+                return "\(log.sets) × \(mins)m \(secs)s"
+            } else if mins > 0 {
+                return "\(log.sets) × \(mins) min"
+            } else {
+                return "\(log.sets) × \(secs) sec"
+            }
+        } else {
+            return "\(log.sets) × \(log.reps) × \(log.weight) lbs"
+        }
+    }
+}
+
+// MARK: - Exercise Picker View
+
+struct ExercisePickerView: View {
+    @Environment(\.managedObjectContext) private var viewContext
+    @Environment(\.dismiss) private var dismiss
+
+    @ObservedObject var workout: Workout
+
+    private var availableExercises: [Exercise] {
+        guard let split = workout.split else { return [] }
+        let existingNames = Set(workout.logsArray.map { $0.exerciseName })
+        return split.exercisesArray.filter { !existingNames.contains($0.name) }
+    }
+
+    var body: some View {
+        NavigationStack {
+            List {
+                if availableExercises.isEmpty {
+                    Text("All exercises added")
+                        .foregroundColor(.secondary)
+                } else {
+                    ForEach(availableExercises, id: \.objectID) { exercise in
+                        Button {
+                            addExercise(exercise)
+                        } label: {
+                            VStack(alignment: .leading) {
+                                Text(exercise.name)
+                                    .font(.headline)
+                                Text(exerciseSubtitle(exercise))
+                                    .font(.caption2)
+                                    .foregroundColor(.secondary)
+                            }
+                        }
+                    }
+                }
+            }
+            .navigationTitle("Add Exercise")
+            .toolbar {
+                ToolbarItem(placement: .cancellationAction) {
+                    Button("Cancel") {
+                        dismiss()
+                    }
+                }
+            }
+        }
+    }
+
+    private func addExercise(_ exercise: Exercise) {
+        let log = WorkoutLog(context: viewContext)
+        log.exerciseName = exercise.name
+        log.date = Date()
+        log.order = Int32(workout.logsArray.count)
+        log.sets = exercise.sets
+        log.reps = exercise.reps
+        log.weight = exercise.weight
+        log.loadType = exercise.loadType
+        log.duration = exercise.duration
+        log.status = .notStarted
+        log.workout = workout
+
+        // Update workout start if first exercise
+        if workout.logsArray.count == 1 {
+            workout.start = Date()
+        }
+
+        try? viewContext.save()
+
+        // Sync to iOS
+        WatchConnectivityManager.shared.syncToiOS()
+
+        dismiss()
+    }
+
+    private func exerciseSubtitle(_ exercise: Exercise) -> String {
+        let loadType = LoadType(rawValue: Int(exercise.loadType)) ?? .weight
+        if loadType == .duration {
+            let mins = exercise.durationMinutes
+            let secs = exercise.durationSeconds
+            if mins > 0 && secs > 0 {
+                return "\(exercise.sets) × \(mins)m \(secs)s"
+            } else if mins > 0 {
+                return "\(exercise.sets) × \(mins) min"
+            } else {
+                return "\(exercise.sets) × \(secs) sec"
+            }
+        } else {
+            return "\(exercise.sets) × \(exercise.reps) × \(exercise.weight) lbs"
+        }
+    }
+}
+
+#Preview {
+    WorkoutLogListView(workout: Workout())
+        .environment(\.managedObjectContext, PersistenceController.preview.viewContext)
+}

Workouts Watch App/Views/WorkoutLogsView.swift

@@ -0,0 +1,99 @@
+//
+// WorkoutLogsView.swift
+// Workouts Watch App
+//
+// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
+//
+
+import SwiftUI
+import CoreData
+
+struct WorkoutLogsView: View {
+    @Environment(\.managedObjectContext) private var viewContext
+    @EnvironmentObject var connectivityManager: WatchConnectivityManager
+
+    @FetchRequest(
+        sortDescriptors: [NSSortDescriptor(keyPath: \Workout.start, ascending: false)],
+        animation: .default
+    )
+    private var workouts: FetchedResults<Workout>
+
+    var body: some View {
+        NavigationStack {
+            List {
+                ForEach(workouts, id: \.objectID) { workout in
+                    NavigationLink(destination: WorkoutLogListView(workout: workout)) {
+                        WorkoutRow(workout: workout)
+                    }
+                }
+            }
+            .overlay {
+                if workouts.isEmpty {
+                    ContentUnavailableView(
+                        "No Workouts",
+                        systemImage: "list.bullet.clipboard",
+                        description: Text("Tap sync or start a workout from iPhone.")
+                    )
+                }
+            }
+            .navigationTitle("Workouts")
+            .toolbar {
+                ToolbarItem(placement: .topBarTrailing) {
+                    Button {
+                        connectivityManager.requestSync()
+                    } label: {
+                        Image(systemName: "arrow.triangle.2.circlepath")
+                    }
+                }
+            }
+        }
+    }
+}
+
+// MARK: - Workout Row
+
+struct WorkoutRow: View {
+    @ObservedObject var workout: Workout
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 4) {
+            Text(workout.split?.name ?? Split.unnamed)
+                .font(.headline)
+                .lineLimit(1)
+
+            HStack {
+                Text(workout.start.formatDate())
+                    .font(.caption2)
+                    .foregroundColor(.secondary)
+
+                Spacer()
+
+                statusIndicator
+            }
+        }
+        .padding(.vertical, 4)
+    }
+
+    @ViewBuilder
+    private var statusIndicator: some View {
+        switch workout.status {
+        case .completed:
+            Image(systemName: "checkmark.circle.fill")
+                .foregroundColor(.green)
+        case .inProgress:
+            Image(systemName: "circle.dotted")
+                .foregroundColor(.orange)
+        case .notStarted:
+            Image(systemName: "circle")
+                .foregroundColor(.secondary)
+        case .skipped:
+            Image(systemName: "xmark.circle")
+                .foregroundColor(.secondary)
+        }
+    }
+}
+
+#Preview {
+    WorkoutLogsView()
+        .environment(\.managedObjectContext, PersistenceController.preview.viewContext)
+}

Workouts Watch App/Workouts Watch App.entitlements

@@ -5,12 +5,16 @@
 	<key>aps-environment</key>
 	<string>development</string>
 	<key>com.apple.developer.icloud-container-identifiers</key>
-	<array>
-		<string>iCloud.dev.rzen.indie.Workouts</string>
-	</array>
+	<array/>
 	<key>com.apple.developer.icloud-services</key>
 	<array>
 		<string>CloudKit</string>
 	</array>
+	<key>com.apple.developer.ubiquity-kvstore-identifier</key>
+	<string>$(TeamIdentifierPrefix)$(CFBundleIdentifier)</string>
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.dev.rzen.indie.Workouts</string>
+	</array>
 </dict>
-</plist>
+</plist>

Workouts Watch App/WorkoutsApp.swift

@@ -14,11 +14,18 @@ import CoreData
 @main
 struct WorkoutsWatchApp: App {
     let persistenceController = PersistenceController.shared
+    let connectivityManager = WatchConnectivityManager.shared
+
+    init() {
+        // Set up iPhone connectivity with Core Data context
+        connectivityManager.setViewContext(persistenceController.viewContext)
+    }
 
     var body: some Scene {
         WindowGroup {
             ContentView()
                 .environment(\.managedObjectContext, persistenceController.viewContext)
+                .environmentObject(connectivityManager)
         }
     }
 }

Workouts.xcodeproj/project.pbxproj

@@ -376,6 +376,7 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CODE_SIGN_ENTITLEMENTS = "Workouts Watch App/Workouts Watch App.entitlements";
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
 				DEVELOPMENT_ASSET_PATHS = "\"Workouts Watch App/Preview Content\"";
@@ -396,7 +397,7 @@
 				SWIFT_EMIT_LOC_STRINGS = YES;
 				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = 4;
-				WATCHOS_DEPLOYMENT_TARGET = 11.2;
+				WATCHOS_DEPLOYMENT_TARGET = 26.0;
 			};
 			name = Debug;
 		};
@@ -405,6 +406,7 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
+				CODE_SIGN_ENTITLEMENTS = "Workouts Watch App/Workouts Watch App.entitlements";
 				CODE_SIGN_STYLE = Automatic;
 				CURRENT_PROJECT_VERSION = 1;
 				DEVELOPMENT_ASSET_PATHS = "\"Workouts Watch App/Preview Content\"";
@@ -426,7 +428,7 @@
 				SWIFT_VERSION = 5.0;
 				TARGETED_DEVICE_FAMILY = 4;
 				VALIDATE_PRODUCT = YES;
-				WATCHOS_DEPLOYMENT_TARGET = 11.2;
+				WATCHOS_DEPLOYMENT_TARGET = 26.0;
 			};
 			name = Release;
 		};
@@ -449,7 +451,7 @@
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
-				IPHONEOS_DEPLOYMENT_TARGET = 18.2;
+				IPHONEOS_DEPLOYMENT_TARGET = 17.6;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -483,7 +485,7 @@
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
-				IPHONEOS_DEPLOYMENT_TARGET = 18.2;
+				IPHONEOS_DEPLOYMENT_TARGET = 17.6;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",

Workouts/Connectivity/WatchConnectivityManager.swift

@@ -0,0 +1,345 @@
+//
+// WatchConnectivityManager.swift
+// Workouts
+//
+// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
+//
+
+import Foundation
+import WatchConnectivity
+import CoreData
+
+class WatchConnectivityManager: NSObject, ObservableObject {
+    static let shared = WatchConnectivityManager()
+
+    private var session: WCSession?
+    private var viewContext: NSManagedObjectContext?
+
+    override init() {
+        super.init()
+
+        if WCSession.isSupported() {
+            session = WCSession.default
+            session?.delegate = self
+            session?.activate()
+        }
+    }
+
+    func setViewContext(_ context: NSManagedObjectContext) {
+        self.viewContext = context
+    }
+
+    // MARK: - Send Data to Watch
+
+    func syncAllData() {
+        guard let session = session else {
+            print("[WC-iOS] No WCSession")
+            return
+        }
+
+        print("[WC-iOS] Session state: \(session.activationState.rawValue), reachable: \(session.isReachable), paired: \(session.isPaired), installed: \(session.isWatchAppInstalled)")
+
+        guard session.activationState == .activated else {
+            print("[WC-iOS] Session not activated")
+            return
+        }
+
+        guard let context = viewContext else {
+            print("[WC-iOS] No view context")
+            return
+        }
+
+        context.perform {
+            do {
+                let workoutsData = try self.encodeAllWorkouts(context: context)
+                let splitsData = try self.encodeAllSplits(context: context)
+
+                let payload: [String: Any] = [
+                    "workouts": workoutsData,
+                    "splits": splitsData,
+                    "timestamp": Date().timeIntervalSince1970
+                ]
+
+                // Use updateApplicationContext for persistent state
+                try session.updateApplicationContext(payload)
+                print("[WC-iOS] Synced \(workoutsData.count) workouts, \(splitsData.count) splits to Watch")
+
+            } catch {
+                print("Failed to sync data: \(error)")
+            }
+        }
+    }
+
+    func sendWorkoutUpdate(_ workout: Workout) {
+        guard let session = session, session.activationState == .activated else { return }
+
+        do {
+            let workoutData = try encodeWorkout(workout)
+            let message: [String: Any] = [
+                "type": "workoutUpdate",
+                "workout": workoutData
+            ]
+
+            if session.isReachable {
+                session.sendMessage(message, replyHandler: nil) { error in
+                    print("Failed to send workout update: \(error)")
+                }
+            } else {
+                // Queue for later via application context
+                syncAllData()
+            }
+        } catch {
+            print("Failed to encode workout: \(error)")
+        }
+    }
+
+    // MARK: - Encoding
+
+    private func encodeAllWorkouts(context: NSManagedObjectContext) throws -> [[String: Any]] {
+        let request = Workout.fetchRequest()
+        request.sortDescriptors = [NSSortDescriptor(keyPath: \Workout.start, ascending: false)]
+        let workouts = try context.fetch(request)
+        return try workouts.map { try encodeWorkout($0) }
+    }
+
+    private func encodeAllSplits(context: NSManagedObjectContext) throws -> [[String: Any]] {
+        let request = Split.fetchRequest()
+        request.sortDescriptors = [NSSortDescriptor(keyPath: \Split.order, ascending: true)]
+        let splits = try context.fetch(request)
+        return try splits.map { try encodeSplit($0) }
+    }
+
+    private func encodeWorkout(_ workout: Workout) throws -> [String: Any] {
+        var data: [String: Any] = [
+            "id": workout.objectID.uriRepresentation().absoluteString,
+            "start": workout.start.timeIntervalSince1970,
+            "status": workout.status.rawValue
+        ]
+
+        if let end = workout.end {
+            data["end"] = end.timeIntervalSince1970
+        }
+
+        if let split = workout.split {
+            data["splitId"] = split.objectID.uriRepresentation().absoluteString
+            data["splitName"] = split.name
+        }
+
+        data["logs"] = workout.logsArray.map { encodeWorkoutLog($0) }
+
+        return data
+    }
+
+    private func encodeWorkoutLog(_ log: WorkoutLog) -> [String: Any] {
+        var data: [String: Any] = [
+            "id": log.objectID.uriRepresentation().absoluteString,
+            "exerciseName": log.exerciseName,
+            "date": log.date.timeIntervalSince1970,
+            "order": log.order,
+            "sets": log.sets,
+            "reps": log.reps,
+            "weight": log.weight,
+            "status": log.status.rawValue,
+            "currentStateIndex": log.currentStateIndex,
+            "completed": log.completed,
+            "loadType": log.loadType
+        ]
+
+        if let duration = log.duration {
+            data["duration"] = duration.timeIntervalSince1970
+        }
+
+        if let notes = log.notes {
+            data["notes"] = notes
+        }
+
+        return data
+    }
+
+    private func encodeSplit(_ split: Split) throws -> [String: Any] {
+        var data: [String: Any] = [
+            "id": split.objectID.uriRepresentation().absoluteString,
+            "name": split.name,
+            "color": split.color,
+            "systemImage": split.systemImage,
+            "order": split.order
+        ]
+
+        data["exercises"] = split.exercisesArray.map { encodeExercise($0) }
+
+        return data
+    }
+
+    private func encodeExercise(_ exercise: Exercise) -> [String: Any] {
+        var data: [String: Any] = [
+            "id": exercise.objectID.uriRepresentation().absoluteString,
+            "name": exercise.name,
+            "order": exercise.order,
+            "sets": exercise.sets,
+            "reps": exercise.reps,
+            "weight": exercise.weight,
+            "loadType": exercise.loadType
+        ]
+
+        if let duration = exercise.duration {
+            data["duration"] = duration.timeIntervalSince1970
+        }
+
+        return data
+    }
+}
+
+// MARK: - WCSessionDelegate
+
+extension WatchConnectivityManager: WCSessionDelegate {
+    func session(_ session: WCSession, activationDidCompleteWith activationState: WCSessionActivationState, error: Error?) {
+        if let error = error {
+            print("[WC-iOS] Activation failed: \(error)")
+        } else {
+            print("[WC-iOS] Activated with state: \(activationState.rawValue), paired: \(session.isPaired), installed: \(session.isWatchAppInstalled)")
+            // Sync data when session activates
+            DispatchQueue.main.async {
+                self.syncAllData()
+            }
+        }
+    }
+
+    func sessionDidBecomeInactive(_ session: WCSession) {
+        print("[WC-iOS] Session became inactive")
+    }
+
+    func sessionDidDeactivate(_ session: WCSession) {
+        print("[WC-iOS] Session deactivated")
+        // Reactivate for switching watches
+        session.activate()
+    }
+
+    func sessionReachabilityDidChange(_ session: WCSession) {
+        print("[WC-iOS] Reachability changed: \(session.isReachable)")
+        if session.isReachable {
+            syncAllData()
+        }
+    }
+
+    // Receive messages from Watch (for bidirectional sync)
+    func session(_ session: WCSession, didReceiveMessage message: [String: Any]) {
+        print("[WC-iOS] Received message with keys: \(message.keys)")
+        if let type = message["type"] as? String {
+            switch type {
+            case "requestSync":
+                syncAllData()
+            case "syncFromWatch":
+                processWatchSync(message)
+            default:
+                break
+            }
+        }
+    }
+
+    // Receive user info transfers from Watch (background delivery)
+    func session(_ session: WCSession, didReceiveUserInfo userInfo: [String: Any]) {
+        print("[WC-iOS] Received userInfo with keys: \(userInfo.keys)")
+        if let type = userInfo["type"] as? String, type == "syncFromWatch" {
+            processWatchSync(userInfo)
+        }
+    }
+
+    // MARK: - Process Watch Sync
+
+    private func processWatchSync(_ data: [String: Any]) {
+        guard let viewContext = viewContext else {
+            print("[WC-iOS] No view context for Watch sync")
+            return
+        }
+
+        guard let workoutsData = data["workouts"] as? [[String: Any]] else {
+            print("[WC-iOS] No workouts in Watch sync data")
+            return
+        }
+
+        print("[WC-iOS] Processing \(workoutsData.count) workouts from Watch")
+
+        DispatchQueue.main.async {
+            viewContext.perform {
+                for workoutData in workoutsData {
+                    self.updateWorkoutFromWatch(workoutData, context: viewContext)
+                }
+
+                do {
+                    try viewContext.save()
+                    print("[WC-iOS] Successfully saved Watch sync data")
+
+                    // Refresh all objects to ensure SwiftUI observes changes
+                    viewContext.refreshAllObjects()
+                } catch {
+                    print("[WC-iOS] Failed to save Watch sync: \(error)")
+                }
+            }
+        }
+    }
+
+    private func updateWorkoutFromWatch(_ data: [String: Any], context: NSManagedObjectContext) {
+        guard let startInterval = data["start"] as? TimeInterval else { return }
+
+        // Find workout by start date
+        let request = Workout.fetchRequest()
+        let startDate = Date(timeIntervalSince1970: startInterval)
+        request.predicate = NSPredicate(
+            format: "start >= %@ AND start <= %@",
+            Date(timeIntervalSince1970: startInterval - 1) as NSDate,
+            Date(timeIntervalSince1970: startInterval + 1) as NSDate
+        )
+        request.fetchLimit = 1
+
+        guard let workout = try? context.fetch(request).first else {
+            print("[WC-iOS] Workout not found for start date: \(startDate)")
+            return
+        }
+
+        // Update workout status
+        if let statusRaw = data["status"] as? String,
+           let status = WorkoutStatus(rawValue: statusRaw) {
+            workout.status = status
+        }
+
+        if let endInterval = data["end"] as? TimeInterval {
+            workout.end = Date(timeIntervalSince1970: endInterval)
+        }
+
+        // Update logs
+        if let logsData = data["logs"] as? [[String: Any]] {
+            for logData in logsData {
+                updateWorkoutLogFromWatch(logData, workout: workout, context: context)
+            }
+        }
+    }
+
+    private func updateWorkoutLogFromWatch(_ data: [String: Any], workout: Workout, context: NSManagedObjectContext) {
+        guard let exerciseName = data["exerciseName"] as? String else { return }
+
+        // Find log by exercise name in this workout
+        guard let log = workout.logsArray.first(where: { $0.exerciseName == exerciseName }) else {
+            print("[WC-iOS] Log not found for exercise: \(exerciseName)")
+            return
+        }
+
+        // Update status and progress
+        if let statusRaw = data["status"] as? String,
+           let status = WorkoutStatus(rawValue: statusRaw) {
+            log.status = status
+        }
+
+        if let currentStateIndex = data["currentStateIndex"] as? Int {
+            log.currentStateIndex = Int32(currentStateIndex)
+        }
+
+        if let completed = data["completed"] as? Bool {
+            log.completed = completed
+        }
+
+        // Update other fields that might have changed
+        if let notes = data["notes"] as? String {
+            log.notes = notes
+        }
+    }
+}

Workouts/Persistence/PersistenceController.swift

@@ -9,6 +9,9 @@ struct PersistenceController {
     // CloudKit container identifier
     static let cloudKitContainerIdentifier = "iCloud.dev.rzen.indie.Workouts"
 
+    // App Group identifier for shared storage between iOS and Watch
+    static let appGroupIdentifier = "group.dev.rzen.indie.Workouts"
+
     var viewContext: NSManagedObjectContext {
         container.viewContext
     }
@@ -57,28 +60,37 @@ struct PersistenceController {
         if inMemory {
             description.url = URL(fileURLWithPath: "/dev/null")
             description.cloudKitContainerOptions = nil
-        } else if cloudKitEnabled {
-            // Check if CloudKit is available before enabling
-            let cloudKitAvailable = FileManager.default.ubiquityIdentityToken != nil
-
-            if cloudKitAvailable {
-                // Set CloudKit container options
-                let cloudKitOptions = NSPersistentCloudKitContainerOptions(
-                    containerIdentifier: Self.cloudKitContainerIdentifier
-                )
-                description.cloudKitContainerOptions = cloudKitOptions
-            } else {
-                // CloudKit not available (not signed in, etc.)
-                description.cloudKitContainerOptions = nil
-                print("CloudKit not available - using local storage only")
+        } else {
+            // Use App Group container for shared storage between iOS and Watch
+            if let appGroupURL = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: Self.appGroupIdentifier) {
+                let storeURL = appGroupURL.appendingPathComponent("Workouts.sqlite")
+                description.url = storeURL
+                print("Using shared App Group store at: \(storeURL)")
             }
 
-            // Enable persistent history tracking (useful even without CloudKit)
-            description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
-            description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
-        } else {
-            // CloudKit explicitly disabled
-            description.cloudKitContainerOptions = nil
+            if cloudKitEnabled {
+                // Check if CloudKit is available before enabling
+                let cloudKitAvailable = FileManager.default.ubiquityIdentityToken != nil
+
+                if cloudKitAvailable {
+                    // Set CloudKit container options
+                    let cloudKitOptions = NSPersistentCloudKitContainerOptions(
+                        containerIdentifier: Self.cloudKitContainerIdentifier
+                    )
+                    description.cloudKitContainerOptions = cloudKitOptions
+                } else {
+                    // CloudKit not available (not signed in, etc.)
+                    description.cloudKitContainerOptions = nil
+                    print("CloudKit not available - using local storage only")
+                }
+
+                // Enable persistent history tracking (useful even without CloudKit)
+                description.setOption(true as NSNumber, forKey: NSPersistentHistoryTrackingKey)
+                description.setOption(true as NSNumber, forKey: NSPersistentStoreRemoteChangeNotificationPostOptionKey)
+            } else {
+                // CloudKit explicitly disabled
+                description.cloudKitContainerOptions = nil
+            }
         }
 
         container.loadPersistentStores { storeDescription, error in

Workouts/Views/WorkoutLogs/ExerciseView.swift

@@ -125,6 +125,14 @@ struct ExerciseView: View {
         .onAppear {
             progress = Int(workoutLog.currentStateIndex)
         }
+        .onChange(of: workoutLog.currentStateIndex) { _, newValue in
+            // Update local state when CoreData changes (e.g., from Watch sync)
+            if progress != Int(newValue) {
+                withAnimation(.easeInOut(duration: 0.2)) {
+                    progress = Int(newValue)
+                }
+            }
+        }
     }
 
     private func updateLogStatus() {
@@ -162,6 +170,7 @@ struct ExerciseView: View {
 
     private func saveChanges() {
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 }
 

Workouts/Views/WorkoutLogs/NotesEditView.swift

@@ -48,5 +48,6 @@ struct NotesEditView: View {
     private func saveChanges() {
         workoutLog.notes = notesText
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 }

Workouts/Views/WorkoutLogs/PlanEditView.swift

@@ -163,5 +163,6 @@ struct PlanEditView: View {
         }
 
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 }

Workouts/Views/WorkoutLogs/WorkoutLogListView.swift

@@ -133,12 +133,14 @@ struct WorkoutLogListView: View {
         }
         updateWorkoutStatus()
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 
     private func completeLog(_ log: WorkoutLog) {
         log.status = .completed
         updateWorkoutStatus()
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 
     private func updateWorkoutStatus() {
@@ -164,6 +166,7 @@ struct WorkoutLogListView: View {
             log.order = Int32(index)
         }
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
     }
 
     private func addExerciseFromSplit(_ exercise: Exercise) {
@@ -188,6 +191,7 @@ struct WorkoutLogListView: View {
         log.workout = workout
 
         try? viewContext.save()
+        WatchConnectivityManager.shared.syncAllData()
 
         // Navigate to the new exercise view
         newlyAddedLog = log

Workouts/Views/WorkoutLogs/WorkoutLogsView.swift

@@ -88,6 +88,7 @@ struct WorkoutLogsView: View {
                         withAnimation {
                             viewContext.delete(item)
                             try? viewContext.save()
+                            WatchConnectivityManager.shared.syncAllData()
                             itemToDelete = nil
                         }
                     }
@@ -167,11 +168,17 @@ struct SplitPickerSheet: View {
             workoutLog.sets = exercise.sets
             workoutLog.reps = exercise.reps
             workoutLog.weight = exercise.weight
+            workoutLog.loadType = exercise.loadType
+            workoutLog.duration = exercise.duration
             workoutLog.status = .notStarted
             workoutLog.workout = workout
         }
 
         try? viewContext.save()
+
+        // Sync to Watch
+        WatchConnectivityManager.shared.syncAllData()
+
         dismiss()
     }
 }

Workouts/Workouts.entitlements

@@ -14,5 +14,9 @@
 	</array>
 	<key>com.apple.developer.ubiquity-kvstore-identifier</key>
 	<string>$(TeamIdentifierPrefix)$(CFBundleIdentifier)</string>
+	<key>com.apple.security.application-groups</key>
+	<array>
+		<string>group.dev.rzen.indie.Workouts</string>
+	</array>
 </dict>
 </plist>

Workouts/WorkoutsApp.swift

@@ -14,11 +14,18 @@ import CoreData
 @main
 struct WorkoutsApp: App {
     let persistenceController = PersistenceController.shared
+    let connectivityManager = WatchConnectivityManager.shared
+
+    init() {
+        // Set up Watch connectivity with Core Data context
+        connectivityManager.setViewContext(persistenceController.viewContext)
+    }
 
     var body: some Scene {
         WindowGroup {
             ContentView()
                 .environment(\.managedObjectContext, persistenceController.viewContext)
+                .environmentObject(connectivityManager)
         }
     }
 }