persist stopwatches

MultiChrono/ContentView.swift

@@ -11,14 +11,22 @@ import Combine
 class ContentViewModel: ObservableObject {
     @Published var stopwatches: [Stopwatch] = []
     
+    private let saveKey = "SavedStopwatches"
+    
+    init() {
+        load()
+    }
+    
     func addStopwatch(name: String) {
         let newStopwatch = Stopwatch(name: name)
         stopwatches.append(newStopwatch)
+        save()
     }
     
     func deleteStopwatch(at index: Int) {
         stopwatches[index].pause() // Ensure timer is stopped
         stopwatches.remove(at: index)
+        save()
     }
     
     func deleteStopwatch(id: UUID) {
@@ -26,11 +34,26 @@ class ContentViewModel: ObservableObject {
             deleteStopwatch(at: index)
         }
     }
+    
+    func save() {
+        if let encoded = try? JSONEncoder().encode(stopwatches) {
+            UserDefaults.standard.set(encoded, forKey: saveKey)
+        }
+    }
+    
+    func load() {
+        if let data = UserDefaults.standard.data(forKey: saveKey) {
+            if let decoded = try? JSONDecoder().decode([Stopwatch].self, from: data) {
+                stopwatches = decoded
+            }
+        }
+    }
 }
 
 struct ContentView: View {
     @StateObject private var viewModel = ContentViewModel()
     @State private var isShowingAddSheet = false
+    @Environment(\.scenePhase) private var scenePhase
     
     var body: some View {
         NavigationStack {
@@ -73,6 +96,11 @@ struct ContentView: View {
                 }
             }
         }
+        .onChange(of: scenePhase) { newPhase in
+            if newPhase == .background || newPhase == .inactive {
+                viewModel.save()
+            }
+        }
     }
 }