Complete Roadmap to iOS Development Mastery: App Lifecycle, Memory Management, and Advanced Internals

// Modern SwiftUI App Lifecycle with comprehensive state management
@main
struct MyApp: App {
    @Environment(\.scenePhase) private var scenePhase
    @StateObject private var appState = AppStateManager()
    @StateObject private var dataManager = DataManager()
    
    var body: some Scene {
        WindowGroup {
            ContentView()
                .environmentObject(appState)
                .environmentObject(dataManager)
                .onReceive(NotificationCenter.default.publisher(for: UIApplication.didReceiveMemoryWarningNotification)) { _ in
                    handleMemoryWarning()
                }
        }
        .onChange(of: scenePhase) { phase in
            handleScenePhaseChange(phase)
        }
        .backgroundTask(.appRefresh("com.myapp.refresh")) {
            await performBackgroundRefresh()
        }
    }
    
    private func handleScenePhaseChange(_ phase: ScenePhase) {
        switch phase {
        case .active:
            Task {
                await appState.handleAppBecameActive()
                await dataManager.refreshDataIfNeeded()
            }
            
        case .background:
            Task {
                await appState.handleAppMovedToBackground()
                await dataManager.saveCurrentState()
            }
            
        default:
            break
        }
    }
    
    private func performBackgroundRefresh() async {
        do {
            let hasNewContent = try await dataManager.syncCriticalData()
            if hasNewContent {
                await NotificationManager.shared.scheduleContentUpdateNotification()
            }
        } catch {
            print("Background refresh failed: \(error)")
        }
    }
}