@main
struct MyWidget: Widget {
    let kind: String = "MyWidget"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: Provider()) { entry in
            MyWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("My Widget")
        .description("This widget displays...")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
    }
}

struct MyConfigurableWidget: Widget {
    let kind: String = "MyConfigurableWidget"

    var body: some WidgetConfiguration {
        AppIntentConfiguration(
            kind: kind,
            intent: SelectProjectIntent.self,
            provider: Provider()
        ) { entry in
            MyWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("Project Status")
        .description("Shows your selected project")
    }
}

Does your widget need user configuration?
├─ NO → Use StaticConfiguration
│  └─ Example: Weather widget for current location
│
└─ YES → Need configuration
   ├─ Simple static options (no dynamic data)?
   │  └─ Use AppIntentConfiguration with WidgetConfigurationIntent
   │     └─ Example: Timer with preset durations (5, 10, 15 minutes)
   │
   └─ Dynamic options (projects, contacts, playlists)?
      └─ Use AppIntentConfiguration + EntityQuery
         └─ Example: Project status widget showing user's projects

struct MyWidget: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: "MyWidget", provider: Provider()) { entry in
            if #available(iOSApplicationExtension 16.0, *) {
                switch entry.family {
                case .systemSmall:
                    SmallWidgetView(entry: entry)
                case .systemMedium:
                    MediumWidgetView(entry: entry)
                case .accessoryCircular:
                    CircularWidgetView(entry: entry)
                case .accessoryRectangular:
                    RectangularWidgetView(entry: entry)
                default:
                    Text("Unsupported")
                }
            } else {
                LegacyWidgetView(entry: entry)
            }
        }
        .supportedFamilies([
            .systemSmall,
            .systemMedium,
            .accessoryCircular,
            .accessoryRectangular
        ])
    }
}

struct Provider: TimelineProvider {
    // Placeholder while loading
    func placeholder(in context: Context) -> SimpleEntry {
        SimpleEntry(date: Date(), emoji: "😀")
    }

    // Shown in widget gallery
    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
        let entry = SimpleEntry(date: Date(), emoji: "📷")
        completion(entry)
    }

    // Actual timeline
    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        var entries: [SimpleEntry] = []
        let currentDate = Date()

        // Create entry every hour for 5 hours
        for hourOffset in 0 ..< 5 {
            let entryDate = Calendar.current.date(byAdding: .hour, value: hourOffset, to: currentDate)!
            let entry = SimpleEntry(date: entryDate, emoji: "⏰")
            entries.append(entry)
        }

        let timeline = Timeline(entries: entries, policy: .atEnd)
        completion(timeline)
    }
}

import WidgetKit

// Reload all widgets of this kind
WidgetCenter.shared.reloadAllTimelines()

// Reload specific kind
WidgetCenter.shared.reloadTimelines(ofKind: "MyWidget")

// ✅ GOOD: Strategic intervals (15-60 min)
let entries = (0..<8).map { offset in
    let date = Calendar.current.date(byAdding: .minute, value: offset * 15, to: now)!
    return SimpleEntry(date: date, data: data)
}

// ❌ BAD: Too frequent (1 min) - will exhaust budget
let entries = (0..<60).map { offset in
    let date = Calendar.current.date(byAdding: .minute, value: offset, to: now)!
    return SimpleEntry(date: date, data: data)
}

// ✅ GOOD: Load only what you need
func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    let data = loadRecentItems(limit: 10)  // Limited dataset
    let entries = generateEntries(from: data)
    completion(Timeline(entries: entries, policy: .atEnd))
}

// ❌ BAD: Loading entire database
func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    let allData = database.loadAllItems()  // Thousands of items = memory spike
    // ...
}

// ❌ CRITICAL ERROR: Network in view
struct MyWidgetView: View {
    var body: some View {
        VStack {
            Text("Weather")
        }
        .onAppear {
            Task {
                // This will NOT work - view is already rendered
                let weather = try? await fetchWeather()
            }
        }
    }
}

// ✅ CORRECT: Network in timeline provider
struct Provider: TimelineProvider {
    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        Task {
            // Fetch data here, before rendering
            let weather = try await fetchWeather()
            let entry = SimpleEntry(date: Date(), weather: weather)
            completion(Timeline(entries: [entry], policy: .atEnd))
        }
    }
}

// ✅ GOOD: Fast timeline generation
func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    // Read pre-computed data from shared container
    let shared = UserDefaults(suiteName: "group.com.myapp")!
    let cachedData = shared.data(forKey: "widgetData")

    let entries = generateQuickEntries(from: cachedData)
    completion(Timeline(entries: entries, policy: .after(Date().addingTimeInterval(3600))))
}

// ❌ BAD: Expensive operations in timeline
func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
    // Parsing large JSON, complex algorithms
    let json = parseHugeJSON()  // 10+ seconds
    let analyzed = runMLModel(on: json)  // 5+ seconds
    // Widget will timeout and show placeholder
}

// ✅ GOOD: Simple, efficient views
struct MyWidgetView: View {
    var entry: Provider.Entry

    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text(entry.title)
                .font(.headline)
            Text(entry.subtitle)
                .font(.caption)
        }
        .padding()
    }
}

// ❌ BAD: Heavy view operations
struct MyWidgetView: View {
    var entry: Provider.Entry

    var body: some View {
        VStack {
            // Avoid expensive operations in view body
            Text(entry.title)
            // Don't compute in body - precompute in entry
            ForEach(complexCalculation(entry.data)) { item in
                Text(item.name)
            }
        }
    }

    func complexCalculation(_ data: [Item]) -> [ProcessedItem] {
        // This runs on EVERY render
        return data.map { /* expensive transform */ }
    }
}

// ✅ GOOD: Asset catalog images (fast)
Image("icon-weather")

// ✅ GOOD: SF Symbols (fast)
Image(systemName: "cloud.rain.fill")

// ⚠️ ACCEPTABLE: Small images from shared container
if let imageData = Data(/* from shared container */),
   let uiImage = UIImage(data: imageData) {
    Image(uiImage: uiImage)
}

// ❌ BAD: Remote images (won't load)
AsyncImage(url: URL(string: "https://..."))  // Doesn't work in widgets

// ❌ BAD: Large images (memory spike)
Image(/* 4K resolution image */)  // Will cause termination

struct MyWidgetView: View {
    var entry: Provider.Entry

    var body: some View {
        VStack {
            Text(entry.count)
            Button(intent: IncrementIntent()) {
                Label("Increment", systemImage: "plus.circle")
            }
        }
    }
}

struct IncrementIntent: AppIntent {
    static var title: LocalizedStringResource = "Increment Counter"

    func perform() async throws -> some IntentResult {
        // Update shared data using App Groups
        let shared = UserDefaults(suiteName: "group.com.myapp")!
        let count = shared.integer(forKey: "count")
        shared.set(count + 1, forKey: "count")
        return .result()
    }
}

struct ToggleFeatureIntent: AppIntent {
    static var title: LocalizedStringResource = "Toggle Feature"

    @Parameter(title: "Enabled")
    var enabled: Bool

    func perform() async throws -> some IntentResult {
        // Update shared data using App Groups
        let shared = UserDefaults(suiteName: "group.com.myapp")!
        shared.set(enabled, forKey: "featureEnabled")
        return .result()
    }
}

struct MyWidgetView: View {
    @State private var isEnabled: Bool = false

    var body: some View {
        Toggle(isOn: $isEnabled) {
            Text("Feature")
        }
        .onChange(of: isEnabled) { newValue in
            Task {
                try? await ToggleFeatureIntent(enabled: newValue).perform()
            }
        }
    }
}

struct MyWidgetView: View {
    var entry: Provider.Entry

    var body: some View {
        VStack {
            Text(entry.status)
                .invalidatableContent() // Dims during intent execution

            Button(intent: RefreshIntent()) {
                Image(systemName: "arrow.clockwise")
            }
        }
    }
}

Text("\(entry.value)")
    .contentTransition(.numericText(value: Double(entry.value)))

VStack {
    if entry.showDetail {
        DetailView()
            .transition(.scale.combined(with: .opacity))
    }
}
.animation(.spring(response: 0.3), value: entry.showDetail)

import AppIntents

struct SelectProjectIntent: WidgetConfigurationIntent {
    static var title: LocalizedStringResource = "Select Project"
    static var description = IntentDescription("Choose which project to display")

    @Parameter(title: "Project")
    var project: ProjectEntity?

    // Provide default value
    static var parameterSummary: some ParameterSummary {
        Summary("Show \(\.$project)")
    }
}

struct ProjectEntity: AppEntity {
    var id: String
    var name: String

    static var typeDisplayRepresentation = TypeDisplayRepresentation(name: "Project")

    var displayRepresentation: DisplayRepresentation {
        DisplayRepresentation(title: "\(name)")
    }
}

struct ProjectQuery: EntityQuery {
    func entities(for identifiers: [String]) async throws -> [ProjectEntity] {
        // Return projects matching these IDs
        return await ProjectStore.shared.projects(withIDs: identifiers)
    }

    func suggestedEntities() async throws -> [ProjectEntity] {
        // Return all available projects
        return await ProjectStore.shared.allProjects()
    }
}

struct Provider: AppIntentTimelineProvider {
    func timeline(for configuration: SelectProjectIntent, in context: Context) async -> Timeline<SimpleEntry> {
        let project = configuration.project // Use selected project
        let entries = await generateEntries(for: project)
        return Timeline(entries: entries, policy: .atEnd)
    }
}

import ActivityKit

struct PizzaDeliveryAttributes: ActivityAttributes {
    // Static data - set when activity starts, never changes
    struct ContentState: Codable, Hashable {
        // Dynamic data - updated throughout activity lifecycle
        var status: DeliveryStatus
        var estimatedDeliveryTime: Date
        var driverName: String?
    }

    // Static attributes
    var orderNumber: String
    var pizzaType: String
}

import ActivityKit

let authorizationInfo = ActivityAuthorizationInfo()
let areActivitiesEnabled = authorizationInfo.areActivitiesEnabled

let attributes = PizzaDeliveryAttributes(
    orderNumber: "12345",
    pizzaType: "Pepperoni"
)

let initialState = PizzaDeliveryAttributes.ContentState(
    status: .preparing,
    estimatedDeliveryTime: Date().addingTimeInterval(30 * 60)
)

let activity = try Activity.request(
    attributes: attributes,
    content: ActivityContent(state: initialState, staleDate: nil),
    pushType: nil // or .token for push notifications
)

import ActivityKit

func startDeliveryActivity(order: Order) {
    // Check authorization first
    let authInfo = ActivityAuthorizationInfo()
    guard authInfo.areActivitiesEnabled else {
        print("Live Activities not enabled by user")
        return
    }

    let attributes = PizzaDeliveryAttributes(
        orderNumber: order.id,
        pizzaType: order.pizzaType
    )

    let initialState = PizzaDeliveryAttributes.ContentState(
        status: .preparing,
        estimatedDeliveryTime: order.estimatedTime
    )

    do {
        let activity = try Activity.request(
            attributes: attributes,
            content: ActivityContent(state: initialState, staleDate: nil),
            pushType: .token
        )

        // Store activity ID for later updates
        UserDefaults.shared.set(activity.id, forKey: "currentDeliveryActivityID")

    } catch let error as ActivityAuthorizationError {
        // User denied Live Activities permission
        print("Authorization error: \(error.localizedDescription)")

    } catch let error as ActivityError {
        switch error {
        case .dataTooLarge:
            // ActivityAttributes exceeds 4KB
            print("Activity data too large - reduce attribute size")
        case .tooManyActivities:
            // System limit reached (typically 2-3 simultaneous)
            print("Too many active Live Activities")
        default:
            print("Activity error: \(error.localizedDescription)")
        }

    } catch {
        print("Unexpected error: \(error)")
    }
}