feat: support ios 16 for swiftui

apps/swift-ios/App/Cloud/T3ConnectCapability.swift

@@ -1,6 +1,6 @@
+import Combine
 import ClerkKit
 import Foundation
-import Observation
 import OSLog
 
 public extension Notification.Name {
@@ -50,16 +50,15 @@ protocol T3ConnectDeviceManaging: AnyObject {
 }
 
 @MainActor
-@Observable
-public final class T3ConnectController: T3ConnectDeviceManaging {
+public final class T3ConnectController: ObservableObject, T3ConnectDeviceManaging {
     private static let logger = Logger(
         subsystem: "codes.t3.swift-ios",
         category: "T3Connect"
     )
     public let resolution: T3ConnectConfigurationResolution
     public let managedAuthorizer: T3ConnectManagedEnvironmentAuthorizer
 
-    public private(set) var account: T3ConnectAccount? {
+    @Published public private(set) var account: T3ConnectAccount? {
         didSet {
             guard oldValue != account else { return }
             var accountIDs: [String: String] = [:]
@@ -76,10 +75,10 @@ public final class T3ConnectController: T3ConnectDeviceManaging {
             )
         }
     }
-    public private(set) var environments: [T3ConnectCloudEnvironment] = []
-    public private(set) var isRefreshing = false
-    public private(set) var busyEnvironmentID: String?
-    public var errorMessage: String?
+    @Published public private(set) var environments: [T3ConnectCloudEnvironment] = []
+    @Published public private(set) var isRefreshing = false
+    @Published public private(set) var busyEnvironmentID: String?
+    @Published public var errorMessage: String?
 
     private let auth: T3ConnectClerkSession?
     private let relay: T3ConnectRelayClient?

apps/swift-ios/App/Platform/PlatformIncomingShare.swift

@@ -1,5 +1,5 @@
+import Combine
 import Foundation
-import Observation
 import SwiftUI
 
 enum PlatformIncomingShareError: LocalizedError, Equatable {
@@ -161,10 +161,9 @@ struct PlatformIncomingSharePipeline: Sendable {
 }
 
 @MainActor
-@Observable
-final class PlatformIncomingShareCoordinator {
-    private(set) var pendingEnvelope: T3IncomingShareEnvelope?
-    private(set) var isImporting = false
+final class PlatformIncomingShareCoordinator: ObservableObject {
+    @Published private(set) var pendingEnvelope: T3IncomingShareEnvelope?
+    @Published private(set) var isImporting = false
 
     private let pipeline: PlatformIncomingSharePipeline
     private var isRefreshing = false

apps/swift-ios/App/Platform/PlatformRootView.swift

@@ -2,13 +2,13 @@ import SwiftUI
 
 struct PlatformRootView: View {
     @SwiftUI.Environment(\.scenePhase) private var scenePhase
-    @Bindable private var model: FeatureRootModel
+    @ObservedObject private var model: FeatureRootModel
 
     @State private var navigationRequest: FeatureWorkspaceNavigationRequest?
     @State private var pendingRoute: PlatformRoute?
     @State private var previousThreadStates: [String: FeatureThreadState]?
     @State private var lastNotificationPreference: Bool?
-    @State private var incomingShareCoordinator = PlatformIncomingShareCoordinator()
+    @StateObject private var incomingShareCoordinator = PlatformIncomingShareCoordinator()
     @State private var incomingShareNeedsProject = false
     @State private var importedShareProjectID: String?
     @State private var recentThreadsPersistenceTask: Task<Void, Never>?
@@ -64,7 +64,7 @@ struct PlatformRootView: View {
                 await model.removeManagedEnvironmentsAfterAccountChange()
             }
         }
-        .onChange(of: model.isLoading, initial: true) { _, isLoading in
+        .t3OnChange(of: model.isLoading, initial: true) { _, isLoading in
             guard !isLoading else { return }
             processThreadChanges()
             synchronizeNotificationPreference()
@@ -73,10 +73,10 @@ struct PlatformRootView: View {
             consumeMailboxRouteIfAvailable()
             refreshIncomingShares()
         }
-        .onChange(of: model.homePresentationRevision) { _, _ in
+        .t3OnChange(of: model.homePresentationRevision) { _, _ in
             processThreadChanges()
         }
-        .onChange(of: scenePhase) { _, phase in
+        .t3OnChange(of: scenePhase) { _, phase in
             if phase == .active {
                 consumeMailboxRouteIfAvailable()
                 synchronizeNotificationPreference()
@@ -86,15 +86,15 @@ struct PlatformRootView: View {
                 PlatformBackgroundRefreshCoordinator.shared.schedule()
             }
         }
-        .onChange(of: model.snapshot.settings.notificationsEnabled) { _, _ in
+        .t3OnChange(of: model.snapshot.settings.notificationsEnabled) { _, _ in
             synchronizeNotificationPreference()
             synchronizeCloudDelivery()
         }
-        .onChange(of: model.snapshot.settings.liveActivitiesEnabled) { _, _ in
+        .t3OnChange(of: model.snapshot.settings.liveActivitiesEnabled) { _, _ in
             synchronizeAgentAwareness()
             synchronizeCloudDelivery()
         }
-        .onChange(of: model.snapshot.projects.map(\.id)) { _, _ in
+        .t3OnChange(of: model.snapshot.projects.map(\.id)) { _, _ in
             refreshIncomingShares()
         }
         .sheet(item: presentedIncomingShare, onDismiss: openImportedShareDraft) { envelope in

apps/swift-ios/App/T3CodeApp.swift

@@ -4,12 +4,12 @@ import SwiftUI
 @MainActor
 struct T3CodeApp: App {
     @UIApplicationDelegateAdaptor(T3PlatformAppDelegate.self) private var appDelegate
-    @State private var model: FeatureRootModel
+    @StateObject private var model: FeatureRootModel
 
     init() {
         let client = NativeFeatureClient()
         let model = FeatureRootModel(client: client)
-        _model = State(initialValue: model)
+        _model = StateObject(wrappedValue: model)
         PlatformCloudDeliveryCoordinator.shared.install(
             controller: client.t3ConnectController
         )

apps/swift-ios/DesignSystem/T3Theme.swift

@@ -99,9 +99,195 @@ enum T3Metrics {
     static let readingWidth: CGFloat = 760
 }
 
+/// Back-deploys the standard iOS 17 empty-state presentation to iOS 16.
+struct T3ContentUnavailableView: View {
+    private let label: AnyView
+    private let description: AnyView
+    private let actions: AnyView
+    private let searchText: String?
+
+    init(
+        _ title: String,
+        systemImage: String,
+        description: Text? = nil
+    ) {
+        label = AnyView(Label(title, systemImage: systemImage))
+        self.description = description.map { AnyView($0) } ?? AnyView(EmptyView())
+        actions = AnyView(EmptyView())
+        searchText = nil
+    }
+
+    init<LabelContent: View, DescriptionContent: View>(
+        @ViewBuilder label: () -> LabelContent,
+        @ViewBuilder description: () -> DescriptionContent
+    ) {
+        self.label = AnyView(label())
+        self.description = AnyView(description())
+        actions = AnyView(EmptyView())
+        searchText = nil
+    }
+
+    init<LabelContent: View, DescriptionContent: View, ActionsContent: View>(
+        @ViewBuilder label: () -> LabelContent,
+        @ViewBuilder description: () -> DescriptionContent,
+        @ViewBuilder actions: () -> ActionsContent
+    ) {
+        self.label = AnyView(label())
+        self.description = AnyView(description())
+        self.actions = AnyView(actions())
+        searchText = nil
+    }
+
+    @ViewBuilder
+    var body: some View {
+        if #available(iOS 17.0, *) {
+            if let searchText {
+                ContentUnavailableView.search(text: searchText)
+            } else {
+                ContentUnavailableView {
+                    label
+                } description: {
+                    description
+                } actions: {
+                    actions
+                }
+            }
+        } else {
+            fallback
+        }
+    }
+
+    private var fallback: some View {
+        VStack(spacing: 12) {
+            label
+                .font(.title3.weight(.semibold))
+                .foregroundStyle(T3Colors.textPrimary)
+            description
+                .font(T3Typography.threadBody)
+                .foregroundStyle(T3Colors.textSecondary)
+                .multilineTextAlignment(.center)
+            actions
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity)
+        .padding(24)
+    }
+
+    static func search(text: String) -> Self {
+        Self(
+            text.isEmpty ? "No results" : "No results for “\(text)”",
+            systemImage: "magnifyingglass",
+            searchText: text
+        )
+    }
+
+    private init(
+        _ title: String,
+        systemImage: String,
+        searchText: String
+    ) {
+        label = AnyView(Label(title, systemImage: systemImage))
+        description = AnyView(EmptyView())
+        actions = AnyView(EmptyView())
+        self.searchText = searchText
+    }
+}
+
 extension View {
     func t3NavigationChrome() -> some View {
         toolbarBackground(T3Colors.sheet, for: .navigationBar)
             .toolbarBackground(.visible, for: .navigationBar)
     }
+
+    @ViewBuilder
+    func t3PresentationBackground(_ color: Color) -> some View {
+        if #available(iOS 16.4, *) {
+            presentationBackground(color)
+        } else {
+            background(color)
+        }
+    }
+
+    @ViewBuilder
+    func t3ListSectionSpacing(_ spacing: CGFloat) -> some View {
+        if #available(iOS 17.0, *) {
+            listSectionSpacing(spacing)
+        } else {
+            self
+        }
+    }
+
+    @ViewBuilder
+    func t3ScrollBounceBasedOnSize() -> some View {
+        if #available(iOS 16.4, *) {
+            scrollBounceBehavior(.basedOnSize)
+        } else {
+            self
+        }
+    }
+
+    /// iOS 16-compatible form of the two-value `onChange` API introduced in iOS 17.
+    /// Uses the native modifier on iOS 17; the manual tracking below exists only for iOS 16.
+    @ViewBuilder
+    func t3OnChange<Value: Equatable>(
+        of value: Value,
+        initial: Bool = false,
+        perform action: @escaping (_ oldValue: Value, _ newValue: Value) -> Void
+    ) -> some View {
+        if #available(iOS 17.0, *) {
+            onChange(of: value, initial: initial, action)
+        } else {
+            modifier(T3OnChangeModifier(value: value, initial: initial, action: action))
+        }
+    }
+
+    func t3OnChange<Value: Equatable>(
+        of value: Value,
+        initial: Bool = false,
+        perform action: @escaping (_ newValue: Value) -> Void
+    ) -> some View {
+        t3OnChange(of: value, initial: initial) { _, newValue in action(newValue) }
+    }
+
+    func t3OnChange<Value: Equatable>(
+        of value: Value,
+        initial: Bool = false,
+        perform action: @escaping () -> Void
+    ) -> some View {
+        t3OnChange(of: value, initial: initial) { _, _ in action() }
+    }
+}
+
+private struct T3OnChangeModifier<Value: Equatable>: ViewModifier {
+    let value: Value
+    let initial: Bool
+    let action: (_ oldValue: Value, _ newValue: Value) -> Void
+
+    @State private var previous: Value
+    @State private var didAppear = false
+
+    init(
+        value: Value,
+        initial: Bool,
+        action: @escaping (_ oldValue: Value, _ newValue: Value) -> Void
+    ) {
+        self.value = value
+        self.initial = initial
+        self.action = action
+        _previous = State(initialValue: value)
+    }
+
+    func body(content: Content) -> some View {
+        content
+            .onAppear {
+                guard !didAppear else { return }
+                didAppear = true
+                previous = value
+                if initial { action(value, value) }
+            }
+            .onChange(of: value) { newValue in
+                let oldValue = previous
+                previous = newValue
+                action(oldValue, newValue)
+            }
+    }
 }

apps/swift-ios/Extensions/Widgets/RecentTasksWidget.swift

@@ -29,14 +29,34 @@ struct T3RecentTasksWidget: Widget {
     var body: some WidgetConfiguration {
         StaticConfiguration(kind: kind, provider: T3TaskWidgetProvider()) { entry in
             T3TaskWidgetView(entry: entry)
-                .containerBackground(Color(uiColor: .systemBackground), for: .widget)
+                .t3WidgetBackground()
         }
         .configurationDisplayName("T3 Code Tasks")
         .description("See active and recent T3 Code tasks at a glance.")
         .supportedFamilies([.systemSmall, .systemMedium, .accessoryRectangular])
     }
 }
 
+private extension View {
+    @ViewBuilder
+    func t3LegacyWidgetContentMargins() -> some View {
+        if #available(iOSApplicationExtension 17.0, *) {
+            self
+        } else {
+            padding()
+        }
+    }
+
+    @ViewBuilder
+    func t3WidgetBackground() -> some View {
+        if #available(iOSApplicationExtension 17.0, *) {
+            containerBackground(Color(uiColor: .systemBackground), for: .widget)
+        } else {
+            background(Color(uiColor: .systemBackground))
+        }
+    }
+}
+
 private struct T3TaskWidgetView: View {
     @Environment(\.widgetFamily) private var family
     let entry: T3TaskWidgetEntry
@@ -88,6 +108,7 @@ private struct T3TaskWidgetView: View {
             }
         }
         .widgetURL(orderedTasks.first?.nativeDeepLinkURL ?? T3WidgetURLs.newTask)
+        .t3LegacyWidgetContentMargins()
     }
 
     private var mediumView: some View {
@@ -128,6 +149,7 @@ private struct T3TaskWidgetView: View {
                 }
             }
         }
+        .t3LegacyWidgetContentMargins()
     }
 
     private var accessoryView: some View {

apps/swift-ios/Features/Chat/FeatureComposerRequestViews.swift

@@ -263,11 +263,11 @@ struct FeatureComposerUserInputPanel: View {
                 .opacity(isResponding ? 0.56 : 1)
             }
         }
-        .onChange(of: input.id) {
+        .t3OnChange(of: input.id) {
             answers = [:]
             questionIndex = 0
         }
-        .onChange(of: questionIDs) { previousIDs, currentIDs in
+        .t3OnChange(of: questionIDs) { previousIDs, currentIDs in
             questionIndex = FeatureComposerQuestionReconciliation.index(
                 current: questionIndex,
                 previousQuestionIDs: previousIDs,