wip

DB/Sources/DB/Entities/Timeline.swift

@@ -18,7 +18,7 @@ public extension Timeline {
     typealias Id = String
 
     static let unauthenticatedDefaults: [Timeline] = [.local, .federated]
-    static let authenticatedDefaults: [Timeline] = [.home, .local, .federated, .favorites, .bookmarks]
+    static let authenticatedDefaults: [Timeline] = [.home, .local, .federated]
 
     var filterContext: Filter.Context? {
         switch self {

Extensions/NavigationViewModel+Extensions.swift

@@ -0,0 +1,33 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import Foundation
+import UIKit
+import ViewModels
+
+extension NavigationViewModel.Tab {
+    var title: String {
+        switch self {
+        case .timelines:
+            return NSLocalizedString("main-navigation.timelines", comment: "")
+        case .explore:
+            return NSLocalizedString("main-navigation.explore", comment: "")
+        case .notifications:
+            return NSLocalizedString("main-navigation.notifications", comment: "")
+        case .messages:
+            return NSLocalizedString("main-navigation.conversations", comment: "")
+        }
+    }
+
+    var systemImageName: String {
+        switch self {
+        case .timelines: return "newspaper"
+        case .explore: return "magnifyingglass"
+        case .notifications: return "bell"
+        case .messages: return "envelope"
+        }
+    }
+
+    var tabBarItem: UITabBarItem {
+        UITabBarItem(title: title, image: UIImage(systemName: systemImageName), selectedImage: nil)
+    }
+}

Localizations/Localizable.strings

@@ -88,6 +88,10 @@
 "identities.pending" = "Pending";
 "lists.new-list-title" = "New List Title";
 "load-more" = "Load More";
+"main-navigation.timelines" = "Timelines";
+"main-navigation.explore" = "Explore";
+"main-navigation.notifications" = "Notifications";
+"main-navigation.conversations" = "Conversations";
 "messages" = "Messages";
 "ok" = "OK";
 "pending.pending-confirmation" = "Your account is pending confirmation";
@@ -201,5 +205,8 @@
 "status.visibility.direct.description" = "Visible for mentioned users only";
 "submit" = "Submit";
 "timelines.home" = "Home";
+"timelines.home.description" = "Posts from accounts you're following";
 "timelines.local" = "Local";
+"timelines.local.description-%@" = "Public posts on %@";
 "timelines.federated" = "Federated";
+"timelines.federated.description-%@" = "Public posts on instances known by %@";

Metatext.xcodeproj/project.pbxproj

@@ -23,6 +23,11 @@
 		D01F41D924F880C400D55A2D /* TouchFallthroughTextView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D01F41D624F880C400D55A2D /* TouchFallthroughTextView.swift */; };
 		D01F41E424F8889700D55A2D /* AttachmentsView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D01F41E224F8889700D55A2D /* AttachmentsView.swift */; };
 		D02E1F95250B13210071AD56 /* SafariView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D02E1F94250B13210071AD56 /* SafariView.swift */; };
+		D035F86925B7F2ED00DC75ED /* MainNavigationViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D035F86825B7F2ED00DC75ED /* MainNavigationViewController.swift */; };
+		D035F86F25B7F30E00DC75ED /* MainNavigationView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D035F86E25B7F30E00DC75ED /* MainNavigationView.swift */; };
+		D035F87D25B7F61600DC75ED /* TimelinesViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D035F87C25B7F61600DC75ED /* TimelinesViewController.swift */; };
+		D035F88725B8016000DC75ED /* NavigationViewModel+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D035F88625B8016000DC75ED /* NavigationViewModel+Extensions.swift */; };
+		D035F89125B8067100DC75ED /* TimelinesTitleView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D035F89025B8067100DC75ED /* TimelinesTitleView.swift */; };
 		D036AA02254B6101009094DF /* NotificationListCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = D036AA01254B6101009094DF /* NotificationListCell.swift */; };
 		D036AA07254B6118009094DF /* NotificationView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D036AA06254B6118009094DF /* NotificationView.swift */; };
 		D036AA0C254B612B009094DF /* NotificationContentConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = D036AA0B254B612B009094DF /* NotificationContentConfiguration.swift */; };
@@ -204,6 +209,11 @@
 		D01F41D624F880C400D55A2D /* TouchFallthroughTextView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TouchFallthroughTextView.swift; sourceTree = "<group>"; };
 		D01F41E224F8889700D55A2D /* AttachmentsView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = AttachmentsView.swift; sourceTree = "<group>"; };
 		D02E1F94250B13210071AD56 /* SafariView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SafariView.swift; sourceTree = "<group>"; };
+		D035F86825B7F2ED00DC75ED /* MainNavigationViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainNavigationViewController.swift; sourceTree = "<group>"; };
+		D035F86E25B7F30E00DC75ED /* MainNavigationView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainNavigationView.swift; sourceTree = "<group>"; };
+		D035F87C25B7F61600DC75ED /* TimelinesViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelinesViewController.swift; sourceTree = "<group>"; };
+		D035F88625B8016000DC75ED /* NavigationViewModel+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NavigationViewModel+Extensions.swift"; sourceTree = "<group>"; };
+		D035F89025B8067100DC75ED /* TimelinesTitleView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelinesTitleView.swift; sourceTree = "<group>"; };
 		D036AA01254B6101009094DF /* NotificationListCell.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationListCell.swift; sourceTree = "<group>"; };
 		D036AA06254B6118009094DF /* NotificationView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationView.swift; sourceTree = "<group>"; };
 		D036AA0B254B612B009094DF /* NotificationContentConfiguration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NotificationContentConfiguration.swift; sourceTree = "<group>"; };
@@ -504,6 +514,7 @@
 				D0B8510B25259E56004E0744 /* LoadMoreCell.swift */,
 				D0E569DF252931B100FA1D72 /* LoadMoreContentConfiguration.swift */,
 				D0E569DA2529319100FA1D72 /* LoadMoreView.swift */,
+				D035F86E25B7F30E00DC75ED /* MainNavigationView.swift */,
 				D05936FE25AA94EA00754FDF /* MarkAttachmentsSensitiveView.swift */,
 				D03B1B29253818F3008F964B /* MediaPreferencesView.swift */,
 				D0FCC10F259C4F20000B67DF /* NewStatusView.swift */,
@@ -526,6 +537,7 @@
 				D0625E55250F086B00502611 /* Status */,
 				D0C7D42524F76169001EBDBB /* TableView.swift */,
 				D0C7D42E24F76169001EBDBB /* TabNavigationView.swift */,
+				D035F89025B8067100DC75ED /* TimelinesTitleView.swift */,
 				D01F41D624F880C400D55A2D /* TouchFallthroughTextView.swift */,
 				D0EA59472522B8B600804347 /* ViewConstants.swift */,
 				D0F2D54A2581CF7D00986197 /* VisualEffectBlur.swift */,
@@ -542,9 +554,11 @@
 				D08B8D49253FC36500B1EBEF /* ImageNavigationController.swift */,
 				D08B8D41253F92B600B1EBEF /* ImagePageViewController.swift */,
 				D08B8D3C253F929E00B1EBEF /* ImageViewController.swift */,
+				D035F86825B7F2ED00DC75ED /* MainNavigationViewController.swift */,
 				D0FCC104259C4E61000B67DF /* NewStatusViewController.swift */,
 				D06BC5E525202AD90079541D /* ProfileViewController.swift */,
 				D0F0B12D251A97E400942152 /* TableViewController.swift */,
+				D035F87C25B7F61600DC75ED /* TimelinesViewController.swift */,
 			);
 			path = "View Controllers";
 			sourceTree = "<group>";
@@ -574,6 +588,7 @@
 				D05E688425B55AE8001FB2C6 /* AVURLAsset+Extensions.swift */,
 				D0F0B135251AA12700942152 /* CollectionItem+Extensions.swift */,
 				D0C7D46E24F76169001EBDBB /* KingfisherOptionsInfo+Extensions.swift */,
+				D035F88625B8016000DC75ED /* NavigationViewModel+Extensions.swift */,
 				D0C7D46B24F76169001EBDBB /* NSMutableAttributedString+Extensions.swift */,
 				D07EC7CE25B13921006DF726 /* PickerEmoji+Extensions.swift */,
 				D0B5FE9A251583DB00478838 /* ProfileCollection+Extensions.swift */,
@@ -856,6 +871,7 @@
 				D08B8D822544D80000B1EBEF /* PollOptionButton.swift in Sources */,
 				D0C7D4DA24F7616A001EBDBB /* View+Extensions.swift in Sources */,
 				D07EC81125B232C2006DF726 /* SystemEmoji+Extensions.swift in Sources */,
+				D035F87D25B7F61600DC75ED /* TimelinesViewController.swift in Sources */,
 				D059373325AAEA7000754FDF /* CompositionPollView.swift in Sources */,
 				D08B8D8D2544E6EC00B1EBEF /* PollResultView.swift in Sources */,
 				D0C7D4D524F7616A001EBDBB /* String+Extensions.swift in Sources */,
@@ -874,7 +890,9 @@
 				D0C7D49724F7616A001EBDBB /* IdentitiesView.swift in Sources */,
 				D01EF22425182B1F00650C6B /* AccountHeaderView.swift in Sources */,
 				D059373E25AB8D5200754FDF /* CompositionPollOptionView.swift in Sources */,
+				D035F89125B8067100DC75ED /* TimelinesTitleView.swift in Sources */,
 				D036AA17254CA824009094DF /* StatusBodyView.swift in Sources */,
+				D035F86F25B7F30E00DC75ED /* MainNavigationView.swift in Sources */,
 				D08E512125786A6600FA2C5F /* UIButton+Extensions.swift in Sources */,
 				D05936F425AA66A600754FDF /* UIView+Extensions.swift in Sources */,
 				D05936E925AA3F3D00754FDF /* EditAttachmentView.swift in Sources */,
@@ -883,6 +901,7 @@
 				D036AA0C254B612B009094DF /* NotificationContentConfiguration.swift in Sources */,
 				D0C7D49824F7616A001EBDBB /* CustomEmojiText.swift in Sources */,
 				D08B8D3D253F929E00B1EBEF /* ImageViewController.swift in Sources */,
+				D035F86925B7F2ED00DC75ED /* MainNavigationViewController.swift in Sources */,
 				D0B8510C25259E56004E0744 /* LoadMoreCell.swift in Sources */,
 				D08E52612579D2E100FA2C5F /* DomainBlocksView.swift in Sources */,
 				D01F41E424F8889700D55A2D /* AttachmentsView.swift in Sources */,
@@ -901,6 +920,7 @@
 				D0C7D4C324F7616A001EBDBB /* MetatextApp.swift in Sources */,
 				D0E1F583251F13EC00D45315 /* WebfingerIndicatorView.swift in Sources */,
 				D0BEB20524FA1107001B0F04 /* FiltersView.swift in Sources */,
+				D035F88725B8016000DC75ED /* NavigationViewModel+Extensions.swift in Sources */,
 				D0FCC110259C4F20000B67DF /* NewStatusView.swift in Sources */,
 				D0C7D49B24F7616A001EBDBB /* PreferencesView.swift in Sources */,
 				D088406D25AFBBE200BB749B /* EmojiPickerViewController.swift in Sources */,

View Controllers/MainNavigationViewController.swift

@@ -0,0 +1,64 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import UIKit
+import ViewModels
+
+final class MainNavigationViewController: UITabBarController {
+    private let viewModel: NavigationViewModel
+    private let rootViewModel: RootViewModel
+
+    init(viewModel: NavigationViewModel, rootViewModel: RootViewModel) {
+        self.viewModel = viewModel
+        self.rootViewModel = rootViewModel
+
+        super.init(nibName: nil, bundle: nil)
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        let timelinesViewController = TimelinesViewController(
+            viewModel: viewModel,
+            rootViewModel: rootViewModel)
+        let timelinesNavigationController = UINavigationController(rootViewController: timelinesViewController)
+
+        if let notificationsViewModel = viewModel.notificationsViewModel,
+           let conversationsViewModel = viewModel.conversationsViewModel {
+            let notificationsViewController = TableViewController(
+                viewModel: notificationsViewModel,
+                rootViewModel: rootViewModel,
+                identification: viewModel.identification)
+
+            notificationsViewController.tabBarItem = NavigationViewModel.Tab.notifications.tabBarItem
+
+            let notificationsNavigationViewController = UINavigationController(
+                rootViewController: notificationsViewController)
+
+            let conversationsViewController = TableViewController(
+                viewModel: conversationsViewModel,
+                rootViewModel: rootViewModel,
+                identification: viewModel.identification)
+
+            conversationsViewController.tabBarItem = NavigationViewModel.Tab.messages.tabBarItem
+            conversationsViewController.navigationItem.title = NavigationViewModel.Tab.messages.title
+
+            let conversationsNavigationViewController = UINavigationController(
+                rootViewController: conversationsViewController)
+
+            viewControllers = [
+                timelinesNavigationController,
+                notificationsNavigationViewController,
+                conversationsNavigationViewController
+            ]
+        } else {
+            viewControllers = [
+                timelinesNavigationController
+            ]
+        }
+    }
+}

View Controllers/TimelinesViewController.swift

@@ -0,0 +1,131 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import Combine
+import UIKit
+import ViewModels
+
+final class TimelinesViewController: UIPageViewController {
+    private let titleView: TimelinesTitleView
+    private let timelineViewControllers: [TableViewController]
+    private let viewModel: NavigationViewModel
+    private let rootViewModel: RootViewModel
+    private var cancellables = Set<AnyCancellable>()
+
+    init(viewModel: NavigationViewModel, rootViewModel: RootViewModel) {
+        self.viewModel = viewModel
+        self.rootViewModel = rootViewModel
+
+        let timelineViewModels: [CollectionViewModel]
+
+        if let homeTimelineViewModel = viewModel.homeTimelineViewModel {
+            timelineViewModels = [
+                homeTimelineViewModel,
+                viewModel.localTimelineViewModel,
+                viewModel.federatedTimelineViewModel]
+        } else {
+            timelineViewModels = [
+                viewModel.localTimelineViewModel,
+                viewModel.federatedTimelineViewModel]
+        }
+
+        titleView = TimelinesTitleView(
+            timelines: viewModel.identification.identity.authenticated
+                ? Timeline.authenticatedDefaults
+                : Timeline.unauthenticatedDefaults,
+            identification: viewModel.identification)
+
+        timelineViewControllers = timelineViewModels.map {
+            TableViewController(
+                viewModel: $0,
+                rootViewModel: rootViewModel,
+                identification: viewModel.identification)
+        }
+
+        super.init(transitionStyle: .scroll,
+                   navigationOrientation: .horizontal,
+                   options: [.interPageSpacing: CGFloat.defaultSpacing])
+
+        if let firstViewController = timelineViewControllers.first {
+            setViewControllers([firstViewController], direction: .forward, animated: false)
+        }
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+
+        dataSource = self
+        delegate = self
+
+        tabBarItem = UITabBarItem(
+            title: NSLocalizedString("main-navigation.timelines", comment: ""),
+            image: UIImage(systemName: "newspaper"),
+            selectedImage: nil)
+
+        navigationItem.titleView = titleView
+
+        navigationItem.leftBarButtonItem = UIBarButtonItem(systemItem: .close)
+        navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "megaphone"), primaryAction: nil)
+
+        titleView.$selectedTimeline
+            .compactMap { [weak self] in self?.titleView.timelines.firstIndex(of: $0) }
+            .sink { [weak self] index in
+                guard let self = self,
+                      let currentViewController = self.viewControllers?.first as? TableViewController,
+                      let currentIndex = self.timelineViewControllers.firstIndex(of: currentViewController),
+                      index != currentIndex
+                else { return }
+
+                self.setViewControllers(
+                    [self.timelineViewControllers[index]],
+                    direction: index > currentIndex ? .forward : .reverse,
+                    animated: !UIAccessibility.isReduceMotionEnabled)
+        }
+        .store(in: &cancellables)
+    }
+}
+
+extension TimelinesViewController: UIPageViewControllerDataSource {
+    func pageViewController(_ pageViewController: UIPageViewController,
+                            viewControllerAfter viewController: UIViewController) -> UIViewController? {
+        guard
+            let timelineViewController = viewController as? TableViewController,
+            let index = timelineViewControllers.firstIndex(of: timelineViewController),
+            index + 1 < timelineViewControllers.count
+        else { return nil }
+
+        return timelineViewControllers[index + 1]
+    }
+
+    func pageViewController(_ pageViewController: UIPageViewController,
+                            viewControllerBefore viewController: UIViewController) -> UIViewController? {
+        guard
+            let timelineViewController = viewController as? TableViewController,
+            let index = timelineViewControllers.firstIndex(of: timelineViewController),
+            index > 0
+        else { return nil }
+
+        return timelineViewControllers[index - 1]
+    }
+}
+
+extension TimelinesViewController: UIPageViewControllerDelegate {
+    func pageViewController(_ pageViewController: UIPageViewController,
+                            didFinishAnimating finished: Bool,
+                            previousViewControllers: [UIViewController],
+                            transitionCompleted completed: Bool) {
+        guard let viewController = viewControllers?.first as? TableViewController,
+              let index = timelineViewControllers.firstIndex(of: viewController)
+        else { return }
+
+        let timeline = titleView.timelines[index]
+
+        if titleView.selectedTimeline != timeline {
+            titleView.selectedTimeline = timeline
+        }
+    }
+}

ViewModels/Sources/ViewModels/NavigationViewModel.swift

@@ -21,38 +21,56 @@ public final class NavigationViewModel: ObservableObject {
     @Published public var alertItem: AlertItem?
     public private(set) var timelineViewModel: CollectionItemsViewModel
 
-    public var notificationsViewModel: CollectionViewModel? {
+    public lazy var homeTimelineViewModel: CollectionViewModel? = {
         if identification.identity.authenticated {
-            if _notificationsViewModel == nil {
+            return CollectionItemsViewModel(
-                _notificationsViewModel = CollectionItemsViewModel(
+                collectionService: identification.service.service(timeline: .home),
+                identification: identification)
+        }
+
+        return nil
+    }()
+
+    public lazy var localTimelineViewModel: CollectionViewModel = {
+        CollectionItemsViewModel(
+            collectionService: identification.service.service(timeline: .local),
+            identification: identification)
+    }()
+
+    public lazy var federatedTimelineViewModel: CollectionViewModel = {
+        CollectionItemsViewModel(
+            collectionService: identification.service.service(timeline: .federated),
+            identification: identification)
+    }()
+
+    public lazy var notificationsViewModel: CollectionViewModel? = {
+        if identification.identity.authenticated {
+                let notificationsViewModel = CollectionItemsViewModel(
                     collectionService: identification.service.notificationsService(),
                     identification: identification)
-                _notificationsViewModel?.request(maxId: nil, minId: nil)
-            }
 
-            return _notificationsViewModel
+                notificationsViewModel.request(maxId: nil, minId: nil)
+
+            return notificationsViewModel
         } else {
             return nil
         }
-    }
+    }()
 
-    public var conversationsViewModel: CollectionViewModel? {
+    public lazy var conversationsViewModel: CollectionViewModel? = {
         if identification.identity.authenticated {
-            if _conversationsViewModel == nil {
+                let conversationsViewModel = CollectionItemsViewModel(
-                _conversationsViewModel = CollectionItemsViewModel(
                     collectionService: identification.service.conversationsService(),
                     identification: identification)
-                _conversationsViewModel?.request(maxId: nil, minId: nil)
-            }
 
-            return _conversationsViewModel
+                conversationsViewModel.request(maxId: nil, minId: nil)
+
+            return conversationsViewModel
         } else {
             return nil
         }
-    }
+    }()
 
-    private var _notificationsViewModel: CollectionViewModel?
-    private var _conversationsViewModel: CollectionViewModel?
     private var cancellables = Set<AnyCancellable>()
 
     public init(identification: Identification) {

Views/MainNavigationView.swift

@@ -0,0 +1,32 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import SwiftUI
+import ViewModels
+
+struct MainNavigationView: UIViewControllerRepresentable {
+    let viewModelClosure: () -> NavigationViewModel
+    @EnvironmentObject var rootViewModel: RootViewModel
+    @EnvironmentObject var identification: Identification
+
+    func makeUIViewController(context: Context) -> MainNavigationViewController {
+        MainNavigationViewController(
+            viewModel: viewModelClosure(),
+            rootViewModel: rootViewModel)
+    }
+
+    func updateUIViewController(_ uiViewController: MainNavigationViewController, context: Context) {
+
+    }
+}
+
+#if DEBUG
+import PreviewViewModels
+
+struct MainNavigationView_Previews: PreviewProvider {
+    static var previews: some View {
+        MainNavigationView { NavigationViewModel(identification: .preview) }
+            .environmentObject(Identification.preview)
+            .environmentObject(RootViewModel.preview)
+    }
+}
+#endif

Views/RootView.swift

@@ -8,10 +8,11 @@ struct RootView: View {
 
     var body: some View {
         if let navigationViewModel = viewModel.navigationViewModel {
-            TabNavigationView(viewModel: navigationViewModel)
+            MainNavigationView { navigationViewModel }
                 .id(navigationViewModel.identification.identity.id)
                 .environmentObject(viewModel)
                 .transition(.opacity)
+                .edgesIgnoringSafeArea(.all)
         } else {
             NavigationView {
                 AddIdentityView(viewModel: viewModel.addIdentityViewModel())

Views/TabNavigationView.swift

@@ -188,7 +188,8 @@ private extension TabNavigationView {
     }
 }
 
-private extension Timeline {
+// TODO: move
+extension Timeline {
     var title: String {
         switch self {
         case .home:
@@ -210,10 +211,40 @@ private extension Timeline {
         }
     }
 
+    func subtitle(identification: Identification) -> String? {
+        switch self {
+        case .home:
+            return identification.identity.handle
+        default:
+            return identification.identity.instance?.uri
+        }
+    }
+
+    func description(instanceName: String?) -> String? {
+        switch self {
+        case .home:
+            return NSLocalizedString("timelines.home.description", comment: "")
+        case .local:
+            guard let instanceName = instanceName else { return nil }
+
+            return String.localizedStringWithFormat(
+                NSLocalizedString("timelines.local.description-%@", comment: ""),
+                instanceName)
+        case .federated:
+            guard let instanceName = instanceName else { return nil }
+
+            return String.localizedStringWithFormat(
+                NSLocalizedString("timelines.federated.description-%@", comment: ""),
+                instanceName)
+        default:
+            return nil
+        }
+    }
+
     var systemImageName: String {
         switch self {
         case .home: return "house"
-        case .local: return "person.3"
+        case .local: return "building.2.crop.circle"
         case .federated: return "network"
         case .list: return "scroll"
         case .tag: return "number"
@@ -224,26 +255,6 @@ private extension Timeline {
     }
 }
 
-extension NavigationViewModel.Tab {
-    var title: String {
-        switch self {
-        case .timelines: return "Timelines"
-        case .explore: return "Explore"
-        case .notifications: return "Notifications"
-        case .messages: return "Messages"
-        }
-    }
-
-    var systemImageName: String {
-        switch self {
-        case .timelines: return "newspaper"
-        case .explore: return "magnifyingglass"
-        case .notifications: return "bell"
-        case .messages: return "envelope"
-        }
-    }
-}
-
 #if DEBUG
 import PreviewViewModels
 

Views/TimelinesTitleView.swift

@@ -0,0 +1,153 @@
+// Copyright © 2021 Metabolist. All rights reserved.
+
+import Combine
+import UIKit
+import ViewModels
+
+final class TimelinesTitleView: UIControl {
+    let timelines: [Timeline]
+    private let titleLabel = UILabel()
+    private let subtitleLabel = UILabel()
+    private let imageView = UIImageView()
+    private let chevronImageView = UIImageView(image: TimelinesTitleView.closedImage)
+    private let identification: Identification
+
+    @Published var selectedTimeline: Timeline {
+        didSet { applyTimelineSelection() }
+    }
+
+    init(timelines: [Timeline], identification: Identification) {
+        self.timelines = timelines
+        self.identification = identification
+
+        guard let timeline = timelines.first else {
+            fatalError("TimelinesTitleView must be initialized with a non-empty timelines array")
+        }
+
+        selectedTimeline = timeline
+
+        super.init(frame: .zero)
+
+        accessibilityTraits = .button
+        isAccessibilityElement = true
+        showsMenuAsPrimaryAction = true
+        isContextMenuInteractionEnabled = true
+
+        addSubview(imageView)
+        imageView.translatesAutoresizingMaskIntoConstraints = false
+        imageView.contentMode = .scaleAspectFit
+        imageView.setContentHuggingPriority(.required, for: .horizontal)
+        imageView.tintColor = .label
+
+        addSubview(chevronImageView)
+        chevronImageView.translatesAutoresizingMaskIntoConstraints = false
+        chevronImageView.contentMode = .scaleAspectFit
+        chevronImageView.setContentHuggingPriority(.required, for: .horizontal)
+
+        addSubview(titleLabel)
+        titleLabel.translatesAutoresizingMaskIntoConstraints = false
+        titleLabel.adjustsFontForContentSizeCategory = true
+        titleLabel.font = .preferredFont(forTextStyle: .headline)
+        titleLabel.adjustsFontSizeToFitWidth = true
+        titleLabel.minimumScaleFactor = 0.5
+        titleLabel.setContentHuggingPriority(.required, for: .horizontal)
+        titleLabel.setContentHuggingPriority(.required, for: .vertical)
+        titleLabel.setContentCompressionResistancePriority(.required, for: .vertical)
+
+        addSubview(subtitleLabel)
+        subtitleLabel.translatesAutoresizingMaskIntoConstraints = false
+        subtitleLabel.adjustsFontForContentSizeCategory = true
+        subtitleLabel.font = .preferredFont(forTextStyle: .caption2)
+        subtitleLabel.adjustsFontSizeToFitWidth = true
+        subtitleLabel.textAlignment = .center
+        subtitleLabel.minimumScaleFactor = 0.5
+        subtitleLabel.textColor = .secondaryLabel
+        subtitleLabel.setContentHuggingPriority(.required, for: .vertical)
+        subtitleLabel.setContentCompressionResistancePriority(.required, for: .horizontal)
+        subtitleLabel.setContentCompressionResistancePriority(.justBelowMax, for: .vertical)
+
+        NSLayoutConstraint.activate([
+            imageView.leadingAnchor.constraint(greaterThanOrEqualTo: leadingAnchor),
+            imageView.topAnchor.constraint(equalTo: titleLabel.topAnchor),
+            imageView.bottomAnchor.constraint(equalTo: titleLabel.bottomAnchor),
+            titleLabel.centerXAnchor.constraint(equalTo: centerXAnchor),
+            titleLabel.leadingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: .compactSpacing),
+            titleLabel.topAnchor.constraint(equalTo: topAnchor),
+            chevronImageView.leadingAnchor.constraint(equalTo: titleLabel.trailingAnchor, constant: .defaultSpacing),
+            chevronImageView.topAnchor.constraint(equalTo: titleLabel.topAnchor),
+            chevronImageView.bottomAnchor.constraint(equalTo: titleLabel.bottomAnchor),
+            chevronImageView.trailingAnchor.constraint(lessThanOrEqualTo: trailingAnchor),
+            subtitleLabel.topAnchor.constraint(equalTo: titleLabel.bottomAnchor),
+            subtitleLabel.leadingAnchor.constraint(equalTo: leadingAnchor),
+            subtitleLabel.trailingAnchor.constraint(equalTo: trailingAnchor),
+            subtitleLabel.bottomAnchor.constraint(equalTo: bottomAnchor)
+        ])
+
+        applyTimelineSelection()
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    override var isHighlighted: Bool {
+        didSet {
+            alpha = isHighlighted ? Self.highlightedAlpha : 1
+        }
+    }
+
+    override func menuAttachmentPoint(for configuration: UIContextMenuConfiguration) -> CGPoint {
+        CGPoint(x: (bounds.width - .systemMenuWidth) / 2 + .systemMenuInset, y: bounds.maxY + .compactSpacing)
+    }
+
+    override func contextMenuInteraction(
+        _ interaction: UIContextMenuInteraction,
+        configurationForMenuAtLocation location: CGPoint) -> UIContextMenuConfiguration? {
+        UIContextMenuConfiguration(identifier: nil, previewProvider: nil) { [weak self] _ in
+            guard let self = self else { return nil }
+
+            return UIMenu(children: self.timelines.map { timeline in
+                UIAction(
+                    title: timeline.title,
+                    image: UIImage(systemName: timeline.systemImageName),
+                    attributes: timeline == self.selectedTimeline ? .disabled : [],
+                    state: timeline == self.selectedTimeline ? .on : .off) { _ in
+                    self.selectedTimeline = timeline
+                }
+            })
+        }
+    }
+
+    override func contextMenuInteraction(
+        _ interaction: UIContextMenuInteraction,
+        willDisplayMenuFor configuration: UIContextMenuConfiguration,
+        animator: UIContextMenuInteractionAnimating?) {
+        chevronImageView.image = Self.openImage
+    }
+
+    override func contextMenuInteraction(
+        _ interaction: UIContextMenuInteraction,
+        willEndFor configuration: UIContextMenuConfiguration,
+        animator: UIContextMenuInteractionAnimating?) {
+        chevronImageView.image = Self.closedImage
+        alpha = 1 // system bug
+    }
+}
+
+private extension TimelinesTitleView {
+    static let highlightedAlpha: CGFloat = 0.5
+    static let openImage = UIImage(
+        systemName: "chevron.compact.up",
+        withConfiguration: UIImage.SymbolConfiguration(scale: .small))
+    static let closedImage = UIImage(
+        systemName: "chevron.compact.down",
+        withConfiguration: UIImage.SymbolConfiguration(scale: .small))
+    func applyTimelineSelection() {
+        imageView.image = UIImage(
+            systemName: selectedTimeline.systemImageName,
+            withConfiguration: UIImage.SymbolConfiguration(scale: .small))
+        titleLabel.text = selectedTimeline.title
+        subtitleLabel.text = selectedTimeline.subtitle(identification: identification)
+    }
+}

Views/ViewConstants.swift

@@ -11,8 +11,10 @@ extension CGFloat {
     static let hairline = 1 / UIScreen.main.scale
     static let minimumButtonDimension: Self = 44
     static let barButtonItemDimension: Self = 28
-    static let newStatusButtonDimension: CGFloat = 54
+    static let newStatusButtonDimension: Self = 54
-    static let defaultShadowRadius: CGFloat = 2
+    static let defaultShadowRadius: Self = 2
+    static let systemMenuWidth: Self = 250
+    static let systemMenuInset: Self = 15
 }
 
 extension CGRect {