Refactoring

Development Assets/DevelopmentModels.swift

@@ -97,11 +97,13 @@ extension Identity {
 
 extension AppEnvironment {
     static func fresh(
+        URLSessionConfiguration: URLSessionConfiguration = .stubbing,
         identityDatabase: IdentityDatabase = .fresh(),
         preferences: Preferences = .fresh(),
         secrets: Secrets = .fresh(),
         webAuthSessionType: WebAuthSession.Type = SuccessfulStubbingWebAuthSession.self) -> AppEnvironment {
         AppEnvironment(
+            URLSessionConfiguration: URLSessionConfiguration,
             identityDatabase: identityDatabase,
             preferences: preferences,
             secrets: secrets,
@@ -109,14 +111,23 @@ extension AppEnvironment {
     }
 
     static let development = AppEnvironment(
+        URLSessionConfiguration: .stubbing,
         identityDatabase: .development,
         preferences: .development,
         secrets: .development,
         webAuthSessionType: SuccessfulStubbingWebAuthSession.self)
 }
 
-extension SceneViewModel {
+extension RootViewModel {
-    static let development = SceneViewModel(networkClient: .development, environment: .development)
+    static let development = RootViewModel(environment: .development)
+}
+
+extension MainNavigationViewModel {
+    static let development = RootViewModel.development.mainNavigationViewModel(identityID: devIdentityID)!
+}
+
+extension SettingsViewModel {
+    static let development = MainNavigationViewModel.development.settingsViewModel()
 }
 
 // swiftlint:enable force_try

Metatext.xcodeproj/project.pbxproj

@@ -21,13 +21,17 @@
 		D04FD73D24D4A83A007D572D /* InstanceEndpoint+Stubbing.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04FD73B24D4A83A007D572D /* InstanceEndpoint+Stubbing.swift */; };
 		D04FD74224D4AA34007D572D /* DevelopmentModels.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04FD74124D4AA34007D572D /* DevelopmentModels.swift */; };
 		D04FD74324D4AA34007D572D /* DevelopmentModels.swift in Sources */ = {isa = PBXBuildFile; fileRef = D04FD74124D4AA34007D572D /* DevelopmentModels.swift */; };
-		D052BBC724D749C800A80A7A /* SceneViewModelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBC624D749C800A80A7A /* SceneViewModelTests.swift */; };
+		D052BBC724D749C800A80A7A /* RootViewModelTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBC624D749C800A80A7A /* RootViewModelTests.swift */; };
 		D052BBCA24D74C9200A80A7A /* FakeUserDefaults.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBC824D74B6400A80A7A /* FakeUserDefaults.swift */; };
 		D052BBCB24D74C9300A80A7A /* FakeUserDefaults.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBC824D74B6400A80A7A /* FakeUserDefaults.swift */; };
 		D052BBCF24D750C000A80A7A /* Preferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBCE24D750C000A80A7A /* Preferences.swift */; };
 		D052BBD024D750C000A80A7A /* Preferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBCE24D750C000A80A7A /* Preferences.swift */; };
 		D052BBD124D750CA00A80A7A /* AppEnvironment.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBCC24D750A100A80A7A /* AppEnvironment.swift */; };
 		D052BBD224D750CB00A80A7A /* AppEnvironment.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBCC24D750A100A80A7A /* AppEnvironment.swift */; };
+		D052BBE024D805E300A80A7A /* MainNavigationViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBDF24D805E300A80A7A /* MainNavigationViewModel.swift */; };
+		D052BBE124D805E300A80A7A /* MainNavigationViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBDF24D805E300A80A7A /* MainNavigationViewModel.swift */; };
+		D052BBE424D81C4700A80A7A /* CurrentValuePublisher.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBE324D81C4700A80A7A /* CurrentValuePublisher.swift */; };
+		D052BBE524D81C4700A80A7A /* CurrentValuePublisher.swift in Sources */ = {isa = PBXBuildFile; fileRef = D052BBE324D81C4700A80A7A /* CurrentValuePublisher.swift */; };
 		D065F53924D37E5100741304 /* CombineExpectations in Frameworks */ = {isa = PBXBuildFile; productRef = D065F53824D37E5100741304 /* CombineExpectations */; };
 		D065F53B24D3B33A00741304 /* View+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D065F53A24D3B33A00741304 /* View+Extensions.swift */; };
 		D065F53C24D3B33A00741304 /* View+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D065F53A24D3B33A00741304 /* View+Extensions.swift */; };
@@ -71,10 +75,10 @@
 		D0B23F0E24D210E90066F411 /* NSError+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B23F0C24D210E90066F411 /* NSError+Extensions.swift */; };
 		D0B93B3024D55098007AF646 /* Screen.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B93B2F24D55098007AF646 /* Screen.swift */; };
 		D0B93B3124D55098007AF646 /* Screen.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0B93B2F24D55098007AF646 /* Screen.swift */; };
-		D0BEC93824C9632800E864C4 /* SceneViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93724C9632800E864C4 /* SceneViewModel.swift */; };
+		D0BEC93824C9632800E864C4 /* RootViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93724C9632800E864C4 /* RootViewModel.swift */; };
-		D0BEC93924C9632800E864C4 /* SceneViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93724C9632800E864C4 /* SceneViewModel.swift */; };
+		D0BEC93924C9632800E864C4 /* RootViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93724C9632800E864C4 /* RootViewModel.swift */; };
-		D0BEC93B24C96FD500E864C4 /* ContentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93A24C96FD500E864C4 /* ContentView.swift */; };
+		D0BEC93B24C96FD500E864C4 /* RootView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93A24C96FD500E864C4 /* RootView.swift */; };
-		D0BEC93C24C96FD500E864C4 /* ContentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93A24C96FD500E864C4 /* ContentView.swift */; };
+		D0BEC93C24C96FD500E864C4 /* RootView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC93A24C96FD500E864C4 /* RootView.swift */; };
 		D0BEC94724CA22C400E864C4 /* TimelineViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC94624CA22C400E864C4 /* TimelineViewModel.swift */; };
 		D0BEC94824CA22C400E864C4 /* TimelineViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC94624CA22C400E864C4 /* TimelineViewModel.swift */; };
 		D0BEC94A24CA231200E864C4 /* TimelineView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0BEC94924CA231200E864C4 /* TimelineView.swift */; };
@@ -157,10 +161,12 @@
 		D04FD73824D4A7B4007D572D /* AccountEndpoint+Stubbing.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "AccountEndpoint+Stubbing.swift"; sourceTree = "<group>"; };
 		D04FD73B24D4A83A007D572D /* InstanceEndpoint+Stubbing.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "InstanceEndpoint+Stubbing.swift"; sourceTree = "<group>"; };
 		D04FD74124D4AA34007D572D /* DevelopmentModels.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DevelopmentModels.swift; sourceTree = "<group>"; };
-		D052BBC624D749C800A80A7A /* SceneViewModelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SceneViewModelTests.swift; sourceTree = "<group>"; };
+		D052BBC624D749C800A80A7A /* RootViewModelTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RootViewModelTests.swift; sourceTree = "<group>"; };
 		D052BBC824D74B6400A80A7A /* FakeUserDefaults.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FakeUserDefaults.swift; sourceTree = "<group>"; };
 		D052BBCC24D750A100A80A7A /* AppEnvironment.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppEnvironment.swift; sourceTree = "<group>"; };
 		D052BBCE24D750C000A80A7A /* Preferences.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Preferences.swift; sourceTree = "<group>"; };
+		D052BBDF24D805E300A80A7A /* MainNavigationViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MainNavigationViewModel.swift; sourceTree = "<group>"; };
+		D052BBE324D81C4700A80A7A /* CurrentValuePublisher.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CurrentValuePublisher.swift; sourceTree = "<group>"; };
 		D065F53A24D3B33A00741304 /* View+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "View+Extensions.swift"; sourceTree = "<group>"; };
 		D065F53D24D3D20300741304 /* InstanceEndpoint.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = InstanceEndpoint.swift; sourceTree = "<group>"; };
 		D0666A2124C677B400F3F04B /* Tests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = Tests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -182,8 +188,8 @@
 		D081A40424D0F1A8001B016E /* String+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "String+Extensions.swift"; sourceTree = "<group>"; };
 		D0B23F0C24D210E90066F411 /* NSError+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NSError+Extensions.swift"; sourceTree = "<group>"; };
 		D0B93B2F24D55098007AF646 /* Screen.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Screen.swift; sourceTree = "<group>"; };
-		D0BEC93724C9632800E864C4 /* SceneViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SceneViewModel.swift; sourceTree = "<group>"; };
+		D0BEC93724C9632800E864C4 /* RootViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RootViewModel.swift; sourceTree = "<group>"; };
-		D0BEC93A24C96FD500E864C4 /* ContentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContentView.swift; sourceTree = "<group>"; };
+		D0BEC93A24C96FD500E864C4 /* RootView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = RootView.swift; sourceTree = "<group>"; };
 		D0BEC94624CA22C400E864C4 /* TimelineViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineViewModel.swift; sourceTree = "<group>"; };
 		D0BEC94924CA231200E864C4 /* TimelineView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TimelineView.swift; sourceTree = "<group>"; };
 		D0BEC94E24CA2B5300E864C4 /* SidebarNavigation.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SidebarNavigation.swift; sourceTree = "<group>"; };
@@ -269,6 +275,7 @@
 				D047FA8524C3E21000AF17C5 /* MetatextApp.swift */,
 				D0666A3A24C6B56200F3F04B /* Model */,
 				D0DB6EFA24C5730600D965FE /* Networking */,
+				D052BBE224D81C2300A80A7A /* Publishers */,
 				D0DB6EFB24C658E400D965FE /* View Models */,
 				D0DB6EF024C5224F00D965FE /* Views */,
 			);
@@ -304,6 +311,14 @@
 			path = macOS;
 			sourceTree = "<group>";
 		};
+		D052BBE224D81C2300A80A7A /* Publishers */ = {
+			isa = PBXGroup;
+			children = (
+				D052BBE324D81C4700A80A7A /* CurrentValuePublisher.swift */,
+			);
+			path = Publishers;
+			sourceTree = "<group>";
+		};
 		D0666A2224C677B400F3F04B /* Tests */ = {
 			isa = PBXGroup;
 			children = (
@@ -354,7 +369,7 @@
 			isa = PBXGroup;
 			children = (
 				D0DB6EF324C5228A00D965FE /* AddIdentityView.swift */,
-				D0BEC93A24C96FD500E864C4 /* ContentView.swift */,
+				D0BEC93A24C96FD500E864C4 /* RootView.swift */,
 				D0B93B2F24D55098007AF646 /* Screen.swift */,
 				D04FD73224D48F37007D572D /* SettingsView.swift */,
 				D0BEC94924CA231200E864C4 /* TimelineView.swift */,
@@ -379,7 +394,8 @@
 			isa = PBXGroup;
 			children = (
 				D0DB6F0824C65AC000D965FE /* AddIdentityViewModel.swift */,
-				D0BEC93724C9632800E864C4 /* SceneViewModel.swift */,
+				D052BBDF24D805E300A80A7A /* MainNavigationViewModel.swift */,
+				D0BEC93724C9632800E864C4 /* RootViewModel.swift */,
 				D04FD73524D49506007D572D /* SettingsViewModel.swift */,
 				D0BEC94624CA22C400E864C4 /* TimelineViewModel.swift */,
 			);
@@ -413,7 +429,7 @@
 			isa = PBXGroup;
 			children = (
 				D0ED1B6D24CE100C00B4899C /* AddIdentityViewModelTests.swift */,
-				D052BBC624D749C800A80A7A /* SceneViewModelTests.swift */,
+				D052BBC624D749C800A80A7A /* RootViewModelTests.swift */,
 			);
 			path = "View Models";
 			sourceTree = "<group>";
@@ -656,8 +672,9 @@
 				D0ED1BE024CF98FB00B4899C /* AccountEndpoint.swift in Sources */,
 				D0B93B3024D55098007AF646 /* Screen.swift in Sources */,
 				D052BBD224D750CB00A80A7A /* AppEnvironment.swift in Sources */,
+				D052BBE424D81C4700A80A7A /* CurrentValuePublisher.swift in Sources */,
 				D081A40524D0F1A8001B016E /* String+Extensions.swift in Sources */,
-				D0BEC93824C9632800E864C4 /* SceneViewModel.swift in Sources */,
+				D0BEC93824C9632800E864C4 /* RootViewModel.swift in Sources */,
 				D0ED1BC124CED48800B4899C /* HTTPClient.swift in Sources */,
 				D0666A4524C6BC0A00F3F04B /* DatabaseError.swift in Sources */,
 				D0ED1BDD24CF982600B4899C /* AccessTokenEndpoint.swift in Sources */,
@@ -669,7 +686,7 @@
 				D0DC175224D008E300A75C65 /* MastodonTarget+Stubbing.swift in Sources */,
 				D0666A4224C6BB7B00F3F04B /* IdentityDatabase.swift in Sources */,
 				D0BEC94A24CA231200E864C4 /* TimelineView.swift in Sources */,
-				D0BEC93B24C96FD500E864C4 /* ContentView.swift in Sources */,
+				D0BEC93B24C96FD500E864C4 /* RootView.swift in Sources */,
 				D04FD73624D49506007D572D /* SettingsViewModel.swift in Sources */,
 				D04FD74224D4AA34007D572D /* DevelopmentModels.swift in Sources */,
 				D0DC175824D0130800A75C65 /* HTTPStubs.swift in Sources */,
@@ -694,6 +711,7 @@
 				D065F53E24D3D20300741304 /* InstanceEndpoint.swift in Sources */,
 				D0666A6F24C6DFB300F3F04B /* AccessToken.swift in Sources */,
 				D0ED1BCB24CF744200B4899C /* MastodonClient.swift in Sources */,
+				D052BBE024D805E300A80A7A /* MainNavigationViewModel.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -719,8 +737,9 @@
 				D0ED1BE124CF98FB00B4899C /* AccountEndpoint.swift in Sources */,
 				D0B93B3124D55098007AF646 /* Screen.swift in Sources */,
 				D052BBD124D750CA00A80A7A /* AppEnvironment.swift in Sources */,
+				D052BBE524D81C4700A80A7A /* CurrentValuePublisher.swift in Sources */,
 				D081A40624D0F1A8001B016E /* String+Extensions.swift in Sources */,
-				D0BEC93924C9632800E864C4 /* SceneViewModel.swift in Sources */,
+				D0BEC93924C9632800E864C4 /* RootViewModel.swift in Sources */,
 				D0ED1BC224CED48800B4899C /* HTTPClient.swift in Sources */,
 				D0666A4624C6BC0A00F3F04B /* DatabaseError.swift in Sources */,
 				D0ED1BDE24CF982600B4899C /* AccessTokenEndpoint.swift in Sources */,
@@ -732,7 +751,7 @@
 				D0DC175324D008E300A75C65 /* MastodonTarget+Stubbing.swift in Sources */,
 				D0666A4324C6BB7B00F3F04B /* IdentityDatabase.swift in Sources */,
 				D0BEC94B24CA231200E864C4 /* TimelineView.swift in Sources */,
-				D0BEC93C24C96FD500E864C4 /* ContentView.swift in Sources */,
+				D0BEC93C24C96FD500E864C4 /* RootView.swift in Sources */,
 				D04FD73724D49506007D572D /* SettingsViewModel.swift in Sources */,
 				D04FD74324D4AA34007D572D /* DevelopmentModels.swift in Sources */,
 				D0DC175924D0130800A75C65 /* HTTPStubs.swift in Sources */,
@@ -757,6 +776,7 @@
 				D065F53F24D3D20300741304 /* InstanceEndpoint.swift in Sources */,
 				D0666A7024C6DFB300F3F04B /* AccessToken.swift in Sources */,
 				D0ED1BCC24CF744200B4899C /* MastodonClient.swift in Sources */,
+				D052BBE124D805E300A80A7A /* MainNavigationViewModel.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -765,7 +785,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				D0ED1B6E24CE100C00B4899C /* AddIdentityViewModelTests.swift in Sources */,
-				D052BBC724D749C800A80A7A /* SceneViewModelTests.swift in Sources */,
+				D052BBC724D749C800A80A7A /* RootViewModelTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

Shared/MetatextApp.swift

@@ -16,6 +16,7 @@ struct MetatextApp: App {
         }
 
         environment = AppEnvironment(
+            URLSessionConfiguration: .default,
             identityDatabase: identityDatabase,
             preferences: Preferences(userDefaults: .standard),
             secrets: Secrets(keychain: Keychain(service: "com.metabolist.metatext")),
@@ -24,11 +25,7 @@ struct MetatextApp: App {
 
     var body: some Scene {
         WindowGroup {
-            ContentView()
+            RootView(viewModel: RootViewModel(environment: environment))
-                .environmentObject(
-                    SceneViewModel(
-                        networkClient: MastodonClient(),
-                        environment: environment))
         }
     }
 }

Shared/Model/AppEnvironment.swift

@@ -3,6 +3,7 @@
 import Foundation
 
 struct AppEnvironment {
+    let URLSessionConfiguration: URLSessionConfiguration
     let identityDatabase: IdentityDatabase
     let preferences: Preferences
     let secrets: Secrets

Shared/Model/Identity.swift

@@ -37,4 +37,6 @@ extension Identity {
 
         return instance?.title ?? url.host ?? url.absoluteString
     }
+
+    var image: URL? { account?.avatar ?? instance?.thumbnail }
 }

Shared/Model/IdentityDatabase.swift

@@ -4,6 +4,10 @@ import Foundation
 import Combine
 import GRDB
 
+enum IdentityDatabaseError: Error {
+    case identityNotFound
+}
+
 struct IdentityDatabase {
     private let databaseQueue: DatabaseQueue
 
@@ -61,7 +65,7 @@ extension IdentityDatabase {
             .eraseToAnyPublisher()
     }
 
-    func identityObservation(id: String) -> AnyPublisher<Identity?, Error> {
+    func identityObservation(id: String) -> AnyPublisher<Identity, Error> {
         ValueObservation.tracking(
             StoredIdentity
                 .filter(Column("id") == id)
@@ -71,8 +75,8 @@ extension IdentityDatabase {
                 .fetchOne)
             .removeDuplicates()
             .publisher(in: databaseQueue, scheduling: .immediate)
-            .map {
+            .tryMap {
-                guard let result = $0 else { return nil }
+                guard let result = $0 else { throw IdentityDatabaseError.identityNotFound }
 
                 return Identity(result: result)
             }

Shared/Networking/HTTPClient.swift

@@ -8,9 +8,7 @@ class HTTPClient {
     private let session: Session
     private let decoder: DataDecoder
 
-    init(
+    init(configuration: URLSessionConfiguration, decoder: DataDecoder = JSONDecoder()) {
-        configuration: URLSessionConfiguration = URLSessionConfiguration.af.default,
-        decoder: DataDecoder = JSONDecoder()) {
         self.session = Session(configuration: configuration)
         self.decoder = decoder
     }

Shared/Publishers/CurrentValuePublisher.swift

@@ -0,0 +1,24 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Combine
+
+// This publisher acts as a `@Published private var` inside ObservableObjects that doesn't trigger `objectWillChange`
+
+class CurrentValuePublisher<Output> {
+    @Published private(set) var value: Output
+    private let internalPublisher: AnyPublisher<Output, Never>
+
+    init<P>(initial: Output, then: P) where P: Publisher, P.Output == Output, P.Failure == Never {
+        value = initial
+        internalPublisher = then.eraseToAnyPublisher()
+        then.assign(to: &$value)
+    }
+}
+
+extension CurrentValuePublisher: Publisher {
+    typealias Failure = Never
+
+    func receive<S>(subscriber: S) where S: Subscriber, Output == S.Input, S.Failure == Never {
+        internalPublisher.receive(subscriber: subscriber)
+    }
+}

Shared/View Models/AddIdentityViewModel.swift

@@ -7,15 +7,18 @@ class AddIdentityViewModel: ObservableObject {
     @Published var urlFieldText = ""
     @Published var alertItem: AlertItem?
     @Published private(set) var loading = false
-    @Published private(set) var addedIdentityID: String?
+    let addedIdentityID: AnyPublisher<String, Never>
 
-    private let networkClient: HTTPClient
     private let environment: AppEnvironment
+    private let networkClient: MastodonClient
     private let webAuthSessionContextProvider = WebAuthSessionContextProvider()
+    private let addedIdentityIDInput = PassthroughSubject<String, Never>()
+    private var cancellables = Set<AnyCancellable>()
 
-    init(networkClient: HTTPClient, environment: AppEnvironment) {
+    init(environment: AppEnvironment) {
-        self.networkClient = networkClient
         self.environment = environment
+        self.networkClient = MastodonClient(configuration: environment.URLSessionConfiguration)
+        addedIdentityID = addedIdentityIDInput.eraseToAnyPublisher()
     }
 
     func goTapped() {
@@ -54,8 +57,8 @@ class AddIdentityViewModel: ObservableObject {
             .handleEvents(
                 receiveSubscription: { [weak self] _ in self?.loading = true },
                 receiveCompletion: { [weak self] _ in self?.loading = false  })
-            .map { $0 as String? }
+            .sink(receiveValue: addedIdentityIDInput.send)
-            .assign(to: &$addedIdentityID)
+            .store(in: &cancellables)
     }
 }
 

Shared/View Models/MainNavigationViewModel.swift

@@ -0,0 +1,96 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import Combine
+
+class MainNavigationViewModel: ObservableObject {
+    var selectedTab: Tab? = .timelines
+    @Published var presentingSettings = false
+    @Published private(set) var alertItem: AlertItem?
+    @Published private(set) var handle: String
+    @Published private(set) var image: URL?
+
+    private let environment: AppEnvironment
+    private let identity: CurrentValuePublisher<Identity>
+    private let networkClient: MastodonClient
+    private var cancellables = Set<AnyCancellable>()
+
+    init(identity: CurrentValuePublisher<Identity>, environment: AppEnvironment) {
+        self.identity = identity
+        self.environment = environment
+        networkClient = MastodonClient(configuration: environment.URLSessionConfiguration)
+
+        networkClient.instanceURL = identity.value.url
+
+        do {
+            networkClient.accessToken = try environment.secrets.item(.accessToken, forIdentityID: identity.value.id)
+        } catch {
+            alertItem = AlertItem(error: error)
+        }
+
+        handle = identity.value.handle
+        identity.map(\.handle).assign(to: &$handle)
+
+        image = identity.value.image
+        identity.map(\.image).assign(to: &$image)
+    }
+}
+
+extension MainNavigationViewModel {
+    func refreshIdentity() {
+        let id = identity.value.id
+
+        if networkClient.accessToken != nil {
+            networkClient.request(AccountEndpoint.verifyCredentials)
+                .map { ($0, id) }
+                .flatMap(environment.identityDatabase.updateAccount)
+                .assignErrorsToAlertItem(to: \.alertItem, on: self)
+                .sink(receiveValue: {})
+                .store(in: &cancellables)
+        }
+
+        networkClient.request(InstanceEndpoint.instance)
+            .map { ($0, id) }
+            .flatMap(environment.identityDatabase.updateInstance)
+            .assignErrorsToAlertItem(to: \.alertItem, on: self)
+            .sink(receiveValue: {})
+            .store(in: &cancellables)
+    }
+
+    func settingsViewModel() -> SettingsViewModel {
+        SettingsViewModel(identity: identity, environment: environment)
+    }
+}
+
+extension MainNavigationViewModel {
+    enum Tab: CaseIterable {
+        case timelines
+        case search
+        case notifications
+        case messages
+    }
+}
+
+extension MainNavigationViewModel.Tab {
+    var title: String {
+        switch self {
+        case .timelines: return "Timelines"
+        case .search: return "Search"
+        case .notifications: return "Notifications"
+        case .messages: return "Messages"
+        }
+    }
+
+    var systemImageName: String {
+        switch self {
+        case .timelines: return "house"
+        case .search: return "magnifyingglass"
+        case .notifications: return "bell"
+        case .messages: return "envelope"
+        }
+    }
+}
+
+extension MainNavigationViewModel.Tab: Identifiable {
+    var id: Self { self }
+}

Shared/View Models/RootViewModel.swift

@@ -0,0 +1,52 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+import Combine
+
+class RootViewModel: ObservableObject {
+    @Published private(set) var identityID: String?
+    @Published var alertItem: AlertItem?
+
+    private let environment: AppEnvironment
+    private var cancellables = Set<AnyCancellable>()
+
+    init(environment: AppEnvironment) {
+        self.environment = environment
+        identityID = environment.preferences[.recentIdentityID]
+    }
+}
+
+extension RootViewModel {
+    func addIdentityViewModel() -> AddIdentityViewModel {
+        let addAccountViewModel = AddIdentityViewModel(environment: environment)
+
+        addAccountViewModel.addedIdentityID.map { $0 as String? }.assign(to: &$identityID)
+
+        return addAccountViewModel
+    }
+
+    func mainNavigationViewModel(identityID: String) -> MainNavigationViewModel? {
+        environment.preferences[.recentIdentityID] = identityID
+
+        let identityObservation = environment.identityDatabase.identityObservation(id: identityID)
+            .share()
+        var initialIdentity: Identity?
+
+        // setting `initialIdentity` works because of immediate scheduling
+        identityObservation.sink(receiveCompletion: { _ in }, receiveValue: { initialIdentity = $0 })
+            .store(in: &cancellables)
+        identityObservation.map { $0.id }
+            .catch { [weak self] _ -> AnyPublisher<String?, Never> in
+                Just(self?.environment.preferences[.recentIdentityID]).eraseToAnyPublisher()
+            }
+            .assign(to: &$identityID)
+
+        guard let presentIdentity = initialIdentity else { return nil }
+
+        return MainNavigationViewModel(
+            identity: CurrentValuePublisher(
+                initial: presentIdentity,
+                then: identityObservation.assignErrorsToAlertItem(to: \.alertItem, on: self)),
+            environment: environment)
+    }
+}

Shared/View Models/SceneViewModel.swift

@@ -1,112 +0,0 @@
-// Copyright © 2020 Metabolist. All rights reserved.
-
-import Foundation
-import Combine
-
-class SceneViewModel: ObservableObject {
-    @Published private(set) var identity: Identity?
-    @Published var alertItem: AlertItem?
-    @Published var presentingSettings = false
-    var selectedTopLevelNavigation: TopLevelNavigation? = .timelines
-
-    private let networkClient: MastodonClient
-    private let environment: AppEnvironment
-    private var cancellables = Set<AnyCancellable>()
-
-    init(networkClient: MastodonClient, environment: AppEnvironment) {
-        self.networkClient = networkClient
-        self.environment = environment
-
-        if let recentIdentityID = environment.preferences[.recentIdentityID] as String? {
-            changeIdentity(id: recentIdentityID)
-        }
-    }
-}
-
-extension SceneViewModel {
-    func refreshIdentity() {
-        guard let identity = identity else { return }
-
-        if networkClient.accessToken != nil {
-            networkClient.request(AccountEndpoint.verifyCredentials)
-                .map { ($0, identity.id) }
-                .flatMap(environment.identityDatabase.updateAccount)
-                .assignErrorsToAlertItem(to: \.alertItem, on: self)
-                .sink(receiveValue: {})
-                .store(in: &cancellables)
-        }
-
-        networkClient.request(InstanceEndpoint.instance)
-            .map { ($0, identity.id) }
-            .flatMap(environment.identityDatabase.updateInstance)
-            .assignErrorsToAlertItem(to: \.alertItem, on: self)
-            .sink(receiveValue: {})
-            .store(in: &cancellables)
-    }
-
-    func addIdentityViewModel() -> AddIdentityViewModel {
-        let addAccountViewModel = AddIdentityViewModel(networkClient: networkClient, environment: environment)
-
-        addAccountViewModel.$addedIdentityID
-            .compactMap { $0 }
-            .sink(receiveValue: changeIdentity(id:))
-            .store(in: &cancellables)
-
-        return addAccountViewModel
-    }
-}
-
-private extension SceneViewModel {
-    private func changeIdentity(id: String) {
-        environment.identityDatabase.identityObservation(id: id)
-            .assignErrorsToAlertItem(to: \.alertItem, on: self)
-            .handleEvents(receiveOutput: { [weak self] in
-                guard let self = self, let identity = $0 else { return }
-
-                self.networkClient.instanceURL = identity.url
-
-                do {
-                    self.networkClient.accessToken =
-                        try self.environment.secrets.item(.accessToken, forIdentityID: identity.id)
-                } catch {
-                    self.alertItem = AlertItem(error: error)
-                }
-            })
-            .assign(to: &$identity)
-
-        refreshIdentity()
-    }
-}
-
-extension SceneViewModel {
-    enum TopLevelNavigation: CaseIterable {
-        case timelines
-        case search
-        case notifications
-        case messages
-    }
-}
-
-extension SceneViewModel.TopLevelNavigation {
-    var title: String {
-        switch self {
-        case .timelines: return "Timelines"
-        case .search: return "Search"
-        case .notifications: return "Notifications"
-        case .messages: return "Messages"
-        }
-    }
-
-    var systemImageName: String {
-        switch self {
-        case .timelines: return "house"
-        case .search: return "magnifyingglass"
-        case .notifications: return "bell"
-        case .messages: return "envelope"
-        }
-    }
-}
-
-extension SceneViewModel.TopLevelNavigation: Identifiable {
-    var id: Self { self }
-}

Shared/View Models/SettingsViewModel.swift

@@ -3,9 +3,11 @@
 import Foundation
 
 class SettingsViewModel: ObservableObject {
-    let identity: Identity
+    private let identity: CurrentValuePublisher<Identity>
+    private let environment: AppEnvironment
 
-    init(identity: Identity) {
+    init(identity: CurrentValuePublisher<Identity>, environment: AppEnvironment) {
         self.identity = identity
+        self.environment = environment
     }
 }

Shared/Views/AddIdentityView.swift

@@ -7,14 +7,14 @@ struct AddIdentityView: View {
 
     var body: some View {
         Form {
+            #if os(macOS)
             Spacer()
-            #if os(iOS)
+            urlTextField
+            #else
             urlTextField
                 .autocapitalization(.none)
                 .disableAutocorrection(true)
                 .keyboardType(.URL)
-            #else
-            urlTextField
             #endif
             Group {
                 if viewModel.loading {
@@ -26,9 +26,11 @@ struct AddIdentityView: View {
                 }
             }
             .frame(maxWidth: .infinity, alignment: .center)
+            #if os(macOS)
             Spacer()
+            #endif
         }
-        .padding()
+        .paddingIfMac()
         .alertItem($viewModel.alertItem)
     }
 }
@@ -39,12 +41,20 @@ extension AddIdentityView {
     }
 }
 
+private extension View {
+    func paddingIfMac() -> some View {
+        #if os(macOS)
+        return padding()
+        #else
+        return self
+        #endif
+    }
+}
+
 #if DEBUG
 struct AddAccountView_Previews: PreviewProvider {
     static var previews: some View {
-        AddIdentityView(viewModel: AddIdentityViewModel(
+        AddIdentityView(viewModel: AddIdentityViewModel(environment: .development))
-                            networkClient: MastodonClient.development,
-                            environment: .development))
     }
 }
 #endif

Shared/Views/ContentView.swift

@@ -2,7 +2,7 @@
 
 import SwiftUI
 
-struct ContentView: View {
+struct RootView: View {
     @EnvironmentObject var sceneViewModel: SceneViewModel
     @Environment(\.scenePhase) private var scenePhase
 
@@ -21,7 +21,7 @@ struct ContentView: View {
     }
 }
 
-private extension ContentView {
+private extension RootView {
     private func mainNavigation(identity: Identity) -> some View {
         #if os(macOS)
         return SidebarNavigation(identity: identity)
@@ -39,7 +39,7 @@ private extension ContentView {
 #if DEBUG
 struct ContentView_Previews: PreviewProvider {
     static var previews: some View {
-        ContentView()
+        RootView()
             .environmentObject(SceneViewModel.development)
     }
 }

Shared/Views/RootView.swift

@@ -0,0 +1,40 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import SwiftUI
+
+struct RootView: View {
+    @StateObject var viewModel: RootViewModel
+
+    var body: some View {
+        if
+            let identityID = viewModel.identityID,
+            let mainNavigationViewModel = viewModel.mainNavigationViewModel(identityID: identityID) {
+            Self.mainNavigation(viewModel: mainNavigationViewModel)
+        } else {
+            addIdentity
+        }
+    }
+}
+
+private extension RootView {
+    private static func mainNavigation(viewModel: MainNavigationViewModel) -> some View {
+        #if os(macOS)
+        return SidebarNavigation().environmentObject(viewModel)
+            .frame(minWidth: 900, maxWidth: .infinity, minHeight: 500, maxHeight: .infinity)
+        #else
+        return TabNavigation().environmentObject(viewModel)
+        #endif
+    }
+
+    private var addIdentity: some View {
+        AddIdentityView(viewModel: viewModel.addIdentityViewModel())
+    }
+}
+
+#if DEBUG
+struct ContentView_Previews: PreviewProvider {
+    static var previews: some View {
+        RootView(viewModel: .development)
+    }
+}
+#endif

Shared/Views/SettingsView.swift

@@ -3,38 +3,37 @@
 import SwiftUI
 import KingfisherSwiftUI
 import struct Kingfisher.DownsamplingImageProcessor
-import struct Kingfisher.RoundCornerImageProcessor
 
 struct SettingsView: View {
     @StateObject var viewModel: SettingsViewModel
-    @EnvironmentObject var sceneViewModel: SceneViewModel
+    @EnvironmentObject var mainNavigationViewModel: MainNavigationViewModel
 
     var body: some View {
         VStack(spacing: 0) {
             NavigationView {
                 Form {
                     HStack {
-                        KFImage(viewModel.identity.account?.avatar,
+                        KFImage(mainNavigationViewModel.image,
                                 options: [
                                     .processor(
                                         DownsamplingImageProcessor(size: CGSize(width: 50, height: 50))
-                                            .append(another: RoundCornerImageProcessor(radius: .widthFraction(0.5)))
                                     ),
                                     .scaleFactor(Screen.scale),
                                     .cacheOriginalImage
                                 ])
-                        Text(viewModel.identity.handle)
+                            .clipShape(Circle())
+                        Text(mainNavigationViewModel.handle)
                             .font(.subheadline)
                     }
                 }
-                .navigationBarTitleAndItems(sceneViewModel: sceneViewModel)
+                .navigationBarTitleAndItems(mainNavigationViewModel: mainNavigationViewModel)
             }
             .navigationViewStyle
             #if os(macOS)
             Divider()
             HStack {
                 Spacer()
-                Button(action: { sceneViewModel.presentingSettings.toggle() }) {
+                Button(action: { mainNavigationViewModel.presentingSettings.toggle() }) {
                     Text("Done")
                 }
                 .keyboardShortcut(.defaultAction)
@@ -48,12 +47,12 @@ struct SettingsView: View {
 }
 
 private extension View {
-    func navigationBarTitleAndItems(sceneViewModel: SceneViewModel) -> some View {
+    func navigationBarTitleAndItems(mainNavigationViewModel: MainNavigationViewModel) -> some View {
         #if os(iOS)
         return navigationBarTitle(Text("settings"), displayMode: .inline)
         .navigationBarItems(
             leading: Button {
-                sceneViewModel.presentingSettings.toggle()
+                mainNavigationViewModel.presentingSettings.toggle()
             } label: {
                 Image(systemName: "xmark.circle.fill").imageScale(.large)
             })
@@ -82,8 +81,8 @@ private extension View {
 #if DEBUG
 struct SettingsView_Previews: PreviewProvider {
     static var previews: some View {
-        SettingsView(viewModel: SettingsViewModel(identity: .development))
+        SettingsView(viewModel: .development)
-            .environmentObject(SceneViewModel.development)
+            .environmentObject(MainNavigationViewModel.development)
     }
 }
 #endif

Tests/View Models/AddIdentityViewModelTests.swift

@@ -8,16 +8,15 @@ import CombineExpectations
 class AddIdentityViewModelTests: XCTestCase {
     func testAddIdentity() throws {
         let environment = AppEnvironment.fresh()
-        let sut = AddIdentityViewModel(networkClient: MastodonClient.fresh(), environment: environment)
+        let sut = AddIdentityViewModel(environment: environment)
-        let addedIDRecorder = sut.$addedIdentityID.record()
+        let addedIDRecorder = sut.addedIdentityID.record()
-        XCTAssertNil(try wait(for: addedIDRecorder.next(), timeout: 1))
 
         sut.urlFieldText = "https://mastodon.social"
         sut.goTapped()
 
-        let addedIdentityID = try wait(for: addedIDRecorder.next(), timeout: 1)!
+        let addedIdentityID = try wait(for: addedIDRecorder.next(), timeout: 1)
         let identityRecorder = environment.identityDatabase.identityObservation(id: addedIdentityID).record()
-        let addedIdentity = try wait(for: identityRecorder.next(), timeout: 1)!
+        let addedIdentity = try wait(for: identityRecorder.next(), timeout: 1)
 
         XCTAssertEqual(addedIdentity.id, addedIdentityID)
         XCTAssertEqual(addedIdentity.url, URL(string: "https://mastodon.social")!)
@@ -35,22 +34,21 @@ class AddIdentityViewModelTests: XCTestCase {
 
     func testAddIdentityWithoutScheme() throws {
         let environment = AppEnvironment.fresh()
-        let sut = AddIdentityViewModel(networkClient: MastodonClient.fresh(), environment: environment)
+        let sut = AddIdentityViewModel(environment: environment)
-        let addedIDRecorder = sut.$addedIdentityID.record()
+        let addedIDRecorder = sut.addedIdentityID.record()
-        XCTAssertNil(try wait(for: addedIDRecorder.next(), timeout: 1))
 
         sut.urlFieldText = "mastodon.social"
         sut.goTapped()
 
-        let addedIdentityID = try wait(for: addedIDRecorder.next(), timeout: 1)!
+        let addedIdentityID = try wait(for: addedIDRecorder.next(), timeout: 1)
         let identityRecorder = environment.identityDatabase.identityObservation(id: addedIdentityID).record()
-        let addedIdentity = try wait(for: identityRecorder.next(), timeout: 1)!
+        let addedIdentity = try wait(for: identityRecorder.next(), timeout: 1)
 
         XCTAssertEqual(addedIdentity.url, URL(string: "https://mastodon.social")!)
     }
 
     func testInvalidURL() throws {
-        let sut = AddIdentityViewModel(networkClient: MastodonClient.fresh(), environment: .fresh())
+        let sut = AddIdentityViewModel(environment: .fresh())
         let recorder = sut.$alertItem.record()
 
         XCTAssertNil(try wait(for: recorder.next(), timeout: 1))
@@ -65,7 +63,7 @@ class AddIdentityViewModelTests: XCTestCase {
 
     func testDoesNotAlertCanceledLogin() throws {
         let environment = AppEnvironment.fresh(webAuthSessionType: CanceledLoginStubbingWebAuthSession.self)
-        let sut = AddIdentityViewModel(networkClient: MastodonClient.fresh(), environment: environment)
+        let sut = AddIdentityViewModel(environment: environment)
         let recorder = sut.$alertItem.record()
 
         XCTAssertNil(try wait(for: recorder.next(), timeout: 1))

Tests/View Models/RootViewModelTests.swift

@@ -0,0 +1,24 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import XCTest
+import Combine
+import CombineExpectations
+@testable import Metatext
+
+class RootViewModelTests: XCTestCase {
+    func testAddIdentity() throws {
+        let sut = RootViewModel(environment: .fresh())
+        let identityIDRecorder = sut.$identityID.record()
+
+        XCTAssertNil(try wait(for: identityIDRecorder.next(), timeout: 1))
+
+        let addIdentityViewModel = sut.addIdentityViewModel()
+
+        addIdentityViewModel.urlFieldText = "https://mastodon.social"
+        addIdentityViewModel.goTapped()
+
+        let identityID = try wait(for: identityIDRecorder.next(), timeout: 1)!
+
+        XCTAssertNotNil(identityID)
+    }
+}

Tests/View Models/SceneViewModelTests.swift

@@ -1,24 +0,0 @@
-// Copyright © 2020 Metabolist. All rights reserved.
-
-import XCTest
-import Combine
-import CombineExpectations
-@testable import Metatext
-
-class SceneViewModelTests: XCTestCase {
-    func testAddIdentity() throws {
-        let sut = SceneViewModel(networkClient: .fresh(), environment: .fresh())
-        let identityRecorder = sut.$identity.record()
-
-        XCTAssertNil(try wait(for: identityRecorder.next(), timeout: 1))
-
-        let addIdentityViewModel = sut.addIdentityViewModel()
-
-        addIdentityViewModel.urlFieldText = "https://mastodon.social"
-        addIdentityViewModel.goTapped()
-
-        let identity = try wait(for: identityRecorder.next(), timeout: 1)!
-
-        XCTAssertEqual(identity.id, addIdentityViewModel.addedIdentityID)
-    }
-}

iOS/TabNavigation.swift

@@ -3,70 +3,66 @@
 import SwiftUI
 import KingfisherSwiftUI
 import struct Kingfisher.DownsamplingImageProcessor
-import struct Kingfisher.RoundCornerImageProcessor
 
 struct TabNavigation: View {
-    let identity: Identity
+    @EnvironmentObject var viewModel: MainNavigationViewModel
-    @EnvironmentObject var sceneViewModel: SceneViewModel
 
     var body: some View {
-        TabView(selection: $sceneViewModel.selectedTopLevelNavigation) {
+        TabView(selection: $viewModel.selectedTab) {
-            ForEach(SceneViewModel.TopLevelNavigation.allCases) { topLevelNavigation in
+            ForEach(MainNavigationViewModel.Tab.allCases) { tab in
                 NavigationView {
-                    view(topLevelNavigation: topLevelNavigation)
+                    view(tab: tab)
                 }
                 .navigationViewStyle(StackNavigationViewStyle())
                 .tabItem {
-                    Label(topLevelNavigation.title, systemImage: topLevelNavigation.systemImageName)
+                    Label(tab.title, systemImage: tab.systemImageName)
-                        .accessibility(label: Text(topLevelNavigation.title))
+                        .accessibility(label: Text(tab.title))
                 }
-                .tag(topLevelNavigation)
+                .tag(tab)
             }
         }
-        .sheet(isPresented: $sceneViewModel.presentingSettings) {
+        .sheet(isPresented: $viewModel.presentingSettings) {
-            SettingsView(viewModel: SettingsViewModel(identity: identity))
+            SettingsView(viewModel: viewModel.settingsViewModel())
-                .environmentObject(sceneViewModel)
+                .environmentObject(viewModel)
         }
+        .onAppear { viewModel.refreshIdentity() }
     }
 }
 
 private extension TabNavigation {
-    func view(topLevelNavigation: SceneViewModel.TopLevelNavigation) -> some View {
+    func view(tab: MainNavigationViewModel.Tab) -> some View {
         Group {
-            switch topLevelNavigation {
+            switch tab {
             case .timelines:
                 TimelineView()
-                    .navigationBarTitle(identity.handle, displayMode: .inline)
+                    .navigationBarTitle(viewModel.handle, displayMode: .inline)
                     .navigationBarItems(
                         leading: Button {
-                            sceneViewModel.presentingSettings.toggle()
+                            viewModel.presentingSettings.toggle()
                         } label: {
-                            KFImage(identity.account?.avatar
+                            KFImage(viewModel.image,
-                                        ?? identity.instance?.thumbnail,
                                     options: [
                                         .processor(
                                             DownsamplingImageProcessor(size: CGSize(width: 28, height: 28))
-                                                .append(another: RoundCornerImageProcessor(radius: .widthFraction(0.5)))
                                         ),
                                         .scaleFactor(Screen.scale),
                                         .cacheOriginalImage
                                     ])
                                 .placeholder { Image(systemName: "gear") }
                                 .renderingMode(.original)
+                                .clipShape(Circle())
                         })
-            default: Text(topLevelNavigation.title)
+            default: Text(tab.title)
             }
         }
     }
 }
 
-// MARK: Preview
-
 #if DEBUG
 struct TabNavigation_Previews: PreviewProvider {
     static var previews: some View {
-        TabNavigation(identity: .development)
+        TabNavigation()
-            .environmentObject(SceneViewModel.development)
+            .environmentObject(MainNavigationViewModel.development)
     }
 }
 #endif

macOS/SidebarNavigation.swift

@@ -6,20 +6,19 @@ import struct Kingfisher.DownsamplingImageProcessor
 import struct Kingfisher.RoundCornerImageProcessor
 
 struct SidebarNavigation: View {
-    let identity: Identity
+    @EnvironmentObject var viewModel: MainNavigationViewModel
-    @EnvironmentObject var sceneViewModel: SceneViewModel
 
     var sidebar: some View {
-        List(selection: $sceneViewModel.selectedTopLevelNavigation) {
+        List(selection: $viewModel.selectedTab) {
-            ForEach(SceneViewModel.TopLevelNavigation.allCases) { topLevelNavigation in
+            ForEach(MainNavigationViewModel.Tab.allCases) { tab in
-                NavigationLink(destination: view(topLevelNavigation: topLevelNavigation)) {
+                NavigationLink(destination: view(topLevelNavigation: tab)) {
-                    Label(topLevelNavigation.title, systemImage: topLevelNavigation.systemImageName)
+                    Label(tab.title, systemImage: tab.systemImageName)
                 }
-                .accessibility(label: Text(topLevelNavigation.title))
+                .accessibility(label: Text(tab.title))
-                .tag(topLevelNavigation)
+                .tag(tab)
             }
         }
-        .overlay(Pocket(identity: identity), alignment: .bottom)
+        .overlay(Pocket(), alignment: .bottom)
         .listStyle(SidebarListStyle())
     }
 
@@ -34,7 +33,7 @@ struct SidebarNavigation: View {
 }
 
 private extension SidebarNavigation {
-    func view(topLevelNavigation: SceneViewModel.TopLevelNavigation) -> some View {
+    func view(topLevelNavigation: MainNavigationViewModel.Tab) -> some View {
         Group {
             switch topLevelNavigation {
             case .timelines:
@@ -45,15 +44,13 @@ private extension SidebarNavigation {
     }
 
     struct Pocket: View {
-        let identity: Identity
+        @EnvironmentObject var viewModel: MainNavigationViewModel
-        @EnvironmentObject var sceneViewModel: SceneViewModel
 
         var body: some View {
             VStack(alignment: .leading, spacing: 0) {
                 Divider()
-                Button(action: { sceneViewModel.presentingSettings.toggle() }) {
+                Button(action: { viewModel.presentingSettings.toggle() }) {
-                    KFImage(identity.account?.avatar
+                    KFImage(viewModel.image,
-                                ?? identity.instance?.thumbnail,
                             options: [
                                 .processor(
                                     DownsamplingImageProcessor(size: CGSize(width: 50, height: 50))
@@ -74,9 +71,9 @@ private extension SidebarNavigation {
                 .padding(.horizontal, 16)
                 .buttonStyle(PlainButtonStyle())
             }
-            .sheet(isPresented: $sceneViewModel.presentingSettings) {
+            .sheet(isPresented: $viewModel.presentingSettings) {
-                SettingsView(viewModel: SettingsViewModel(identity: identity))
+                SettingsView(viewModel: viewModel.settingsViewModel())
-                    .environmentObject(sceneViewModel)
+                    .environmentObject(viewModel)
             }
         }
     }
@@ -85,8 +82,8 @@ private extension SidebarNavigation {
 #if DEBUG
 struct SidebarNavigation_Previews: PreviewProvider {
     static var previews: some View {
-        SidebarNavigation(identity: .development)
+        SidebarNavigation()
-            .environmentObject(SceneViewModel.development)
+            .environmentObject(MainNavigationViewModel.development)
     }
 }
 #endif