Refactoring/preferences

Development Assets/DevelopmentModels.swift

@@ -118,12 +118,16 @@ extension AppEnvironment {
         webAuthSessionType: SuccessfulStubbingWebAuthSession.self)
 }
 
+extension IdentifiedEnvironment {
+    static let development = try! IdentifiedEnvironment(identityID: devIdentityID, appEnvironment: .development)
+}
+
 extension RootViewModel {
     static let development = RootViewModel(environment: .development)
 }
 
 extension MainNavigationViewModel {
-    static let development = try! MainNavigationViewModel(identityID: devIdentityID, environment: .development)
+    static let development = MainNavigationViewModel(environment: .development)
 }
 
 extension SettingsViewModel {

Metatext.xcodeproj/project.pbxproj

@@ -7,6 +7,10 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		D0091B6824DC10B30040E8D2 /* PreferencesView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0091B6724DC10B30040E8D2 /* PreferencesView.swift */; };
+		D0091B6924DC10B30040E8D2 /* PreferencesView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0091B6724DC10B30040E8D2 /* PreferencesView.swift */; };
+		D0091B6B24DC10CE0040E8D2 /* PreferencesViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0091B6A24DC10CE0040E8D2 /* PreferencesViewModel.swift */; };
+		D0091B6C24DC10CE0040E8D2 /* PreferencesViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0091B6A24DC10CE0040E8D2 /* PreferencesViewModel.swift */; };
 		D047FAAE24C3E21200AF17C5 /* MetatextApp.swift in Sources */ = {isa = PBXBuildFile; fileRef = D047FA8524C3E21000AF17C5 /* MetatextApp.swift */; };
 		D047FAAF24C3E21200AF17C5 /* MetatextApp.swift in Sources */ = {isa = PBXBuildFile; fileRef = D047FA8524C3E21000AF17C5 /* MetatextApp.swift */; };
 		D047FAB224C3E21200AF17C5 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = D047FA8724C3E21200AF17C5 /* Assets.xcassets */; };
@@ -91,6 +95,14 @@
 		D0C963FC24CC359D003BD330 /* AlertItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0C963FA24CC359D003BD330 /* AlertItem.swift */; };
 		D0C963FE24CC3812003BD330 /* Publisher+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0C963FD24CC3812003BD330 /* Publisher+Extensions.swift */; };
 		D0C963FF24CC3812003BD330 /* Publisher+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0C963FD24CC3812003BD330 /* Publisher+Extensions.swift */; };
+		D0CD847324DBDEC700CF380C /* MastodonPreferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847224DBDEC700CF380C /* MastodonPreferences.swift */; };
+		D0CD847424DBDEC700CF380C /* MastodonPreferences.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847224DBDEC700CF380C /* MastodonPreferences.swift */; };
+		D0CD847624DBDF3C00CF380C /* Status.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847524DBDF3C00CF380C /* Status.swift */; };
+		D0CD847724DBDF3C00CF380C /* Status.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847524DBDF3C00CF380C /* Status.swift */; };
+		D0CD847C24DBEA9F00CF380C /* Unknowable.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847B24DBEA9F00CF380C /* Unknowable.swift */; };
+		D0CD847D24DBEA9F00CF380C /* Unknowable.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847B24DBEA9F00CF380C /* Unknowable.swift */; };
+		D0CD847F24DBF1BB00CF380C /* PreferencesEndpoint.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847E24DBF1BB00CF380C /* PreferencesEndpoint.swift */; };
+		D0CD848024DBF1BB00CF380C /* PreferencesEndpoint.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0CD847E24DBF1BB00CF380C /* PreferencesEndpoint.swift */; };
 		D0DB6EF424C5228A00D965FE /* AddIdentityView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DB6EF324C5228A00D965FE /* AddIdentityView.swift */; };
 		D0DB6EF524C5233E00D965FE /* AddIdentityView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DB6EF324C5228A00D965FE /* AddIdentityView.swift */; };
 		D0DB6F0924C65AC000D965FE /* AddIdentityViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = D0DB6F0824C65AC000D965FE /* AddIdentityViewModel.swift */; };
@@ -151,6 +163,8 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		D0091B6724DC10B30040E8D2 /* PreferencesView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesView.swift; sourceTree = "<group>"; };
+		D0091B6A24DC10CE0040E8D2 /* PreferencesViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesViewModel.swift; sourceTree = "<group>"; };
 		D047FA8524C3E21000AF17C5 /* MetatextApp.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MetatextApp.swift; sourceTree = "<group>"; };
 		D047FA8724C3E21200AF17C5 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		D047FA8C24C3E21200AF17C5 /* Metatext.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Metatext.app; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -199,6 +213,10 @@
 		D0BEC95024CA2B7E00E864C4 /* TabNavigation.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TabNavigation.swift; sourceTree = "<group>"; };
 		D0C963FA24CC359D003BD330 /* AlertItem.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AlertItem.swift; sourceTree = "<group>"; };
 		D0C963FD24CC3812003BD330 /* Publisher+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Publisher+Extensions.swift"; sourceTree = "<group>"; };
+		D0CD847224DBDEC700CF380C /* MastodonPreferences.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MastodonPreferences.swift; sourceTree = "<group>"; };
+		D0CD847524DBDF3C00CF380C /* Status.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Status.swift; sourceTree = "<group>"; };
+		D0CD847B24DBEA9F00CF380C /* Unknowable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Unknowable.swift; sourceTree = "<group>"; };
+		D0CD847E24DBF1BB00CF380C /* PreferencesEndpoint.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesEndpoint.swift; sourceTree = "<group>"; };
 		D0DB6EF324C5228A00D965FE /* AddIdentityView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AddIdentityView.swift; sourceTree = "<group>"; };
 		D0DB6F0824C65AC000D965FE /* AddIdentityViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AddIdentityViewModel.swift; sourceTree = "<group>"; };
 		D0DC174524CFEC2000A75C65 /* StubbingURLProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = StubbingURLProtocol.swift; sourceTree = "<group>"; };
@@ -332,14 +350,17 @@
 				D052BBCC24D750A100A80A7A /* AppEnvironment.swift */,
 				D0ED1BD624CF94B200B4899C /* Application.swift */,
 				D0666A4424C6BC0A00F3F04B /* DatabaseError.swift */,
+				D052BBCE24D750C000A80A7A /* Defaults.swift */,
 				D0666A5324C6C3E500F3F04B /* Emoji.swift */,
 				D0666A4A24C6C37700F3F04B /* Identity.swift */,
 				D0666A4124C6BB7B00F3F04B /* IdentityDatabase.swift */,
 				D0666A4D24C6C39600F3F04B /* Instance.swift */,
 				D0DC177324D0B58800A75C65 /* Keychain.swift */,
 				D0ED1BE224CFA84400B4899C /* MastodonError.swift */,
-				D052BBCE24D750C000A80A7A /* Defaults.swift */,
+				D0CD847224DBDEC700CF380C /* MastodonPreferences.swift */,
 				D0666A7124C6E0D300F3F04B /* Secrets.swift */,
+				D0CD847524DBDF3C00CF380C /* Status.swift */,
+				D0CD847B24DBEA9F00CF380C /* Unknowable.swift */,
 			);
 			path = Model;
 			sourceTree = "<group>";
@@ -364,6 +385,7 @@
 			children = (
 				D0DB6EF324C5228A00D965FE /* AddIdentityView.swift */,
 				D06BAB5024D942CF0081B8FD /* IdentitiesView.swift */,
+				D0091B6724DC10B30040E8D2 /* PreferencesView.swift */,
 				D0BEC93A24C96FD500E864C4 /* RootView.swift */,
 				D04FD73224D48F37007D572D /* SettingsView.swift */,
 				D0BEC94924CA231200E864C4 /* TimelineView.swift */,
@@ -390,6 +412,7 @@
 				D0DB6F0824C65AC000D965FE /* AddIdentityViewModel.swift */,
 				D06BAB4D24D942BC0081B8FD /* IdentitiesViewModel.swift */,
 				D052BBDF24D805E300A80A7A /* MainNavigationViewModel.swift */,
+				D0091B6A24DC10CE0040E8D2 /* PreferencesViewModel.swift */,
 				D0BEC93724C9632800E864C4 /* RootViewModel.swift */,
 				D04FD73524D49506007D572D /* SettingsViewModel.swift */,
 				D0BEC94624CA22C400E864C4 /* TimelineViewModel.swift */,
@@ -457,6 +480,7 @@
 				D0ED1BCA24CF744200B4899C /* MastodonClient.swift */,
 				D0ED1BCD24CF768200B4899C /* MastodonEndpoint.swift */,
 				D0ED1BD024CF779B00B4899C /* MastodonTarget.swift */,
+				D0CD847E24DBF1BB00CF380C /* PreferencesEndpoint.swift */,
 			);
 			path = "Mastodon API";
 			sourceTree = "<group>";
@@ -652,6 +676,7 @@
 			files = (
 				D04FD73924D4A7B4007D572D /* AccountEndpoint+Stubbing.swift in Sources */,
 				D0DB6F0924C65AC000D965FE /* AddIdentityViewModel.swift in Sources */,
+				D0CD847324DBDEC700CF380C /* MastodonPreferences.swift in Sources */,
 				D0ED1BD724CF94B200B4899C /* Application.swift in Sources */,
 				D047FAAE24C3E21200AF17C5 /* MetatextApp.swift in Sources */,
 				D0BEC94724CA22C400E864C4 /* TimelineViewModel.swift in Sources */,
@@ -672,6 +697,7 @@
 				D0ED1BC124CED48800B4899C /* HTTPClient.swift in Sources */,
 				D0666A4524C6BC0A00F3F04B /* DatabaseError.swift in Sources */,
 				D0ED1BDD24CF982600B4899C /* AccessTokenEndpoint.swift in Sources */,
+				D0CD847F24DBF1BB00CF380C /* PreferencesEndpoint.swift in Sources */,
 				D0666A4B24C6C37700F3F04B /* Identity.swift in Sources */,
 				D0666A5424C6C3E500F3F04B /* Emoji.swift in Sources */,
 				D0DC175524D00F0A00A75C65 /* AccessTokenEndpoint+Stubbing.swift in Sources */,
@@ -689,6 +715,7 @@
 				D0C963FB24CC359D003BD330 /* AlertItem.swift in Sources */,
 				D0DC174624CFEC2000A75C65 /* StubbingURLProtocol.swift in Sources */,
 				D0DC174D24CFF1F100A75C65 /* Stubbing.swift in Sources */,
+				D0091B6B24DC10CE0040E8D2 /* PreferencesViewModel.swift in Sources */,
 				D0666A5724C6C63400F3F04B /* MastodonDecoder.swift in Sources */,
 				D0DB6EF424C5228A00D965FE /* AddIdentityView.swift in Sources */,
 				D0DC177424D0B58800A75C65 /* Keychain.swift in Sources */,
@@ -706,8 +733,11 @@
 				D0DC175B24D0154F00A75C65 /* MastodonAPI.swift in Sources */,
 				D0ED1BD124CF779B00B4899C /* MastodonTarget.swift in Sources */,
 				D065F53E24D3D20300741304 /* InstanceEndpoint.swift in Sources */,
+				D0CD847C24DBEA9F00CF380C /* Unknowable.swift in Sources */,
 				D0666A6F24C6DFB300F3F04B /* AccessToken.swift in Sources */,
 				D0ED1BCB24CF744200B4899C /* MastodonClient.swift in Sources */,
+				D0091B6824DC10B30040E8D2 /* PreferencesView.swift in Sources */,
+				D0CD847624DBDF3C00CF380C /* Status.swift in Sources */,
 				D052BBE024D805E300A80A7A /* MainNavigationViewModel.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -718,6 +748,7 @@
 			files = (
 				D04FD73A24D4A7B4007D572D /* AccountEndpoint+Stubbing.swift in Sources */,
 				D0DB6F0A24C65AC000D965FE /* AddIdentityViewModel.swift in Sources */,
+				D0CD847424DBDEC700CF380C /* MastodonPreferences.swift in Sources */,
 				D0ED1BD824CF94B200B4899C /* Application.swift in Sources */,
 				D047FAAF24C3E21200AF17C5 /* MetatextApp.swift in Sources */,
 				D0BEC94824CA22C400E864C4 /* TimelineViewModel.swift in Sources */,
@@ -738,6 +769,7 @@
 				D0ED1BC224CED48800B4899C /* HTTPClient.swift in Sources */,
 				D0666A4624C6BC0A00F3F04B /* DatabaseError.swift in Sources */,
 				D0ED1BDE24CF982600B4899C /* AccessTokenEndpoint.swift in Sources */,
+				D0CD848024DBF1BB00CF380C /* PreferencesEndpoint.swift in Sources */,
 				D0666A4C24C6C37700F3F04B /* Identity.swift in Sources */,
 				D0666A5524C6C3E500F3F04B /* Emoji.swift in Sources */,
 				D0DC175624D00F0A00A75C65 /* AccessTokenEndpoint+Stubbing.swift in Sources */,
@@ -755,6 +787,7 @@
 				D0C963FC24CC359D003BD330 /* AlertItem.swift in Sources */,
 				D0DC174724CFEC2000A75C65 /* StubbingURLProtocol.swift in Sources */,
 				D0DC174E24CFF1F100A75C65 /* Stubbing.swift in Sources */,
+				D0091B6C24DC10CE0040E8D2 /* PreferencesViewModel.swift in Sources */,
 				D0666A5824C6C63400F3F04B /* MastodonDecoder.swift in Sources */,
 				D0DB6EF524C5233E00D965FE /* AddIdentityView.swift in Sources */,
 				D0DC177524D0B58800A75C65 /* Keychain.swift in Sources */,
@@ -772,8 +805,11 @@
 				D0DC175C24D0154F00A75C65 /* MastodonAPI.swift in Sources */,
 				D0ED1BD224CF779B00B4899C /* MastodonTarget.swift in Sources */,
 				D065F53F24D3D20300741304 /* InstanceEndpoint.swift in Sources */,
+				D0CD847D24DBEA9F00CF380C /* Unknowable.swift in Sources */,
 				D0666A7024C6DFB300F3F04B /* AccessToken.swift in Sources */,
 				D0ED1BCC24CF744200B4899C /* MastodonClient.swift in Sources */,
+				D0091B6924DC10B30040E8D2 /* PreferencesView.swift in Sources */,
+				D0CD847724DBDF3C00CF380C /* Status.swift in Sources */,
 				D052BBE124D805E300A80A7A /* MainNavigationViewModel.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

Shared/Extensions/Publisher+Extensions.swift

@@ -7,12 +7,12 @@ extension Publisher {
     func assignErrorsToAlertItem<Root: AnyObject>(
         to keyPath: ReferenceWritableKeyPath<Root, AlertItem?>,
         on object: Root) -> AnyPublisher<Output, Never> {
-        self.catch { [weak object] error -> AnyPublisher<Output, Never> in
+        self.catch { [weak object] error -> Empty<Output, Never> in
             DispatchQueue.main.async {
                 object?[keyPath: keyPath] = AlertItem(error: error)
             }
 
-            return Empty().eraseToAnyPublisher()
+            return Empty()
         }
         .eraseToAnyPublisher()
     }

Shared/Model/AppEnvironment.swift

@@ -1,6 +1,7 @@
 // Copyright © 2020 Metabolist. All rights reserved.
 
 import Foundation
+import Combine
 
 struct AppEnvironment {
     let URLSessionConfiguration: URLSessionConfiguration
@@ -9,3 +10,41 @@ struct AppEnvironment {
     let secrets: Secrets
     let webAuthSessionType: WebAuthSession.Type
 }
+
+class IdentifiedEnvironment {
+    @Published var identity: Identity
+    let observationErrors: AnyPublisher<Error, Never>
+    let networkClient: MastodonClient
+    let appEnvironment: AppEnvironment
+
+    private var cancellables = Set<AnyCancellable>()
+    private let observationErrorsInput = PassthroughSubject<Error, Never>()
+
+    init(identityID: String, appEnvironment: AppEnvironment) throws {
+        self.appEnvironment = appEnvironment
+        observationErrors = observationErrorsInput.eraseToAnyPublisher()
+        networkClient = MastodonClient(configuration: appEnvironment.URLSessionConfiguration)
+        networkClient.accessToken = try appEnvironment.secrets.item(.accessToken, forIdentityID: identityID)
+
+        let observation = appEnvironment.identityDatabase.identityObservation(id: identityID).share()
+
+        var initialIdentity: Identity?
+
+        observation.first().sink(
+            receiveCompletion: { _ in },
+            receiveValue: { initialIdentity = $0 })
+            .store(in: &cancellables)
+
+        guard let identity = initialIdentity else { throw IdentityDatabaseError.identityNotFound }
+
+        self.identity = identity
+        networkClient.instanceURL = identity.url
+
+        observation.catch { [weak self] error -> Empty<Identity, Never> in
+            self?.observationErrorsInput.send(error)
+
+            return Empty()
+        }
+        .assign(to: &$identity)
+    }
+}

Shared/Model/Identity.swift

@@ -6,6 +6,7 @@ struct Identity: Codable, Hashable, Identifiable {
     let id: String
     let url: URL
     let lastUsedAt: Date
+    let preferences: Identity.Preferences
     let instance: Identity.Instance?
     let account: Identity.Account?
 }
@@ -28,6 +29,16 @@ extension Identity {
         let header: URL
         let headerStatic: URL
     }
+
+    struct Preferences: Codable, Hashable {
+        var useServerPostingPreferences = true
+        var postingDefaultVisibility = Status.Visibility.public
+        var postingDefaultSensitive = false
+        var postingDefaultLanguage: String?
+        var useServerReadingPreferences = true
+        var readingExpandMedia = MastodonPreferences.ExpandMedia.default
+        var readingExpandSpoilers = false
+    }
 }
 
 extension Identity {

Shared/Model/IdentityDatabase.swift

@@ -36,6 +36,7 @@ extension IdentityDatabase {
                 id: id,
                 url: url,
                 lastUsedAt: Date(),
+                preferences: Identity.Preferences(),
                 instanceURI: nil).save)
             .eraseToAnyPublisher()
     }
@@ -150,6 +151,7 @@ private extension IdentityDatabase {
                 t.column("instanceURI", .text)
                     .indexed()
                     .references("instance", column: "uri")
+                t.column("preferences", .blob).notNull()
             }
 
             try db.create(table: "account", ifNotExists: true) { t in
@@ -175,6 +177,7 @@ private struct StoredIdentity: Codable, Hashable, TableRecord, FetchableRecord,
     let id: String
     let url: URL
     let lastUsedAt: Date
+    let preferences: Identity.Preferences
     let instanceURI: String?
 }
 
@@ -203,6 +206,7 @@ private extension Identity {
             id: result.identity.id,
             url: result.identity.url,
             lastUsedAt: result.identity.lastUsedAt,
+            preferences: result.identity.preferences,
             instance: result.instance,
             account: result.account)
     }

Shared/Model/MastodonPreferences.swift

@@ -0,0 +1,28 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+struct MastodonPreferences: Codable {
+    enum CodingKeys: String, CodingKey {
+        case postingDefaultVisibility = "posting:default:visibility"
+        case postingDefaultSensitive = "posting:default:sensitive"
+        case postingDefaultLanguage = "posting:default:language"
+        case readingExpandMedia = "reading:expand:media"
+        case readingExpandSpoilers = "reading:expand:spoilers"
+    }
+
+    let postingDefaultVisibility: Status.Visibility
+    let postingDefaultSensitive: Bool
+    let postingDefaultLanguage: String?
+    let readingExpandMedia: ExpandMedia
+    let readingExpandSpoilers: Bool
+}
+
+extension MastodonPreferences {
+    enum ExpandMedia: String, Codable, Unknowable {
+        case `default`
+        case showAll
+        case hideAll
+        case unknown
+    }
+}

Shared/Model/Status.swift

@@ -0,0 +1,13 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+struct Status {
+    enum Visibility: String, Codable, Unknowable {
+        case `public`
+        case unlisted
+        case `private`
+        case direct
+        case unknown
+    }
+}

Shared/Model/Unknowable.swift

@@ -0,0 +1,17 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+protocol Unknowable: RawRepresentable, CaseIterable where RawValue: Equatable {
+    static var unknown: RawValue { get }
+}
+
+extension Unknowable {
+    init(rawValue: RawValue) {
+        self = Self.allCases.first { $0.rawValue == rawValue } ?? Self(rawValue: Self.unknown)
+    }
+}
+
+extension Unknowable where RawValue == String {
+    static var unknown: String { "unknown" }
+}

Shared/Networking/Mastodon API/PreferencesEndpoint.swift

@@ -0,0 +1,23 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+enum PreferencesEndpoint {
+    case preferences
+}
+
+extension PreferencesEndpoint: MastodonEndpoint {
+    typealias ResultType = MastodonPreferences
+
+    var pathComponentsInContext: [String] {
+        switch self {
+        case .preferences: return ["instance"]
+        }
+    }
+
+    var method: HTTPMethod {
+        switch self {
+        case .preferences: return .get
+        }
+    }
+}

Shared/View Models/IdentitiesViewModel.swift

@@ -8,24 +8,15 @@ class IdentitiesViewModel: ObservableObject {
     @Published var identities = [Identity]()
     @Published var alertItem: AlertItem?
 
-    private let environment: AppEnvironment
+    private let environment: IdentifiedEnvironment
     private var cancellables = Set<AnyCancellable>()
 
-    init(identity: Published<Identity>, environment: AppEnvironment) {
+    init(environment: IdentifiedEnvironment) {
-        _identity = identity
         self.environment = environment
+        identity = environment.identity
 
-        environment.identityDatabase.identitiesObservation()
+        environment.appEnvironment.identityDatabase.identitiesObservation()
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
             .assign(to: &$identities)
     }
 }
-
-extension IdentitiesViewModel {
-    func identitySelected(id: String) {
-        environment.identityDatabase.updateLastUsedAt(identityID: id)
-            .assignErrorsToAlertItem(to: \.alertItem, on: self)
-            .sink(receiveValue: {})
-            .store(in: &cancellables)
-    }
-}

Shared/View Models/MainNavigationViewModel.swift

@@ -10,39 +10,21 @@ class MainNavigationViewModel: ObservableObject {
     @Published var alertItem: AlertItem?
     var selectedTab: Tab? = .timelines
 
-    private let environment: AppEnvironment
+    private let environment: IdentifiedEnvironment
-    private let networkClient: MastodonClient
     private var cancellables = Set<AnyCancellable>()
 
-    init(identityID: String, environment: AppEnvironment) throws {
+    init(environment: IdentifiedEnvironment) {
         self.environment = environment
-        networkClient = MastodonClient(configuration: environment.URLSessionConfiguration)
+        identity = environment.identity
+        environment.$identity.dropFirst().assign(to: &$identity)
 
-        let observation = environment.identityDatabase.identityObservation(id: identityID).share()
+        environment.appEnvironment.identityDatabase
-        var initialIdentity: Identity?
+            .recentIdentitiesObservation(excluding: environment.identity.id)
-
-        observation.first().sink(
-            receiveCompletion: { _ in },
-            receiveValue: { initialIdentity = $0 })
-            .store(in: &cancellables)
-
-        guard let identity = initialIdentity else { throw IdentityDatabaseError.identityNotFound }
-
-        self.identity = identity
-        networkClient.instanceURL = identity.url
-
-        do {
-            networkClient.accessToken = try environment.secrets.item(.accessToken, forIdentityID: identity.id)
-        } catch {
-            alertItem = AlertItem(error: error)
-        }
-
-        observation.assignErrorsToAlertItem(to: \.alertItem, on: self).assign(to: &$identity)
-        environment.identityDatabase.recentIdentitiesObservation(excluding: identityID)
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
             .assign(to: &$recentIdentities)
 
-        environment.identityDatabase.updateLastUsedAt(identityID: identityID)
+        environment.appEnvironment.identityDatabase
+            .updateLastUsedAt(identityID: environment.identity.id)
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
             .sink(receiveValue: {})
             .store(in: &cancellables)
@@ -53,25 +35,25 @@ extension MainNavigationViewModel {
     func refreshIdentity() {
         let id = identity.id
 
-        if networkClient.accessToken != nil {
+        if environment.networkClient.accessToken != nil {
-            networkClient.request(AccountEndpoint.verifyCredentials)
+            environment.networkClient.request(AccountEndpoint.verifyCredentials)
                 .map { ($0, id) }
-                .flatMap(environment.identityDatabase.updateAccount)
+                .flatMap(environment.appEnvironment.identityDatabase.updateAccount)
                 .assignErrorsToAlertItem(to: \.alertItem, on: self)
                 .sink(receiveValue: {})
                 .store(in: &cancellables)
         }
 
-        networkClient.request(InstanceEndpoint.instance)
+        environment.networkClient.request(InstanceEndpoint.instance)
             .map { ($0, id) }
-            .flatMap(environment.identityDatabase.updateInstance)
+            .flatMap(environment.appEnvironment.identityDatabase.updateInstance)
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
             .sink(receiveValue: {})
             .store(in: &cancellables)
     }
 
     func settingsViewModel() -> SettingsViewModel {
-        SettingsViewModel(identity: _identity, environment: environment)
+        SettingsViewModel(environment: environment)
     }
 }
 

Shared/View Models/PreferencesViewModel.swift

@@ -0,0 +1,15 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import Foundation
+
+class PreferencesViewModel: ObservableObject {
+    @Published var preferences: Identity.Preferences
+
+    private let environment: IdentifiedEnvironment
+
+    init(environment: IdentifiedEnvironment) {
+        self.environment = environment
+        preferences = environment.identity.preferences
+        environment.$identity.map(\.preferences).assign(to: &$preferences)
+    }
+}

Shared/View Models/RootViewModel.swift

@@ -4,24 +4,13 @@ import Foundation
 import Combine
 
 class RootViewModel: ObservableObject {
-    @Published private(set) var mainNavigationViewModel: MainNavigationViewModel?
+    @Published private(set) var identityID: String?
-
-    @Published private var identityID: String?
     private let environment: AppEnvironment
     private var cancellables = Set<AnyCancellable>()
 
     init(environment: AppEnvironment) {
         self.environment = environment
         identityID = environment.identityDatabase.mostRecentlyUsedIdentityID
-
-        $identityID
-            .tryMap {
-                guard let id = $0 else { return nil }
-
-                return try MainNavigationViewModel(identityID: id, environment: environment)
-            }
-            .replaceError(with: nil)
-            .assign(to: &$mainNavigationViewModel)
     }
 }
 
@@ -31,12 +20,23 @@ extension RootViewModel {
     }
 
     func addIdentityViewModel() -> AddIdentityViewModel {
-        let addAccountViewModel = AddIdentityViewModel(environment: environment)
+        AddIdentityViewModel(environment: environment)
+    }
 
-        addAccountViewModel.addedIdentityID
+    func mainNavigationViewModel(identityID: String) -> MainNavigationViewModel? {
-            .sink(receiveValue: newIdentitySelected(id:))
+        let identifiedEnvironment: IdentifiedEnvironment
-            .store(in: &cancellables)
 
-        return addAccountViewModel
+        do {
+            identifiedEnvironment = try IdentifiedEnvironment(identityID: identityID, appEnvironment: environment)
+        } catch {
+            return nil
+        }
+
+        identifiedEnvironment.observationErrors
+            .receive(on: RunLoop.main)
+            .map { [weak self] _ in self?.environment.identityDatabase.mostRecentlyUsedIdentityID }
+            .assign(to: &$identityID)
+
+        return MainNavigationViewModel(environment: identifiedEnvironment)
     }
 }

Shared/View Models/SettingsViewModel.swift

@@ -4,16 +4,17 @@ import Foundation
 
 class SettingsViewModel: ObservableObject {
     @Published private(set) var identity: Identity
-    private let environment: AppEnvironment
+    private let environment: IdentifiedEnvironment
 
-    init(identity: Published<Identity>, environment: AppEnvironment) {
+    init(environment: IdentifiedEnvironment) {
-        _identity = identity
         self.environment = environment
+        identity = environment.identity
+        environment.$identity.dropFirst().assign(to: &$identity)
     }
 }
 
 extension SettingsViewModel {
     func identitiesViewModel() -> IdentitiesViewModel {
-        IdentitiesViewModel(identity: _identity, environment: environment)
+        IdentitiesViewModel(environment: environment)
     }
 }

Shared/Views/AddIdentityView.swift

@@ -4,6 +4,7 @@ import SwiftUI
 
 struct AddIdentityView: View {
     @StateObject var viewModel: AddIdentityViewModel
+    @EnvironmentObject var rootViewModel: RootViewModel
 
     var body: some View {
         Form {
@@ -32,6 +33,11 @@ struct AddIdentityView: View {
         }
         .paddingIfMac()
         .alertItem($viewModel.alertItem)
+        .onReceive(viewModel.addedIdentityID) { id in
+            withAnimation {
+                rootViewModel.newIdentitySelected(id: id)
+            }
+        }
     }
 }
 

Shared/Views/IdentitiesView.swift

@@ -18,12 +18,14 @@ struct IdentitiesView: View {
             Section {
                 List(viewModel.identities) { identity in
                     Button(identity.handle) {
+                        withAnimation {
                             rootViewModel.newIdentitySelected(id: identity.id)
                         }
                     }
                 }
             }
         }
+    }
 }
 
 struct IdentitiesView_Previews: PreviewProvider {

Shared/Views/PreferencesView.swift

@@ -0,0 +1,15 @@
+// Copyright © 2020 Metabolist. All rights reserved.
+
+import SwiftUI
+
+struct PreferencesView: View {
+    var body: some View {
+        Text(/*@START_MENU_TOKEN@*/"Hello, World!"/*@END_MENU_TOKEN@*/)
+    }
+}
+
+struct PreferencesView_Previews: PreviewProvider {
+    static var previews: some View {
+        PreferencesView()
+    }
+}

Shared/Views/RootView.swift

@@ -6,13 +6,16 @@ struct RootView: View {
     @StateObject var viewModel: RootViewModel
 
     var body: some View {
-        ZStack {
+        if let id = viewModel.identityID,
-            if let mainNavigationViewModel = viewModel.mainNavigationViewModel {
+           let mainNavigationViewModel = viewModel.mainNavigationViewModel(identityID: id) {
             Self.mainNavigation(mainNavigationViewModel: mainNavigationViewModel)
+                .id(id)
                 .environmentObject(viewModel)
+                .transition(.opacity)
         } else {
             AddIdentityView(viewModel: viewModel.addIdentityViewModel())
-            }
+                .environmentObject(viewModel)
+                .transition(.opacity)
         }
     }
 }

Tests/View Models/RootViewModelTests.swift

@@ -6,19 +6,26 @@ import CombineExpectations
 @testable import Metatext
 
 class RootViewModelTests: XCTestCase {
+    var cancellables = Set<AnyCancellable>()
+
     func testAddIdentity() throws {
         let sut = RootViewModel(environment: .fresh())
-        let recorder = sut.$mainNavigationViewModel.record()
+        let recorder = sut.$identityID.record()
 
         XCTAssertNil(try wait(for: recorder.next(), timeout: 1))
 
         let addIdentityViewModel = sut.addIdentityViewModel()
 
+        addIdentityViewModel.addedIdentityID
+            .sink(receiveValue: sut.newIdentitySelected(id:))
+            .store(in: &cancellables)
+
         addIdentityViewModel.urlFieldText = "https://mastodon.social"
         addIdentityViewModel.goTapped()
 
-        let mainNavigationViewModel = try wait(for: recorder.next(), timeout: 1)!
+        let identityID = try wait(for: recorder.next(), timeout: 1)!
 
-        XCTAssertNotNil(mainNavigationViewModel)
+        XCTAssertNotNil(identityID)
+        XCTAssertNotNil(sut.mainNavigationViewModel(identityID: identityID))
     }
 }

iOS/TabNavigation.swift

@@ -26,8 +26,8 @@ struct TabNavigation: View {
             SettingsView(viewModel: viewModel.settingsViewModel())
                 .environmentObject(rootViewModel)
         }
-        .onReceive(rootViewModel.$mainNavigationViewModel.map { _ in ()},
+        .alertItem($viewModel.alertItem)
-                   perform: viewModel.refreshIdentity)
+        .onAppear(perform: viewModel.refreshIdentity)
         .onReceive(NotificationCenter.default
                     .publisher(for: UIScene.willEnterForegroundNotification)
                     .map { _ in () },