Refactoring

Development Assets/DevelopmentModels.swift

@@ -56,7 +56,16 @@ extension IdentityDatabase {
 }
 
 extension Identity {
-    static let development = try! IdentityDatabase.development.identity(id: devIdentityID)!
+    static let development: Identity = {
+        var identity: Identity?
+
+        IdentityDatabase.development.identityObservation(id: devIdentityID)
+            .assertNoFailure()
+            .sink(receiveValue: { identity = $0 })
+            .store(in: &cancellables)
+
+        return identity!
+    }()
 }
 
 extension SceneViewModel {

Shared/Extensions/Publisher+Extensions.swift

@@ -4,12 +4,12 @@ import Foundation
 import Combine
 
 extension Publisher {
-    func assignErrorsToAlertItem<Root>(
+    func assignErrorsToAlertItem<Root: AnyObject>(
         to keyPath: ReferenceWritableKeyPath<Root, AlertItem?>,
         on object: Root) -> AnyPublisher<Output, Never> {
-        self.catch { error -> AnyPublisher<Output, Never> in
+        self.catch { [weak object] error -> AnyPublisher<Output, Never> in
             DispatchQueue.main.async {
-                object[keyPath: keyPath] = AlertItem(error: error)
+                object?[keyPath: keyPath] = AlertItem(error: error)
             }
 
             return Empty().eraseToAnyPublisher()

Shared/Model/IdentityDatabase.swift

@@ -26,16 +26,12 @@ struct IdentityDatabase {
 }
 
 extension IdentityDatabase {
-    func createIdentity(id: String, url: URL) -> AnyPublisher<Identity, Error> {
+    func createIdentity(id: String, url: URL) -> AnyPublisher<Void, Error> {
-        databaseQueue.writePublisher {
+        databaseQueue.writePublisher(updates: StoredIdentity(id: id, url: url, instanceURI: nil).save)
-            try StoredIdentity(id: id, url: url, instanceURI: nil).save($0)
+            .eraseToAnyPublisher()
-
-            return Identity(id: id, url: url, instance: nil, account: nil)
-        }
-        .eraseToAnyPublisher()
     }
 
-    func updateInstance(_ instance: Instance, forIdentityID identityID: String) -> AnyPublisher<Identity?, Error> {
+    func updateInstance(_ instance: Instance, forIdentityID identityID: String) -> AnyPublisher<Void, Error> {
         databaseQueue.writePublisher {
             try Identity.Instance(
                 uri: instance.uri,
@@ -46,15 +42,13 @@ extension IdentityDatabase {
             try StoredIdentity
                 .filter(Column("id") == identityID)
                 .updateAll($0, Column("instanceURI").set(to: instance.uri))
-
-            return try Self.fetchIdentity(id: identityID, db: $0)
         }
         .eraseToAnyPublisher()
     }
 
-    func updateAccount(_ account: Account, forIdentityID identityID: String) -> AnyPublisher<Identity?, Error> {
+    func updateAccount(_ account: Account, forIdentityID identityID: String) -> AnyPublisher<Void, Error> {
-        databaseQueue.writePublisher {
+        databaseQueue.writePublisher(
-            try Identity.Account(
+            updates: Identity.Account(
                 id: account.id,
                 identityID: identityID,
                 username: account.username,
@@ -63,15 +57,26 @@ extension IdentityDatabase {
                 avatarStatic: account.avatarStatic,
                 header: account.header,
                 headerStatic: account.headerStatic)
-                .save($0)
+                .save)
-
+            .eraseToAnyPublisher()
-            return try Self.fetchIdentity(id: identityID, db: $0)
-        }
-        .eraseToAnyPublisher()
     }
 
-    func identity(id: String) throws -> Identity? {
+    func identityObservation(id: String) -> AnyPublisher<Identity?, Error> {
-        try databaseQueue.read { try Self.fetchIdentity(id: id, db: $0) }
+        ValueObservation.tracking(
+            StoredIdentity
+                .filter(Column("id") == id)
+                .including(optional: StoredIdentity.instance)
+                .including(optional: StoredIdentity.account)
+                .asRequest(of: IdentityResult.self)
+                .fetchOne)
+            .removeDuplicates()
+            .publisher(in: databaseQueue, scheduling: .immediate)
+            .map {
+                guard let result = $0 else { return nil }
+
+                return Identity(result: result)
+            }
+            .eraseToAnyPublisher()
     }
 }
 
@@ -112,19 +117,6 @@ private extension IdentityDatabase {
 
         try migrator.migrate(writer)
     }
-
-    private static func fetchIdentity(id: String, db: Database) throws -> Identity? {
-        if let result = try StoredIdentity
-            .filter(Column("id") == id)
-            .including(optional: StoredIdentity.instance)
-            .including(optional: StoredIdentity.account)
-            .asRequest(of: IdentityResult.self)
-            .fetchOne(db) {
-            return Identity(result: result)
-        }
-
-        return nil
-    }
 }
 
 private struct StoredIdentity: Codable, Hashable, TableRecord, FetchableRecord, PersistableRecord {

Shared/View Models/AddIdentityViewModel.swift

@@ -8,15 +8,13 @@ class AddIdentityViewModel: ObservableObject {
     @Published var urlFieldText = ""
     @Published var alertItem: AlertItem?
     @Published private(set) var loading = false
-    private(set) var addedIdentity: AnyPublisher<Identity, Never>
+    @Published private(set) var addedIdentityID: String?
 
     private let networkClient: HTTPClient
     private let identityDatabase: IdentityDatabase
     private let secrets: Secrets
     private let webAuthenticationSessionType: WebAuthenticationSessionType.Type
     private let webAuthenticationSessionContextProvider = WebAuthenticationSessionContextProvider()
-    private let addedIdentityInput = PassthroughSubject<Identity, Never>()
-    private var cancellables = Set<AnyCancellable>()
 
     init(
         networkClient: HTTPClient,
@@ -27,7 +25,6 @@ class AddIdentityViewModel: ObservableObject {
         self.identityDatabase = identityDatabase
         self.secrets = secrets
         self.webAuthenticationSessionType = webAuthenticationSessionType
-        addedIdentity = addedIdentityInput.eraseToAnyPublisher()
     }
 
     func goTapped() {
@@ -65,11 +62,12 @@ class AddIdentityViewModel: ObservableObject {
                 identityDatabase: identityDatabase,
                 secrets: secrets)
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
+            .receive(on: RunLoop.main)
             .handleEvents(
                 receiveSubscription: { [weak self] _ in self?.loading = true },
                 receiveCompletion: { [weak self] _ in self?.loading = false  })
-            .sink(receiveValue: addedIdentityInput.send)
+            .map { $0 as String? }
-            .store(in: &cancellables)
+            .assign(to: &$addedIdentityID)
     }
 }
 
@@ -196,13 +194,14 @@ private extension Publisher where Output == AccessToken {
         id: String,
         instanceURL: URL,
         identityDatabase: IdentityDatabase,
-        secrets: Secrets) -> AnyPublisher<Identity, Error> {
+        secrets: Secrets) -> AnyPublisher<String, Error> {
         tryMap { accessToken -> (String, URL) in
             try secrets.set(accessToken.accessToken, forItem: .accessToken, forIdentityID: id)
 
             return (id, instanceURL)
         }
         .flatMap(identityDatabase.createIdentity)
+        .map { id }
         .eraseToAnyPublisher()
     }
 }

Shared/View Models/SceneViewModel.swift

@@ -4,21 +4,7 @@ import Foundation
 import Combine
 
 class SceneViewModel: ObservableObject {
-    @Published private(set) var identity: Identity? {
+    @Published private(set) var identity: Identity?
-        didSet {
-            if let identity = identity {
-                recentIdentityID = identity.id
-                networkClient.instanceURL = identity.url
-
-                do {
-                    networkClient.accessToken = try secrets.item(.accessToken, forIdentityID: identity.id)
-                } catch {
-                    alertItem = AlertItem(error: error)
-                }
-            }
-        }
-    }
-
     @Published var alertItem: AlertItem?
     @Published var presentingSettings = false
     var selectedTopLevelNavigation: TopLevelNavigation? = .timelines
@@ -39,8 +25,7 @@ class SceneViewModel: ObservableObject {
         self.userDefaults = userDefaults
 
         if let recentIdentityID = recentIdentityID {
-            identity = try? identityDatabase.identity(id: recentIdentityID)
+            changeIdentity(id: recentIdentityID)
-            refreshIdentity()
         }
     }
 }
@@ -54,7 +39,7 @@ extension SceneViewModel {
                 .map { ($0, identity.id) }
                 .flatMap(identityDatabase.updateAccount)
                 .assignErrorsToAlertItem(to: \.alertItem, on: self)
-                .assign(to: \.identity, on: self)
+                .sink(receiveValue: {})
                 .store(in: &cancellables)
         }
 
@@ -62,7 +47,7 @@ extension SceneViewModel {
             .map { ($0, identity.id) }
             .flatMap(identityDatabase.updateInstance)
             .assignErrorsToAlertItem(to: \.alertItem, on: self)
-            .assign(to: \.identity, on: self)
+            .sink(receiveValue: {})
             .store(in: &cancellables)
     }
 
@@ -72,8 +57,9 @@ extension SceneViewModel {
             identityDatabase: identityDatabase,
             secrets: secrets)
 
-        addAccountViewModel.addedIdentity
+        addAccountViewModel.$addedIdentityID
-            .sink(receiveValue: addIdentity(_:))
+            .compactMap { $0 }
+            .sink(receiveValue: changeIdentity(id:))
             .store(in: &cancellables)
 
         return addAccountViewModel
@@ -88,8 +74,23 @@ private extension SceneViewModel {
         set { userDefaults.set(newValue, forKey: Self.recentIdentityIDKey) }
     }
 
-    private func addIdentity(_ identity: Identity) {
+    private func changeIdentity(id: String) {
-        self.identity = identity
+        identityDatabase.identityObservation(id: id)
+            .assignErrorsToAlertItem(to: \.alertItem, on: self)
+            .handleEvents(receiveOutput: { [weak self] in
+                guard let self = self, let identity = $0 else { return }
+
+                self.recentIdentityID = identity.id
+                self.networkClient.instanceURL = identity.url
+
+                do {
+                    self.networkClient.accessToken = try self.secrets.item(.accessToken, forIdentityID: identity.id)
+                } catch {
+                    self.alertItem = AlertItem(error: error)
+                }
+            })
+            .assign(to: &$identity)
+
         refreshIdentity()
     }
 }

Tests/View Models/AddIdentityViewModelTests.swift

@@ -23,23 +23,26 @@ class AddIdentityViewModelTests: XCTestCase {
             identityDatabase: identityDatabase,
             secrets: secrets,
             webAuthenticationSessionType: SuccessfulStubbingWebAuthenticationSession.self)
-        let recorder = sut.addedIdentity.record()
+        let addedIDRecorder = sut.$addedIdentityID.record()
+        _ = try wait(for: addedIDRecorder.next(), timeout: 1)
 
         sut.urlFieldText = "https://mastodon.social"
         sut.goTapped()
 
-        let addedIdentity = try wait(for: recorder.next(), timeout: 1)
+        let addedIdentityID = try wait(for: addedIDRecorder.next(), timeout: 1)!
+        let identityRecorder = identityDatabase.identityObservation(id: addedIdentityID).record()
+        let addedIdentity = try wait(for: identityRecorder.next(), timeout: 1)!
 
-        XCTAssertEqual(try identityDatabase.identity(id: addedIdentity.id), addedIdentity)
+        XCTAssertEqual(addedIdentity.id, addedIdentityID)
         XCTAssertEqual(addedIdentity.url, URL(string: "https://mastodon.social")!)
         XCTAssertEqual(
-            try secrets.item(.clientID, forIdentityID: addedIdentity.id) as String?,
+            try secrets.item(.clientID, forIdentityID: addedIdentityID) as String?,
             "AUTHORIZATION_CLIENT_ID_STUB_VALUE")
         XCTAssertEqual(
-            try secrets.item(.clientSecret, forIdentityID: addedIdentity.id) as String?,
+            try secrets.item(.clientSecret, forIdentityID: addedIdentityID) as String?,
             "AUTHORIZATION_CLIENT_SECRET_STUB_VALUE")
         XCTAssertEqual(
-            try secrets.item(.accessToken, forIdentityID: addedIdentity.id) as String?,
+            try secrets.item(.accessToken, forIdentityID: addedIdentityID) as String?,
             "ACCESS_TOKEN_STUB_VALUE")
     }
 
@@ -49,14 +52,16 @@ class AddIdentityViewModelTests: XCTestCase {
             identityDatabase: identityDatabase,
             secrets: secrets,
             webAuthenticationSessionType: SuccessfulStubbingWebAuthenticationSession.self)
-        let recorder = sut.addedIdentity.record()
+        let addedIDRecorder = sut.$addedIdentityID.record()
+        _ = try wait(for: addedIDRecorder.next(), timeout: 1)
 
         sut.urlFieldText = "mastodon.social"
         sut.goTapped()
 
-        let addedIdentity = try wait(for: recorder.next(), timeout: 1)
+        let addedIdentityID = try wait(for: addedIDRecorder.next(), timeout: 1)!
+        let identityRecorder = identityDatabase.identityObservation(id: addedIdentityID).record()
+        let addedIdentity = try wait(for: identityRecorder.next(), timeout: 1)!
 
-        XCTAssertEqual(try identityDatabase.identity(id: addedIdentity.id), addedIdentity)
         XCTAssertEqual(addedIdentity.url, URL(string: "https://mastodon.social")!)
     }