From 92e515e2b450f170dbcc30c116e2299e050e1498 Mon Sep 17 00:00:00 2001
From: Justin Mazzocchi <2831158+jzzocc@users.noreply.github.com>
Date: Thu, 4 Mar 2021 18:13:30 -0800
Subject: [PATCH] Root view model per-scene

---
 System/MetatextApp.swift                      | 11 +++----
 .../PreviewViewModels/PreviewViewModels.swift |  3 +-
 .../View Models/RootViewModel.swift           | 31 +++++++++----------
 3 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/System/MetatextApp.swift b/System/MetatextApp.swift
index d6288f9..28def51 100644
--- a/System/MetatextApp.swift
+++ b/System/MetatextApp.swift
@@ -8,8 +8,6 @@ import ViewModels
 @main
 struct MetatextApp: App {
     @UIApplicationDelegateAdaptor(AppDelegate.self) private var appDelegate
-    // swiftlint:disable:next force_try
-    private let viewModel = try! RootViewModel(environment: Self.environment)
 
     init() {
         try? AVAudioSession.sharedInstance().setCategory(.ambient, mode: .default)
@@ -17,10 +15,11 @@ struct MetatextApp: App {
     }
 
     var body: some Scene {
-        viewModel.registerForRemoteNotifications = appDelegate.registerForRemoteNotifications
-
-        return WindowGroup {
-            RootView(viewModel: viewModel)
+        WindowGroup {
+            // swiftlint:disable:next force_try
+            RootView(viewModel: try! RootViewModel(
+                        environment: Self.environment,
+                        registerForRemoteNotifications: appDelegate.registerForRemoteNotifications))
         }
     }
 }
diff --git a/ViewModels/Sources/PreviewViewModels/PreviewViewModels.swift b/ViewModels/Sources/PreviewViewModels/PreviewViewModels.swift
index 8c855fa..3c3bd05 100644
--- a/ViewModels/Sources/PreviewViewModels/PreviewViewModels.swift
+++ b/ViewModels/Sources/PreviewViewModels/PreviewViewModels.swift
@@ -69,7 +69,8 @@ public extension Instance {
 }
 
 public extension RootViewModel {
-    static let preview = try! RootViewModel(environment: environment)
+    static let preview = try! RootViewModel(environment: environment,
+                                            registerForRemoteNotifications: { Empty().eraseToAnyPublisher() })
 }
 
 public extension IdentityContext {
diff --git a/ViewModels/Sources/ViewModels/View Models/RootViewModel.swift b/ViewModels/Sources/ViewModels/View Models/RootViewModel.swift
index 592cbb5..d2bc3a0 100644
--- a/ViewModels/Sources/ViewModels/View Models/RootViewModel.swift	
+++ b/ViewModels/Sources/ViewModels/View Models/RootViewModel.swift	
@@ -7,28 +7,18 @@ import ServiceLayer
 
 public final class RootViewModel: ObservableObject {
     @Published public private(set) var navigationViewModel: NavigationViewModel?
-    public var registerForRemoteNotifications: (() -> AnyPublisher<Data, Error>)? {
-        didSet {
-            guard let registerForRemoteNotifications = registerForRemoteNotifications else { return }
-
-            userNotificationService.isAuthorized(request: false)
-                .filter { $0 }
-                .zip(registerForRemoteNotifications())
-                .map { $1 }
-                .flatMap(allIdentitiesService.updatePushSubscriptions(deviceToken:))
-                .sink { _ in } receiveValue: { _ in }
-                .store(in: &cancellables)
-        }
-    }
 
     @Published private var mostRecentlyUsedIdentityId: Identity.Id?
     private let environment: AppEnvironment
+    private let registerForRemoteNotifications: () -> AnyPublisher<Data, Error>
     private let allIdentitiesService: AllIdentitiesService
     private let userNotificationService: UserNotificationService
     private var cancellables = Set<AnyCancellable>()
 
-    public init(environment: AppEnvironment) throws {
+    public init(environment: AppEnvironment,
+                registerForRemoteNotifications: @escaping () -> AnyPublisher<Data, Error>) throws {
         self.environment = environment
+        self.registerForRemoteNotifications = registerForRemoteNotifications
         allIdentitiesService = try AllIdentitiesService(environment: environment)
         userNotificationService = UserNotificationService(environment: environment)
 
@@ -42,6 +32,14 @@ public final class RootViewModel: ObservableObject {
             .sink { [weak self] in self?.identitySelected(id: $0) }
             .store(in: &cancellables)
 
+        userNotificationService.isAuthorized(request: false)
+            .filter { $0 }
+            .zip(registerForRemoteNotifications())
+            .map { $1 }
+            .flatMap(allIdentitiesService.updatePushSubscriptions(deviceToken:))
+            .sink { _ in } receiveValue: { _ in }
+            .store(in: &cancellables)
+
         userNotificationService.events
             .sink { [weak self] in self?.handle(event: $0) }
             .store(in: &cancellables)
@@ -128,11 +126,10 @@ private extension RootViewModel {
                     .store(in: &self.cancellables)
 
                 if identityContext.identity.authenticated,
-                   !identityContext.identity.pending,
-                   let registerForRemoteNotifications = self.registerForRemoteNotifications {
+                   !identityContext.identity.pending {
                     self.userNotificationService.isAuthorized(request: true)
                         .filter { $0 }
-                        .zip(registerForRemoteNotifications())
+                        .zip(self.registerForRemoteNotifications())
                         .filter { identityContext.identity.lastRegisteredDeviceToken != $1 }
                         .map { ($1, identityContext.identity.pushSubscriptionAlerts) }
                         .flatMap(identityContext.service.createPushSubscription(deviceToken:alerts:))