Fix crash when opening Compose screen before account/instance is loaded

Prevents when opening the Compose screen with poor network connectivity

Tusker/Controllers/MastodonController.swift

@@ -9,7 +9,7 @@
 import Foundation
 import Pachyderm
 
-class MastodonController {
+class MastodonController: ObservableObject {
 
     static private(set) var all = [LocalData.UserAccountInfo: MastodonController]()
     
@@ -42,8 +42,8 @@ class MastodonController {
     
     let client: Client!
     
-    var account: Account!
-    var instance: Instance!
+    @Published private(set) var account: Account!
+    @Published private(set) var instance: Instance!
     
     var loggedIn: Bool {
         accountInfo != nil
@@ -95,7 +95,9 @@ class MastodonController {
                     completion?(.failure(error))
                     
                 case let .success(account, _):
-                    self.account = account
+                    DispatchQueue.main.async {
+                        self.account = account
+                    }
                     self.persistentContainer.backgroundContext.perform {
                         if let accountMO = self.persistentContainer.account(for: account.id, in: self.persistentContainer.backgroundContext) {
                             accountMO.updateFrom(apiAccount: account, container: self.persistentContainer)
@@ -118,13 +120,12 @@ class MastodonController {
             let request = Client.getInstance()
             run(request) { (response) in
                 guard case let .success(instance, _) = response else { fatalError() }
-                self.instance = instance
-                completion?(instance)
+                DispatchQueue.main.async {
+                    self.instance = instance
+                    completion?(instance)
+                }
             }
         }
     }
     
 }
-
-// ObservableObject so that SwiftUI views can receive it through @EnvironmentObject
-extension MastodonController: ObservableObject {}

Tusker/Screens/Compose/ComposeAttachmentsList.swift

@@ -91,7 +91,9 @@ struct ComposeAttachmentsList: View {
     }
     
     private var canAddAttachment: Bool {
-        switch mastodonController.instance.instanceType {
+        switch mastodonController.instance?.instanceType {
+        case nil:
+            return false
         case .pleroma:
             return true
         case .mastodon:

Tusker/Screens/Compose/ComposeAvatarImageView.swift

@@ -9,7 +9,7 @@
 import SwiftUI
 
 struct ComposeAvatarImageView: View {
-    let url: URL
+    let url: URL?
     @State var request: ImageCache.Request? = nil
     @State var avatarImage: UIImage? = nil
     @ObservedObject var preferences = Preferences.shared
@@ -19,7 +19,9 @@ struct ComposeAvatarImageView: View {
             .resizable()
             .frame(width: 50, height: 50)
             .cornerRadius(preferences.avatarStyle.cornerRadiusFraction * 50)
-            .onAppear(perform: self.loadImage)
+            .conditionally(url != nil) {
+                $0.onAppear(perform: self.loadImage)
+            }
             .onDisappear(perform: self.cancelRequest)
     }
     
@@ -27,24 +29,33 @@ struct ComposeAvatarImageView: View {
         if let avatarImage = avatarImage {
             return Image(uiImage: avatarImage)
         } else {
-            let imageName: String
-            switch preferences.avatarStyle {
-            case .circle:
-                imageName = "person.crop.circle"
-            case .roundRect:
-                imageName = "person.crop.square"
-            }
-            return Image(systemName: imageName)
+            return placeholderImage
         }
     }
     
+    private var placeholderImage: Image {
+        let imageName: String
+        switch preferences.avatarStyle {
+        case .circle:
+            imageName = "person.crop.circle"
+        case .roundRect:
+            imageName = "person.crop.square"
+        }
+        return Image(systemName: imageName)
+    }
+    
     private func loadImage() {
+        guard let url = url else { return }
         request = ImageCache.avatars.get(url) { (data) in
-            DispatchQueue.main.async {
-                self.request = nil
-                if let data = data, let image = UIImage(data: data) {
+            if let data = data, let image = UIImage(data: data) {
+                DispatchQueue.main.async {
+                    self.request = nil
                     self.avatarImage = image
                 }
+            } else {
+                DispatchQueue.main.async {
+                    self.request = nil
+                }
             }
         }
     }

Tusker/Screens/Compose/ComposeCurrentAccount.swift

@@ -12,24 +12,29 @@ import Pachyderm
 struct ComposeCurrentAccount: View {
     @EnvironmentObject var mastodonController: MastodonController
     
-    var account: Account {
-        mastodonController.account!
+    var account: Account? {
+        mastodonController.account
     }
     
     var body: some View {
         HStack(alignment: .top) {
-            ComposeAvatarImageView(url: account.avatar)
-                .accessibility(label: Text("\(account.displayName) avatar"))
+            ComposeAvatarImageView(url: account?.avatar)
+                .accessibility(label: Text(account != nil ? "\(account!.displayName) avatar" : "Avatar"))
             
-            VStack(alignment: .leading) {
-                AccountDisplayNameLabel(account: mastodonController.persistentContainer.account(for: account.id)!, fontSize: 20)
-                    .lineLimit(1)
-                
-                Text(verbatim: "@\(account.acct)")
-                    .font(.system(size: 17, weight: .light))
-                    .foregroundColor(.secondary)
-                    .lineLimit(1)
+            if let id = account?.id,
+               let account = mastodonController.persistentContainer.account(for: id) {
+                VStack(alignment: .leading) {
+                    AccountDisplayNameLabel(account: account, fontSize: 20)
+                        .lineLimit(1)
+                    
+                    Text(verbatim: "@\(account.acct)")
+                        .font(.system(size: 17, weight: .light))
+                        .foregroundColor(.secondary)
+                        .lineLimit(1)
+                }
             }
+            
+            Spacer()
         }
     }
 }

Tusker/Screens/Compose/ComposeView.swift

@@ -28,7 +28,7 @@ struct ComposeView: View {
     }
     
     var charactersRemaining: Int {
-        let limit = mastodonController.instance.maxStatusCharacters ?? 500
+        let limit = mastodonController.instance?.maxStatusCharacters ?? 500
         let cwCount = draft.contentWarningEnabled ? draft.contentWarning.count : 0
         return limit - (cwCount + CharacterCounter.count(text: draft.text))
     }