Refactor code structure for improved readability and maintainability

SocialIO/Sources/App/AppViewModel.swift

@@ -13,6 +13,7 @@ final class AppViewModel {
     var composeDraft = ComposeDraft()
     var threads: [MailThread] = []
     var isLoading = false
+    var isSending = false
     var errorMessage: String?
     var mailboxNavigationToken = UUID()
     var threadNavigationToken = UUID()
@@ -158,6 +159,7 @@ final class AppViewModel {
     func beginBackendControl() async {
         guard !isListeningForBackendCommands else { return }
         isListeningForBackendCommands = true
+        defer { isListeningForBackendCommands = false }
 
         for await command in controlService.commands() {
             apply(command: command)
@@ -206,17 +208,23 @@ final class AppViewModel {
         }
     }
 
-    func sendCurrentDraft() async {
+    func sendCurrentDraft() async -> Bool {
+        guard !isSending else { return false }
+
         let draft = composeDraft
-        isComposing = false
+        isSending = true
+        defer { isSending = false }
 
         do {
             let sentThread = try await service.send(draft: draft)
             threads.insert(sentThread, at: 0)
             selectedMailbox = .sent
             openThread(withID: sentThread.id)
+            isComposing = false
+            return true
         } catch {
             errorMessage = "Unable to send message."
+            return false
         }
     }
 

SocialIO/Sources/Features/Mail/MailRootView.swift

@@ -919,6 +919,7 @@ private struct ComposeView: View {
                         ComposeFieldCard(title: "Subject") {
                             TextField("What's this about?", text: $model.composeDraft.subject)
                                 .textFieldStyle(.plain)
+                                .disabled(model.isSending)
                                 .accessibilityIdentifier("compose.subject")
                         }
 
@@ -926,6 +927,7 @@ private struct ComposeView: View {
                             TextEditor(text: $model.composeDraft.body)
                                 .scrollContentBackground(.hidden)
                                 .frame(minHeight: 240)
+                                .disabled(model.isSending)
                                 .accessibilityIdentifier("compose.body")
                         }
 
@@ -937,23 +939,23 @@ private struct ComposeView: View {
                 }
             }
             .navigationTitle("Compose")
-            .navigationBarTitleDisplayMode(usesCompactComposeLayout ? .inline : .automatic)
+            .composeNavigationTitleDisplayMode(isCompact: usesCompactComposeLayout)
             .toolbar {
                 ToolbarItem(placement: .cancellationAction) {
                     Button("Cancel") {
                         dismiss()
                     }
+                    .disabled(model.isSending)
                     .accessibilityIdentifier("compose.cancel")
                 }
 
                 ToolbarItem(placement: .confirmationAction) {
-                    Button("Send") {
+                    Button(model.isSending ? "Sending…" : "Send") {
                         Task {
-                            await model.sendCurrentDraft()
-                            dismiss()
+                            _ = await model.sendCurrentDraft()
                         }
                     }
-                    .disabled(model.composeDraft.to.isEmpty || model.composeDraft.body.isEmpty)
+                    .disabled(model.isSending || model.composeDraft.to.isEmpty || model.composeDraft.body.isEmpty)
                     .accessibilityIdentifier("compose.send")
                 }
             }
@@ -968,11 +970,13 @@ private struct ComposeView: View {
             .textContentType(.emailAddress)
             .keyboardType(.emailAddress)
             .textInputAutocapitalization(.never)
+            .disabled(model.isSending)
             .accessibilityIdentifier("compose.to")
         #else
         TextField("name@example.com", text: $model.composeDraft.to)
             .textFieldStyle(.plain)
             .textContentType(.emailAddress)
+            .disabled(model.isSending)
             .accessibilityIdentifier("compose.to")
         #endif
     }
@@ -986,6 +990,17 @@ private struct ComposeView: View {
     }
 }
 
+private extension View {
+    @ViewBuilder
+    func composeNavigationTitleDisplayMode(isCompact: Bool) -> some View {
+        #if os(iOS)
+        navigationBarTitleDisplayMode(isCompact ? .inline : .automatic)
+        #else
+        self
+        #endif
+    }
+}
+
 private struct ComposeFieldCard<Content: View>: View {
     let title: String
     let content: Content