Rename completion to callback and simplify actor usage. (#6141)

RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionViewModel.swift

@@ -28,7 +28,7 @@ class AuthenticationServerSelectionViewModel: AuthenticationServerSelectionViewM
 
     // MARK: Public
 
-    var completion: ((AuthenticationServerSelectionViewModelResult) -> Void)?
+    @MainActor var callback: ((AuthenticationServerSelectionViewModelResult) -> Void)?
 
     // MARK: - Setup
 
@@ -41,20 +41,15 @@ class AuthenticationServerSelectionViewModel: AuthenticationServerSelectionViewM
     // MARK: - Public
 
     override func process(viewAction: AuthenticationServerSelectionViewAction) {
-        Task {
-            await MainActor.run {
-                switch viewAction {
-                case .confirm:
-                    completion?(.confirm(homeserverAddress: state.bindings.homeserverAddress))
-                case .dismiss:
-                    completion?(.dismiss)
-                case .getInTouch:
-                    getInTouch()
-                case .clearFooterError:
-                    guard state.footerErrorMessage != nil else { return }
-                    withAnimation { state.footerErrorMessage = nil }
-                }
-            }
+        switch viewAction {
+        case .confirm:
+            Task { await callback?(.confirm(homeserverAddress: state.bindings.homeserverAddress)) }
+        case .dismiss:
+            Task { await callback?(.dismiss) }
+        case .getInTouch:
+            Task { await getInTouch() }
+        case .clearFooterError:
+            Task { await clearFooterError() }
         }
     }
     
@@ -71,6 +66,12 @@ class AuthenticationServerSelectionViewModel: AuthenticationServerSelectionViewM
     
     // MARK: - Private
     
+    /// Clear any errors shown in the text field footer.
+    @MainActor private func clearFooterError() {
+        guard state.footerErrorMessage != nil else { return }
+        withAnimation { state.footerErrorMessage = nil }
+    }
+    
     /// Opens the EMS link in the user's browser.
     @MainActor private func getInTouch() {
         let url = BuildSettings.onboardingHostYourOwnServerLink

RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionViewModelProtocol.swift

@@ -18,7 +18,7 @@ import Foundation
 
 protocol AuthenticationServerSelectionViewModelProtocol {
     
-    @MainActor var completion: ((AuthenticationServerSelectionViewModelResult) -> Void)? { get set }
+    @MainActor var callback: ((AuthenticationServerSelectionViewModelResult) -> Void)? { get set }
     var context: AuthenticationServerSelectionViewModelType.Context { get }
     
     /// Displays an error to the user.

RiotSwiftUI/Modules/Authentication/ServerSelection/Coordinator/AuthenticationServerSelectionCoordinator.swift

@@ -48,7 +48,7 @@ final class AuthenticationServerSelectionCoordinator: Coordinator, Presentable {
 
     // Must be used only internally
     var childCoordinators: [Coordinator] = []
-    @MainActor var completion: ((AuthenticationServerSelectionCoordinatorResult) -> Void)?
+    @MainActor var callback: ((AuthenticationServerSelectionCoordinatorResult) -> Void)?
     
     // MARK: - Setup
     
@@ -70,22 +70,8 @@ final class AuthenticationServerSelectionCoordinator: Coordinator, Presentable {
     // MARK: - Public
     
     func start() {
-        Task {
-            await MainActor.run {
-                MXLog.debug("[AuthenticationServerSelectionCoordinator] did start.")
-                authenticationServerSelectionViewModel.completion = { [weak self] result in
-                    guard let self = self else { return }
-                    MXLog.debug("[AuthenticationServerSelectionCoordinator] AuthenticationServerSelectionViewModel did complete with result: \(result).")
-                    
-                    switch result {
-                    case .confirm(let homeserverAddress):
-                        self.useHomeserver(homeserverAddress)
-                    case .dismiss:
-                        self.completion?(.dismiss)
-                    }
-                }
-            }
-        }
+        MXLog.debug("[AuthenticationServerSelectionCoordinator] did start.")
+        Task { await setupViewModel() }
     }
     
     func toPresentable() -> UIViewController {
@@ -94,6 +80,21 @@ final class AuthenticationServerSelectionCoordinator: Coordinator, Presentable {
     
     // MARK: - Private
     
+    /// Set up the view model. This method is extracted from `start()` so it can run on the `MainActor`.
+    @MainActor private func setupViewModel() {
+        authenticationServerSelectionViewModel.callback = { [weak self] result in
+            guard let self = self else { return }
+            MXLog.debug("[AuthenticationServerSelectionCoordinator] AuthenticationServerSelectionViewModel did complete with result: \(result).")
+            
+            switch result {
+            case .confirm(let homeserverAddress):
+                self.useHomeserver(homeserverAddress)
+            case .dismiss:
+                self.callback?(.dismiss)
+            }
+        }
+    }
+    
     /// Show an activity indicator whilst loading.
     /// - Parameters:
     ///   - label: The label to show on the indicator.
@@ -120,7 +121,7 @@ final class AuthenticationServerSelectionCoordinator: Coordinator, Presentable {
                 try await authenticationService.startFlow(.register, for: homeserverAddress)
                 stopLoading()
                 
-                completion?(.updated)
+                callback?(.updated)
             } catch {
                 stopLoading()