Fix authentication activity indicators when the authentication server is being slow

* Fetch the OIDC login URL as part of the Server Confirmation screen.

The loading indicator would show and hide while configuring and then immediately show again while fetching the URL.

* Allow the OIDCAuthenticationPresenter to show its own errors.

We no longer need to present errors in the authentication flow coordinator.

ElementX/Sources/FlowCoordinators/AuthenticationFlowCoordinator.swift

@@ -144,12 +144,10 @@ class AuthenticationFlowCoordinator: FlowCoordinatorProtocol {
             guard let self else { return }
             
             switch action {
-            case .continue(let window):
-                if authenticationService.homeserver.value.loginMode.supportsOIDCFlow, let window {
-                    showOIDCAuthentication(presentationAnchor: window)
-                } else {
-                    showLoginScreen()
-                }
+            case .continueWithOIDC(let oidcData, let window):
+                showOIDCAuthentication(oidcData: oidcData, presentationAnchor: window)
+            case .continueWithPassword:
+                showLoginScreen()
             case .changeServer:
                 showServerSelectionScreen(authenticationFlow: authenticationFlow)
             }
@@ -185,29 +183,21 @@ class AuthenticationFlowCoordinator: FlowCoordinatorProtocol {
         navigationStackCoordinator.setSheetCoordinator(navigationCoordinator)
     }
     
-    private func showOIDCAuthentication(presentationAnchor: UIWindow) {
-        startLoading()
+    private func showOIDCAuthentication(oidcData: OIDCAuthorizationDataProxy, presentationAnchor: UIWindow) {
+        let presenter = OIDCAuthenticationPresenter(authenticationService: authenticationService,
+                                                    oidcRedirectURL: appSettings.oidcRedirectURL,
+                                                    presentationAnchor: presentationAnchor,
+                                                    userIndicatorController: userIndicatorController)
+        oidcPresenter = presenter
         
         Task {
-            switch await authenticationService.urlForOIDCLogin() {
-            case .failure(let error):
-                stopLoading()
-                handleError(error)
-            case .success(let oidcData):
-                stopLoading()
-                
-                let presenter = OIDCAuthenticationPresenter(authenticationService: authenticationService,
-                                                            oidcRedirectURL: appSettings.oidcRedirectURL,
-                                                            presentationAnchor: presentationAnchor)
-                self.oidcPresenter = presenter
-                switch await presenter.authenticate(using: oidcData) {
-                case .success(let userSession):
-                    userHasSignedIn(userSession: userSession)
-                case .failure(let error):
-                    handleError(error)
-                }
-                oidcPresenter = nil
+            switch await presenter.authenticate(using: oidcData) {
+            case .success(let userSession):
+                userHasSignedIn(userSession: userSession)
+            case .failure:
+                break // Nothing to do, the alerts are handled by the presenter.
             }
+            oidcPresenter = nil
         }
     }
     
@@ -238,35 +228,4 @@ class AuthenticationFlowCoordinator: FlowCoordinatorProtocol {
     private func userHasSignedIn(userSession: UserSessionProtocol) {
         delegate?.authenticationFlowCoordinator(didLoginWithSession: userSession)
     }
-    
-    private static let loadingIndicatorIdentifier = "\(AuthenticationFlowCoordinator.self)-Loading"
-    
-    private func startLoading() {
-        userIndicatorController.submitIndicator(UserIndicator(id: Self.loadingIndicatorIdentifier,
-                                                              type: .modal,
-                                                              title: L10n.commonLoading,
-                                                              persistent: true))
-    }
-    
-    private func stopLoading() {
-        userIndicatorController.retractIndicatorWithId(Self.loadingIndicatorIdentifier)
-    }
-    
-    /// Processes an error to either update the flow or display it to the user.
-    private func handleError(_ error: AuthenticationServiceError) {
-        MXLog.warning("Error occurred: \(error)")
-        
-        switch error {
-        case .oidcError(.notSupported):
-            // Temporary alert hijacking the use of .notSupported, can be removed when OIDC support is in the SDK.
-            userIndicatorController.alertInfo = AlertInfo(id: UUID(),
-                                                          title: L10n.commonError,
-                                                          message: L10n.commonServerNotSupported)
-        case .oidcError(.userCancellation):
-            // No need to show an error, the user cancelled authentication.
-            break
-        default:
-            userIndicatorController.alertInfo = AlertInfo(id: UUID())
-        }
-    }
 }