Show cancel button when showing authenticationViewController

Signed-off-by: Marcel Müller <marcel-mueller@gmx.de>

NextcloudTalk/AuthenticationViewController.m

@@ -49,7 +49,6 @@ NSString * const kNCAuthTokenFlowEndpoint               = @"/index.php/login/flo
     self = [super init];
     if (self) {
         self.serverUrl = serverUrl;
-        self.modalPresentationStyle = ([[NCDatabaseManager sharedInstance] numberOfAccounts] == 0) ? UIModalPresentationFullScreen : UIModalPresentationAutomatic;
     }
     
     return self;
@@ -101,6 +100,36 @@ NSString * const kNCAuthTokenFlowEndpoint               = @"/index.php/login/flo
     }];
 }
 
+- (void)viewWillAppear:(BOOL)animated
+{
+    UIColor *themeColor = [NCAppBranding themeColor];
+    [self.view setBackgroundColor:themeColor];
+
+    [self.navigationController.navigationBar setTitleTextAttributes:
+     @{NSForegroundColorAttributeName:[NCAppBranding themeTextColor]}];
+    self.navigationController.navigationBar.tintColor = [NCAppBranding themeTextColor];
+    self.navigationController.navigationBar.translucent = YES;
+    self.navigationController.navigationBar.barTintColor = [NCAppBranding themeColor];
+
+    UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
+                                                                                  target:self action:@selector(cancelButtonPressed)];
+    cancelButton.accessibilityHint = NSLocalizedString(@"Double tap to dismiss authentication dialog", nil);
+    self.navigationController.navigationBar.topItem.leftBarButtonItem = cancelButton;
+
+    UINavigationBarAppearance *appearance = [[UINavigationBarAppearance alloc] init];
+    [appearance configureWithOpaqueBackground];
+    appearance.backgroundColor = themeColor;
+    appearance.titleTextAttributes = @{NSForegroundColorAttributeName:[NCAppBranding themeTextColor]};
+    self.navigationItem.standardAppearance = appearance;
+    self.navigationItem.compactAppearance = appearance;
+    self.navigationItem.scrollEdgeAppearance = appearance;
+}
+
+- (void)cancelButtonPressed
+{
+    [self dismissViewControllerAnimated:YES completion:nil];
+}
+
 - (void)didReceiveMemoryWarning
 {
     [super didReceiveMemoryWarning];

NextcloudTalk/LoginViewController.m

@@ -201,7 +201,8 @@
         _authenticationViewController.user = user;
     }
 
-    [self presentViewController:_authenticationViewController animated:YES completion:nil];
+    UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:_authenticationViewController];
+    [self presentViewController:navController animated:YES completion:nil];
 }
 
 #pragma mark - Alerts