fix: Storing Nextcloud credentials on Windows does not work

lib/components/nextcloud/done_login_step.dart

@@ -22,16 +22,23 @@ class DoneLoginStep extends StatefulWidget {
 class _DoneLoginStepState extends State<DoneLoginStep> {
   static const width = 400.0;
 
-  void _logout() {
+  void _logout() async {
     Prefs.url.value = '';
+    await Prefs.url.waitUntilSaved(); // wait for write value is finished
     Prefs.username.value = '';
+    await Prefs.username.waitUntilSaved(); // wait for write value is finished
     Prefs.ncPassword.value = '';
+    await Prefs.ncPassword.waitUntilSaved(); // wait for write value is finished
     Prefs.ncPasswordIsAnAppPassword.value = false;
+    await Prefs.ncPasswordIsAnAppPassword.waitUntilSaved(); // wait for write value is finished
     Prefs.encPassword.value = '';
+    await Prefs.encPassword.waitUntilSaved(); // wait for write value is finished
     Prefs.pfp.value = null;
     Prefs.lastStorageQuota.value = null;
     Prefs.key.value = '';
+    await Prefs.key.waitUntilSaved(); // wait for write value is finished
     Prefs.iv.value = '';
+    await Prefs.iv.waitUntilSaved(); // wait for write value is finished
     widget.recheckCurrentStep();
   }
 

lib/components/nextcloud/enc_login_step.dart

@@ -64,10 +64,13 @@ class _EncLoginStepState extends State<EncLoginStep> {
               text: text,
               style: TextStyle(color: colorScheme.link),
               recognizer: TapGestureRecognizer()
-                ..onTap = () {
+                ..onTap = () async {
                   Prefs.url.value = '';
+                  await Prefs.url.waitUntilSaved();
                   Prefs.username.value = '';
+                  await Prefs.username.waitUntilSaved();
                   Prefs.ncPassword.value = '';
+                  await Prefs.ncPassword.waitUntilSaved();
                   widget.recheckCurrentStep();
                 },
             ),
@@ -140,16 +143,21 @@ class _EncLoginStepState extends State<EncLoginStep> {
 
     try {
       Prefs.encPassword.value = encPassword;
+      await Prefs.encPassword.waitUntilSaved();
+
       final client = NextcloudClientExtension.withSavedDetails()!;
       _isChecking.value = true;
       await client.loadEncryptionKey();
       widget.recheckCurrentStep();
     } on EncLoginFailure {
       Prefs.encPassword.value = '';
+      await Prefs.encPassword.waitUntilSaved();
+
 
       _errorMessage.value = t.login.encLoginStep.wrongEncPassword;
     } catch (e) {
       Prefs.encPassword.value = '';
+      await Prefs.encPassword.waitUntilSaved();
       log.severe('Failed to load encryption key: $e', e);
 
       _errorMessage.value = '${t.login.encLoginStep.connectionFailed}\n\n$e';

lib/components/nextcloud/nc_login_step.dart

@@ -53,14 +53,21 @@ class _NcLoginStepState extends State<NcLoginStep> {
       );
       final username = await client.getUsername();
 
-      Prefs.url.value = credentials.server ==
-              NextcloudClientExtension.defaultNextcloudUri.toString()
+      Prefs.url.value= credentials.server ==
+          NextcloudClientExtension.defaultNextcloudUri.toString()
           ? ''
           : credentials.server;
+      await Prefs.url.waitUntilSaved(); // wait until properly saved
+
       Prefs.username.value = username;
+      await Prefs.username.waitUntilSaved();
+
       Prefs.ncPassword.value = credentials.appPassword;
+      await Prefs.ncPassword.waitUntilSaved();
       Prefs.ncPasswordIsAnAppPassword.value = true;
+
       Prefs.encPassword.value = '';
+      await Prefs.encPassword.waitUntilSaved();
 
       Prefs.pfp.value = null;
       client.core.avatar

lib/components/settings/nextcloud_profile.dart

@@ -31,6 +31,7 @@ class _NextcloudProfileState extends State<NextcloudProfile> {
   @override
   void initState() {
     Prefs.username.addListener(_usernameChanged);
+    Prefs.url.addListener(_usernameChanged);
     Prefs.encPassword.addListener(_usernameChanged);
     Prefs.key.addListener(_usernameChanged);
     Prefs.iv.addListener(_usernameChanged);
@@ -40,6 +41,7 @@ class _NextcloudProfileState extends State<NextcloudProfile> {
   @override
   void dispose() {
     Prefs.username.removeListener(_usernameChanged);
+    Prefs.url.removeListener(_usernameChanged);
     Prefs.encPassword.removeListener(_usernameChanged);
     Prefs.key.removeListener(_usernameChanged);
     Prefs.iv.removeListener(_usernameChanged);

lib/data/nextcloud/nextcloud_client_extension.dart

@@ -120,7 +120,9 @@ extension NextcloudClientExtension on NextcloudClient {
       try {
         final String key = encrypter.decrypt64(encryptedKey, iv: iv);
         Prefs.key.value = key;
+        await Prefs.key.waitUntilSaved();
         Prefs.iv.value = iv.base64;
+        await Prefs.iv.waitUntilSaved();
         return key;
       } catch (e) {
         // can't decrypt, so we need to get the previous encryption key (user's password)
@@ -142,8 +144,9 @@ extension NextcloudClientExtension on NextcloudClient {
     await setConfig(config);
 
     Prefs.key.value = key.base64;
+    await Prefs.key.waitUntilSaved();
     Prefs.iv.value = iv.base64;
-
+    await Prefs.iv.waitUntilSaved();
     return key.base64;
   }
 

lib/data/nextcloud/saber_syncer.dart

@@ -168,8 +168,11 @@ class SaberSyncInterface
       } on EncLoginFailure {
         // enc password has changed since the user last logged in, so log out
         Prefs.encPassword.value = '';
+        await Prefs.encPassword.waitUntilSaved();
         Prefs.key.value = '';
+        await Prefs.key.waitUntilSaved();
         Prefs.iv.value = '';
+        await Prefs.iv.waitUntilSaved();
       }
       return Uint8List(0);
     } else if (file.remoteFile?.size == 0) {