yea boy, now I got it!

OwnChar/Manager/OwnCharManager.cs

@@ -8,11 +8,11 @@ namespace OwnChar.Manager
     public class OwnCharManager
     {
         // User
-        public bool IsLoggedIn => DataProvider != null && DataProvider.IsLoggedIn;
-        public UserAccount? CurrentUser => DataProvider?.CurrentUserAccount;
+        public bool IsLoggedIn => CurrentUser != null;
+        public UserAccount? CurrentUser { get; private set; }
 
         // Data Provider
-        public IDataProvider? DataProvider { get; set; }
+        public IDataProxy? DataProxy { get; set; }
 
         // Manager
         public UserManager Users { get; }
@@ -26,7 +26,7 @@ namespace OwnChar.Manager
             Characters = new(this);
         }
 
-        private void CheckLogin()
+        internal protected void CheckLogin()
         {
             if (!IsLoggedIn)
                 throw new LoginException("You are already logged in!");
@@ -36,11 +36,15 @@ namespace OwnChar.Manager
         /// Tries to login on the given data provider.
         /// </summary>
         /// <returns>Returns <see cref="true"/> if the login was successfull and <see cref="false"/> if not.</returns>
-        public bool Login(IDataProvider? dataProvider, string username, SecureString password)
+        public bool Login(IDataProxy? proxy, string? username, SecureString? password)
         {
-            CheckLogin();
-            ArgumentNullException.ThrowIfNull(dataProvider);
-            return dataProvider.Login(username, password) != null;
+            ArgumentNullException.ThrowIfNull(proxy, nameof(proxy));
+            ArgumentException.ThrowIfNullOrWhiteSpace(username, nameof(username));
+            ArgumentException.ThrowIfNullOrWhiteSpace(password, nameof(password));
+
+            CurrentUser = proxy.Login(username, password);
+
+            return IsLoggedIn;
         }
 
         /// <summary>
@@ -49,9 +53,7 @@ namespace OwnChar.Manager
         /// <returns></returns>
         public bool Logout()
         {
-            if (DataProvider != null)
-                return DataProvider.Logout();
-            return true;
+            return DataProxy?.Logout(CurrentUser) ?? true;
         }
     }
 }