some work

OwnChar/Manager/OwnCharManager.cs

@@ -1,4 +1,5 @@
 using OwnChar.Data;
+using OwnChar.Manager.Exceptions;
 using OwnChar.Model;
 using Pilz.Cryptography;
 
@@ -7,32 +8,50 @@ namespace OwnChar.Manager
     public class OwnCharManager
     {
         // User
-        public bool IsLoggedIn { get; set; }
-        public UserAccount? CurrentUser { get; set; }
+        public bool IsLoggedIn => DataProvider != null && DataProvider.IsLoggedIn;
+        public UserAccount? CurrentUser => DataProvider?.CurrentUserAccount;
 
         // Data Provider
-        public IDataProvider DataProvider { get; set; }
+        public IDataProvider? DataProvider { get; set; }
 
         // Manager
         public UserManager Users { get; }
         public GroupsManager Groups { get; }
         public CharacterManager Characters { get; }
 
-        public OwnCharManager(IDataProvider dataProvider)
+        public OwnCharManager()
         {
-            DataProvider = dataProvider;
             Users = new(this);
             Groups = new(this);
             Characters = new(this);
         }
 
+        private void CheckLogin()
+        {
+            if (!IsLoggedIn)
+                throw new LoginException("You are already logged in!");
+        }
+
         /// <summary>
-        /// Tries to login on the server.
+        /// 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(string username, SecureString password)
+        public bool Login(IDataProvider? dataProvider, string username, SecureString password)
         {
-            return IsLoggedIn = true; // TODO: Change `true` to the real check.
+            CheckLogin();
+            ArgumentNullException.ThrowIfNull(dataProvider);
+            return dataProvider.Login(username, password) != null;
+        }
+
+        /// <summary>
+        /// Closes the session on the current data provider.
+        /// </summary>
+        /// <returns></returns>
+        public bool Logout()
+        {
+            if (DataProvider != null)
+                return DataProvider.Logout();
+            return true;
         }
     }
 }