Fix remaining code review issues: extract common error handling, add null checks, use timestamped backups

Co-authored-by: BornToBeRoot <[email protected]>

Author: Copilot

Source/NETworkManager.Settings/SettingsManager.cs

@@ -1,6 +1,7 @@
 using log4net;
 using NETworkManager.Models;
 using NETworkManager.Models.Network;
+using NETworkManager.Utilities;
 using System;
 using System.IO;
 using System.Linq;
@@ -150,10 +151,10 @@ public static void Load()
             // Save in new JSON format
             Save();
 
-            // Backup the old XML file
+            // Backup the old XML file with timestamp to avoid overwriting existing backups
             var backupFilePath = Path.Combine(GetSettingsFolderLocation(), 
-                $"{SettingsFileName}{LegacySettingsFileExtension}.backup");
-            File.Copy(legacyFilePath, backupFilePath, true);
+                $"{SettingsFileName}_{TimestampHelper.GetTimestamp()}{LegacySettingsFileExtension}.backup");
+            File.Copy(legacyFilePath, backupFilePath, false);
             Log.Info($"Legacy XML settings file backed up to: {backupFilePath}");
 
             // Note: The original XML file is intentionally not deleted to allow users to revert if needed.
@@ -198,7 +199,12 @@ private static SettingsInfo DeserializeFromXmlFile(string filePath)
 
         using var fileStream = new FileStream(filePath, FileMode.Open);
 
-        var settingsInfo = (SettingsInfo)xmlSerializer.Deserialize(fileStream);
+        var settingsInfo = xmlSerializer.Deserialize(fileStream) as SettingsInfo;
+
+        if (settingsInfo == null)
+        {
+            throw new InvalidOperationException("Failed to deserialize settings from XML file. The result was null.");
+        }
 
         return settingsInfo;
     }

Source/NETworkManager/App.xaml.cs

@@ -96,36 +96,14 @@ by BornToBeRoot
             Log.Error("Could not load application settings!");
             Log.Error(ex.Message + "-" + ex.StackTrace);
 
-            // Create backup of corrupted file
-            var destinationFile =
-                $"{TimestampHelper.GetTimestamp()}_corrupted_" + SettingsManager.GetSettingsFileName();
-            File.Copy(SettingsManager.GetSettingsFilePath(),
-                Path.Combine(SettingsManager.GetSettingsFolderLocation(), destinationFile));
-            Log.Info($"A backup of the corrupted settings file has been saved under {destinationFile}");
-
-            // Initialize default application settings
-            Log.Info("Initialize default application settings...");
-
-            SettingsManager.Initialize();
-            ConfigurationManager.Current.ShowSettingsResetNoteOnStartup = true;
+            HandleCorruptedSettingsFile();
         }
         catch (JsonException ex)
         {
             Log.Error("Could not load application settings! JSON file is corrupted or invalid.");
             Log.Error(ex.Message + "-" + ex.StackTrace);
 
-            // Create backup of corrupted file
-            var destinationFile =
-                $"{TimestampHelper.GetTimestamp()}_corrupted_" + SettingsManager.GetSettingsFileName();
-            File.Copy(SettingsManager.GetSettingsFilePath(),
-                Path.Combine(SettingsManager.GetSettingsFolderLocation(), destinationFile));
-            Log.Info($"A backup of the corrupted settings file has been saved under {destinationFile}");
-
-            // Initialize default application settings
-            Log.Info("Initialize default application settings...");
-
-            SettingsManager.Initialize();
-            ConfigurationManager.Current.ShowSettingsResetNoteOnStartup = true;
+            HandleCorruptedSettingsFile();
         }
 
         // Upgrade settings if necessary
@@ -239,6 +217,25 @@ by BornToBeRoot
         }
     }
 
+    /// <summary>
+    ///     Handles a corrupted settings file by creating a backup and initializing default settings.
+    /// </summary>
+    private void HandleCorruptedSettingsFile()
+    {
+        // Create backup of corrupted file
+        var destinationFile =
+            $"{TimestampHelper.GetTimestamp()}_corrupted_" + SettingsManager.GetSettingsFileName();
+        File.Copy(SettingsManager.GetSettingsFilePath(),
+            Path.Combine(SettingsManager.GetSettingsFolderLocation(), destinationFile));
+        Log.Info($"A backup of the corrupted settings file has been saved under {destinationFile}");
+
+        // Initialize default application settings
+        Log.Info("Initialize default application settings...");
+
+        SettingsManager.Initialize();
+        ConfigurationManager.Current.ShowSettingsResetNoteOnStartup = true;
+    }
+
     private void DispatcherTimer_Tick(object sender, EventArgs e)
     {
         Log.Info("Run background job...");