Use a logging sync to ensure GUI users are aware of any errors that occur while downloading

OF DL.Core/Services/DownloadService.cs

@@ -939,7 +939,8 @@ public class DownloadService(
         using HttpClient client = new();
         HttpRequestMessage request = new() { Method = HttpMethod.Get, RequestUri = new Uri(url) };
 
-        using HttpResponseMessage response = await client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, progressReporter.CancellationToken);
+        using HttpResponseMessage response = await client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead,
+            progressReporter.CancellationToken);
         response.EnsureSuccessStatusCode();
         Stream body = await response.Content.ReadAsStreamAsync(progressReporter.CancellationToken);
 

OF DL.Core/Services/LoggingService.cs

@@ -7,8 +7,11 @@ namespace OF_DL.Services;
 
 public class LoggingService : ILoggingService
 {
-    public LoggingService()
+    private readonly ILogEventSink? _optionalErrorSink;
+
+    public LoggingService(ILogEventSink? optionalErrorSink = null)
     {
+        _optionalErrorSink = optionalErrorSink;
         LevelSwitch = new LoggingLevelSwitch();
         InitializeLogger();
     }
@@ -38,10 +41,17 @@ public class LoggingService : ILoggingService
         // Set the initial level to Error (until we've read from config)
         LevelSwitch.MinimumLevel = LogEventLevel.Error;
 
-        Log.Logger = new LoggerConfiguration()
+        LoggerConfiguration loggerConfiguration = new LoggerConfiguration()
             .MinimumLevel.ControlledBy(LevelSwitch)
-            .WriteTo.File("logs/OFDL.txt", rollingInterval: RollingInterval.Day)
+            .WriteTo.File("logs/OFDL.txt", rollingInterval: RollingInterval.Day);
-            .CreateLogger();
+
+        if (_optionalErrorSink != null)
+        {
+            loggerConfiguration = loggerConfiguration.WriteTo.Sink(_optionalErrorSink,
+                LogEventLevel.Error);
+        }
+
+        Log.Logger = loggerConfiguration.CreateLogger();
 
         Log.Debug("Logging service initialized");
     }

OF DL.Gui/Program.cs

@@ -1,6 +1,5 @@
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
-using Microsoft.Extensions.DependencyInjection;
 using OF_DL.Helpers;
 using OF_DL.Services;
 using Serilog;
@@ -20,13 +19,10 @@ public static class Program
             // Parse command line arguments
             HidePrivateInfo = args.Contains("--hide-private-info", StringComparer.OrdinalIgnoreCase);
 
-            ServiceCollection services = new();
+            // Initialize the logging service to ensure that logs are written before Avalonia starts (with a new logging service)
-            services.AddSingleton<ILoggingService, LoggingService>();
+            LoggingService _ = new();
-            ServiceProvider tempProvider = services.BuildServiceProvider();
-            ILoggingService loggingService = tempProvider.GetRequiredService<ILoggingService>();
 
             RegisterGlobalExceptionHandlers();
-            Log.Information("Starting OF DL GUI");
 
             // Check if running in Docker and print a message
             if (EnvironmentHelper.IsRunningInDocker())
@@ -40,7 +36,7 @@ public static class Program
         }
         catch (Exception ex)
         {
-            HandleUnhandledException(ex, "Program.Main", isTerminating: true);
+            HandleUnhandledException(ex, "Program.Main", true);
         }
         finally
         {
@@ -65,7 +61,7 @@ public static class Program
         TaskScheduler.UnobservedTaskException += (_, eventArgs) =>
         {
             HandleUnhandledException(eventArgs.Exception, "TaskScheduler.UnobservedTaskException",
-                isTerminating: false);
+                false);
             eventArgs.SetObserved();
         };
     }

OF DL.Gui/Services/DownloadErrorLogTracking.cs

@@ -0,0 +1,45 @@
+using Serilog.Core;
+using Serilog.Events;
+
+namespace OF_DL.Gui.Services;
+
+public sealed class DownloadErrorLogTracker
+{
+    private int _sessionActive;
+    private int _errorLoggedInSession;
+
+    public bool IsSessionActive => Volatile.Read(ref _sessionActive) == 1;
+
+    public void StartSession()
+    {
+        Interlocked.Exchange(ref _errorLoggedInSession, 0);
+        Interlocked.Exchange(ref _sessionActive, 1);
+    }
+
+    public bool StopSession()
+    {
+        Interlocked.Exchange(ref _sessionActive, 0);
+        return Volatile.Read(ref _errorLoggedInSession) == 1;
+    }
+
+    public void RecordError()
+    {
+        if (!IsSessionActive)
+        {
+            return;
+        }
+
+        Interlocked.Exchange(ref _errorLoggedInSession, 1);
+    }
+}
+
+internal sealed class DownloadErrorTrackingSink(DownloadErrorLogTracker tracker) : ILogEventSink
+{
+    public void Emit(LogEvent logEvent)
+    {
+        if (logEvent.Level >= LogEventLevel.Error)
+        {
+            tracker.RecordError();
+        }
+    }
+}

OF DL.Gui/Services/ServiceCollectionFactory.cs

@@ -2,6 +2,7 @@ using Microsoft.Extensions.DependencyInjection;
 using OF_DL.Gui.ViewModels;
 using OF_DL.Gui.Views;
 using OF_DL.Services;
+using Serilog.Core;
 
 namespace OF_DL.Gui.Services;
 
@@ -11,6 +12,8 @@ internal static class ServiceCollectionFactory
     {
         IServiceCollection services = new ServiceCollection();
 
+        services.AddSingleton<DownloadErrorLogTracker>();
+        services.AddSingleton<ILogEventSink, DownloadErrorTrackingSink>();
         services.AddSingleton<ILoggingService, LoggingService>();
         services.AddSingleton<IConfigService, ConfigService>();
         services.AddSingleton<IAuthService, AuthService>();

OF DL.Gui/ViewModels/MainWindowViewModel.cs

@@ -26,7 +26,8 @@ public partial class MainWindowViewModel(
     IConfigService configService,
     IAuthService authService,
     IStartupService startupService,
-    IDownloadOrchestrationService downloadOrchestrationService) : ViewModelBase
+    IDownloadOrchestrationService downloadOrchestrationService,
+    DownloadErrorLogTracker downloadErrorLogTracker) : ViewModelBase
 {
     private enum SingleDownloadType
     {
@@ -946,6 +947,7 @@ public partial class MainWindowViewModel(
             return;
         }
 
+        downloadErrorLogTracker.StartSession();
         IsDownloading = true;
         _workCancellationSource?.Dispose();
         _workCancellationSource = new CancellationTokenSource();
@@ -1000,18 +1002,39 @@ public partial class MainWindowViewModel(
             }
 
             ThrowIfStopRequested();
+            if (downloadErrorLogTracker.StopSession())
+            {
+                AppendLog(
+                    "Errors were encountered during the download. Check the logs saved to the logs folder for details.");
+            }
+
             eventHandler.OnScrapeComplete(DateTime.Now - start);
         }
         catch (OperationCanceledException)
         {
+            if (downloadErrorLogTracker.IsSessionActive)
+            {
+                downloadErrorLogTracker.StopSession();
+            }
+
             AppendLog("Operation canceled.");
         }
         catch (Exception ex)
         {
+            if (downloadErrorLogTracker.IsSessionActive)
+            {
+                downloadErrorLogTracker.StopSession();
+            }
+
             AppendLog($"Download failed: {ex.Message}");
         }
         finally
         {
+            if (downloadErrorLogTracker.IsSessionActive)
+            {
+                downloadErrorLogTracker.StopSession();
+            }
+
             IsDownloading = false;
             _workCancellationSource?.Dispose();
             _workCancellationSource = null;
@@ -1228,6 +1251,7 @@ public partial class MainWindowViewModel(
             return;
         }
 
+        downloadErrorLogTracker.StartSession();
         IsDownloading = true;
         _workCancellationSource?.Dispose();
         _workCancellationSource = new CancellationTokenSource();
@@ -1306,18 +1330,39 @@ public partial class MainWindowViewModel(
             }
 
             ThrowIfStopRequested();
+            if (downloadErrorLogTracker.StopSession())
+            {
+                AppendLog(
+                    "Errors were encountered during the download. Check the logs saved to the logs folder for details.");
+            }
+
             eventHandler.OnScrapeComplete(DateTime.Now - start);
         }
         catch (OperationCanceledException)
         {
+            if (downloadErrorLogTracker.IsSessionActive)
+            {
+                downloadErrorLogTracker.StopSession();
+            }
+
             AppendLog("Operation canceled.");
         }
         catch (Exception ex)
         {
+            if (downloadErrorLogTracker.IsSessionActive)
+            {
+                downloadErrorLogTracker.StopSession();
+            }
+
             AppendLog($"Download failed: {ex.Message}");
         }
         finally
         {
+            if (downloadErrorLogTracker.IsSessionActive)
+            {
+                downloadErrorLogTracker.StopSession();
+            }
+
             IsDownloading = false;
             _workCancellationSource?.Dispose();
             _workCancellationSource = null;