Fix retry button by re-adding failed downloads to tracking dict before resuming

Author: NeuralFault

StabilityMatrix.Avalonia/ViewModels/Progress/DownloadProgressItemViewModel.cs

@@ -99,10 +99,11 @@ public override Task Resume()
 
     /// <inheritdoc />
     /// Resets the internal retry counter so the user gets a fresh 3-attempt budget,
-    /// then re-queues the download exactly as if it were being resumed from pause.
+    /// then re-registers the download in the service dictionary (it was removed on
+    /// failure) and resumes it through the normal concurrency queue.
     public override Task Retry()
     {
         download.ResetAttempts();
-        return downloadService.TryResumeDownload(download);
+        return downloadService.TryRestartDownload(download);
     }
 }

StabilityMatrix.Avalonia/Views/ProgressManagerPage.axaml

@@ -120,7 +120,7 @@
                                         Command="{Binding RetryCommand}"
                                         IsVisible="{Binding CanRetry}"
                                         ToolTip.Tip="Retry download">
-                                        <ui:SymbolIcon Symbol="ArrowCounterclockwise" />
+                                        <ui:SymbolIcon Symbol="Refresh" />
                                     </Button>
                                 </StackPanel>
 

StabilityMatrix.Core/Models/TrackedDownload.cs

@@ -318,11 +318,8 @@ private void DoCleanup()
     }
 
     /// <summary>
-    /// Returns true for transient network/SSL exceptions that are safe to retry.
-    /// Catches direct IOException/AuthenticationException, the same types wrapped as
-    /// InnerException (common AggregateException shape from HttpClient), and any leg
-    /// of a multi-inner AggregateException — covering VPN tunnel resets
-    /// ("Connection reset by peer") and TLS re-key failures (OpenSSL SSL_ERROR_SSL).
+    /// Returns true for transient network/SSL exceptions that are safe to retry (ie: VPN tunnel resets or TLS re-key failures)
+    /// (IOException, AuthenticationException, or either wrapped in an AggregateException).
     /// </summary>
     private static bool IsTransientNetworkException(Exception? ex) =>
         ex is IOException or AuthenticationException
@@ -385,8 +382,7 @@ private void OnDownloadTaskCompleted(Task task)
                     attempts
                 );
 
-                // Persist Inactive state to disk before the delay so that a restart
-                // during the backoff window loads the download as a resumable entry.
+                // Persist Inactive to disk before the delay so a restart during backoff loads it as resumable.
                 OnProgressStateChanging(ProgressState.Inactive);
                 ProgressState = ProgressState.Inactive;
                 OnProgressStateChanged(ProgressState.Inactive);
@@ -424,13 +420,14 @@ private void OnDownloadTaskCompleted(Task task)
     }
 
     /// <summary>
-    /// Resets the internal retry attempt counter back to zero.
-    /// Call this before a user-initiated retry so the download gets
-    /// a fresh budget of automatic retries on the new attempt.
+    /// Resets the retry counter and silently sets state to Inactive without firing events.
+    /// Must be called before re-adding to TrackedDownloadService to avoid events
+    /// firing while the download is absent from the dictionary.
     /// </summary>
     public void ResetAttempts()
     {
         attempts = 0;
+        ProgressState = ProgressState.Inactive;
     }
 
     public void SetDownloadService(IDownloadService service)

StabilityMatrix.Core/Services/ITrackedDownloadService.cs

@@ -15,5 +15,7 @@ TrackedDownload NewDownload(string downloadUrl, FilePath downloadPath) =>
         NewDownload(new Uri(downloadUrl), downloadPath);
     Task TryStartDownload(TrackedDownload download);
     Task TryResumeDownload(TrackedDownload download);
+    Task TryRestartDownload(TrackedDownload download);
+
     void UpdateMaxConcurrentDownloads(int newMax);
 }

StabilityMatrix.Core/Services/TrackedDownloadService.cs

@@ -129,6 +129,26 @@ public async Task TryStartDownload(TrackedDownload download)
         }
     }
 
+    public async Task TryRestartDownload(TrackedDownload download)
+    {
+        // Re-create the backing JSON file and re-add to the dictionary.
+        // Downloads are removed on failure, so this restores the tracking entry
+        // so that subsequent state-change events can persist normally.
+        var downloadsDir = new DirectoryPath(settingsManager.DownloadsDirectory);
+        downloadsDir.Create();
+        var jsonFile = downloadsDir.JoinFile($"{download.Id}.json");
+
+        var jsonFileStream = jsonFile.Info.Open(FileMode.Create, FileAccess.ReadWrite, FileShare.Read);
+        var json = JsonSerializer.Serialize(download);
+        jsonFileStream.Write(Encoding.UTF8.GetBytes(json));
+        jsonFileStream.Flush();
+
+        // Handlers are already attached from the original AddDownload call.
+        downloads.TryAdd(download.Id, (download, jsonFileStream));
+
+        await TryResumeDownload(download).ConfigureAwait(false);
+    }
+
     public async Task TryResumeDownload(TrackedDownload download)
     {
         if (IsQueueEnabled && ActiveDownloads >= MaxConcurrentDownloads)