Fixed attached files silently reaching the AI as empty documents (#904)

app/MindWork AI Studio/Tools/UserFile.cs

@@ -1,5 +1,6 @@
 using AIStudio.Dialogs;
 using AIStudio.Tools.PluginSystem;
+using AIStudio.Tools.Rust;
 using AIStudio.Tools.Services;
 using DialogOptions = AIStudio.Dialogs.DialogOptions;
 
@@ -14,38 +15,71 @@ public static class UserFile
     /// <summary>
     /// Attempts to load the content of a file at the specified path, ensuring Pandoc is installed and available before proceeding.
     /// </summary>
+    /// <remarks>
+    /// This is the one place which reports a failed load to the user, so callers neither have to
+    /// repeat that nor may they treat a failure as an empty file.
+    /// </remarks>
     /// <param name="filePath">The full path to the file to be read. Must not be null or empty.</param>
     /// <param name="rustService">Rust service used to read file content.</param>
     /// <param name="dialogService">Dialogservice used to display the Pandoc installation dialog if needed.</param>
-    public static async Task<string> LoadFileData(string filePath, RustService rustService, IDialogService dialogService)
+    /// <returns>The result of reading the file.</returns>
+    public static async Task<FileExtractionResult> LoadFileData(string filePath, RustService rustService, IDialogService dialogService)
     {
         if (string.IsNullOrEmpty(filePath))
         {
             LOGGER.LogError("Can't load from an empty or null file path.");
             await MessageBus.INSTANCE.SendError(new(Icons.Material.Filled.Cancel, TB("The file path is null or empty and the file therefore can not be loaded.")));
+            return FileExtractionResult.Failed(FileExtractionErrorCode.INVALID_REQUEST, "The file path is null or empty.");
         }
-        
-        // Ensure that Pandoc is installed and ready:
-        var pandocState = await Pandoc.CheckAvailabilityAsync(rustService, showSuccessMessage: false);
-        if (!pandocState.IsAvailable)
+
+        var fileName = Path.GetFileName(filePath);
+
+        //
+        // Ensure that Pandoc is installed and ready. This is only needed for the formats we
+        // convert with it: PDFs and the other document types are read by the Rust runtime itself.
+        //
+        if (FileTypes.RequiresPandoc(filePath))
         {
-            var dialogParameters = new DialogParameters<PandocDialog>
-            {
-                { x => x.ShowInitialResultInSnackbar, false },
-            };
-                
-            var dialogReference = await dialogService.ShowAsync<PandocDialog>(TB("Pandoc Installation"), dialogParameters, DialogOptions.FULLSCREEN);
-            await dialogReference.Result;
-                
-            pandocState = await Pandoc.CheckAvailabilityAsync(rustService, showSuccessMessage: true);
+            var pandocState = await Pandoc.CheckAvailabilityAsync(rustService, showSuccessMessage: false);
             if (!pandocState.IsAvailable)
             {
-                LOGGER.LogError("Pandoc is not available after installation attempt.");
-                await MessageBus.INSTANCE.SendError(new(Icons.Material.Filled.Cancel, TB("Pandoc may be required for importing files.")));
+                var dialogParameters = new DialogParameters<PandocDialog>
+                {
+                    { x => x.ShowInitialResultInSnackbar, false },
+                };
+
+                var dialogReference = await dialogService.ShowAsync<PandocDialog>(TB("Pandoc Installation"), dialogParameters, DialogOptions.FULLSCREEN);
+                await dialogReference.Result;
+
+                pandocState = await Pandoc.CheckAvailabilityAsync(rustService, showSuccessMessage: true);
+                if (!pandocState.IsAvailable)
+                {
+                    LOGGER.LogError("Pandoc is not available after installation attempt, so '{FilePath}' cannot be read.", filePath);
+                    await MessageBus.INSTANCE.SendError(new(Icons.Material.Filled.Cancel, FileExtractionErrorCode.PANDOC_UNAVAILABLE.ToUserMessage(fileName)));
+                    return FileExtractionResult.Failed(FileExtractionErrorCode.PANDOC_UNAVAILABLE, "Pandoc is required to read this file, but it is not available.");
+                }
             }
         }
-        
-        var fileContent = await rustService.ReadArbitraryFileData(filePath, int.MaxValue);
-        return fileContent;
+
+        var result = await rustService.ReadArbitraryFileData(filePath, int.MaxValue);
+        if (!result.HasUsableContent)
+        {
+            LOGGER.LogError("Reading the file '{FilePath}' failed: code={ErrorCode}, message='{ErrorMessage}'.", filePath, result.ErrorCode, result.ErrorMessage);
+            await MessageBus.INSTANCE.SendError(new(Icons.Material.Filled.Description, result.ToUserMessage(fileName)));
+        }
+        else if (result.Outcome is FileExtractionOutcome.PARTIAL)
+        {
+            LOGGER.LogWarning("Parts of the file '{FilePath}' could not be read: pages={FailedPages}.", filePath, string.Join(", ", result.FailedPages));
+            await MessageBus.INSTANCE.SendWarning(new(Icons.Material.Filled.Description, result.ToPartialUserMessage(fileName)));
+        }
+
+        // The file was read correctly, but its extension lies about what it contains:
+        if (result.HasExtensionMismatch)
+        {
+            LOGGER.LogWarning("The file '{FilePath}' is actually a '{DetectedFormat}'.", filePath, result.DetectedFormat);
+            await MessageBus.INSTANCE.SendWarning(new(Icons.Material.Filled.RuleFolder, result.ToExtensionMismatchUserMessage(fileName)));
+        }
+
+        return result;
     }
 }