Fixed exports and the clipboard losing the sources of an answer (#966)

app/MindWork AI Studio/Chat/ContentBlockComponent.razor.cs

@@ -732,7 +732,7 @@ public partial class ContentBlockComponent : MSGComponentBase
             //
             if (format.UsesPandoc())
                 await PandocExport.ToDocument(this.RustService, this.PandocAvailability, this.EffectiveExportTitle, format, this.Content);
-            else if (this.Content.TryGetMarkdownText(out var markdown))
+            else if (this.Content.TryGetExportMarkdown(out var markdown))
                 await PlainFileExport.ToFile(this.RustService, this.EffectiveExportTitle, format, markdown);
         }
         catch (ArgumentOutOfRangeException e)

app/MindWork AI Studio/Chat/IContentExtensions.cs

@@ -24,7 +24,9 @@ public static class IContentExtensions
     /// <remarks>
     /// Only text content carries Markdown. Everything else, an image for example, has no text
     /// representation at all, which is why this reports failure instead of returning a placeholder:
-    /// a caller which writes files must not put an excuse into the file it writes.
+    /// a caller which writes files must not put an excuse into the file it writes. This is the text
+    /// the model wrote and nothing else: whoever reads a table out of a message wants exactly that,
+    /// while whoever writes a file wants the sources along with it and asks for the export reading.
     /// </remarks>
     /// <param name="content">The content to read.</param>
     /// <param name="markdown">The Markdown text, or an empty string when there is none.</param>
@@ -40,4 +42,48 @@ public static class IContentExtensions
         markdown = string.Empty;
         return false;
     }
+
+    /// <summary>
+    /// Reads this content the way it leaves AI Studio, as a file or through the clipboard.
+    /// </summary>
+    /// <remarks>
+    /// What the user sees is the answer together with the sources AI Studio collected for it, and
+    /// that is what a document has to hold as well: an answer built on a web page a tool read, or on
+    /// a document of the user, is worth little when the reader cannot tell which one it was. Those
+    /// sources are not part of the text the model wrote, they hang on the content, which is why
+    /// every path out of the app asks for this and not for the text alone.
+    /// </remarks>
+    /// <param name="content">The content to read.</param>
+    /// <param name="markdown">The Markdown text including its sources, or an empty string when there is none.</param>
+    /// <returns>True, when this content carries Markdown text.</returns>
+    public static bool TryGetExportMarkdown(this IContent content, out string markdown)
+    {
+        if (content is not ContentText text)
+        {
+            markdown = string.Empty;
+            return false;
+        }
+
+        var answer = text.Text.Trim();
+        var sources = text.Sources.ToExportMarkdown();
+        if (sources.Length == 0)
+        {
+            markdown = answer;
+            return true;
+        }
+
+        if (answer.Length == 0)
+        {
+            markdown = sources;
+            return true;
+        }
+
+        //
+        // The blank line is not cosmetic: it ends a paragraph, a list, a table, or a block quote, so
+        // that the heading of the source list stands on its own instead of being pulled into the
+        // last block of the answer.
+        //
+        markdown = $"{Markdown.CloseOpenCodeFence(answer)}{Environment.NewLine}{Environment.NewLine}{sources}";
+        return true;
+    }
 }