Improved the OpenAI provider (#548)

app/MindWork AI Studio/Provider/OpenAI/ResponsesAnnotationStreamLine.cs

@@ -0,0 +1,45 @@
+namespace AIStudio.Provider.OpenAI;
+
+/// <summary>
+/// Data structure for a line in the response stream of the Responses API, containing an annotation.
+/// </summary>
+/// <param name="Type">The type of the annotation.</param>
+/// <param name="AnnotationIndex">The continuous index of the annotation in the response.</param>
+/// <param name="Annotation">The annotation details.</param>
+public sealed record ResponsesAnnotationStreamLine(string Type, int AnnotationIndex, Annotation Annotation) : IAnnotationStreamLine
+{
+    #region Implementation of IAnnotationStreamLine
+
+    /// <inheritdoc />
+    public bool ContainsSources()
+    {
+        return this.Annotation is not AnnotatingUnknown;
+    }
+
+    /// <inheritdoc />
+    public IList<ISource> GetSources()
+    {
+        //
+        // Check for the unexpected annotation type of the chat completion API.
+        //
+        // This seems weird at first. But there are two possibilities why this could happen:
+        // - Anyone of the open source providers such as ollama, LM Studio, etc. could
+        //   implement and use the chat completion API data structures for annotations in their
+        //   Responses API endpoint.
+        //
+        // - Our custom JSON converter checks for all possible annotation data types. So,
+        //   when the streamed data is valid for any annotation type, it will be deserialized
+        //   into that type, even though we are calling the Responses API endpoint.
+        //
+        if (this.Annotation is ChatCompletionAnnotatingURL urlAnnotation)
+            return [new Source(urlAnnotation.UrlCitation.Title, urlAnnotation.UrlCitation.URL)];
+        
+        // Check for the expected annotation type of the Responses API:
+        if (this.Annotation is ResponsesAnnotatingUrlCitationData urlCitationData)
+            return [new Source(urlCitationData.Title, urlCitationData.URL)];
+
+        return [];
+    }
+
+    #endregion
+}