Update LLamaSharpChatCompletion Semantic Kernel inference to send only the most recent user message in SK ChatHistory instance when using StatefulExecutor models

LLama.SemanticKernel/ChatCompletion/LLamaSharpChatCompletion.cs

@@ -7,6 +7,7 @@ using System;
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Text;
+using static LLama.InteractiveExecutor;
 using static LLama.LLamaTransforms;
 
 namespace LLamaSharp.SemanticKernel.ChatCompletion;
@@ -22,6 +23,7 @@ public sealed class LLamaSharpChatCompletion : IChatCompletionService
     private readonly ITextStreamTransform outputTransform;
 
     private readonly Dictionary<string, object?> _attributes = new();
+    private readonly bool _isStatefulExecutor;
 
     public IReadOnlyDictionary<string, object?> Attributes => this._attributes;
 
@@ -42,6 +44,7 @@ public sealed class LLamaSharpChatCompletion : IChatCompletionService
         ITextStreamTransform? outputTransform = null)
     {
         this._model = model;
+        this._isStatefulExecutor = this._model is StatefulExecutorBase;
         this.defaultRequestSettings = defaultRequestSettings ?? GetDefaultSettings();
         this.historyTransform = historyTransform ?? new HistoryTransform();
         this.outputTransform = outputTransform ?? new KeywordTextOutputStreamTransform(new[] { $"{LLama.Common.AuthorRole.User}:",
@@ -67,8 +70,8 @@ public sealed class LLamaSharpChatCompletion : IChatCompletionService
         var settings = executionSettings != null
            ? ChatRequestSettings.FromRequestSettings(executionSettings)
            : defaultRequestSettings;
-        var prompt = historyTransform.HistoryToText(chatHistory.ToLLamaSharpChatHistory());
 
+        string prompt = this._getFormattedPrompt(chatHistory);
         var result = _model.InferAsync(prompt, settings.ToLLamaSharpInferenceParams(), cancellationToken);
 
         var output = outputTransform.TransformAsync(result);
@@ -88,8 +91,8 @@ public sealed class LLamaSharpChatCompletion : IChatCompletionService
         var settings = executionSettings != null
           ? ChatRequestSettings.FromRequestSettings(executionSettings)
           : defaultRequestSettings;
-        var prompt = historyTransform.HistoryToText(chatHistory.ToLLamaSharpChatHistory());
 
+        string prompt = this._getFormattedPrompt(chatHistory);
         var result = _model.InferAsync(prompt, settings.ToLLamaSharpInferenceParams(), cancellationToken);
 
         var output = outputTransform.TransformAsync(result);
@@ -99,4 +102,33 @@ public sealed class LLamaSharpChatCompletion : IChatCompletionService
             yield return new StreamingChatMessageContent(AuthorRole.Assistant, token);
         }
     }
+
+    /// <summary>
+    /// Return either the entire formatted chatHistory or just the most recent message based on
+    /// whether the model extends StatefulExecutorBase or not.
+    /// </summary>
+    /// <param name="chatHistory"></param>
+    /// <returns>The formatted prompt</returns>
+    private string _getFormattedPrompt(ChatHistory chatHistory){
+        string prompt;
+        if (this._isStatefulExecutor){
+            InteractiveExecutorState state = (InteractiveExecutorState)((StatefulExecutorBase)this._model).GetStateData();
+            if (state.IsPromptRun)
+            {
+                prompt = historyTransform.HistoryToText(chatHistory.ToLLamaSharpChatHistory());
+            }
+            else
+            {
+                ChatHistory temp_history = new();
+                temp_history.AddUserMessage(chatHistory.Last().Content);
+                prompt = historyTransform.HistoryToText(temp_history.ToLLamaSharpChatHistory());
+            }
+        }
+        else
+        {
+            prompt = historyTransform.HistoryToText(chatHistory.ToLLamaSharpChatHistory());
+        }
+
+        return prompt;
+    }
 }