Use full history only when the ChatSession runs the first time

LLama/ChatSession.cs

@@ -1,11 +1,14 @@
 using LLama.Abstractions;
 using LLama.Common;
+using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using static LLama.InteractiveExecutor;
 
 namespace LLama
 {
@@ -151,11 +154,17 @@ namespace LLama
 
             History.Messages.Add(new ChatHistory.Message(AuthorRole.User, prompt));
 
-            string internalPrompt = HistoryTransform.HistoryToText(History);
+            if (_executor is InteractiveExecutor executor)
+            {
+                InteractiveExecutorState state = (InteractiveExecutorState)executor.GetStateData();
+                prompt = state.IsPromptRun
+                    ? HistoryTransform.HistoryToText(History)
+                    : prompt;
+            }
 
             StringBuilder sb = new();
 
-            await foreach (var result in ChatAsyncInternal(internalPrompt, inferenceParams, cancellationToken))
+            await foreach (var result in ChatAsyncInternal(prompt, inferenceParams, cancellationToken))
             {
                 yield return result;
                 sb.Append(result);
@@ -190,14 +199,28 @@ namespace LLama
         /// <returns></returns>
         public async IAsyncEnumerable<string> ChatAsync(ChatHistory history, IInferenceParams? inferenceParams = null, [EnumeratorCancellation] CancellationToken cancellationToken = default)
         {
-            var prompt = HistoryTransform.HistoryToText(history);
+            if (history.Messages.Count == 0)
+            {
+                throw new ArgumentException("History must contain at least one message.");
+            }
 
-            StringBuilder sb = new();
+            string prompt;
+            if (_executor is InteractiveExecutor executor)
+            {
+                InteractiveExecutorState state = (InteractiveExecutorState)executor.GetStateData();
+
+                prompt = state.IsPromptRun
+                    ? HistoryTransform.HistoryToText(History)
+                    : history.Messages.Last().Content;
+            }
+            else
+            {
+                prompt = history.Messages.Last().Content;
+            }
 
             await foreach (var result in ChatAsyncInternal(prompt, inferenceParams, cancellationToken))
             {
                 yield return result;
-                sb.Append(result);
             }
         }