Introduce ChatHistory interface

LLama.Examples/Examples/ChatChineseGB2312.cs

@@ -49,7 +49,7 @@ public static async Task Run()
         else
         {
             var chatHistoryJson = File.ReadAllText("Assets/chat-with-kunkun-chinese.json");
-            ChatHistory chatHistory = ChatHistory.FromJson(chatHistoryJson) ?? new ChatHistory();
+            IChatHistory chatHistory = ChatHistorySerializer.FromJson(chatHistoryJson, typeof(ChatHistory)) ?? new ChatHistory();
 
             session = new ChatSession(executor, chatHistory);
         }
@@ -105,7 +105,7 @@ in session.RegenerateAssistantMessageAsync(
                 await foreach (
                     var text
                     in session.ChatAsync(
-                        new ChatHistory.Message(AuthorRole.User, userInput),
+                        new Message(AuthorRole.User, userInput),
                         inferenceParams))
                 {
                     Console.ForegroundColor = ConsoleColor.White;

LLama.Examples/Examples/ChatSessionStripRoleName.cs

@@ -21,7 +21,7 @@ public static async Task Run()
         var executor = new InteractiveExecutor(context);
 
         var chatHistoryJson = File.ReadAllText("Assets/chat-with-bob.json");
-        ChatHistory chatHistory = ChatHistory.FromJson(chatHistoryJson) ?? new ChatHistory();
+        IChatHistory chatHistory = ChatHistorySerializer.FromJson(chatHistoryJson, typeof(ChatHistory)) ?? new ChatHistory();
 
         ChatSession session = new(executor, chatHistory);
         session.WithOutputTransform(new LLamaTransforms.KeywordTextOutputStreamTransform(
@@ -46,7 +46,7 @@ public static async Task Run()
             await foreach (
                 var text
                 in session.ChatAsync(
-                    new ChatHistory.Message(AuthorRole.User, userInput),
+                    new Message(AuthorRole.User, userInput),
                     inferenceParams))
             {
                 Console.ForegroundColor = ConsoleColor.White;

LLama.Examples/Examples/ChatSessionWithHistory.cs

@@ -31,7 +31,7 @@ public static async Task Run()
         else
         {
             var chatHistoryJson = File.ReadAllText("Assets/chat-with-bob.json");
-            ChatHistory chatHistory = ChatHistory.FromJson(chatHistoryJson) ?? new ChatHistory();
+            IChatHistory chatHistory = ChatHistorySerializer.FromJson(chatHistoryJson, typeof(ChatHistory)) ?? new ChatHistory();
 
             session = new ChatSession(executor, chatHistory);
         }
@@ -92,7 +92,7 @@ in session.RegenerateAssistantMessageAsync(
                 await foreach (
                     var text
                     in session.ChatAsync(
-                        new ChatHistory.Message(AuthorRole.User, userInput),
+                        new Message(AuthorRole.User, userInput),
                         inferenceParams))
                 {
                     Console.ForegroundColor = ConsoleColor.White;

LLama.Examples/Examples/ChatSessionWithRestart.cs

@@ -19,8 +19,8 @@ public static async Task Run()
         var executor = new InteractiveExecutor(context);
 
         var chatHistoryJson = File.ReadAllText("Assets/chat-with-bob.json");
-        ChatHistory chatHistory = ChatHistory.FromJson(chatHistoryJson) ?? new ChatHistory();
-        ChatSession prototypeSession = 
+        IChatHistory chatHistory = ChatHistorySerializer.FromJson(chatHistoryJson, typeof(ChatHistory)) ?? new ChatHistory();
+        ChatSession prototypeSession =
             await ChatSession.InitializeSessionFromHistoryAsync(executor, chatHistory);
         prototypeSession.WithOutputTransform(new LLamaTransforms.KeywordTextOutputStreamTransform(
             new string[] { "User:", "Assistant:" },
@@ -50,10 +50,10 @@ public static async Task Run()
         while (userInput != "exit")
         {
             // Load the session state from the reset state
-            if(userInput == "reset")
+            if (userInput == "reset")
             {
                 session.LoadSession(resetState);
-                Console.WriteLine($"Reset to history:\n{session.HistoryTransform.HistoryToText(session.History)}");
+                Console.WriteLine($"Reset to history:\n{session.HistoryTransform.HistoryToText(session.SessionChatHistory)}");
                 Console.ForegroundColor = ConsoleColor.Yellow;
                 Console.WriteLine("Session reset.");
             }
@@ -75,10 +75,10 @@ public static async Task Run()
 
                 Console.ForegroundColor = ConsoleColor.Yellow;
                 Console.WriteLine("Provide assistant input: ");
-                
+
                 Console.ForegroundColor = ConsoleColor.Green;
                 string assistantInputOverride = Console.ReadLine() ?? "";
-                
+
                 await session.AddAndProcessUserMessage(userInputOverride);
                 await session.AddAndProcessAssistantMessage(assistantInputOverride);
 
@@ -90,7 +90,7 @@ public static async Task Run()
                 await foreach (
                     var text
                     in session.ChatAsync(
-                        new ChatHistory.Message(AuthorRole.User, userInput),
+                        new Message(AuthorRole.User, userInput),
                         inferenceParams))
                 {
                     Console.ForegroundColor = ConsoleColor.White;

LLama.Examples/Examples/ChatSessionWithRoleName.cs

@@ -19,7 +19,7 @@ public static async Task Run()
         var executor = new InteractiveExecutor(context);
 
         var chatHistoryJson = File.ReadAllText("Assets/chat-with-bob.json");
-        ChatHistory chatHistory = ChatHistory.FromJson(chatHistoryJson) ?? new ChatHistory();
+        IChatHistory chatHistory = ChatHistorySerializer.FromJson(chatHistoryJson, typeof(ChatHistory)) ?? new ChatHistory();
 
         ChatSession session = new(executor, chatHistory);
 
@@ -41,7 +41,7 @@ public static async Task Run()
             await foreach (
                 var text
                 in session.ChatAsync(
-                    new ChatHistory.Message(AuthorRole.User, userInput),
+                    new Message(AuthorRole.User, userInput),
                     inferenceParams))
             {
                 Console.ForegroundColor = ConsoleColor.White;

LLama.Examples/Examples/LoadAndSaveSession.cs

@@ -33,7 +33,7 @@ public static async Task Run()
                 await foreach (
                     var text
                     in session.ChatAsync(
-                        new ChatHistory.Message(AuthorRole.User, prompt),
+                        new Message(AuthorRole.User, prompt),
                         new InferenceParams()
                         {
                             Temperature = 0.6f,

LLama.SemanticKernel/ChatCompletion/HistoryTransform.cs

@@ -10,7 +10,7 @@ namespace LLamaSharp.SemanticKernel.ChatCompletion;
 public class HistoryTransform : DefaultHistoryTransform
 {
     /// <inheritdoc/>
-    public override string HistoryToText(global::LLama.Common.ChatHistory history)
+    public string HistoryToText(global::LLama.Common.ChatHistory history)
     {
         return base.HistoryToText(history) + $"{AuthorRole.Assistant}: ";
     }

LLama.WebAPI/Controllers/ChatController.cs

@@ -43,7 +43,7 @@ public async Task<string> SendHistory([FromBody] HistoryInput input, [FromServic
         {
             var history = new ChatHistory();
 
-            var messages = input.Messages.Select(m => new ChatHistory.Message(Enum.Parse<AuthorRole>(m.Role), m.Content));
+            var messages = input.Messages.Select(m => new Message(Enum.Parse<AuthorRole>(m.Role), m.Content));
 
             history.Messages.AddRange(messages);
 

LLama.WebAPI/Services/StatefulChatService.cs

@@ -28,7 +28,7 @@ public StatefulChatService(IConfiguration configuration, ILogger<StatefulChatSer
         _context = new LLamaContext(weights, @params);
 
         _session = new ChatSession(new InteractiveExecutor(_context));
-        _session.History.AddMessage(Common.AuthorRole.System, SystemPrompt);
+        _session.SessionChatHistory.AddMessage(Common.AuthorRole.System, SystemPrompt);
     }
 
     public void Dispose()
@@ -46,7 +46,7 @@ public async Task<string> Send(SendMessageInput input)
         }
         _logger.LogInformation("Input: {text}", input.Text);
         var outputs = _session.ChatAsync(
-            new Common.ChatHistory.Message(Common.AuthorRole.User, input.Text),
+            new Common.Message(Common.AuthorRole.User, input.Text),
             new Common.InferenceParams()
             {
                 RepeatPenalty = 1.0f,
@@ -74,7 +74,7 @@ public async IAsyncEnumerable<string> SendStream(SendMessageInput input)
         _logger.LogInformation(input.Text);
 
         var outputs = _session.ChatAsync(
-            new Common.ChatHistory.Message(Common.AuthorRole.User, input.Text!)
+            new Common.Message(Common.AuthorRole.User, input.Text!)
             , new Common.InferenceParams()
             {
                 RepeatPenalty = 1.0f,

LLama.WebAPI/Services/StatelessChatService.cs

@@ -48,10 +48,9 @@ public async Task<string> SendAsync(ChatHistory history)
     }
     public class HistoryTransform : DefaultHistoryTransform
     {
-        public override string HistoryToText(ChatHistory history)
+        public override string HistoryToText(IChatHistory history)
         {
             return base.HistoryToText(history) + "\n Assistant:";
         }
-
     }
 }

LLama/Abstractions/IHistoryTransform.cs

@@ -1,4 +1,5 @@
 using LLama.Common;
+using System;
 using System.Text.Json.Serialization;
 
 namespace LLama.Abstractions
@@ -14,15 +15,16 @@ public interface IHistoryTransform
         /// </summary>
         /// <param name="history">The ChatHistory instance</param>
         /// <returns></returns>
-        string HistoryToText(ChatHistory history);
-        
+        string HistoryToText(IChatHistory history);
+
         /// <summary>
         /// Converts plain text to a ChatHistory instance.
         /// </summary>
         /// <param name="role">The role for the author.</param>
         /// <param name="text">The chat history as plain text.</param>
+        /// <param name="type">The type of the chat history.</param>
         /// <returns>The updated history.</returns>
-        ChatHistory TextToHistory(AuthorRole role, string text);
+        IChatHistory TextToHistory(AuthorRole role, string text, Type type);
 
         /// <summary>
         /// Copy the transform.

LLama/Common/ChatHistory.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Serialization;
@@ -33,41 +34,60 @@ public enum AuthorRole
 
     // copy from semantic-kernel
     /// <summary>
-    /// The chat history class
+    /// The message class
     /// </summary>
-    public class ChatHistory
+    public class Message
     {
-        private static readonly JsonSerializerOptions _jsonOptions = new() { WriteIndented = true };
+        /// <summary>
+        /// Role of the message author, e.g. user/assistant/system
+        /// </summary>
+        [JsonConverter(typeof(JsonStringEnumConverter))]
+        [JsonPropertyName("author_role")]
+        public AuthorRole AuthorRole { get; set; }
 
         /// <summary>
-        /// Chat message representation
+        /// Message content
         /// </summary>
-        public class Message
+        [JsonPropertyName("content")]
+        public string Content { get; set; }
+
+        /// <summary>
+        /// Create a new instance
+        /// </summary>
+        /// <param name="authorRole">Role of message author</param>
+        /// <param name="content">Message content</param>
+        public Message(AuthorRole authorRole, string content)
         {
-            /// <summary>
-            /// Role of the message author, e.g. user/assistant/system
-            /// </summary>
-            [JsonConverter(typeof(JsonStringEnumConverter))]
-            [JsonPropertyName("author_role")]
-            public AuthorRole AuthorRole { get; set; }
-
-            /// <summary>
-            /// Message content
-            /// </summary>
-            [JsonPropertyName("content")]
-            public string Content { get; set; }
-
-            /// <summary>
-            /// Create a new instance
-            /// </summary>
-            /// <param name="authorRole">Role of message author</param>
-            /// <param name="content">Message content</param>
-            public Message(AuthorRole authorRole, string content)
-            {
-                this.AuthorRole = authorRole;
-                this.Content = content;
-            }
+            this.AuthorRole = authorRole;
+            this.Content = content;
         }
+    }
+
+    /// <summary>
+    /// Interface for chat history
+    /// </summary>
+    public interface IChatHistory
+    {
+        /// <summary>
+        /// List of messages in the chat
+        /// </summary>
+        List<Message> Messages { get; set; }
+
+        /// <summary>
+        /// Add a message to the chat history
+        /// </summary>
+        /// <param name="authorRole">Role of the message author</param>
+        /// <param name="content">Message content</param>
+        void AddMessage(AuthorRole authorRole, string content);
+    }
+
+    // copy from semantic-kernel
+    /// <summary>
+    /// The chat history class
+    /// </summary>
+    public class ChatHistory : IChatHistory
+    {
+        private static readonly JsonSerializerOptions _jsonOptions = new() { WriteIndented = true };
 
         /// <summary>
         /// List of messages in the chat
@@ -99,24 +119,33 @@ public void AddMessage(AuthorRole authorRole, string content)
         {
             this.Messages.Add(new Message(authorRole, content));
         }
+    }
+
+    /// <summary>
+    /// Serializer for chat history
+    /// </summary>
+    public class ChatHistorySerializer
+    {
+        private static readonly JsonSerializerOptions _jsonOptions = new() { WriteIndented = true };
 
         /// <summary>
         /// Serialize the chat history to JSON
         /// </summary>
         /// <returns></returns>
-        public string ToJson()
+        public static string ToJson(IChatHistory chatHistory)
         {
-            return JsonSerializer.Serialize(this, _jsonOptions);
+            return JsonSerializer.Serialize(chatHistory, _jsonOptions);
         }
 
         /// <summary>
         /// Deserialize a chat history from JSON
         /// </summary>
         /// <param name="json"></param>
+        /// <param name="type"></param>
         /// <returns></returns>
-        public static ChatHistory? FromJson(string json)
+        public static IChatHistory? FromJson(string json, Type type)
         {
-            return JsonSerializer.Deserialize<ChatHistory>(json);
+            return JsonSerializer.Deserialize(json, type) as IChatHistory;
         }
     }
 }

LLama/LLamaTransforms.cs

@@ -1,5 +1,6 @@
 using LLama.Abstractions;
 using LLama.Common;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -44,7 +45,7 @@ public class DefaultHistoryTransform : IHistoryTransform
             /// <param name="systemName"></param>
             /// <param name="unknownName"></param>
             /// <param name="isInstructMode"></param>
-            public DefaultHistoryTransform(string? userName = null, string? assistantName = null, 
+            public DefaultHistoryTransform(string? userName = null, string? assistantName = null,
                 string? systemName = null, string? unknownName = null, bool isInstructMode = false)
             {
                 _userName = userName ?? defaultUserName;
@@ -61,7 +62,7 @@ public IHistoryTransform Clone()
             }
 
             /// <inheritdoc />
-            public virtual string HistoryToText(ChatHistory history)
+            public virtual string HistoryToText(IChatHistory history)
             {
                 StringBuilder sb = new();
                 foreach (var message in history.Messages)
@@ -87,9 +88,9 @@ public virtual string HistoryToText(ChatHistory history)
             }
 
             /// <inheritdoc />
-            public virtual ChatHistory TextToHistory(AuthorRole role, string text)
+            public virtual IChatHistory TextToHistory(AuthorRole role, string text, Type type)
             {
-                ChatHistory history = new ChatHistory();
+                IChatHistory history = (IChatHistory)(Activator.CreateInstance(type) ?? new ChatHistory());
                 history.AddMessage(role, TrimNamesFromText(text, role));
                 return history;
             }