Initial commit

SqlDatabaseVectorSearch/Services/ChatService.cs

@@ -0,0 +1,53 @@
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Options;
+using Microsoft.SemanticKernel.ChatCompletion;
+using SqlDatabaseVectorSearch.Settings;
+
+namespace SqlDatabaseVectorSearch.Services;
+
+public class ChatService(IMemoryCache cache, IChatCompletionService chatCompletionService, IOptions<AppSettings> appSettingsOptions)
+{
+    public async Task<string> CreateQuestionAsync(Guid conversationId, string question)
+    {
+        var chat = new ChatHistory(cache.Get<ChatHistory?>(conversationId) ?? []);
+
+        var embeddingQuestion = $"""
+            Reformulate the following question taking into account the context of the chat to perform embeddings search:
+            ---
+            {question}
+            ---
+            You must reformulate the question in the same language of the user's question.
+            Never add "in this chat", "in the context of this chat", "in the context of our conversation", "search for" or something like that in your answer.
+            """;
+
+        chat.AddUserMessage(embeddingQuestion);
+        var reformulatedQuestion = await chatCompletionService.GetChatMessageContentAsync(chat)!;
+        chat.AddAssistantMessage(reformulatedQuestion.Content!);
+
+        await UpdateCacheAsync(conversationId, chat);
+
+        return reformulatedQuestion.Content!;
+    }
+
+    public async Task AddInteractionAsync(Guid conversationId, string question, string answer)
+    {
+        var chat = new ChatHistory(cache.Get<ChatHistory?>(conversationId) ?? []);
+
+        chat.AddUserMessage(question);
+        chat.AddAssistantMessage(answer);
+
+        await UpdateCacheAsync(conversationId, chat);
+    }
+
+    private Task UpdateCacheAsync(Guid conversationId, ChatHistory chat)
+    {
+        if (chat.Count > appSettingsOptions.Value.MessageLimit)
+        {
+            chat = new ChatHistory(chat.TakeLast(appSettingsOptions.Value.MessageLimit));
+        }
+
+        cache.Set(conversationId, chat, appSettingsOptions.Value.MessageExpiration);
+
+        return Task.CompletedTask;
+    }
+}