GOA/LLMApi/Services/ChatGpt3_5.cs

using LLMApi.Data.Contracts.ChatGpt3_5;
using LLMApi.Data.Contracts.Game.ChatGpt3_5;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;

namespace LLMApi.Services;

public class ChatGpt3_5Service : ILlmApiService
{
    private readonly HttpClient _client;
    private static readonly JsonSerializerSettings jsonDeserializerSettings = new()
    {
        ContractResolver = new DefaultContractResolver()
        {
            NamingStrategy = new SnakeCaseNamingStrategy()
        }
    };
    private const string VERSION_IDENTIFIER = "gpt-3.5-turbo";

    private readonly string _llmRuleset;

    public ChatGpt3_5Service(HttpClient client, IConfiguration configuration)
    {
        _client = client;
        
        _client.BaseAddress = new Uri("https://api.openai.com");

        var api_key = configuration["api_key"];
        
        _client.DefaultRequestHeaders.Add("Authorization", $"Bearer {api_key}");

        _llmRuleset = configuration["llm_ruleset"] ?? "";
    }

    // public async Task<IEnumerable<Choice>> GetAnswerToPrompt(string prompt)
    // {
    //     var requestContract = new ChatCompletionRequest(VERSION_IDENTIFIER, 
    //         new Message[] 
    //         { 
    //             new("system", "You are a helpful assistant."), 
    //             new("user", prompt),
    //         });
        
    //     var responseMessage = await _client.PostAsJsonAsync("/v1/chat/completions", requestContract);
        
    //     var responseContent = await responseMessage.Content.ReadAsStringAsync();

    //     var response = JsonConvert.DeserializeObject<ChatCompletionResponse>(responseContent, jsonDeserializerSettings);
        
    //     ArgumentNullException.ThrowIfNull(response);

    //     var choices = response.Choices.OrderBy(c => c.Index);

    //     return choices;
    // }

    public async Task<AnswerResponse> GetAnswer(AnswerRequest answerRequest)
    {
        var (context, prompt) = answerRequest;

        Message[] newContext;
        if (context is null)
        {
            newContext = new[] 
            {
                new Message("system", _llmRuleset),
                new Message("user", prompt)
            }; 
        }
        else
        {
            newContext = new List<Message>(context)
            {
                new("user", prompt)
            }.ToArray();
        }

        var requestContract = new ChatCompletionRequest(VERSION_IDENTIFIER, newContext);
        
        var responseMessage = await _client.PostAsJsonAsync("/v1/chat/completions", requestContract);
        var responseContent = await responseMessage.Content.ReadAsStringAsync();
        // var responseContent = await File.ReadAllTextAsync("/home/finn/Documents/pit_hackathon/GOA.git/llmapi/LLMApi/test.json");
        var response = JsonConvert.DeserializeObject<ChatCompletionResponse>(responseContent, jsonDeserializerSettings);
        
        ArgumentNullException.ThrowIfNull(response);

        var choices = response.Choices.OrderBy(c => c.Index);
        return new(newContext, choices);
    }
}