dotnet add package OpenAI

{
  "AiConfiguration": {
    "ApiKey": "your-api-key-here"
  }
}

public record AiResponse(string Answer);

public class ChatGptService
{
    private readonly AiConfiguration _configuration;

    public ChatGptService(IOptions<AiConfiguration> configuration)
    {
        _configuration = configuration.Value;
    }

    public async Task<AiResponse> RespondAsync(string prompt, string model, CancellationToken cancellationToken = default)
    {
        var client = new ChatClient(model: model, apiKey: _configuration.ApiKey);
        var message = new UserChatMessage(prompt);
        var response = await client.CompleteChatAsync(new[] { message }, cancellationToken: cancellationToken);
        return new AiResponse(response.Value.Content[0].Text);
    }
}

public static class AiModels
{
    public const string Gpt35Turbo = "gpt-3.5-turbo";
    public const string Gpt4 = "gpt-4o";
}

public record ChatResponse(Guid PromptId, string Response, string Model);

app.MapPost("/api/ai/chat", async ([FromBody] ChatRequest request, ChatGptService aiService, CancellationToken cancellationToken) =>
{
    var aiResponse = await aiService.RespondAsync(request.Prompt, AiModels.Gpt35Turbo, cancellationToken);
    var response = new ChatResponse(Guid.NewGuid(), aiResponse.Answer, AiModels.Gpt35Turbo);
    return Results.Ok(response);
}).WithName("ChatWithAi").WithOpenApi();

public class AiPrompt
{
    public required Guid Id { get; set; }
    public required DateTime CreatedAt { get; set; }
    public required string Prompt { get; set; }
    public required string Model { get; set; }
    public required string Answer { get; set; }
    public required decimal? Score { get; set; }
}

"ConnectionStrings": {
  "PostgresGpt35": "your-connection-string-gpt35",
  "PostgresGpt4": "your-connection-string-gpt4"
}

public class AiDbContextFactory
{
    private readonly IConfiguration _configuration;
    private readonly IDbContextFactory<AiDbContext> _dbContextFactory;

    private static readonly Dictionary<string, string> ConnectionStringMapping = new()
    {
        { AiModels.Gpt35Turbo, "PostgresGpt35" },
        { AiModels.Gpt4, "PostgresGpt4" }
    };

    public AiDbContextFactory(IConfiguration configuration, IDbContextFactory<AiDbContext> dbContextFactory)
    {
        _configuration = configuration;
        _dbContextFactory = dbContextFactory;
    }

    public async Task<AiDbContext> CreateDbContextAsync(string model)
    {
        var dbContext = await _dbContextFactory.CreateDbContextAsync();
        var connectionString = _configuration.GetConnectionString(ConnectionStringMapping[model]);
        dbContext.Database.SetConnectionString(connectionString);
        return dbContext;
    }

    public async Task MigrateDatabaseAsync(string model)
    {
        await using var dbContext = await _dbContextFactory.CreateDbContextAsync();
        var connectionString = _configuration.GetConnectionString(ConnectionStringMapping[model]);
        dbContext.Database.SetConnectionString(connectionString);
        await dbContext.Database.MigrateAsync();
    }
}

app.MapPost("/api/ai/chat", async ([FromBody] ChatRequest request, AiDbContextFactory dbContextFactory, ChatGptService aiService, CancellationToken cancellationToken) =>
{
    string[] models = new[] { AiModels.Gpt35Turbo, AiModels.Gpt4 };
    var aiTasks = models.Select(model => aiService.RespondAsync(request.Prompt, model, cancellationToken)).ToArray();
    var aiResponses = await Task.WhenAll(aiTasks);

    var modelResponses = new List<ModelResponse>();

    for (var i = 0; i < models.Length; i++)
    {
        var model = models[i];
        var response = aiResponses[i];
        var dbContext = await dbContextFactory.CreateDbContextAsync(model);

        var aiPrompt = CreateAiPrompt(model, request, response);
        dbContext.AiPrompts.Add(aiPrompt);
        await dbContext.SaveChangesAsync(cancellationToken);

        modelResponses.Add(new ModelResponse(aiPrompt.Id, response.Answer, model));
    }

    return Results.Ok(new ChatResponse(modelResponses.ToArray()));
}).WithName("ChatWithAi").WithOpenApi();