Simple usage example

 {C#}

internal class Program

{

    const string OpenAIKey = "<insert your OpenAI API key here>";

    const string RequestText = "How much o'clock? Also, can you say the current date? And day of the week.";


    static async Task Main(string[] args)

    {

        var messages = new List<ChatMessage>()

        {

            new ChatMessage() { Role = ChatMessage.ChatMessageRole.User, Content = RequestText }

        };

        var functions = new Dictionary<string, GptFunction>

        {

            ["get_time"] = new GptFunction()

            {

                Description = "Returns current time in ISO 8601 format",

                Function = (args) => Task.FromResult(DateTime.Now.ToString("o")),

                Parameters = new JsonObjectSchema()

            }

        };


        var gptApi = new ChatGptClient(OpenAIKey);

        while (true)

        {

            var request = new ChatRequest()

            {

                Model = "gpt-4-0613",

                Messages = messages,

                Functions = new List<ChatFunction>(functions.Select(kv => new ChatFunction() { Name = kv.Key, Description = kv.Value.Description, Parameters = kv.Value.Parameters })),

                Temperature = 0.5

            };

            // Create empty response

            var completionResult = new ChatResponse();

            var completionResultStream = gptApi.RequestStreamAsync(request);

            // Process stream data

            await foreach (var p in completionResultStream)

            {

                // You can just use + operator to combine stream chunks

                completionResult = completionResult! + p;

                // Skip if it's function call

                if (completionResult?.Choices?.First()?.Message?.FunctionCall != null)

                    continue;

                // Print partial data

                if (p.Choices?.FirstOrDefault()?.Delta != null)

                    Console.Write(p.Choices.First().Delta!.Content);

            }

            if (completionResult?.Choices?.First()?.Message?.FunctionCall == null)

                Console.WriteLine();

            else

                Console.WriteLine($"Function call: {completionResult?.Choices?.First()?.Message?.FunctionCall}");

            // Append message to the chat history

            var msg = completionResult!.Choices.FirstOrDefault()?.Message!;

            messages.Add(msg);

            if (msg.FunctionCall?.Name != null)

            {

                // It's function call

                if (!functions.TryGetValue(msg.FunctionCall.Name, out GptFunction? function))

                    throw new NotImplementedException($"Unknown function: {msg.FunctionCall.Name}");

                // calling the fuctions

                var argsDoc = JsonDocument.Parse(msg.FunctionCall.Arguments!);

                var functionResult = await function!.Function(argsDoc.RootElement);

                Console.WriteLine($"Function call result: {functionResult}");


                // Need to add function result to the chat history

                var functionResultMessage = new ChatMessage(ChatMessageRole.Function, functionResult, msg.FunctionCall.Name);

                messages.Add(functionResultMessage);

            }

            else

            {

                // Text answer received, done.

                break;

            }

        }

    }


    class GptFunction

    {

        public delegate Task<string> GptFunctionMethod(JsonElement args);


        class GptFunction

        {

            public delegate Task<string> GptFunctionMethod(JsonElement args);


            public required string Description { get; init; }

            public required GptFunctionMethod Function { get; init; }

            public required IJsonSchema Parameters { get; init; }

        }

    }

}