using AIAssistantModule.Core.Interfaces.SPI;
using AIAssistantModule.Core.Options;
using Microsoft.Extensions.Options;
using OpenAI;
using OpenAI.Chat;

namespace AIAssistantModule.Infrastructure.Services
{
    public class OpenAILLMService : ILLMService
    {
        private readonly ChatClient _chatClient;
        private readonly OpenAIOptions _options;

        public OpenAILLMService(IOptions<OpenAIOptions> options)
        {
            _options = options.Value;

            var openAiClient = new OpenAIClient(_options.ApiKey);
            _chatClient = openAiClient.GetChatClient(_options.Model);
        }

        public async Task<string> CallAsync(
            string prompt,
            string? schema = null,
            CancellationToken cancellationToken = default)
        {
            var messages = new List<ChatMessage>
            {
                ChatMessage.CreateSystemMessage("You are a precise and structured AI assistant."),
                ChatMessage.CreateUserMessage(prompt)
            };

            var request = new ChatCompletionOptions
            {
                Temperature = (float)_options.Temperature,
                MaxOutputTokenCount = _options.MaxTokens
            };

            // If schema provided → enforce structured JSON output
            if (!string.IsNullOrWhiteSpace(schema))
            {
                request.ResponseFormat = ChatResponseFormat.CreateJsonSchemaFormat(
                    "structured_output",
                    BinaryData.FromString(schema));
            }

            var response = await _chatClient.CompleteChatAsync(
                messages,
                request,
                cancellationToken);

            return response.Value.Content[0].Text;
        }
    }
}