using System.Net.Http.Json;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace GymLogAI.AI;

public sealed class OpenRouterChatClient(
    HttpClient httpClient,
    IOptions<OpenRouterOptions> options,
    ILogger<OpenRouterChatClient> logger)
{
    private readonly OpenRouterOptions _options = options.Value;

    public async Task<string?> CompleteAsync(string prompt, CancellationToken cancellationToken)
    {
        if (string.IsNullOrWhiteSpace(_options.ApiKey))
        {
            logger.LogInformation("OpenRouter API key is not configured. Returning stubbed chat completion.");
            return null;
        }

        using var request = new HttpRequestMessage(HttpMethod.Post, "chat/completions")
        {
            Content = JsonContent.Create(new
            {
                model = _options.ChatModel,
                messages = new[] { new { role = "user", content = prompt } }
            })
        };

        request.Headers.Authorization = new("Bearer", _options.ApiKey);
        var response = await httpClient.SendAsync(request, cancellationToken);
        response.EnsureSuccessStatusCode();
        return await response.Content.ReadAsStringAsync(cancellationToken);
    }
}