using System.Net.Http.Headers;

namespace AnchorCli.Providers;

/// <summary>
/// Token extractor for Groq responses.
/// </summary>
internal sealed class GroqTokenExtractor : ITokenExtractor
{
    public string ProviderName => "Groq";

    public (int inputTokens, int outputTokens)? ExtractTokens(HttpResponseHeaders headers, string? responseBody)
    {
        // Groq provides x-groq-tokens header (format: "n;<prompt_tokens>,n;<completion_tokens>")
        if (headers.TryGetValues("x-groq-tokens", out var values))
        {
            var tokenStr = values.FirstOrDefault();
            if (!string.IsNullOrEmpty(tokenStr))
            {
                // Parse format: "n;123,n;45" where first is prompt, second is completion
                var parts = tokenStr.Split(',');
                if (parts.Length >= 2)
                {
                    var inputPart = parts[0].Trim();
                    var outputPart = parts[1].Trim();

                    // Extract numbers after "n;"
                    if (inputPart.StartsWith("n;") && outputPart.StartsWith("n;"))
                    {
                        if (int.TryParse(inputPart[2..], out var input) &&
                            int.TryParse(outputPart[2..], out var output))
                        {
                            return (input, output);
                        }
                    }
                }
            }
        }

        // Fallback: try parsing from response body
        if (!string.IsNullOrEmpty(responseBody))
        {
            // TODO: Parse usage from JSON body if headers aren't available
        }

        return null;
    }

    public int? ExtractLatency(HttpResponseHeaders headers)
    {
        if (headers.TryGetValues("x-groq-response-time", out var values))
        {
            if (int.TryParse(values.FirstOrDefault(), out var latency))
            {
                return latency;
            }
        }

        return null;
    }
}