using System.Net.Http.Headers;

namespace AnchorCli.Providers;

/// <summary>
/// Token extractor for Ollama responses.
/// Ollama doesn't provide official token counts, so we estimate.
/// </summary>
internal sealed class OllamaTokenExtractor : ITokenExtractor
{
    public string ProviderName => "Ollama";

    public (int inputTokens, int outputTokens)? ExtractTokens(HttpResponseHeaders headers, string? responseBody)
    {
        // Ollama doesn't provide token headers
        return null;
    }

    public int? ExtractLatency(HttpResponseHeaders headers)
    {
        // Ollama doesn't provide latency headers
        return null;
    }

    /// <summary>
    /// Estimates token count from text length (rough approximation).
    /// Assumes ~4 characters per token on average.
    /// </summary>
    public static int EstimateTokens(string text)
    {
        if (string.IsNullOrEmpty(text))
        {
            return 0;
        }

        // Rough estimate: 4 characters per token
        return text.Length / 4;
    }
}