using System.Net.Http.Json;
using System.Text.Json;
using AnchorCli.OpenRouter;

namespace AnchorCli.Providers;

/// <summary>
/// Pricing provider for OpenRouter API.
/// </summary>
internal sealed class OpenRouterProvider : IPricingProvider
{
    private const string ModelsUrl = "https://openrouter.ai/api/v1/models";
    private static readonly HttpClient Http = new();
    private Dictionary<string, ModelInfo>? _models;

    static OpenRouterProvider()
    {
        OpenRouterHeaders.ApplyTo(Http);
    }

    public async Task<Dictionary<string, ModelInfo>> GetAllModelsAsync(CancellationToken ct = default)
    {
        if (_models != null) return _models;

        var response = await Http.GetAsync(ModelsUrl, ct);
        response.EnsureSuccessStatusCode();

        var json = await response.Content.ReadAsStringAsync(ct);
        var result = JsonSerializer.Deserialize(json, AppJsonContext.Default.ModelsResponse);

        _models = result?.Data?.ToDictionary(m => m.Id) ?? [];
        return _models;
    }

    public async Task<ModelInfo?> GetModelInfoAsync(string modelId, CancellationToken ct = default)
    {
        var models = await GetAllModelsAsync(ct);
        return models.GetValueOrDefault(modelId);
    }
}