initial commit

OpenRouter/PricingProvider.cs

@@ -0,0 +1,52 @@
+using System.Globalization;
+using System.Net.Http.Json;
+using System.Text.Json;
+
+namespace AnchorCli.OpenRouter;
+
+/// <summary>
+/// Fetches and caches model pricing from the OpenRouter API.
+/// </summary>
+internal sealed class PricingProvider
+{
+    private const string ModelsUrl = "https://openrouter.ai/api/v1/models";
+
+    private static readonly HttpClient Http = new();
+    private Dictionary<string, ModelInfo>? _models;
+
+    /// <summary>
+    /// Fetches the full model list from OpenRouter (cached after first call).
+    /// </summary>
+    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;
+    }
+
+    /// <summary>
+    /// Looks up pricing for a specific model ID. Returns null if not found.
+    /// </summary>
+    public async Task<ModelInfo?> GetModelInfoAsync(
+        string modelId, CancellationToken ct = default)
+    {
+        var models = await GetAllModelsAsync(ct);
+        return models.GetValueOrDefault(modelId);
+    }
+
+    /// <summary>
+    /// Parses a pricing string (USD per token) to decimal. Returns 0 on failure.
+    /// </summary>
+    public static decimal ParsePrice(string? priceStr) =>
+        decimal.TryParse(priceStr, NumberStyles.Float, CultureInfo.InvariantCulture, out var v)
+            ? v
+            : 0m;
+}