RdvQuery from PostIt

src/Yavsc.Api.Client/BillingApiClient.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Yavsc.Api.Client;
+
+/// <summary>
+/// HTTP client for posting commands to the business billing routes.
+/// Uses absolute URLs so it can coexist with blog-targeting clients on
+/// the same shared transport.
+/// </summary>
+public sealed class BillingApiClient
+{
+    private const string PathPrefix = "billing";
+
+    private readonly IYavscApiClient _api;
+    private readonly Uri _baseAddress;
+
+    public BillingApiClient(IYavscApiClient api, string businessBaseAddress)
+    {
+        _api = api ?? throw new ArgumentNullException(nameof(api));
+        if (string.IsNullOrWhiteSpace(businessBaseAddress))
+            throw new ArgumentException("Base address is required.", nameof(businessBaseAddress));
+
+        _baseAddress = new Uri(businessBaseAddress, UriKind.Absolute);
+    }
+
+    public Task CreateAsync(string billingCode, object payload, CancellationToken ct = default)
+    {
+        if (string.IsNullOrWhiteSpace(billingCode))
+            throw new ArgumentException("Billing code is required.", nameof(billingCode));
+
+        return _api.CallAsync(
+            HttpMethod.Post,
+            Absolute($"{PathPrefix}/{Uri.EscapeDataString(billingCode)}"),
+            body: payload,
+            ct: ct);
+    }
+
+    private string Absolute(string relativePath) => new Uri(_baseAddress, relativePath).ToString();
+}