stabilizaiton work - projects rework for maintenanceability and ui livening

src/__Libraries/StellaOps.Auth.Security/Dpop/DpopProofValidator.Helpers.cs

@@ -0,0 +1,53 @@
+using Microsoft.IdentityModel.Tokens;
+using System.Text.Json;
+
+namespace StellaOps.Auth.Security.Dpop;
+
+public sealed partial class DpopProofValidator
+{
+    private static string NormalizeHtu(Uri uri)
+    {
+        var builder = new UriBuilder(uri)
+        {
+            Fragment = null,
+            Query = null
+        };
+        return builder.Uri.ToString();
+    }
+
+    private static bool TryDecodeSegment(
+        string token,
+        int segmentIndex,
+        out JsonElement element,
+        out string? error)
+    {
+        element = default;
+        error = null;
+
+        var segments = token.Split('.');
+        if (segments.Length != 3)
+        {
+            error = "Token must contain three segments.";
+            return false;
+        }
+
+        if (segmentIndex < 0 || segmentIndex > 2)
+        {
+            error = "Segment index out of range.";
+            return false;
+        }
+
+        try
+        {
+            var json = Base64UrlEncoder.Decode(segments[segmentIndex]);
+            using var document = JsonDocument.Parse(json);
+            element = document.RootElement.Clone();
+            return true;
+        }
+        catch (Exception ex)
+        {
+            error = ex.Message;
+            return false;
+        }
+    }
+}