Practice battles work

SVSim.EmulatedEntrypoint/Controllers/SVSimController.cs

@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using SVSim.EmulatedEntrypoint.Constants;
 using SVSim.EmulatedEntrypoint.Security;
 using SVSim.EmulatedEntrypoint.Security.SteamSessionAuthentication;
 
@@ -14,5 +15,16 @@ namespace SVSim.EmulatedEntrypoint.Controllers
     [Authorize(AuthenticationSchemes = SteamAuthenticationConstants.SchemeName)]
     public abstract class SVSimController : ControllerBase
     {
+        /// <summary>
+        /// Reads the authenticated viewer's internal id from the ViewerId claim populated by
+        /// <c>SteamSessionAuthenticationHandler</c>. Returns false (and viewerId = 0) when the
+        /// claim is missing or unparseable — handler should respond with Unauthorized().
+        /// </summary>
+        protected bool TryGetViewerId(out long viewerId)
+        {
+            viewerId = 0;
+            var claim = User.Claims.FirstOrDefault(c => c.Type == ShadowverseClaimTypes.ViewerIdClaim)?.Value;
+            return claim is not null && long.TryParse(claim, out viewerId);
+        }
     }
 }