territory claiming modification

microservices/LocationsApi/Services/LocationService.cs

@@ -145,8 +145,12 @@ public class LocationService
         var existing = await GetAsync(q, r);
         if (existing is not null)
         {
-            if (!string.IsNullOrWhiteSpace(existing.OwnerUsername) &&
-                !string.Equals(existing.OwnerUsername, username, StringComparison.OrdinalIgnoreCase))
+            if (string.Equals(existing.OwnerUsername, username, StringComparison.OrdinalIgnoreCase))
+            {
+                return existing;
+            }
+
+            if (!await CanScoutClaimAsync(username, q, r))
             {
                 return null;
             }
@@ -164,6 +168,26 @@ public class LocationService
         return await UpsertAsync(new UpsertLocationRequest { Q = q, R = r, Terrain = "Field" }, username);
     }
 
+    public async Task<bool> CanScoutClaimAsync(string username, int q, int r)
+    {
+        var existing = await GetAsync(q, r);
+        if (existing is not null)
+        {
+            if (string.Equals(existing.OwnerUsername, username, StringComparison.OrdinalIgnoreCase))
+            {
+                return true;
+            }
+
+            if (string.Equals(existing.Kind, "Home", StringComparison.OrdinalIgnoreCase) ||
+                !string.IsNullOrWhiteSpace(existing.BuildingType))
+            {
+                return false;
+            }
+        }
+
+        return !await _units.Find(x => x.Q == q && x.R == r).AnyAsync();
+    }
+
     public async Task<Location?> BuildAsync(BuildLocationRequest request, string username)
     {
         var buildingType = NormalizeBuildingType(request.BuildingType);