detect campaign tie

src/warchron/model/result_checker.py

@@ -0,0 +1,24 @@
+from warchron.constants import ContextType
+from warchron.model.war import War
+from warchron.model.war_event import TieResolved
+
+
+class ResultChecker:
+    @staticmethod
+    def get_effective_winner_id(
+        war: War,
+        context_type: ContextType,
+        context_id: str,
+        base_winner_id: str | None,
+    ) -> str | None:
+        if base_winner_id is not None:
+            return base_winner_id
+        for ev in reversed(war.events):
+            if (
+                isinstance(ev, TieResolved)
+                and ev.context_type == context_type
+                and ev.context_id == context_id
+            ):
+                return ev.participant_id  # None if confirmed draw
+
+        return None