1 files changed, 36 insertions, 0 deletions
diff --git a/strategy.py b/strategy.py
new file mode 100644
index 0000000..85ea3e0
--- /dev/null
+++ b/strategy.py
@@ -0,0 +1,36 @@
+from typing import Protocol
+
+from game import Game
+from player import Player
+
+
+class GameEloChangeStrategy(Protocol):
+    def proccess_game(
+        self, game: Game, current_elo: dict[Player, int]
+    ) -> dict[Player, float]:
+        ...
+
+
+class SimpleEloChangeStrategy(GameEloChangeStrategy):
+    D = 400
+    K = 32
+
+    def proccess_game(
+        self, game: Game, current_elo: dict[Player, int]
+    ) -> dict[Player, float]:
+        players_elo_updates = {player: 0.0 for player in game.scores}
+
+        for player_1, score_1 in game.scores.items():
+            for player_2, score_2 in game.scores.items():
+                if player_1 != player_2:
+                    expected_score = 1 / (
+                        1
+                        + 10
+                        ** ((current_elo[player_2] - current_elo[player_1]) / self.D)
+                    )
+                    result = (
+                        1.0 if score_1 > score_2 else 0.0 if score_1 < score_2 else 0.5
+                    )
+                    players_elo_updates[player_1] += self.K * (result - expected_score)
+
+        return players_elo_updates