diff --git a/backend/src/room.py b/backend/src/room.py
index 996a5a1..92b0ee6 100644
--- a/backend/src/room.py
+++ b/backend/src/room.py
@@ -2,7 +2,16 @@ from dataclasses import dataclass
 
 from .song import Song
 
-type UserScoredSong = tuple[Song, int]
+USER_SCORE_WEIGHT = 0.7
+GENRE_WEIGHT = 0.1
+RANDOM_WEIGHT = 0.1
+RECENT_PENALTY = 0.5
+RECENT_COUNT = 10
+
+
+@dataclass
+class UserScoredSong(Song):
+    user_score: int
 
 
 @dataclass
@@ -14,5 +23,25 @@ class Room:
     tags: set[str]
     creative: bool
 
-    playlist: set[UserScoredSong]
+    songs: dict[str, UserScoredSong]
     history: list[Song]
+
+    def rank_song(
+        self,
+        song: UserScoredSong,
+    ) -> float:
+        rank = 0.0
+        song_items = self.songs.items()
+
+        lowest_score = min(song_items, key=lambda item: item[1].user_score)[1].user_score
+        highest_score = min(song_items, key=lambda item: item[1].user_score)[1].user_score
+
+        rank += translate(song.user_score, lowest_score, highest_score, 0.0, USER_SCORE_WEIGHT)
+
+        # last10items = self.history[-10:]
+
+        return rank
+
+
+def translate(value: float, in_min: float, in_max: float, out_min: float, out_max: float):
+    return (value - in_min) / (in_max - in_min) * (out_max - out_min) + out_min
diff --git a/ruff.toml b/ruff.toml
new file mode 100644
index 0000000..d461c74
--- /dev/null
+++ b/ruff.toml
@@ -0,0 +1 @@
+line-length = 200