Starting rating implementation: Fetch current ratings

install/database_schema.sql

@@ -288,7 +288,11 @@ CREATE TABLE user_base_ratings (
 
 DROP TABLE IF EXISTS user_ratings CASCADE;
 CREATE TABLE user_ratings (
-  /** This should reference the game that triggered the elo update. I would use the league_id here for proper ordering. */
+  /**
+  * This should reference the game that triggered the elo update.
+  * I would use the league_id here for proper ordering.
+  * Also note that this can then be used to identify whether a given league game has already been processed for rating change.
+  */
   league_id INTEGER PRIMARY KEY REFERENCES games,
 
   user_id SMALLINT NOT NULL,

ratings.py

@@ -0,0 +1,87 @@
+from typing import List, Dict
+
+import utils
+from database import conn_manager
+
+from log_setup import logger
+
+
+def next_game_to_rate():
+    cur = conn_manager.get_new_cursor()
+    cur.execute("SELECT games.id FROM games "
+                "LEFT OUTER JOIN user_ratings"
+                "  ON games.league_id = user_ratings.league_id "
+                "WHERE user_ratings.league_id IS NULL "
+                "ORDER BY games.league_id ASC "
+                "LIMIT 1"
+                )
+    query_result = cur.fetchone()
+    if query_result is None:
+        return
+
+    (game_id,) = query_result
+    return game_id
+
+
+def get_current_ratings(user_ids: List[int], rating_type: int) -> Dict[int, float]:
+    """
+    Fetches the current ratings for specified players and rating type from DB
+    @return: Mapping user_id -> current rating
+    """
+    cur = conn_manager.get_new_cursor()
+    cur.execute("SELECT user_id, rating FROM user_base_ratings "
+                "WHERE user_id IN ({}) AND type = %s".format(", ".join("%s" for _ in user_ids)),
+                user_ids + [rating_type]
+                )
+    base_ratings = cur.fetchall()
+    cur.execute("SELECT user_ratings.user_id, value_after FROM user_ratings "
+                "INNER JOIN ("
+                "    SELECT user_id, type, MAX(league_id) AS max_league_id"
+                "    FROM user_ratings "
+                "    GROUP BY (user_id, type)"
+                "  ) AS latest_user_ratings "
+                "  ON user_ratings.league_id = latest_user_ratings.max_league_id "
+                )
+    current_ratings = cur.fetchall()
+
+    ratings: Dict[int, float] = {}
+    for user_id, base_rating in base_ratings:
+        ratings[user_id] = base_rating
+    for user_id, rating in current_ratings:
+        ratings[user_id] = rating
+
+    return ratings
+
+
+def process_rating_of_next_game():
+    game_id = next_game_to_rate()
+    if game_id is None:
+        logger.info("All games already processed for rating changes.")
+        return
+    logger.verbose("Processing rating for game {}".format)
+    cur = conn_manager.get_new_cursor()
+    cur.execute("SELECT games.league_id, games.num_players, games.score, variants.num_suits, variants.clue_starved "
+                "FROM games "
+                "INNER JOIN variants "
+                "  ON games.variant_id = variants.id "
+                "WHERE games.id = %s",
+                (game_id,)
+                )
+    league_id, num_players, score, num_suits, clue_starved = cur.fetchone()
+
+    cur.execute("SELECT game_participants.user_id FROM games "
+                "INNER JOIN game_participants "
+                "  ON games.id = game_participants.game_id "
+                "WHERE games.id = %s",
+                (game_id,)
+                )
+    user_ids = cur.fetchall()
+    if len(user_ids) != num_players:
+        err_msg = "Player number mismatch: Expected {} participants for game {}, but only found {} in DB: [{}]".format(
+            num_players, game_id, len(user_ids), ", ".join(user_ids)
+        )
+        logger.error(err_msg)
+        raise ValueError(err_msg)
+
+    rating_type = utils.get_rating_type(clue_starved)
+    ratings = get_current_ratings(user_ids, rating_type)

utils.py

@@ -34,3 +34,13 @@ def is_player_count_allowed(game_id: int, num_players: int) -> bool:
         logger.debug("Rejected game {} due to invalid number of players ({})".format(game_id, num_players))
         return False
     return True
+
+
+def get_rating_type(clue_starved: bool):
+    """
+    Convenience function to get the magic values that we use to identify the different rating types of a player
+    """
+    if clue_starved:
+        return 1
+    else:
+        return 0