Feat: add rating

components/stats.html

@@ -25,6 +25,7 @@
             <thead class="bg-gray-800 text-white">
                 <tr>
                     <th class="py-2 px-4">Player</th>
+                    <th class="py-2 px-4">Rating</th>
                     <th class="py-2 px-4">Games Played</th>
                     <th class="py-2 px-4">Games Won</th>
                     <th class="py-2 px-4">Games Lost</th>
@@ -36,6 +37,7 @@
                 {{range .}}
                 <tr>
                     <td class="py-2 px-4 border">{{.Username}}</td>
+                    <td class="py-2 px-4 border">{{.Rating}}</td>
                     <td class="py-2 px-4 border">{{.GamesPlayed}}</td>
                     <td class="py-2 px-4 border">{{.GamesWon}}</td>
                     <td class="py-2 px-4 border">{{.GamesLost}}</td>

migrations/002_add_stats_elo.down.sql

@@ -0,0 +1,3 @@
+DROP TRIGGER IF EXISTS update_player_rating;
+
+ALTER TABLE DROP COLUMN rating;

migrations/002_add_stats_elo.up.sql

@@ -0,0 +1,20 @@
+ALTER TABLE player_stats 
+ADD COLUMN rating REAL NOT NULL DEFAULT 1000.0;
+
+CREATE TRIGGER update_player_rating 
+BEFORE UPDATE OF games_played, games_won ON player_stats
+WHEN NEW.games_played = OLD.games_played + 1
+BEGIN
+    UPDATE player_stats
+    SET rating = OLD.rating + 
+                 32.0 * (
+                     CASE 
+                         WHEN NEW.games_won = OLD.games_won + 1 
+                             THEN 1.0 - 0.5  -- Win term: 0.5
+                         ELSE 0.0 - 0.5      -- Loss term: -0.5
+                     END
+                 ) + 
+                 0.05 * (1000.0 - OLD.rating)
+    WHERE id = OLD.id;
+END;
+

models/main.go

@@ -152,6 +152,7 @@ type PlayerStats struct {
 	GuesserWinrate      float64 `db:"guesser_winrate"`
 	PlayedAsMime        int     `db:"played_as_mime"`
 	PlayedAsGuesser     int     `db:"played_as_guesser"`
+	Rating              float32 `db:"rating"`
 }
 
 type Room struct {

repos/player_stats.go

@@ -38,6 +38,7 @@ func (p *RepoProvider) UpdatePlayerStats(ctx context.Context, stats *models.Play
 		guesser_winrate = :guesser_winrate,
 		played_as_mime = :played_as_mime,
 		played_as_guesser = :played_as_guesser
+		rating = :rating
 	WHERE username = :username`, stats)
 	return err
 }