From d858d04e84353f9f1a42f70a4a9a2eee167c0307 Mon Sep 17 00:00:00 2001
From: Blake Ridgway <blake@blakeridgway.com>
Date: Thu, 28 May 2026 14:16:02 -0500
Subject: [PATCH] Fix duplicate leaderboard entries with correlated subquery
 dedup

Replace GROUP BY user_id,username with GROUP BY user_id and a

correlated subquery that picks the latest username per user.

This fixes the case where a user changes their Discord display

name and appears as two separate leaderboard entries.

Affected queries: GetLeaderboard, GetUserStats, GetStatsInRange,

GetYearlyLeaderboard, GetUserYearlyStats.

Also keeps the write-time username sync in AddLog for long-term

data cleanup.

Signed-off-by: Blake Ridgway <blake@blakeridgway.com>
---
 db/db.go | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/db/db.go b/db/db.go
index 9ff0cfb..12ca748 100644
--- a/db/db.go
+++ b/db/db.go
@@ -185,15 +185,17 @@ func (d *DB) AdjustKM(ctx context.Context, guildID, userID, username string, km
 // ── Stats Queries ─────────────────────────────────────────────────────────────
 
 func (d *DB) GetLeaderboard(ctx context.Context, guildID string, since time.Time, limit int) ([]*UserStats, error) {
-	q := `SELECT user_id, username, SUM(km), COUNT(*), MAX(logged_at)
-	      FROM distance_logs WHERE guild_id = $1`
+	q := `SELECT user_id,
+	             (SELECT username FROM distance_logs sub WHERE sub.user_id = dl.user_id AND sub.guild_id = dl.guild_id ORDER BY logged_at DESC LIMIT 1),
+	             SUM(km), COUNT(*), MAX(logged_at)
+	      FROM distance_logs dl WHERE guild_id = $1`
 	args := []interface{}{guildID}
 	if !since.IsZero() {
 		args = append(args, since)
 		q += fmt.Sprintf(` AND logged_at >= $%d`, len(args))
 	}
 	args = append(args, limit)
-	q += fmt.Sprintf(` GROUP BY user_id, username ORDER BY SUM(km) DESC LIMIT $%d`, len(args))
+	q += fmt.Sprintf(` GROUP BY user_id ORDER BY SUM(km) DESC LIMIT $%d`, len(args))
 
 	rows, err := d.conn.QueryContext(ctx, q, args...)
 	if err != nil {
@@ -227,14 +229,16 @@ func (d *DB) GetTotalKM(ctx context.Context, guildID string, since time.Time) (f
 }
 
 func (d *DB) GetUserStats(ctx context.Context, guildID, userID string, since time.Time) (*UserStats, error) {
-	q := `SELECT user_id, username, COALESCE(SUM(km), 0), COUNT(*), COALESCE(MAX(logged_at)::text, '')
-	      FROM distance_logs WHERE guild_id = $1 AND user_id = $2`
+	q := `SELECT user_id,
+	             COALESCE((SELECT username FROM distance_logs sub WHERE sub.user_id = dl.user_id AND sub.guild_id = dl.guild_id ORDER BY logged_at DESC LIMIT 1), ''),
+	             COALESCE(SUM(km), 0), COUNT(*), COALESCE(MAX(logged_at)::text, '')
+	      FROM distance_logs dl WHERE guild_id = $1 AND user_id = $2`
 	args := []interface{}{guildID, userID}
 	if !since.IsZero() {
 		args = append(args, since)
 		q += fmt.Sprintf(` AND logged_at >= $%d`, len(args))
 	}
-	q += ` GROUP BY user_id, username`
+	q += ` GROUP BY user_id`
 
 	s := &UserStats{}
 	err := d.conn.QueryRowContext(ctx, q, args...).Scan(
@@ -247,10 +251,12 @@ func (d *DB) GetUserStats(ctx context.Context, guildID, userID string, since tim
 
 func (d *DB) GetStatsInRange(ctx context.Context, guildID string, from, to time.Time, limit int) ([]*UserStats, error) {
 	rows, err := d.conn.QueryContext(ctx, `
-		SELECT user_id, username, SUM(km), COUNT(*), MAX(logged_at)
-		FROM distance_logs
+		SELECT user_id,
+		       (SELECT username FROM distance_logs sub WHERE sub.user_id = dl.user_id AND sub.guild_id = dl.guild_id ORDER BY logged_at DESC LIMIT 1),
+		       SUM(km), COUNT(*), MAX(logged_at)
+		FROM distance_logs dl
 		WHERE guild_id = $1 AND logged_at >= $2 AND logged_at <= $3
-		GROUP BY user_id, username
+		GROUP BY user_id
 		ORDER BY SUM(km) DESC
 		LIMIT $4
 	`, guildID, from, to, limit)
@@ -303,10 +309,12 @@ type YearTotal struct {
 
 func (d *DB) GetYearlyLeaderboard(ctx context.Context, guildID string, year, limit int) ([]*UserStats, error) {
 	rows, err := d.conn.QueryContext(ctx, `
-		SELECT user_id, username, SUM(km), COUNT(*), MAX(logged_at)
-		FROM distance_logs
+		SELECT user_id,
+		       (SELECT username FROM distance_logs sub WHERE sub.user_id = dl.user_id AND sub.guild_id = dl.guild_id ORDER BY logged_at DESC LIMIT 1),
+		       SUM(km), COUNT(*), MAX(logged_at)
+		FROM distance_logs dl
 		WHERE guild_id = $1 AND EXTRACT(YEAR FROM logged_at) = $2
-		GROUP BY user_id, username
+		GROUP BY user_id
 		ORDER BY SUM(km) DESC
 		LIMIT $3
 	`, guildID, year, limit)
@@ -332,10 +340,12 @@ func (d *DB) GetUserYearlyStats(ctx context.Context, guildID, userID string, yea
 	s := &UserStats{UserID: userID}
 	var lastUpdated sql.NullTime
 	err := d.conn.QueryRowContext(ctx, `
-		SELECT user_id, username, COALESCE(SUM(km), 0), COUNT(*), MAX(logged_at)
-		FROM distance_logs
+		SELECT user_id,
+		       (SELECT username FROM distance_logs sub WHERE sub.user_id = dl.user_id AND sub.guild_id = dl.guild_id ORDER BY logged_at DESC LIMIT 1),
+		       COALESCE(SUM(km), 0), COUNT(*), MAX(logged_at)
+		FROM distance_logs dl
 		WHERE guild_id = $1 AND user_id = $2 AND EXTRACT(YEAR FROM logged_at) = $3
-		GROUP BY user_id, username
+		GROUP BY user_id
 	`, guildID, userID, year).Scan(&s.UserID, &s.Username, &s.TotalKM, &s.LogCount, &lastUpdated)
 	if err == sql.ErrNoRows {
 		return s, nil