Function leaderboard

backend/app/main.py:392–407

(challenge_id: str)

@app.get("/api/challenges/{challenge_id}/leaderboard")
def leaderboard(challenge_id: str) -> dict:
    with connect() as conn:
        rows = conn.execute(
            """
            SELECT p.id, p.nickname, COUNT(u.cell_id) AS unlocked_cells,
                   MAX(u.created_at) AS last_unlocked_at
            FROM user_unlocked_cells u
            JOIN participants p ON p.id = u.participant_id
            WHERE u.challenge_id = ?
            GROUP BY p.id, p.nickname
            ORDER BY unlocked_cells DESC, last_unlocked_at ASC
            LIMIT 100
            """,
            (challenge_id,),
        ).fetchall()
        return {"leaderboard": [row_to_dict(row) for row in rows]}


@app.post("/api/challenges/{challenge_id}/unlock")