from dbutils.pooled_db import PooledDB
import pymysql
from config import DB_CONFIG

_pool = None
def get_pool():
    global _pool
    if _pool is None:
        _pool = PooledDB(
            creator=pymysql, maxconnections=20, mincached=2, blocking=True,
            **DB_CONFIG, cursorclass=pymysql.cursors.DictCursor
        )
    return _pool

def query(sql, params=None):
    conn = get_pool().connection()
    try:
        with conn.cursor() as cur:
            cur.execute(sql, params or ())
            if sql.strip().upper().startswith("SELECT"):
                return cur.fetchall()
            conn.commit()
            return cur.lastrowid
    finally:
        conn.close()