import mysql.connector.pooling
import logging

logger = logging.getLogger("db_pool")

DB_CONFIG = {
    "host": "localhost",
    "port": 3306,
    "user": "ctnt_root",
    "password": "Umsang6595!!",
    "database": "carbon_cutting_mc_db",
    "autocommit": True,
}

try:
    dbpool = mysql.connector.pooling.MySQLConnectionPool(
        pool_name="carbon_cutting_pool",
        pool_size=5,
        pool_reset_session=True,
        **DB_CONFIG
    )
    logger.info("[DB POOL] Connection pool initialized (pool_size=5)")
except Exception as e:
    logger.error(f"[DB POOL ERROR] Failed to initialize pool: {e}", exc_info=True)
    dbpool = None

def get_pooled_connection():
    """풀에서 연결 획득"""
    if dbpool is None:
        raise RuntimeError("[DB POOL ERROR] Pool not initialized")
    conn = dbpool.get_connection()
    try:
        # DB 세션이 만료되거나 끊어진 경우 자동 재연결 시도
        conn.ping(reconnect=True, attempts=3, delay=1)
    except Exception as e:
        logger.warning(f"[DB POOL] Ping/Reconnect failed: {e}")
    return conn