"""
config_db.py
데이터베이스 연결 설정 (MariaDB + aiomysql)

비동기 연결 풀 생성 및 관리.
"""

from typing import Optional

import aiomysql

from .config_system import (
    DB_HOST,
    DB_NAME,
    DB_PASSWORD,
    DB_POOL_MAX,
    DB_POOL_MIN,
    DB_PORT,
    DB_USER,
)

# 글로벌 DB 풀 (앱 시작/종료 시 관리)
db_pool: Optional[aiomysql.Pool] = None


async def init_db_pool() -> aiomysql.Pool:
    """MariaDB 연결 풀 초기화"""
    global db_pool
    db_pool = await aiomysql.create_pool(
        host=DB_HOST,
        port=DB_PORT,
        db=DB_NAME,
        user=DB_USER,
        password=DB_PASSWORD,
        minsize=DB_POOL_MIN,
        maxsize=DB_POOL_MAX,
        autocommit=False,
        charset="utf8mb4",
    )
    return db_pool


async def close_db_pool() -> None:
    """MariaDB 연결 풀 종료"""
    global db_pool
    if db_pool:
        db_pool.close()
        await db_pool.wait_closed()
        db_pool = None


def get_db_pool() -> aiomysql.Pool:
    """현재 활성 DB 풀 반환. 없으면 RuntimeError"""
    if not db_pool:
        raise RuntimeError("DB pool not initialized. Call init_db_pool() first.")
    return db_pool