"""
config_db.py
데이터베이스 연결 설정 (PostgreSQL + asyncpg)

비동기 연결 풀 생성 및 관리.
"""

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

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


async def init_db_pool() -> asyncpg.Pool:
    """PostgreSQL 연결 풀 초기화"""
    global db_pool
    db_pool = await asyncpg.create_pool(
        host=DB_HOST,
        port=DB_PORT,
        database=DB_NAME,
        user=DB_USER,
        password=DB_PASSWORD,
        min_size=DB_POOL_MIN,
        max_size=DB_POOL_MAX,
    )
    return db_pool


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


def get_db_pool() -> asyncpg.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