"""
資料庫連線設定 (MySQL)
"""
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base

from app.core.config import settings

# 建立資料庫引擎 (MySQL)
engine = create_engine(
    settings.DATABASE_URL,
    pool_pre_ping=True,
    pool_size=10,
    max_overflow=20,
    pool_recycle=3600,  # MySQL 連線回收
)

# 建立 Session 工廠
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# 建立 Base 類別
Base = declarative_base()


def get_db():
    """
    取得資料庫 Session
    用於 FastAPI 依賴注入
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    """初始化資料庫（建立所有表）"""
    Base.metadata.create_all(bind=engine)