from collections.abc import Generator

from sqlalchemy import create_engine, text
from sqlalchemy.orm import Session, sessionmaker

try:
    # For module mode: `uvicorn app.main:app`
    from app.settings import settings
except ModuleNotFoundError:
    # For script mode: `python app/main.py` or VS Code "Run Python File"
    from settings import settings


engine = create_engine(
    settings.mysql_dsn,
    pool_size=5,
    max_overflow=10,
    pool_pre_ping=True,
    pool_recycle=1800,
    future=True,
)

SessionLocal = sessionmaker(
    bind=engine,
    autocommit=False,
    autoflush=False,
    expire_on_commit=False,
)


def get_db() -> Generator[Session, None, None]:
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def check_db_connection() -> None:
    with engine.connect() as conn:
        conn.execute(text("SELECT 1"))


def close_db_engine() -> None:
    engine.dispose()