"""SQLAlchemy engine + session. Sync (react.md: sync def for DB routes;
FastAPI runs them in a threadpool)."""
from collections.abc import Iterator

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

from .config import settings

engine = create_engine(settings.database_url, pool_pre_ping=True, future=True)
SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)


def get_db() -> Iterator[Session]:
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()