"""Database engine and session plumbing.

`create_engine` does not connect eagerly, so importing this module is safe in the
OpenAPI dump build stage where no database exists.
"""

from collections.abc import Iterator

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

from app.config import get_settings

_engine = create_engine(get_settings().scout_db_url, pool_pre_ping=True, future=True)
SessionLocal = sessionmaker(bind=_engine, autoflush=False, expire_on_commit=False)


def get_engine():
    return _engine


def get_db() -> Iterator[Session]:
    """FastAPI dependency: one session per request, always closed."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()