"""Database engine, session factory, and the FastAPI session dependency."""

from collections.abc import Generator

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

from app.core.config import get_settings

settings = get_settings()

engine = create_engine(
    settings.sqlalchemy_url,
    echo=settings.db_echo,
    pool_pre_ping=settings.db_pool_pre_ping,
    pool_recycle=settings.db_pool_recycle,
    future=True,
)

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


def get_db() -> Generator[Session, None, None]:
    """Yield a session per request and always close it."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()