"""
Database engine and session management.
Provides get_db dependency for FastAPI route injection.
"""

from sqlmodel import SQLModel, Session, create_engine
from app.core.config import settings
from typing import Generator

engine = create_engine(settings.DATABASE_URL, echo=settings.DEBUG)


def create_db_tables():
    """Create all database tables from SQLModel metadata."""
    from app.models.user import User  # noqa: F401 - ensure model is registered
    from app.models.todo import Todo  # noqa: F401 - ensure model is registered
    SQLModel.metadata.create_all(engine)


def get_db() -> Generator[Session, None, None]:
    """Yield a database session for request-scoped dependency injection."""
    with Session(engine) as session:
        yield session