from typing import Generator

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

from app.core.config import settings
from app.models.ecg import Base

# Synchronous engine for database connections (works with SQLite reliably here)
engine = create_engine(
    settings.DATABASE_URL,
    echo=False,
    future=True,
)

# Session factory
SessionLocal = sessionmaker(
    bind=engine,
    autocommit=False,
    autoflush=False,
)


def get_session() -> Generator[Session, None, None]:
    """
    FastAPI dependency providing a synchronous Session.
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db() -> None:
    """
    Create database tables on startup.
    """
    Base.metadata.create_all(bind=engine)


def close_engine() -> None:
    """
    Dispose of the engine on shutdown.
    """
    engine.dispose()