from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base
from config import DATABASE_URL

engine = create_engine(DATABASE_URL, pool_pre_ping=True)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()


def get_db():
    """FastAPI dependency that yields a DB session and closes it after use."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    """Create all tables. Called once at startup."""
    Base.metadata.create_all(bind=engine)