from __future__ import annotations

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

from .config import DATABASE_URL

_is_sqlite = DATABASE_URL.startswith("sqlite")
connect_args = {"check_same_thread": False} if _is_sqlite else {}

engine = create_engine(
    DATABASE_URL,
    connect_args=connect_args,
    pool_pre_ping=not _is_sqlite,
    future=True,
)

SessionLocal = sessionmaker(bind=engine, autoflush=False, autocommit=False, future=True)


class Base(DeclarativeBase):
    """所有模型的基类。"""


def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()