from alembic import context
from sqlalchemy import create_engine, pool

from app import models  # noqa: F401
from app.core.config import settings
from app.db.session import Base

config = context.config


def run_migrations(connection):
    context.configure(connection=connection, target_metadata=Base.metadata, compare_type=True)
    with context.begin_transaction():
        context.run_migrations()


if context.is_offline_mode():
    raise RuntimeError("迁移需要连接数据库，以检查并保留已有表；请使用 alembic upgrade head")
elif config.attributes.get("connection") is not None:
    run_migrations(config.attributes["connection"])
else:
    engine = create_engine(
        settings.database_url, poolclass=pool.NullPool, connect_args={"connect_timeout": 5}
    )
    with engine.connect() as connection:
        run_migrations(connection)