import aiosqlite
from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver
from langgraph.checkpoint.memory import InMemorySaver


_checkpointer = None

async def get_checkpointer():
    global _checkpointer
    if _checkpointer is None:
        conn = await aiosqlite.connect("db.sqlite")
        _checkpointer = AsyncSqliteSaver(conn)

    # _checkpointer=InMemorySaver()
    return _checkpointer