import threading
from typing import Optional
from config import Singleton

class GlobalStore(metaclass=Singleton):
    def __init__(self):
        self._id_counter = 0
        self._lock = threading.Lock()
        self._id_map = {}

    def get_new_id(self) -> int:
        with self._lock:
            new_id = self._id_counter
            self._id_counter += 1
        return new_id

    def add_value(self, id: int, value: str) -> int:
        with self._lock:
            self._id_map[id] = value
        return id

    def get_value(self, id: int) -> Optional[str]:
        with self._lock:
            value = self._id_map.get(id)
            if value is not None:
                del self._id_map[id]
        return value