import asyncio
from asyncio_throttle import Throttler as AsyncThrottler

class GlobalThrottler:
    _instance = None
    _lock = asyncio.Lock()
    
    def __init__(self, rate_limit: int = 500, period: int = 60) -> None:
        if not hasattr(self, '_initialized'):
            self.rate_limit = rate_limit
            self.period = period
            self.throttler = AsyncThrottler(rate_limit=self.rate_limit, period=self.period)
            self._initialized = True
    
    @classmethod
    async def get_instance(cls, rate_limit: int = 500, period: int = 60) -> 'GlobalThrottler':
        async with cls._lock:
            if not cls._instance:
                cls._instance = cls(rate_limit, period)
            return cls._instance
    
    async def acquire(self):
        await self.throttler.acquire()
        
    def release(self):
        self.throttler.release()
    
    async def __aenter__(self):
        await self.acquire()
        return self
        
    async def __aexit__(self, exc_type, exc_val, exc_tb):
        self.release()