app/utils/rate_limiter.py

import asyncio
import time
from collections import deque


class RateLimiter:
    """Token bucket rate limiter"""

    def __init__(self, max_requests: int = 60, time_window: int = 60):
        self.max_requests = max_requests
        self.time_window = time_window
        self.requests = deque()
        self._lock = asyncio.Lock()

    async def acquire(self):
        """Acquire permission to make a request"""
        async with self._lock:
            now = time.time()

            # Remove old requests outside time window
            while self.requests and self.requests[0] <= now - self.time_window:
                self.requests.popleft()

            # Check if we can make a request
            if len(self.requests) < self.max_requests:
                self.requests.append(now)
                return

            # Calculate wait time
            oldest_request = self.requests[0]
            wait_time = oldest_request + self.time_window - now

            if wait_time > 0:
                await asyncio.sleep(wait_time)
                # Retry after waiting
                await self.acquire()
            else:
                self.requests.append(now)