app/services/rate_limiter.py

import time
from collections import defaultdict, deque
from typing import Deque, Dict


class InMemoryRateLimiter:
    def __init__(self, max_requests: int, window_seconds: int) -> None:
        self.max_requests = max_requests
        self.window_seconds = window_seconds
        self._hits: Dict[str, Deque[float]] = defaultdict(deque)

    def allow(self, key: str) -> bool:
        now = time.time()
        window_start = now - self.window_seconds
        q = self._hits[key]

        while q and q[0] < window_start:
            q.popleft()

        if len(q) >= self.max_requests:
            return False

        q.append(now)
        return True