from window import SlidingWindow


class RateLimiter:
    def __init__(self, limit, span):
        self.limit = limit
        self.window = SlidingWindow(span)

    def allow(self, at):
        if self.window.count(at) >= self.limit:
            return False
        self.window.add(at)
        return True

    def remaining(self, at):
        return max(0, self.limit - self.window.count(at))