rate

type Limit struct {
	Rate   int
	Burst  int
	Period time.Duration
}

type Manager interface {
	// Login 检查是登录限流。
	Login(ctx context.Context, ip string) (allowed bool, remain int, err error)

	AllowAction(
		ctx context.Context,
		u model.UserID,
		action action.Action,
		limit Limit,
	) (allowed bool, remain int, err error)
	Reset(ctx context.Context, ip string) error
}

type Result struct {
	// Limit is the limit that was used to obtain this result.
	Limit Limit

	// Allowed is the number of events that may happen at time now.
	Allowed int

	// Remaining is the maximum number of requests that could be
	// permitted instantaneously for this key given the current
	// state. For example, if a rate limiter allows 10 requests per
	// second and has already received 6 requests for this key this
	// second, Remaining would be 4.
	Remaining int

	// RetryAfter is the time until the next request will be permitted.
	// It should be -1 unless the rate limit has been exceeded.
	RetryAfter time.Duration

	// ResetAfter is the time until the RateLimiter returns to its
	// initial state for a given key. For example, if a rate limiter
	// manages requests per second and received one request 200ms ago,
	// Reset would return 800ms. You can also think of this as the time
	// until Limit and Remaining will be equal.
	ResetAfter time.Duration
}