import { Request, Response } from "express";
export interface RateLimiterOptions {
    /**
     * 🔗 The REST API URL of your Upstash Redis instance.
     *
     * You can find this in the "REST API" section of your Upstash Redis dashboard.
     * Example: "https://us1-cool-penguin-12345.upstash.io"
     */
    redisUrl: string;
    /**
     * 🛡 The access token for your Upstash Redis instance.
     *
     * Used to authenticate REST requests to Upstash Redis.
     * Example: "upstash-secret-abc123..."
     */
    redisToken: string;
    /**
     * 📊 The maximum number of requests allowed during the time window.
     *
     * If the number of requests exceeds this, the middleware blocks further requests.
     * Example: 100 (i.e., 100 requests allowed per window)
     */
    maxRequests: number;
    /**
     * ⏱ The length of the rate-limiting window in seconds.
     *
     * Determines the duration for which request counts are tracked.
     * Example: 60 (i.e., 1-minute window)
     */
    windowInSeconds: number;
    /**
     * 🧠 A custom function that generates the unique key to track requests.
     *
     * Defaults to `req.ip`. You can customize it to use a user ID, API key, etc.
     * Example: (req) => req.headers['x-user-id'] as string
     */
    keyFn?: (req: Request) => string;
    /**
     * 🚫 A custom callback function that is called when the rate limit is exceeded.
     *
     * You can use this to send a custom response instead of the default 429.
     * If not provided, a default JSON response is returned.
     */
    onLimitReached?: (req: Request, res: Response) => void;
    /**
     * 🐞 If true, logs request usage details and Redis activity to the console.
     *
     * Helpful for development and debugging.
     */
    debug?: boolean;
    /**
     * 🧯 A custom error handler that is called when Redis errors occur (e.g., invalid token or connection issue).
     *
     * Use this to log the error or respond with a fallback message.
     */
    onError?: (error: unknown, req: Request, res: Response) => void;
}