// 简单的内存速率限制器（基于 IP）

interface RateLimitEntry {
    count: number;
    resetAt: number;
}

const store = new Map<string, RateLimitEntry>();

// 定期清理过期条目，防止内存泄漏
const CLEANUP_INTERVAL_MS = 5 * 60 * 1000; // 5 分钟
setInterval(() => {
    const now = Date.now();
    for (const [key, entry] of store) {
        if (now >= entry.resetAt) {
            store.delete(key);
        }
    }
}, CLEANUP_INTERVAL_MS);

/**
 * 检查请求是否超过速率限制
 * @param key 限制键（通常是 IP 地址）
 * @param maxAttempts 窗口期内最大尝试次数
 * @param windowMs 窗口期（毫秒）
 * @returns 如果超限返回 true，否则返回 false
 */
export function isRateLimited(
    key: string,
    maxAttempts: number = 5,
    windowMs: number = 60 * 1000
): boolean {
    const now = Date.now();
    const entry = store.get(key);

    if (!entry || now >= entry.resetAt) {
        store.set(key, { count: 1, resetAt: now + windowMs });
        return false;
    }

    entry.count += 1;
    return entry.count > maxAttempts;
}

/**
 * 从 Request 对象中提取客户端 IP
 */
export function getClientIp(req: Request): string {
    // 常见的代理头
    const forwarded = req.headers.get("x-forwarded-for");
    if (forwarded) {
        return forwarded.split(",")[0].trim();
    }
    const realIp = req.headers.get("x-real-ip");
    if (realIp) {
        return realIp.trim();
    }
    return "unknown";
}