/**
 * 简单内存速率限制
 * 每个 IP 每小时最多允许 MAX_REQUESTS 次提交
 */

const WINDOW_MS = 60 * 60 * 1000 // 1 小时
const MAX_REQUESTS = 5

// Map<ip, { count: number, resetAt: number }>
const store = new Map()

// 每 2 小时清理一次过期记录，防止内存泄漏
setInterval(() => {
  const now = Date.now()
  for (const [ip, record] of store.entries()) {
    if (now > record.resetAt) {
      store.delete(ip)
    }
  }
}, 2 * 60 * 60 * 1000)

/**
 * 检查并记录一次请求
 * @param {string} ip
 * @returns {{ allowed: boolean, remaining: number, resetAt: number }}
 */
export function checkRateLimit(ip) {
  const now = Date.now()
  const record = store.get(ip)

  if (!record || now > record.resetAt) {
    store.set(ip, { count: 1, resetAt: now + WINDOW_MS })
    return { allowed: true, remaining: MAX_REQUESTS - 1, resetAt: now + WINDOW_MS }
  }

  if (record.count >= MAX_REQUESTS) {
    return { allowed: false, remaining: 0, resetAt: record.resetAt }
  }

  record.count++
  return { allowed: true, remaining: MAX_REQUESTS - record.count, resetAt: record.resetAt }
}