import { fail } from "@/lib/response";
import { checkIpRateLimit } from "@/modules/cache/ip-rate-limiter";
import { checkRateLimit } from "@/modules/cache/rate-limiter";
import type { NextResponse } from "next/server";

function extractClientIp(request: Request): string {
  const forwarded = request.headers.get("x-forwarded-for");
  if (forwarded) {
    return forwarded.split(",")[0]?.trim() || "unknown";
  }
  return request.headers.get("x-real-ip") ?? "unknown";
}

/** 客户 + IP 双限流，超限返回 429 响应 */
export async function enforceRateLimits(
  request: Request,
  customerId: string,
): Promise<NextResponse | null> {
  const ip = extractClientIp(request);
  const ipResult = await checkIpRateLimit(ip);
  if (!ipResult.allowed) {
    const message = ipResult.banned
      ? "IP 已被临时封禁，请稍后再试"
      : "请求过于频繁，请稍后再试";
    return fail("RATE_LIMITED", message, 429);
  }

  const customerResult = await checkRateLimit(customerId);
  if (!customerResult.allowed) {
    return fail("RATE_LIMITED", "请求过于频繁，请稍后再试", 429);
  }

  return null;
}