import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';

const RATE_LIMIT_WINDOW = 60 * 1000; // 1 minute
const MAX_REQUESTS = 100; // 100 requests per window
const CLEANUP_THRESHOLD = 500;

const ipMap = new Map<string, { count: number; expires: number }>();

export function middleware(request: NextRequest) {
    const forwarded = request.headers.get('x-forwarded-for');
    const ip = forwarded ? forwarded.split(',')[0].trim() : 'unknown';
    const now = Date.now();

    console.log(`[${new Date().toISOString()}] Request to ${request.nextUrl.pathname} from ${ip}`);

    const record = ipMap.get(ip);

    if (!record || now > record.expires) {
        ipMap.set(ip, { count: 1, expires: now + RATE_LIMIT_WINDOW });
    } else {
        record.count++;
        if (record.count > MAX_REQUESTS) {
            return new NextResponse('Too Many Requests', { status: 429 });
        }
    }

    // Cleanup old entries probabilistically (1-in-10 requests)
    if (ipMap.size > CLEANUP_THRESHOLD && Math.random() < 0.1) {
        for (const [key, val] of ipMap.entries()) {
            if (now > val.expires) {
                ipMap.delete(key);
            }
        }
    }

    return NextResponse.next();
}

export const config = {
    matcher: ['/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp|ico)$).*)'],
};