/**
 * Server request shell. Reads the incoming request once, classifies it via
 * the pure domain decision, and records a page view without touching the
 * response. All analytics happen server-side; no tracking script ships to
 * the browser.
 *
 * Page views are browser navigations (`sec-fetch-dest: document`).
 * Router-internal headers (RSC, next-router-prefetch) are stripped by the
 * server before this shell runs and cannot be used here.
 */

import { NextResponse, type NextRequest } from "next/server";

import { recordPageviewToUmami } from "@/src/analytics/recordPageviewToUmami";
import { decidePageview } from "@/src/domain/pageview-decision";

const primaryLanguage = (acceptLanguage: string | null): string =>
  acceptLanguage?.split(",")[0]?.split(";")[0]?.trim() ?? "";

const firstForwardedIp = (forwardedFor: string | null): string =>
  forwardedFor?.split(",")[0]?.trim() ?? "";

const hostnameWithoutPort = (host: string): string => host.replace(/:\d+$/, "");

export default function proxy(request: NextRequest): NextResponse {
  const decision = decidePageview({
    method: request.method,
    secFetchDest: request.headers.get("sec-fetch-dest") ?? "",
    pathname: request.nextUrl.pathname,
    search: request.nextUrl.search,
    hostname: hostnameWithoutPort(
      request.headers.get("x-forwarded-host") ??
        request.headers.get("host") ??
        "",
    ),
    referrer: request.headers.get("referer") ?? "",
    language: primaryLanguage(request.headers.get("accept-language")),
    userAgent: request.headers.get("user-agent") ?? "",
    clientIp: firstForwardedIp(request.headers.get("x-forwarded-for")),
  });

  if (decision.track) {
    recordPageviewToUmami(decision.facts);
  }

  return NextResponse.next();
}

export const config = {
  matcher: [
    "/((?!_next/static|_next/image|.*\\.(?:png|jpe?g|gif|svg|webp|avif|ico|css|mjs|cjs|js|map|txt|xml|json|webmanifest|woff2?|ttf|otf|mp4|webm|mov|pdf|zip)$).*)",
  ],
};