import { NextRequest, NextResponse } from "next/server";
import { getSessionCookie } from "better-auth/cookies";
import { applyRateLimit } from "@/lib/rate-limit";

const PUBLIC_PATHS = ["/login", "/signup", "/verify-email", "/verify-2fa", "/forgot-password", "/reset-password", "/api/auth", "/r/", "/c/", "/u/", "/s/", "/docs", "/api/v1/openapi.json", "/api/webhooks", "/api/v1/invites/", "/api/internal/", "/features", "/pricing", "/about", "/privacy", "/terms", "/contact"];
// Exact-match only — "/" can't go in PUBLIC_PATHS's startsWith list, since
// every path starts with "/" and that would make the whole app public.
const PUBLIC_EXACT_PATHS = ["/"];
const ADMIN_PATHS = ["/admin"];

// A public-editable shopping list's own items endpoint — no session cookie to
// require, since an anonymous visitor's only credential is the link (the list
// id) itself. getShoppingListAccess (lib/shopping-list-access.ts) is what
// actually enforces that the specific list allows this; a non-public list
// hitting this route just gets a 404/403 from the handler, same as today.
const SHOPPING_LIST_ITEMS_RE = /^\/api\/v1\/shopping-lists\/[^/]+\/items(\/|$)/;

// Unauthenticated, publicly-linked pages/endpoints (shared recipes/shopping
// lists) — no per-user identity to key on, so rate-limit by IP to deter abuse.
const IP_RATE_LIMITED_PATHS = ["/r/", "/s/"];
const IP_RATE_LIMIT = 60;
const IP_RATE_LIMIT_WINDOW_SECONDS = 60;

// Epicure sits behind exactly one reverse proxy (Traefik — see traefik/epicure.yml).
// Each hop *appends* the address it saw to X-Forwarded-For, so with a single
// trusted hop in front of us, the rightmost entry is the address Traefik itself
// observed — i.e. the real client — while anything to its left (including the
// entire header, on a direct request with no proxy at all) is attacker-supplied
// and must not be trusted. Taking the leftmost entry, as before, let a client
// set an arbitrary X-Forwarded-For and get a fresh rate-limit bucket on every
// request. If another reverse proxy is ever added in front of Traefik, this
// needs to pop one more entry per added hop.
function getClientIp(request: NextRequest): string {
  const forwardedFor = request.headers.get("x-forwarded-for");
  if (forwardedFor) {
    const parts = forwardedFor.split(",");
    return parts[parts.length - 1]!.trim();
  }
  return request.headers.get("x-real-ip") ?? "unknown";
}

export async function proxy(request: NextRequest) {
  const { pathname } = request.nextUrl;

  const sessionCookie = getSessionCookie(request);
  const isShoppingListItems = SHOPPING_LIST_ITEMS_RE.test(pathname);
  // Only treat the items endpoint as public for requests with no session —
  // an authenticated collaborator's own polling/edits should never be bucketed
  // into the anonymous-visitor IP rate limit below.
  const isPublic = PUBLIC_PATHS.some((p) => pathname.startsWith(p)) || PUBLIC_EXACT_PATHS.includes(pathname) || (isShoppingListItems && !sessionCookie);
  const isAdmin = ADMIN_PATHS.some((p) => pathname.startsWith(p));
  const isApi = pathname.startsWith("/api/v1");

  if (isPublic) {
    if (IP_RATE_LIMITED_PATHS.some((p) => pathname.startsWith(p)) || isShoppingListItems) {
      const ip = getClientIp(request);
      const limited = await applyRateLimit(`rl:public:${ip}`, IP_RATE_LIMIT, IP_RATE_LIMIT_WINDOW_SECONDS);
      if (limited) return limited;
    }
    return NextResponse.next();
  }

  // API-key clients authenticate via `Authorization: Bearer ek_...`, not a
  // session cookie — they'd otherwise be rejected here before ever reaching
  // requireSessionOrApiKey (lib/api-auth.ts), which is the only place that
  // actually verifies the key. Defer to it instead of requiring a cookie.
  const authHeader = request.headers.get("authorization");
  const hasApiKeyHeader = isApi && authHeader?.startsWith("Bearer ek_");

  if (!sessionCookie && !hasApiKeyHeader) {
    if (isApi) {
      return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
    }
    return NextResponse.redirect(new URL("/login", request.url));
  }

  if (isAdmin) {
    // Role check happens inside admin pages — middleware only checks auth
    // Full role verification requires DB lookup, done server-side in admin layout
  }

  return NextResponse.next();
}

export default proxy;

export const config = {
  matcher: [
    "/((?!_next/static|_next/image|favicon.ico|icon.svg|icon-192.svg|icon-512.svg|manifest.webmanifest|sw.js|public/).*)",
  ],
};