import { mkdir, readdir, writeFile } from "fs/promises";
import path from "path";
import { NextResponse } from "next/server";
import { requireAdminSession } from "@/lib/admin/auth";

const uploadDir = path.join(process.cwd(), "public", "uploads", "images");
const allowedTypes = new Set(["image/jpeg", "image/png", "image/webp", "application/pdf"]);

async function ensureUploadDir() {
  await mkdir(uploadDir, { recursive: true });
}

export async function GET() {
  if (!await requireAdminSession()) return NextResponse.json({ message: "Nicht autorisiert." }, { status: 401 });
  await ensureUploadDir();
  const files = await readdir(uploadDir);
  return NextResponse.json({
    files: files.map((file) => ({ name: file, url: `/uploads/images/${file}` })),
  });
}

export async function POST(request: Request) {
  if (!await requireAdminSession()) return NextResponse.json({ message: "Nicht autorisiert." }, { status: 401 });
  await ensureUploadDir();
  const form = await request.formData();
  const file = form.get("file");

  if (!(file instanceof File) || !allowedTypes.has(file.type) || file.size > 5 * 1024 * 1024) {
    return NextResponse.json({ message: "Bitte eine JPG-, PNG-, WebP- oder PDF-Datei bis 5 MB hochladen." }, { status: 400 });
  }

  const extension = path.extname(file.name).toLowerCase();
  const safeName = `${Date.now()}-${file.name.toLowerCase().replace(/[^a-z0-9.-]/g, "-")}`;
  const target = safeName.endsWith(extension) ? safeName : `${safeName}${extension}`;
  await writeFile(path.join(uploadDir, target), Buffer.from(await file.arrayBuffer()));

  return NextResponse.redirect(new URL("/admin/medien?uploaded=1", request.url));
}