import { mkdir, writeFile } from "node:fs/promises";
import path from "node:path";
import { randomUUID } from "node:crypto";
import sharp from "sharp";
import { cookies } from "next/headers";
import { NextResponse } from "next/server";

const MAX_UPLOAD_SIZE_BYTES = 20 * 1024 * 1024;
const ALLOWED_MIME_TYPES = new Set([
  "image/avif",
  "image/gif",
  "image/jpeg",
  "image/png",
  "image/tiff",
  "image/webp",
]);

export const runtime = "nodejs";

function sanitizeFilenameStem(filename: string) {
  const stem = path.parse(filename).name;
  const normalized = stem
    .normalize("NFKD")
    .replace(/[\u0300-\u036f]/g, "")
    .toLowerCase()
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "");

  return normalized || "image";
}

export async function POST(request: Request) {
  const cookieStore = await cookies();
  if (!cookieStore.get("admin_session")) {
    return NextResponse.json({ detail: "Admin-innlogging kreves" }, { status: 401 });
  }

  try {
    const formData = await request.formData();
    const file = formData.get("file");

    if (!(file instanceof File)) {
      return NextResponse.json({ detail: "Fant ingen bildefil i requesten." }, { status: 400 });
    }

    if (!ALLOWED_MIME_TYPES.has(file.type)) {
      return NextResponse.json(
        { detail: "Filtypen støttes ikke. Bruk JPG, PNG, WebP, TIFF, GIF eller AVIF." },
        { status: 415 },
      );
    }

    if (file.size > MAX_UPLOAD_SIZE_BYTES) {
      return NextResponse.json(
        { detail: "Bildeopplasting er begrenset til 20 MB per fil." },
        { status: 413 },
      );
    }

    const inputBuffer = Buffer.from(await file.arrayBuffer());
    const image = sharp(inputBuffer, { animated: false }).rotate();
    const metadata = await image.metadata();

    if (!metadata.width || !metadata.height) {
      return NextResponse.json({ detail: "Kunne ikke lese bildedimensjonene." }, { status: 400 });
    }

    const dateSegment = new Date().toISOString().slice(0, 10);
    const safeName = sanitizeFilenameStem(file.name);
    const filename = `${safeName}-${randomUUID()}.avif`;
    const relativeDirectory = path.join("uploads", "articles", dateSegment);
    const absoluteDirectory = path.join(process.cwd(), "public", relativeDirectory);
    const absolutePath = path.join(absoluteDirectory, filename);

    await mkdir(absoluteDirectory, { recursive: true });

    const outputBuffer = await image
      .resize({
        width: 2400,
        withoutEnlargement: true,
      })
      .avif({
        quality: 68,
        effort: 6,
      })
      .toBuffer();

    await writeFile(absolutePath, outputBuffer);

    return NextResponse.json({
      url: `/${relativeDirectory.replaceAll(path.sep, "/")}/${filename}`,
      contentType: "image/avif",
      width: metadata.width,
      height: metadata.height,
    });
  } catch (error) {
    console.error("Image upload failed", error);
    return NextResponse.json({ detail: "Kunne ikke prosessere bildefilen." }, { status: 500 });
  }
}