import multer from "multer";
import path from "path";
import crypto from "crypto";
import { fileURLToPath } from "url";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
export const UPLOAD_DIR = path.join(__dirname, "uploads");

const ALLOWED = new Set(["image/gif", "image/png", "image/webp"]);

const storage = multer.diskStorage({
  destination: (_req, _file, cb) => cb(null, UPLOAD_DIR),
  filename: (_req, file, cb) => {
    const ext = path.extname(file.originalname).toLowerCase().replace(/[^.a-z0-9]/g, "");
    const safeExt = [".gif", ".png", ".webp"].includes(ext) ? ext : ".gif";
    cb(null, crypto.randomUUID() + safeExt);
  },
});

export const upload = multer({
  storage,
  limits: { fileSize: 8 * 1024 * 1024 }, // 8 MB
  fileFilter: (_req, file, cb) => {
    if (ALLOWED.has(file.mimetype)) cb(null, true);
    else cb(new Error("Only GIF, PNG, or WebP images are allowed"));
  },
});