const multer = require("multer");
const path = require("path");
const { nanoid } = require("nanoid");
const config = require("../config");

const ALLOWED_MIMES = new Set([
  "image/jpeg",
  "image/png",
  "image/webp",
  "image/avif",
  "image/tiff",
  "image/gif",
  "image/svg+xml",
]);

const storage = multer.diskStorage({
  destination: config.storage.uploadDir,
  filename: (_req, file, cb) => {
    const ext = path.extname(file.originalname).toLowerCase();
    cb(null, `${nanoid(12)}${ext}`);
  },
});

const upload = multer({
  storage,
  limits: { fileSize: config.storage.maxFileSize },
  fileFilter: (_req, file, cb) => {
    if (!ALLOWED_MIMES.has(file.mimetype)) {
      return cb(new Error(`Unsupported format: ${file.mimetype}`));
    }
    cb(null, true);
  },
});

module.exports = upload;