import type { Request, Response } from 'express';
import multer from 'multer';

import type { FileUploadProcessor } from '../types/index.ts';

const processFile = multer({
  storage: multer.memoryStorage(),
}).single('file');

function formatUnknownError(error: unknown): string {
  if (typeof error === 'string') return error;
  if (typeof error === 'number') return `${error}`;
  if (typeof error === 'boolean') return `${error}`;
  return 'File upload failed';
}

const processFileMiddleware: FileUploadProcessor = (
  req: Request,
  res: Response,
) =>
  new Promise((resolve, reject) => {
    processFile(req, res, (error: unknown) => {
      if (error) {
        reject(
          error instanceof Error ? error : new Error(formatUnknownError(error)),
        );
        return;
      }

      resolve();
    });
  });

export default processFileMiddleware;