import path from 'node:path';
import type { Handle } from '@sveltejs/kit';

const MIME_TYPES: Record<string, string> = {
  '.js': 'application/javascript; charset=utf-8',
  '.mjs': 'application/javascript; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.json': 'application/json; charset=utf-8',
  '.svg': 'image/svg+xml; charset=utf-8',
  '.woff2': 'font/woff2',
  '.woff': 'font/woff',
  '.ttf': 'font/ttf',
  '.otf': 'font/otf'
};

export const handle: Handle = async ({ event, resolve }) => {
  const response = await resolve(event);
  if (event.url.pathname.startsWith('/_app/')) {
    const existing = response.headers.get('content-type');
    const hasValidHeader = existing && existing.trim().length > 0;
    if (!hasValidHeader) {
      const extension = path.extname(event.url.pathname).toLowerCase();
      const mime = extension && MIME_TYPES[extension];
      if (mime) {
        response.headers.set('content-type', mime);
      }
    }
  }

  return response;
};