import path from 'path';

/**
 * 把磁盘绝对路径转换成可访问的相对 URL
 * 例如：/Users/xxx/server/uploads/2026/01/abc.jpg -> /uploads/2026/01/abc.jpg
 */
export function filePathToUrl(absPath: string): string {
  const root = (process.env.UPLOAD_ROOT ?? './uploads').replace(/^\.\/?/, '');
  const idx = absPath.replace(/\\/g, '/').indexOf(root);
  if (idx >= 0) {
    return '/' + absPath.replace(/\\/g, '/').slice(idx).replace(/^\/+/, '/');
  }
  return '/' + path.basename(absPath);
}