const MARKDOWN_EXTENSIONS = new Set(['.md', '.markdown', '.mdx'])

export const getPreviewFileExtension = (path) => {
  const normalizedPath = String(path || '')
    .trim()
    .toLowerCase()
  if (!normalizedPath) return ''

  const fileName = normalizedPath.split('/').pop() || ''
  const dotIndex = fileName.lastIndexOf('.')
  if (dotIndex <= 0) return ''
  return fileName.slice(dotIndex)
}

export const isMarkdownPreview = (path, previewType) => {
  if (previewType === 'markdown') return true
  return MARKDOWN_EXTENSIONS.has(getPreviewFileExtension(path))
}