import sanitizeHtml from 'sanitize-html'

const ALLOWED_HTML_BLOCK_TAGS = [
  'a',
  'abbr',
  'b',
  'blockquote',
  'br',
  'caption',
  'code',
  'col',
  'colgroup',
  'dd',
  'details',
  'div',
  'dl',
  'dt',
  'em',
  'figcaption',
  'figure',
  'h2',
  'h3',
  'h4',
  'h5',
  'h6',
  'hr',
  'i',
  'img',
  'li',
  'mark',
  'ol',
  'p',
  'pre',
  's',
  'small',
  'span',
  'strong',
  'sub',
  'summary',
  'sup',
  'table',
  'tbody',
  'td',
  'tfoot',
  'th',
  'thead',
  'time',
  'tr',
  'u',
  'ul'
]

const HTML_BLOCK_SANITIZE_OPTIONS = {
  allowedTags: ALLOWED_HTML_BLOCK_TAGS,
  allowedAttributes: {
    '*': ['class', 'title', 'aria-label', 'aria-hidden'],
    a: ['href', 'target', 'rel'],
    col: ['span', 'width'],
    img: ['src', 'alt', 'width', 'height', 'loading'],
    li: ['value'],
    ol: ['start', 'type'],
    td: ['colspan', 'rowspan', 'headers'],
    th: ['colspan', 'rowspan', 'headers', 'scope'],
    time: ['datetime']
  },
  allowedSchemes: ['http', 'https', 'mailto', 'tel'],
  allowedSchemesAppliedToAttributes: ['href', 'src'],
  allowProtocolRelative: false,
  nonTextTags: ['script', 'style', 'textarea', 'option', 'template', 'noscript'],
  transformTags: {
    a: (tagName, attribs) => {
      if (attribs.target !== '_blank') {
        return { tagName, attribs }
      }

      const relValues = new Set(String(attribs.rel || '').split(/\s+/).filter(Boolean))
      relValues.add('noopener')
      relValues.add('noreferrer')

      return {
        tagName,
        attribs: {
          ...attribs,
          rel: [...relValues].join(' ')
        }
      }
    }
  }
}

/**
 * 본문 HTML 블록에서 실행성 코드와 위험 속성을 제거한다.
 * @param {string} value - 원본 HTML
 * @returns {string} 정리된 HTML
 */
export const sanitizeHtmlBlock = (value) => {
  const html = String(value || '').trim()
  return html ? sanitizeHtml(html, HTML_BLOCK_SANITIZE_OPTIONS).trim() : ''
}