import DOMPurify from 'dompurify';

const ALLOWED_TAGS = [
  'a',
  'b',
  'blockquote',
  'br',
  'caption',
  'col',
  'colgroup',
  'div',
  'em',
  'h1',
  'h2',
  'h3',
  'h4',
  'h5',
  'h6',
  'hr',
  'i',
  'img',
  'li',
  'ol',
  'p',
  'span',
  'strong',
  'style',
  'sub',
  'sup',
  'table',
  'tbody',
  'td',
  'tfoot',
  'th',
  'thead',
  'tr',
  'u',
  'ul'
];

const ALLOWED_ATTR = ['href', 'title', 'target', 'rel', 'src', 'alt', 'width', 'height', 'colspan', 'rowspan', 'scope', 'class', 'style'];

if (typeof window !== 'undefined') {
  DOMPurify.addHook('afterSanitizeAttributes', (node) => {
    if (node.tagName === 'A' && node.getAttribute('target') === '_blank') {
      node.setAttribute('rel', 'noopener noreferrer');
    }
  });
}

/**
 * Strict allow-list sanitize for API / i18n HTML before innerHTML.
 * Scripts, event handlers, iframes, and javascript: URLs are dropped.
 */
export function sanitizeHtml(dirty) {
  if (dirty == null) {
    return '';
  }
  return DOMPurify.sanitize(String(dirty), {
    ALLOWED_TAGS,
    ALLOWED_ATTR,
    ALLOWED_URI_REGEXP: /^(?:(?:(?:f|ht)tps?|mailto):|[^a-z]|[a-z+.-]+(?:[^a-z+.-:]|$))/i
  });
}