import { escapeHtml } from './utils';

const WIKI_LINK_PATTERN = /\[\[([^|\]]+)(?:\|([^\]]+))?\]\]/g;
const PROTOCOL_PATTERN = /^[\w-]+:/i;

export interface ProcessedLink {
  href: string;
  text: string;
  isExternal: boolean;
  className: string;
}

export function processWikiLink(target: string, displayText?: string): ProcessedLink {
  const isExternal = PROTOCOL_PATTERN.test(target);
  const href = isExternal ? target : `/t/${target}`;
  const text = displayText || target;

  return {
    href,
    text,
    isExternal,
    className: 'bogam-link',
  };
}

export function processWikiLinks(text: string): string {
  return text.replace(WIKI_LINK_PATTERN, (_, target, displayText) => {
    const link = processWikiLink(target, displayText);

    const attrs = [`class="${link.className}"`];
    attrs.push(`href="${escapeHtml(link.href)}"`);

    if (link.isExternal) {
      attrs.push('target="_blank"');
      attrs.push('rel="noopener noreferrer"');
    }

    return `<a ${attrs.join(' ')}>${link.text}</a>`;
  });
}

export { WIKI_LINK_PATTERN, PROTOCOL_PATTERN };