import type { PageHead } from '../seo';
import { JSON_LD_ATTRIBUTE, serializeStructuredData } from '../structured-data';

/** Update the existing SSR tags and remove stale/duplicate tags after SPA navigation. */
export function applyPageHead(head:PageHead,doc:Document=document):void {
  doc.title=head.title;
  function tag(selector:string,element:'meta'|'link',attributes:Record<string,string>,value:string|undefined){
    const matches=Array.from(doc.head.querySelectorAll(selector));
    const node=matches.shift();matches.forEach(item=>item.remove());
    if(!value){node?.remove();return;}
    const target=node||doc.createElement(element);
    for(const [name,content] of Object.entries(attributes))target.setAttribute(name,content);
    target.setAttribute(element==='meta'?'content':'href',value);
    if(!node)doc.head.appendChild(target);
  }
  const meta=(name:string,value:string|undefined)=>tag(`meta[name="${name}"]`,'meta',{name},value);
  const og=(property:string,value:string|undefined)=>tag(`meta[property="${property}"]`,'meta',{property},value);
  const link=(rel:string,value:string|undefined)=>tag(`link[rel="${rel}"]`,'link',{rel},value);
  meta('description',head.description);meta('keywords',head.keywords.join(','));meta('application-name',head.siteName);
  meta('robots',head.robots);meta('googlebot',head.robots);
  link('canonical',head.canonical);link('prev',head.previous);link('next',head.next);
  og('og:locale','zh_CN');og('og:type',head.type);og('og:site_name',head.siteName);
  og('og:title',head.title);og('og:description',head.description);og('og:url',head.canonical);og('og:image',head.image||undefined);
  og('og:image:width',head.image?'1200':undefined);og('og:image:height',head.image?'630':undefined);og('og:image:alt',head.image?head.siteName:undefined);
  meta('twitter:card','summary_large_image');meta('twitter:title',head.title);meta('twitter:description',head.description);
  meta('twitter:image',head.image||undefined);meta('twitter:image:alt',head.image?head.siteName:undefined);
  const selector=`script[${JSON_LD_ATTRIBUTE}]`;
  const scripts=[...new Set([...doc.head.querySelectorAll(selector),...doc.querySelectorAll(selector)])];
  const script=scripts.shift();scripts.forEach(item=>item.remove());
  if(!head.jsonLd){script?.remove();return;}
  const target=script||doc.createElement('script');
  target.setAttribute('id','site-json-ld');target.setAttribute('type','application/ld+json');target.setAttribute(JSON_LD_ATTRIBUTE,'');
  target.textContent=serializeStructuredData(head.jsonLd);
  if(!script)doc.head.appendChild(target);
}