/**
 * Premium SEO Dynamic Header and Schema Manager
 * Enhances search engine indexing, click-through rates, and Google ranking signals.
 */

export interface SEOConfig {
  title: string;
  description: string;
  keywords: string;
  schema?: string;
  canonicalUrl?: string;
}

export function updateSEO({ title, description, keywords, schema, canonicalUrl }: SEOConfig) {
  // Update document title
  document.title = title;

  // Update or create Meta Description
  let metaDesc = document.querySelector('meta[name="description"]');
  if (!metaDesc) {
    metaDesc = document.createElement("meta");
    metaDesc.setAttribute("name", "description");
    document.head.appendChild(metaDesc);
  }
  metaDesc.setAttribute("content", description);

  // Update or create Meta Keywords
  let metaKeywords = document.querySelector('meta[name="keywords"]');
  if (!metaKeywords) {
    metaKeywords = document.createElement("meta");
    metaKeywords.setAttribute("name", "keywords");
    document.head.appendChild(metaKeywords);
  }
  metaKeywords.setAttribute("content", keywords);

  // Open Graph Facebook/LinkedIn tags
  let ogTitle = document.querySelector('meta[property="og:title"]');
  if (!ogTitle) {
    ogTitle = document.createElement("meta");
    ogTitle.setAttribute("property", "og:title");
    document.head.appendChild(ogTitle);
  }
  ogTitle.setAttribute("content", title);

  let ogDesc = document.querySelector('meta[property="og:description"]');
  if (!ogDesc) {
    ogDesc = document.createElement("meta");
    ogDesc.setAttribute("property", "og:description");
    document.head.appendChild(ogDesc);
  }
  ogDesc.setAttribute("content", description);

  // Canonical URL Link
  const fullUrl = canonicalUrl || window.location.href;
  let linkCanonical = document.querySelector('link[rel="canonical"]');
  if (!linkCanonical) {
    linkCanonical = document.createElement("link");
    linkCanonical.setAttribute("rel", "canonical");
    document.head.appendChild(linkCanonical);
  }
  linkCanonical.setAttribute("href", fullUrl);

  // Structured Data Schema markup for rich snippet display
  let schemaScript = document.getElementById("lumina-structured-data");
  if (schemaScript) {
    schemaScript.remove();
  }
  
  if (schema) {
    schemaScript = document.createElement("script");
    schemaScript.id = "lumina-structured-data";
    schemaScript.setAttribute("type", "application/ld+json");
    schemaScript.innerHTML = schema;
    document.head.appendChild(schemaScript);
  }
}