/**
 * OG Image Scraper — holt og:image aus beliebiger URL
 * Funktioniert mit Pinterest, Chefkoch, Allrecipes, Blogs etc.
 */

const USER_AGENTS: Record<string, string> = {
  'pinterest.com': 'Twitterbot/1.0',
  'pinterest.de': 'Twitterbot/1.0',
  'pin.it': 'Twitterbot/1.0',
  default: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
};

function getUserAgent(url: string): string {
  for (const [domain, ua] of Object.entries(USER_AGENTS)) {
    if (domain !== 'default' && url.includes(domain)) return ua;
  }
  return USER_AGENTS.default;
}

export interface OgData {
  image?: string;
  title?: string;
  description?: string;
}

export async function scrapeOgData(url: string): Promise<OgData> {
  const ua = getUserAgent(url);

  const res = await fetch(url, {
    headers: { 'User-Agent': ua },
    redirect: 'follow',
    signal: AbortSignal.timeout(10000),
  });

  if (!res.ok) throw new Error(`HTTP ${res.status}`);

  const html = await res.text();
  const result: OgData = {};

  // Extract og:image
  const imageMatch = html.match(/<meta[^>]+(?:property|name)="og:image"[^>]+content="([^"]+)"/i)
    || html.match(/<meta[^>]+content="([^"]+)"[^>]+(?:property|name)="og:image"/i);
  if (imageMatch) result.image = imageMatch[1];

  // Extract og:title
  const titleMatch = html.match(/<meta[^>]+(?:property|name)="og:title"[^>]+content="([^"]+)"/i)
    || html.match(/<meta[^>]+content="([^"]+)"[^>]+(?:property|name)="og:title"/i);
  if (titleMatch) result.title = decodeHtmlEntities(titleMatch[1]);

  // Extract og:description
  const descMatch = html.match(/<meta[^>]+(?:property|name)="og:description"[^>]+content="([^"]+)"/i)
    || html.match(/<meta[^>]+content="([^"]+)"[^>]+(?:property|name)="og:description"/i);
  if (descMatch) result.description = decodeHtmlEntities(descMatch[1]);

  // Pinterest special: higher-res image from JSON data
  if (url.includes('pinterest') && result.image) {
    // Try to get orig resolution instead of 736x
    const origMatch = html.match(/"orig":\s*\{[^}]*"url"\s*:\s*"([^"]+)"/);
    if (origMatch) result.image = origMatch[1];
  }

  return result;
}

function decodeHtmlEntities(str: string): string {
  return str
    .replace(/&amp;/g, '&')
    .replace(/&lt;/g, '<')
    .replace(/&gt;/g, '>')
    .replace(/&quot;/g, '"')
    .replace(/&#39;/g, "'")
    .replace(/&#x27;/g, "'");
}