import { readFileSync, existsSync } from 'fs';
import { join, resolve } from 'path';
import { loadFeedback } from './feedback-store.js';

const SITE_URL = 'https://www.ypchat.net';
const DEFAULT_IMAGE = `${SITE_URL}/static/favicon.png`;
const SEO_LOCALES = [
  { code: 'de', label: 'Deutsch' },
  { code: 'en', label: 'English' },
  { code: 'fr', label: 'Francais' },
  { code: 'es', label: 'Espanol' },
  { code: 'it', label: 'Italiano' },
  { code: 'ja', label: 'Japanese' },
  { code: 'zh', label: 'Chinese' },
  { code: 'th', label: 'Thai' },
  { code: 'tl', label: 'Tagalog' }
];
const LOCALE_SEO_META = {
  de: {
    title: 'SingleChat: Kostenloser Single Chat, privat & anonym',
    description: 'Kostenloser Single Chat für private und anonyme Gespräche. Lerne neue Kontakte kennen und teile Bilder sicher online.',
    keywords: 'single chat, kostenloser chat, privat chatten, anonym chat, free chat, private chat, anonymous chat, online chat'
  },
  en: {
    title: 'SingleChat: Free Private & Anonymous Single Chat',
    description: 'Free single chat for private and anonymous conversations. Meet new people and share images safely online.',
    keywords: 'single chat, free chat, private chat, anonymous chat, online chat, meet singles'
  },
  fr: {
    title: 'SingleChat: Chat célibataire gratuit, privé et anonyme',
    description: 'Chat célibataire gratuit pour des conversations privées et anonymes. Rencontrez de nouvelles personnes en toute sécurité.',
    keywords: 'chat célibataire, chat gratuit, chat privé, chat anonyme, rencontre en ligne'
  },
  es: {
    title: 'SingleChat: Chat gratis, privado y anónimo',
    description: 'Chat gratis para solteros con conversaciones privadas y anónimas. Conoce gente nueva y comparte imágenes de forma segura.',
    keywords: 'chat gratis, chat privado, chat anónimo, chat para solteros, conocer gente'
  },
  it: {
    title: 'SingleChat: Chat single gratis, privata e anonima',
    description: 'Chat single gratis per conversazioni private e anonime. Conosci nuove persone e condividi immagini in sicurezza.',
    keywords: 'chat single, chat gratis, chat privata, chat anonima, incontri online'
  },
  ja: {
    title: 'SingleChat: 無料・匿名・プライベートのシングルチャット',
    description: '無料で使えるシングルチャット。匿名かつプライベートに会話でき、画像共有も安全です。',
    keywords: 'シングルチャット, 無料チャット, 匿名チャット, プライベートチャット, オンラインチャット'
  },
  zh: {
    title: 'SingleChat：免费、私密、匿名的单身聊天',
    description: '免费单身聊天，支持私密和匿名交流，安全分享图片并结识新朋友。',
    keywords: '单身聊天, 免费聊天, 私密聊天, 匿名聊天, 在线聊天'
  },
  th: {
    title: 'SingleChat: แชตคนโสดฟรี แบบส่วนตัวและไม่ระบุตัวตน',
    description: 'แชตคนโสดฟรี สำหรับการสนทนาแบบส่วนตัวและไม่ระบุตัวตน พบผู้คนใหม่ ๆ และแชร์รูปได้อย่างปลอดภัย',
    keywords: 'แชตคนโสด, แชตฟรี, แชตส่วนตัว, แชตไม่ระบุตัวตน, แชตออนไลน์'
  },
  tl: {
    title: 'SingleChat: Libreng private at anonymous na single chat',
    description: 'Libreng single chat para sa private at anonymous na usapan. Kumilala ng bagong tao at magbahagi ng larawan nang ligtas.',
    keywords: 'single chat, libreng chat, private chat, anonymous chat, online chat'
  }
};

const seoData = {
  '/': {
    title: 'SingleChat: Kostenloser Single Chat, privat & anonym',
    description: 'Kostenloser Single Chat für private und anonyme Gespräche. Lerne neue Kontakte kennen und teile Bilder sicher online.',
    keywords: 'single chat, kostenloser chat, privat chatten, anonym chat, free chat, private chat, anonymous chat, online chat',
    ogTitle: 'SingleChat: Kostenloser Single Chat, privat & anonym',
    ogDescription: 'Kostenlos chatten, privat bleiben und neue Kontakte kennenlernen - mit sicherem Bildaustausch.',
    ogType: 'website',
    ogUrl: `${SITE_URL}/`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'WebSite',
      name: 'SingleChat',
      url: `${SITE_URL}/`,
      description: 'Kostenloser Single Chat für private und anonyme Gespräche. Lerne neue Kontakte kennen und tausche Bilder sicher aus.',
      inLanguage: 'de-DE'
    }
  },
  '/partners': {
    title: 'Partner für Single Chat & Community - SingleChat',
    description: 'Partnerseiten rund um Single Chat, Community und Online-Kontakte. Entdecke weitere Angebote und hilfreiche Ressourcen.',
    keywords: 'single chat partner, chat community, kontaktseiten, single-chat links, online dating chat',
    ogTitle: 'Partner für Single Chat & Community - SingleChat',
    ogDescription: 'Befreundete Seiten und Ressourcen rund um Chat, Kontakte und Community.',
    ogType: 'website',
    ogUrl: `${SITE_URL}/partners`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'CollectionPage',
      name: 'Partner - SingleChat',
      url: `${SITE_URL}/partners`,
      description: 'Partnerseiten rund um Single Chat, Community und Online-Kontakte. Entdecke weitere Angebote und hilfreiche Ressourcen.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  },
  '/feedback': {
    title: 'Feedback zur Chat-Plattform - SingleChat',
    description: 'Öffentliches Feedback zu SingleChat: Meinungen, Vorschläge und Erfahrungsberichte für einen besseren privaten Chat.',
    keywords: 'chat feedback, single chat erfahrungen, rückmeldung chat, verbesserungsvorschläge',
    ogTitle: 'Feedback zur Chat-Plattform - SingleChat',
    ogDescription: 'Teile deine Erfahrungen und Verbesserungsvorschläge für SingleChat.',
    ogType: 'website',
    ogUrl: `${SITE_URL}/feedback`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'CollectionPage',
      name: 'Feedback - SingleChat',
      url: `${SITE_URL}/feedback`,
      description: 'Öffentliches Feedback zu SingleChat: Meinungen, Vorschläge und Erfahrungsberichte für einen besseren privaten Chat.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  },
  '/faq': {
    title: 'FAQ: Kostenlos, privat und anonym chatten - SingleChat',
    description: 'FAQ zum kostenlosen Single Chat: anonym chatten, Privatsphäre schützen, Bilder sicher teilen und Nutzer blockieren.',
    keywords: 'single chat faq, kostenlos chatten, anonym chatten, privater chat, safe chat',
    ogTitle: 'FAQ: Kostenlos, privat und anonym chatten - SingleChat',
    ogDescription: 'Antworten auf Fragen zu Sicherheit, Privatsphäre und Funktionen im Single Chat.',
    ogType: 'website',
    ogUrl: `${SITE_URL}/faq`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'FAQPage',
      name: 'FAQ - SingleChat',
      url: `${SITE_URL}/faq`,
      description: 'FAQ zum kostenlosen Single Chat: anonym chatten, Privatsphäre schützen, Bilder sicher teilen und Nutzer blockieren.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  },
  '/regeln': {
    title: 'Chat-Regeln für sicheren Single Chat - SingleChat',
    description: 'Regeln für respektvollen, privaten und sicheren Single Chat. Hinweise zu Verhalten, Spam und verbotenen Inhalten.',
    keywords: 'chat regeln, single chat regeln, sicher chatten, spam vermeiden, community richtlinien',
    ogTitle: 'Chat-Regeln für sicheren Single Chat - SingleChat',
    ogDescription: 'Unsere Richtlinien für respektvolle und sichere Gespräche im Chat.',
    ogType: 'website',
    ogUrl: `${SITE_URL}/regeln`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'WebPage',
      name: 'Regeln - SingleChat',
      url: `${SITE_URL}/regeln`,
      description: 'Regeln für respektvollen, privaten und sicheren Single Chat. Hinweise zu Verhalten, Spam und verbotenen Inhalten.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  },
  '/sicherheit': {
    title: 'Sicherheit & Privatsphäre im privaten Chat - SingleChat',
    description: 'Sicherheitsseite für privaten und anonymen Chat: Privatsphäre, Schutz vor Spam, Blockieren und Melden.',
    keywords: 'privatsphäre chat, anonym chat sicherheit, blockieren melden, private chat safety',
    ogTitle: 'Sicherheit & Privatsphäre im privaten Chat - SingleChat',
    ogDescription: 'So schützt du deine Daten und chattest sicher und anonym.',
    ogType: 'website',
    ogUrl: `${SITE_URL}/sicherheit`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'WebPage',
      name: 'Sicherheit & Privatsphäre - SingleChat',
      url: `${SITE_URL}/sicherheit`,
      description: 'Sicherheitsseite für privaten und anonymen Chat: Privatsphäre, Schutz vor Spam, Blockieren und Melden.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  }
};

for (const locale of SEO_LOCALES) {
  const meta = LOCALE_SEO_META[locale.code] || LOCALE_SEO_META.de;
  seoData[`/${locale.code}`] = {
    title: meta.title,
    description: meta.description,
    keywords: meta.keywords,
    ogTitle: meta.title,
    ogDescription: meta.description,
    ogType: 'website',
    ogUrl: `${SITE_URL}/${locale.code}`,
    ogImage: DEFAULT_IMAGE,
    robots: 'index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1',
    schema: {
      '@context': 'https://schema.org',
      '@type': 'WebSite',
      name: 'SingleChat',
      url: `${SITE_URL}/${locale.code}`,
      description: meta.description,
      inLanguage: locale.code
    }
  };
}

function buildSitemapXml() {
  const currentDate = new Date().toISOString().split('T')[0];
  const urls = Object.entries(seoData)
    .map(([route, meta]) => {
      const priority = route === '/' ? '1.0' : '0.8';
      const changefreq = route === '/' ? 'daily' : 'weekly';
      return `  <url>
    <loc>${meta.ogUrl}</loc>
    <lastmod>${currentDate}</lastmod>
    <changefreq>${changefreq}</changefreq>
    <priority>${priority}</priority>
  </url>`;
    })
    .join('\n');

  return `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
${urls}
</urlset>`;
}

function escapeHtml(value = '') {
  return String(value)
    .replace(/&/g, '&amp;')
    .replace(/"/g, '&quot;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;');
}

function upsertMetaTag(html, name, content, attribute = 'name') {
  const escapedContent = escapeHtml(content);
  const regex = new RegExp(`<meta\\s+${attribute}="${name}"[^>]*>`, 'g');
  const tag = `<meta ${attribute}="${name}" content="${escapedContent}">`;

  if (regex.test(html)) {
    return html.replace(regex, tag);
  }

  return html.replace('</head>', `  ${tag}\n</head>`);
}

function upsertLinkTag(html, rel, href) {
  const escapedHref = escapeHtml(href);
  const regex = new RegExp(`<link\\s+rel="${rel}"[^>]*>`, 'g');
  const tag = `<link rel="${rel}" href="${escapedHref}">`;

  if (regex.test(html)) {
    return html.replace(regex, tag);
  }

  return html.replace('</head>', `  ${tag}\n</head>`);
}

function upsertJsonLd(html, schema) {
  const tag = schema
    ? `<script type="application/ld+json" id="seo-json-ld">${JSON.stringify(schema)}</script>`
    : '<script type="application/ld+json" id="seo-json-ld"></script>';

  if (html.includes('id="seo-json-ld"')) {
    return html.replace(/<script type="application\/ld\+json" id="seo-json-ld">.*?<\/script>/s, tag);
  }

  return html.replace('</head>', `  ${tag}\n</head>`);
}

function upsertHreflangLinks(html, route) {
  const cleaned = html.replace(/<link\s+rel="alternate"\s+hreflang="[^"]+"\s+href="[^"]*"\s*>\n?/g, '');
  const links = SEO_LOCALES.map(
    (locale) => `  <link rel="alternate" hreflang="${locale.code}" href="${SITE_URL}/${locale.code}">`
  );
  links.push(`  <link rel="alternate" hreflang="x-default" href="${SITE_URL}${route}">`);
  return cleaned.replace('</head>', `${links.join('\n')}\n</head>`);
}

function sanitizeLocalizedHtml(input = '') {
  return String(input)
    .replace(/<script[\s\S]*?>[\s\S]*?<\/script>/gi, '')
    .trim();
}

function loadLocaleSeoSections(__dirname, localeCode) {
  const localesDir = join(__dirname, '../client/src/i18n/locales');
  const filePath = join(localesDir, `${localeCode}.json`);
  if (!existsSync(filePath)) return { welcome: '', intro: '' };
  try {
    const parsed = JSON.parse(readFileSync(filePath, 'utf-8'));
    return {
      welcome: sanitizeLocalizedHtml(parsed.welcome || ''),
      intro: sanitizeLocalizedHtml(parsed.introduction || '')
    };
  } catch (error) {
    console.warn(`[SEO] Locale konnte nicht gelesen werden (${localeCode}): ${error.message}`);
    return { welcome: '', intro: '' };
  }
}

function buildLocalizedLandingContent(route, __dirname) {
  const localeCode = route.replace('/', '') || 'de';
  const locale = SEO_LOCALES.find((entry) => entry.code === localeCode) || SEO_LOCALES[0];
  const sections = loadLocaleSeoSections(__dirname, locale.code);
  if (!sections.welcome && !sections.intro) return '';

  return `<section lang="${escapeHtml(locale.code)}" style="max-width:960px;margin:24px auto;padding:0 16px;">
  <h2 style="font:600 28px/1.15 sans-serif;color:#18201b;margin:0 0 12px;">${escapeHtml(locale.label)}</h2>
  ${sections.welcome}
  ${sections.intro}
</section>`;
}

function generateHTML(route, meta, __dirname) {
  const distIndexPath = join(__dirname, '../docroot/dist/index.html');

  if (!existsSync(distIndexPath)) {
    console.error('WARNUNG: Gebaute index.html nicht gefunden:', distIndexPath);
    return null;
  }

  let html = readFileSync(distIndexPath, 'utf-8');

  html = html.replace(/<title>.*?<\/title>/, `<title>${escapeHtml(meta.title)}</title>`);
  html = upsertMetaTag(html, 'description', meta.description);
  html = upsertMetaTag(html, 'keywords', meta.keywords);
  html = upsertMetaTag(html, 'robots', meta.robots);
  html = upsertMetaTag(html, 'theme-color', '#2f6f46');

  html = upsertMetaTag(html, 'og:title', meta.ogTitle, 'property');
  html = upsertMetaTag(html, 'og:description', meta.ogDescription, 'property');
  html = upsertMetaTag(html, 'og:type', meta.ogType, 'property');
  html = upsertMetaTag(html, 'og:url', meta.ogUrl, 'property');
  html = upsertMetaTag(html, 'og:image', meta.ogImage, 'property');
  html = upsertMetaTag(html, 'og:site_name', 'SingleChat', 'property');
  html = upsertMetaTag(html, 'og:locale', 'de_DE', 'property');

  html = upsertMetaTag(html, 'twitter:card', 'summary_large_image');
  html = upsertMetaTag(html, 'twitter:title', meta.ogTitle);
  html = upsertMetaTag(html, 'twitter:description', meta.ogDescription);
  html = upsertMetaTag(html, 'twitter:image', meta.ogImage);

  html = upsertLinkTag(html, 'canonical', meta.ogUrl);
  html = upsertJsonLd(html, meta.schema);
  html = upsertHreflangLinks(html, route);

  if (route === '/') {
    const deLanding = buildLocalizedLandingContent('/de', __dirname);
    if (deLanding) {
      html = html.replace('<div id="app"></div>', `<div id="app">${deLanding}</div>`);
    }
  }

  if (SEO_LOCALES.some((locale) => `/${locale.code}` === route)) {
    const localizedLanding = buildLocalizedLandingContent(route, __dirname);
    if (localizedLanding) {
      html = html.replace('<div id="app"></div>', `<div id="app">${localizedLanding}</div>`);
    }
  }

  if (route === '/feedback') {
    const feedbackItems = loadFeedback(__dirname)
      .sort((a, b) => new Date(b.createdAt) - new Date(a.createdAt))
      .slice(0, 20);

    const feedbackMarkup = feedbackItems.length > 0
      ? feedbackItems.map((item) => {
          const metaLine = [item.country, item.age, item.gender].filter(Boolean).join(' · ');
          return `<article style="border:1px solid #d7dfd9;border-radius:12px;padding:14px 16px;margin-bottom:12px;background:#fff;">
  <strong style="display:block;color:#18201b;">${escapeHtml(item.name || 'Anonym')}</strong>
  ${metaLine ? `<div style="font-size:12px;color:#637067;margin-top:4px;">${escapeHtml(metaLine)}</div>` : ''}
  <div style="font-size:12px;color:#637067;margin-top:4px;">${escapeHtml(new Date(item.createdAt).toLocaleString('de-DE'))}</div>
  <p style="margin-top:10px;color:#2c362f;white-space:pre-wrap;">${escapeHtml(item.comment)}</p>
</article>`;
        }).join('\n')
      : '<p>Noch kein Feedback vorhanden.</p>';

    const preview = `<section style="max-width:960px;margin:24px auto;padding:0 16px;">
  <h2 style="font:600 28px/1.15 sans-serif;color:#18201b;margin:0 0 10px;">Feedback zu SingleChat</h2>
  <p style="font:400 15px/1.5 sans-serif;color:#4f5d54;margin:0 0 18px;">Oeffentliche Rueckmeldungen und Verbesserungsvorschlaege.</p>
  ${feedbackMarkup}
</section>`;

    html = html.replace('<div id="app"></div>', `<div id="app">${preview}</div>`);
  }

  return html;
}

export function setupSEORoutes(app, __dirname) {
  const IS_PRODUCTION = process.env.NODE_ENV === 'production';

  if (IS_PRODUCTION) {
    const distIndexPath = resolve(__dirname, '../docroot/dist/index.html');

    Object.entries(seoData).forEach(([route, meta]) => {
      app.get(route, (req, res) => {
        const html = generateHTML(route, meta, __dirname);
        if (html) {
          // Zusätzliches kanonisches Signal (neben link rel= im HTML) – hilft Google bei der Zuordnung.
          res.set('Link', `<${meta.ogUrl}>; rel="canonical"`);
          res.send(html);
          return;
        }

        if (existsSync(distIndexPath)) {
          res.set('Link', `<${meta.ogUrl}>; rel="canonical"`);
          res.sendFile(distIndexPath);
          return;
        }

        console.error('FEHLER: Gebaute index.html nicht gefunden:', distIndexPath);
        res.status(500).send('Gebaute index.html nicht gefunden. Bitte führe "npm run build" aus.');
      });
    });
  }

  app.get('/robots.txt', (req, res) => {
    const robotsTxt = `User-agent: *
Allow: /
Allow: /partners
Allow: /feedback
Allow: /faq
Allow: /regeln
Allow: /sicherheit
Disallow: /api/
Disallow: /static/logs/
Disallow: /mockup-redesign

Sitemap: ${SITE_URL}/sitemap.xml
`;
    res.type('text/plain');
    res.send(robotsTxt);
  });

  app.get('/sitemap.xml', (req, res) => {
    try {
      const sitemap = buildSitemapXml();
      // Stabilere Auslieferung fuer Crawler und Reverse-Proxy-Caches.
      res.set('Cache-Control', 'public, max-age=300, s-maxage=300, stale-while-revalidate=600');
      res.type('application/xml');
      res.status(200).send(sitemap);
    } catch (error) {
      console.error('[SEO] Fehler beim Generieren der sitemap.xml:', error);
      // Fallback: niemals 500 fuer die Sitemap ausliefern.
      const fallback = `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url><loc>${SITE_URL}/</loc></url>
</urlset>`;
      res.set('Cache-Control', 'no-store');
      res.type('application/xml');
      res.status(200).send(fallback);
    }
  });
}