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

const SITE_URL = 'https://ypchat.net';
const DEFAULT_IMAGE = `${SITE_URL}/static/favicon.png`;

const seoData = {
  '/': {
    title: 'SingleChat - Chat, Single-Chat und Bildaustausch',
    description: 'Willkommen auf SingleChat - deine erste Adresse für Chat, Single-Chat und Bildaustausch. Chatte mit Menschen aus aller Welt, finde neue Kontakte und teile Erinnerungen sicher und komfortabel.',
    keywords: 'Chat, Single-Chat, Bildaustausch, Online-Chat, Singles, Kontakte, Community',
    ogTitle: 'SingleChat - Chat, Single-Chat und Bildaustausch',
    ogDescription: 'Willkommen auf SingleChat - deine erste Adresse für Chat, Single-Chat und 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: 'Willkommen auf SingleChat - deine erste Adresse für Chat, Single-Chat und Bildaustausch.',
      inLanguage: 'de-DE'
    }
  },
  '/partners': {
    title: 'Partner - SingleChat',
    description: 'Unsere Partner und befreundete Seiten. Entdecke weitere interessante Angebote und Communities.',
    keywords: 'Partner, Links, befreundete Seiten, Community',
    ogTitle: 'Partner - SingleChat',
    ogDescription: 'Unsere Partner und befreundete Seiten.',
    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: 'Unsere Partner und befreundete Seiten. Entdecke weitere interessante Angebote und Communities.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  },
  '/feedback': {
    title: 'Feedback - SingleChat',
    description: 'Oeffentliche Rueckmeldungen, Meinungen und Verbesserungsvorschlaege zu SingleChat.',
    keywords: 'SingleChat Feedback, Kommentare, Rueckmeldungen, Verbesserungsvorschlaege',
    ogTitle: 'Feedback - SingleChat',
    ogDescription: 'Oeffentliche Rueckmeldungen, Meinungen und Verbesserungsvorschlaege zu SingleChat.',
    ogType: 'website',
    ogUrl: `${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: `${SITE_URL}/feedback`,
      description: 'Oeffentliche Rueckmeldungen, Meinungen und Verbesserungsvorschlaege zu SingleChat.',
      isPartOf: {
        '@type': 'WebSite',
        name: 'SingleChat',
        url: `${SITE_URL}/`
      },
      inLanguage: 'de-DE'
    }
  }
};

function escapeHtml(value = '') {
  return String(value)
    .replace(/&/g, '&')
    .replace(/"/g, '"')
    .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 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);

  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) {
          res.send(html);
          return;
        }

        if (existsSync(distIndexPath)) {
          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
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) => {
    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');

    const sitemap = `<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
${urls}
</urlset>`;
    res.type('application/xml');
    res.send(sitemap);
  });
}