import express from 'express';
import { chromium } from 'playwright';
import cors from 'cors';

const app = express();
const PORT = process.env.PORT || 3000;

// Middleware
app.use(express.json({ limit: '50mb' }));
app.use(cors());

// Utility function untuk mengekstrak konten dari URL
async function extractContentFromUrl(url, browser) {
  const page = await browser.newPage();
  
  try {
    // Set user agent untuk menghindari blocking
    await page.setUserAgent('Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36');
    
    // Navigate ke URL dengan timeout
    await page.goto(url, { 
      waitUntil: 'domcontentloaded',
      timeout: 30000 
    });
    
    // Wait untuk memastikan konten dimuat
    await page.waitForTimeout(2000);
    
    // Ekstrak berbagai informasi dari halaman
    const content = await page.evaluate(() => {
      // Helper function untuk membersihkan text
      const cleanText = (text) => {
        return text ? text.replace(/\s+/g, ' ').trim() : '';
      };
      
      // Ekstrak title
      const title = document.title || '';
      
      // Ekstrak meta description
      const metaDescription = document.querySelector('meta[name="description"]')?.content || '';
      
      // Ekstrak heading utama
      const h1Elements = Array.from(document.querySelectorAll('h1')).map(h1 => cleanText(h1.innerText));
      const h2Elements = Array.from(document.querySelectorAll('h2')).map(h2 => cleanText(h2.innerText));
      
      // Ekstrak semua paragraf
      const paragraphs = Array.from(document.querySelectorAll('p'))
        .map(p => cleanText(p.innerText))
        .filter(text => text.length > 20); // Filter paragraf yang terlalu pendek
      
      // Ekstrak text dari main content area (jika ada)
      const mainContent = document.querySelector('main, article, .content, #content, .post-content');
      const mainText = mainContent ? cleanText(mainContent.innerText) : '';
      
      // Ekstrak semua link
      const links = Array.from(document.querySelectorAll('a[href]'))
        .map(a => ({
          text: cleanText(a.innerText),
          href: a.href
        }))
        .filter(link => link.text && link.href);
      
      // Ekstrak images
      const images = Array.from(document.querySelectorAll('img[src]'))
        .map(img => ({
          src: img.src,
          alt: img.alt || '',
          title: img.title || ''
        }));
      
      return {
        title,
        metaDescription,
        headings: {
          h1: h1Elements,
          h2: h2Elements
        },
        paragraphs,
        mainText,
        links: links.slice(0, 20), // Batasi jumlah link
        images: images.slice(0, 10), // Batasi jumlah gambar
        wordCount: (mainText || paragraphs.join(' ')).split(/\s+/).length
      };
    });
    
    return {
      url,
      success: true,
      content,
      extractedAt: new Date().toISOString()
    };
    
  } catch (error) {
    return {
      url,
      success: false,
      error: error.message,
      extractedAt: new Date().toISOString()
    };
  } finally {
    await page.close();
  }
}

// Endpoint untuk mengekstrak konten dari multiple URLs
app.post('/extract-content', async (req, res) => {
  const { urls } = req.body;
  
  // Validasi input
  if (!urls || !Array.isArray(urls)) {
    return res.status(400).json({
      success: false,
      message: 'Body harus berisi array urls'
    });
  }
  
  if (urls.length === 0) {
    return res.status(400).json({
      success: false,
      message: 'Array urls tidak boleh kosong'
    });
  }
  
  if (urls.length > 10) {
    return res.status(400).json({
      success: false,
      message: 'Maksimal 10 URLs per request'
    });
  }
  
  // Validasi format URL
  const validUrls = [];
  const invalidUrls = [];
  
  urls.forEach(url => {
    try {
      new URL(url);
      validUrls.push(url);
    } catch (error) {
      invalidUrls.push(url);
    }
  });
  
  if (invalidUrls.length > 0) {
    return res.status(400).json({
      success: false,
      message: 'Format URL tidak valid',
      invalidUrls
    });
  }
  
  let browser;
  
  try {
    // Launch browser
    browser = await chromium.launch({
      headless: true,
      args: ['--no-sandbox', '--disable-setuid-sandbox']
    });
    
    console.log(`Memproses ${validUrls.length} URLs...`);
    
    // Process URLs secara paralel dengan batasan concurrency
    const concurrencyLimit = 3;
    const results = [];
    
    for (let i = 0; i < validUrls.length; i += concurrencyLimit) {
      const batch = validUrls.slice(i, i + concurrencyLimit);
      const batchPromises = batch.map(url => extractContentFromUrl(url, browser));
      const batchResults = await Promise.all(batchPromises);
      results.push(...batchResults);
    }
    
    // Statistik hasil
    const successCount = results.filter(r => r.success).length;
    const failCount = results.filter(r => !r.success).length;
    
    res.json({
      success: true,
      message: `Berhasil memproses ${validUrls.length} URLs`,
      statistics: {
        total: validUrls.length,
        success: successCount,
        failed: failCount
      },
      results
    });
    
  } catch (error) {
    console.error('Error:', error);
    res.status(500).json({
      success: false,
      message: 'Terjadi kesalahan saat memproses URLs',
      error: error.message
    });
  } finally {
    if (browser) {
      await browser.close();
    }
  }
});

// Health check endpoint
app.get('/health', (req, res) => {
  res.json({
    success: true,
    message: 'Content Extractor API is running',
    timestamp: new Date().toISOString()
  });
});

// Root endpoint
app.get('/', (req, res) => {
  res.json({
    success: true,
    message: 'Content Extractor API',
    endpoints: {
      'POST /extract-content': 'Extract content from URLs',
      'GET /health': 'Health check',
      'GET /': 'API information'
    },
    usage: {
      method: 'POST',
      endpoint: '/extract-content',
      body: {
        urls: ['https://example.com', 'https://another-site.com']
      }
    }
  });
});

// Error handling middleware
app.use((err, req, res, next) => {
  console.error('Unhandled error:', err);
  res.status(500).json({
    success: false,
    message: 'Internal server error',
    error: process.env.NODE_ENV === 'development' ? err.message : 'Something went wrong'
  });
});

// 404 handler
app.use('*', (req, res) => {
  res.status(404).json({
    success: false,
    message: 'Endpoint not found'
  });
});

// Start server
app.listen(PORT, () => {
  console.log(`🚀 Content Extractor API running on port ${PORT}`);
  console.log(`📖 API Documentation: http://localhost:${PORT}`);
  console.log(`🏥 Health Check: http://localhost:${PORT}/health`);
});