const express = require('express');
const { chromium } = require('playwright');
const app = express();
const PORT = process.env.PORT || 3000;

// Middleware
app.use(express.json({ limit: '10mb' }));
app.use(express.urlencoded({ extended: true }));

// CORS middleware (opsional)
app.use((req, res, next) => {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
  res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization');
  if (req.method === 'OPTIONS') {
    res.sendStatus(200);
  } else {
    next();
  }
});

// Fungsi untuk mengekstrak konten dari URL
async function extractContentFromUrl(url, timeout = 30000) {
  let browser;
  try {
    // Launch browser
    browser = await chromium.launch({
      headless: true,
      args: ['--no-sandbox', '--disable-setuid-sandbox']
    });
    
    const context = await browser.newContext({
      userAgent: 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36'
    });
    
    const page = await context.newPage();
    
    // Set timeout
    page.setDefaultTimeout(timeout);
    
    // Navigate to URL
    await page.goto(url, { 
      waitUntil: 'domcontentloaded',
      timeout: timeout 
    });
    
    // Wait for page to load completely
    await page.waitForLoadState('networkidle');
    
    // Extract content
    const content = await page.evaluate(() => {
      // Remove script and style elements
      const scripts = document.querySelectorAll('script, style, noscript');
      scripts.forEach(el => el.remove());
      
      // Get title
      const title = document.title || '';
      
      // Get meta description
      const metaDescription = document.querySelector('meta[name="description"]')?.content || '';
      
      // Get all text content
      const textContent = document.body?.innerText || '';
      
      // Get all links
      const links = Array.from(document.querySelectorAll('a[href]')).map(a => ({
        text: a.innerText.trim(),
        href: a.href
      })).filter(link => link.text && link.href);
      
      // Get all images
      const images = Array.from(document.querySelectorAll('img[src]')).map(img => ({
        alt: img.alt || '',
        src: img.src
      }));
      
      // Get headings
      const headings = Array.from(document.querySelectorAll('h1, h2, h3, h4, h5, h6')).map(h => ({
        level: h.tagName.toLowerCase(),
        text: h.innerText.trim()
      })).filter(h => h.text);
      
      return {
        title,
        metaDescription,
        textContent: textContent.substring(0, 10000), // Limit text content
        links: links.slice(0, 50), // Limit links
        images: images.slice(0, 20), // Limit images
        headings: headings.slice(0, 30), // Limit headings
        wordCount: textContent.split(/\s+/).length
      };
    });
    
    await browser.close();
    
    return {
      url,
      success: true,
      data: content,
      extractedAt: new Date().toISOString()
    };
    
  } catch (error) {
    if (browser) {
      await browser.close();
    }
    
    return {
      url,
      success: false,
      error: error.message,
      extractedAt: new Date().toISOString()
    };
  }
}

// Validasi URL
function isValidUrl(string) {
  try {
    const url = new URL(string);
    return url.protocol === 'http:' || url.protocol === 'https:';
  } catch {
    return false;
  }
}

// Route untuk ekstrak konten
app.post('/extract-content', async (req, res) => {
  try {
    const { urls, timeout } = req.body;
    
    // Validasi input
    if (!urls || !Array.isArray(urls)) {
      return res.status(400).json({
        success: false,
        message: 'URLs harus berupa array'
      });
    }
    
    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 URL per request'
      });
    }
    
    // Validasi setiap URL
    const invalidUrls = urls.filter(url => !isValidUrl(url));
    if (invalidUrls.length > 0) {
      return res.status(400).json({
        success: false,
        message: 'URL tidak valid ditemukan',
        invalidUrls
      });
    }
    
    // Ekstrak konten dari setiap URL
    const results = [];
    const requestTimeout = timeout || 30000;
    
    for (const url of urls) {
      console.log(`Extracting content from: ${url}`);
      const result = await extractContentFromUrl(url, requestTimeout);
      results.push(result);
    }
    
    // Hitung statistik
    const successCount = results.filter(r => r.success).length;
    const failCount = results.filter(r => !r.success).length;
    
    res.json({
      success: true,
      message: `Berhasil memproses ${results.length} URL`,
      statistics: {
        total: results.length,
        success: successCount,
        failed: failCount
      },
      results
    });
    
  } catch (error) {
    console.error('Error in /extract-content:', error);
    res.status(500).json({
      success: false,
      message: 'Internal server error',
      error: error.message
    });
  }
});

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

// Route untuk info API
app.get('/', (req, res) => {
  res.json({
    name: 'URL Content Extractor API',
    version: '1.0.0',
    description: 'API untuk mengekstrak konten dari URL menggunakan Playwright',
    endpoints: {
      'POST /extract-content': {
        description: 'Ekstrak konten dari array URL',
        body: {
          urls: ['http://example.com', 'https://example2.com'],
          timeout: 30000
        }
      },
      'GET /health': 'Health check endpoint',
      'GET /': 'API information'
    }
  });
});

// Error handler
app.use((err, req, res, next) => {
  console.error('Unhandled error:', err);
  res.status(500).json({
    success: false,
    message: 'Internal server error'
  });
});

// 404 handler
app.use('*', (req, res) => {
  res.status(404).json({
    success: false,
    message: 'Endpoint tidak ditemukan'
  });
});

// Start server
app.listen(PORT, () => {
  console.log(`🚀 Server berjalan di port ${PORT}`);
  console.log(`📝 API Documentation: http://localhost:${PORT}`);
  console.log(`❤️  Health Check: http://localhost:${PORT}/health`);
});