/**
 * Lokaler Reverse Proxy für PTV Geocoding API
 * Umgeht CORS-Probleme bei der Entwicklung
 */

const http = require('http');
const https = require('https');
const url = require('url');

const PORT = 3000;
const PTV_API_BASE = 'https://api.myptv.com';

// CORS Headers für alle Responses
const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
  'Access-Control-Allow-Headers': 'Content-Type, Authorization',
  'Content-Type': 'application/json',
};

const server = http.createServer((req, res) => {
  console.log(`📨 ${req.method} ${req.url}`);

  // Health check endpoint
  if (req.url === '/health') {
    res.writeHead(200, { 'Content-Type': 'text/plain' });
    res.end('healthy');
    return;
  }

  // Handle preflight requests
  if (req.method === 'OPTIONS') {
    res.writeHead(200, corsHeaders);
    res.end();
    return;
  }

  // Nur GET Requests erlauben
  if (req.method !== 'GET') {
    res.writeHead(405, corsHeaders);
    res.end(JSON.stringify({ error: 'Method not allowed' }));
    return;
  }

  // Parse URL
  const parsedUrl = url.parse(req.url, true);
  const { lat, lon, apiKey } = parsedUrl.query;

  // Validierung
  if (!lat || !lon || !apiKey) {
    res.writeHead(400, corsHeaders);
    res.end(JSON.stringify({
      error: 'Missing parameters: lat, lon, apiKey are required',
    }));
    return;
  }

  // PTV API URL erstellen
  const ptvUrl = `${PTV_API_BASE}/geocoding/v1/locations/by-position/${lat}/${lon}?language=de&apiKey=${apiKey}`;
  
  console.log(`🔄 Weiterleitung an: ${ptvUrl.replace(apiKey, 'API_KEY_HIDDEN')}`);

  // Request an PTV API
  https.get(ptvUrl, (ptvRes) => {
    let data = '';

    ptvRes.on('data', (chunk) => {
      data += chunk;
    });

    ptvRes.on('end', () => {
      try {
        const jsonData = JSON.parse(data);
        
        // Erfolgreiche Response
        if (ptvRes.statusCode === 200) {
          console.log('✅ PTV API Response erfolgreich');
          
          // Adresse extrahieren
          if (jsonData.locations && jsonData.locations.length > 0) {
            const location = jsonData.locations[0];
            if (location.address) {
              const address = location.address;
              const street = address.street || '';
              const houseNumber = address.houseNumber || '';
              const postalCode = address.postalCode || '';
              const city = address.city || '';
              
              const formattedAddress = `${street} ${houseNumber}, ${postalCode} ${city}`.trim();
              
              const response = {
                success: true,
                location: formattedAddress,
                coordinates: {
                  lat: parseFloat(lat),
                  lon: parseFloat(lon),
                },
                rawData: location,
              };
              
              console.log(`📍 Adresse: ${formattedAddress}`);
              res.writeHead(200, corsHeaders);
              res.end(JSON.stringify(response));
              return;
            }
          }
          
          // Fallback auf Koordinaten
          const response = {
            success: true,
            location: `Lat: ${parseFloat(lat).toFixed(6)}, Lon: ${parseFloat(lon).toFixed(6)}`,
            coordinates: {
              lat: parseFloat(lat),
              lon: parseFloat(lon),
            },
          };
          
          res.writeHead(200, corsHeaders);
          res.end(JSON.stringify(response));
        } else {
          // Fehler von PTV API
          console.log(`❌ PTV API Fehler: ${ptvRes.statusCode}`);
          res.writeHead(ptvRes.statusCode, corsHeaders);
          res.end(JSON.stringify({
            success: false,
            error: `PTV API Error: ${ptvRes.statusCode}`,
            fallbackLocation: `Lat: ${parseFloat(lat).toFixed(6)}, Lon: ${parseFloat(lon).toFixed(6)}`,
          }));
        }
      } catch (error) {
        console.error('❌ JSON Parse Fehler:', error.message);
        res.writeHead(500, corsHeaders);
        res.end(JSON.stringify({
          success: false,
          error: 'Failed to parse PTV API response',
          fallbackLocation: `Lat: ${parseFloat(lat).toFixed(6)}, Lon: ${parseFloat(lon).toFixed(6)}`,
        }));
      }
    });
  }).on('error', (error) => {
    console.error('❌ Request Fehler:', error.message);
    res.writeHead(500, corsHeaders);
    res.end(JSON.stringify({
      success: false,
      error: error.message,
      fallbackLocation: `Lat: ${parseFloat(lat).toFixed(6)}, Lon: ${parseFloat(lon).toFixed(6)}`,
    }));
  });
});

server.listen(PORT, () => {
  console.log('═══════════════════════════════════════════════════════');
  console.log('🚀 Lokaler Reverse Proxy Server gestartet!');
  console.log(`📡 Läuft auf: http://localhost:${PORT}`);
  console.log('');
  console.log('📌 Verwendung:');
  console.log(`   http://localhost:${PORT}/?lat=47.9385&lon=13.7629&apiKey=YOUR_KEY`);
  console.log('');
  console.log('⚠️  Hinweis: Nur für Entwicklung verwenden!');
  console.log('   Für Produktion: Appwrite Function deployen');
  console.log('═══════════════════════════════════════════════════════');
  console.log('');
  console.log('💡 Zum Beenden: Strg+C drücken');
  console.log('');
});

// Graceful shutdown
process.on('SIGINT', () => {
  console.log('\n\n👋 Server wird beendet...');
  server.close(() => {
    console.log('✅ Server erfolgreich gestoppt');
    process.exit(0);
  });
});