/**
 * Point d'entrée du serveur SourceFinder
 * Démarrage et arrêt gracieux de l'application
 */
require('dotenv').config();

const SourceFinderApp = require('./src/app');
const logger = require('./src/utils/logger');

class Server {
  constructor() {
    this.app = null;
    this.server = null;
    this.sourceFinderApp = new SourceFinderApp();
  }

  /**
   * Démarrer le serveur
   */
  async start() {
    try {
      // Initialiser l'application avec toutes ses dépendances
      this.app = await this.sourceFinderApp.initialize();

      // Configuration du port
      const port = parseInt(process.env.PORT) || 3000;
      const host = process.env.HOST || '0.0.0.0';

      // Démarrer le serveur HTTP
      this.server = this.app.listen(port, host, () => {
        logger.info('🚀 SourceFinder server started', {
          server: {
            port,
            host,
            environment: process.env.NODE_ENV || 'development',
            apiVersion: process.env.API_VERSION || 'v1',
            pid: process.pid
          },
          endpoints: {
            health: `http://${host}:${port}/health`,
            api: `http://${host}:${port}/api/v1`,
            docs: `http://${host}:${port}/api/v1/docs` // TODO: implémenter docs
          }
        });

        // Log configuration active
        const container = this.sourceFinderApp.getContainer();
        const config = container.get('config');

        logger.info('📦 Active configuration', {
          components: {
            newsProvider: config.newsProvider.type,
            stockRepository: config.stockRepository.type,
            scoringEngine: config.scoringEngine.type
          },
          features: {
            rateLimiting: true,
            cors: true,
            requestLogging: true,
            errorHandling: true
          }
        });
      });

      // Configuration serveur
      this.server.keepAliveTimeout = 65000; // Plus que le load balancer
      this.server.headersTimeout = 66000; // Plus que keepAliveTimeout

      // Gestion des signaux de fermeture
      this.setupGracefulShutdown();

    } catch (error) {
      logger.error('❌ Failed to start SourceFinder server', error);
      process.exit(1);
    }
  }

  /**
   * Configurer l'arrêt gracieux
   */
  setupGracefulShutdown() {
    // Gestion des signaux système
    const signals = ['SIGTERM', 'SIGINT', 'SIGUSR2'];

    signals.forEach((signal) => {
      process.on(signal, () => {
        logger.info(`📡 Received ${signal}, starting graceful shutdown...`);
        this.shutdown();
      });
    });

    // Gestion des exceptions non catchées
    process.on('uncaughtException', (error) => {
      logger.error('💥 Uncaught Exception', error);
      this.shutdown(1);
    });

    process.on('unhandledRejection', (reason, promise) => {
      logger.error('💥 Unhandled Rejection', new Error(reason), { promise });
      this.shutdown(1);
    });

    // Gestion mémoire (warning si > 80% utilisée)
    if (process.env.NODE_ENV === 'production') {
      setInterval(() => {
        const memUsage = process.memoryUsage();
        const memUsedMB = Math.round(memUsage.heapUsed / 1024 / 1024);
        const memTotalMB = Math.round(memUsage.heapTotal / 1024 / 1024);
        const memPercent = (memUsage.heapUsed / memUsage.heapTotal) * 100;

        if (memPercent > 80) {
          logger.warn(`⚠️ High memory usage: ${memUsedMB}MB / ${memTotalMB}MB (${memPercent.toFixed(1)}%)`, {
            memory: {
              used: memUsedMB,
              total: memTotalMB,
              percent: memPercent,
              rss: Math.round(memUsage.rss / 1024 / 1024)
            }
          });
        }
      }, 30000); // Check toutes les 30s
    }
  }

  /**
   * Arrêter le serveur gracieusement
   */
  async shutdown(exitCode = 0) {
    logger.info('🔄 Starting graceful shutdown...');

    try {
      // Arrêter d'accepter nouvelles connexions
      if (this.server) {
        await new Promise((resolve, reject) => {
          this.server.close((err) => {
            if (err) {
              logger.error('❌ Error closing HTTP server', err);
              reject(err);
            } else {
              logger.info('✅ HTTP server closed');
              resolve();
            }
          });
        });
      }

      // Fermer l'application et ses dépendances
      if (this.sourceFinderApp) {
        await this.sourceFinderApp.shutdown();
      }

      // Forcer fermeture après timeout
      setTimeout(() => {
        logger.warn('⚠️ Forceful shutdown after timeout');
        process.exit(1);
      }, 30000); // 30 secondes max

      logger.info('✅ Graceful shutdown completed');
      process.exit(exitCode);

    } catch (error) {
      logger.error('❌ Error during shutdown', error);
      process.exit(1);
    }
  }
}

// Démarrer le serveur si ce fichier est exécuté directement
if (require.main === module) {
  const server = new Server();
  server.start().catch((error) => {
    console.error('Failed to start server:', error);
    process.exit(1);
  });
}

module.exports = Server;