import { NestFactory } from '@nestjs/core';
import { ValidationPipe } from '@nestjs/common';
import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';
import { ConfigService } from '@nestjs/config';
import { Logger } from 'nestjs-pino';
import helmet from 'helmet';
import cookieParser from 'cookie-parser';
import { AppModule } from './app.module';
import { GlobalExceptionFilter } from './common/filters/http-exception.filter';

async function bootstrap() {
  const app = await NestFactory.create(AppModule, { bufferLogs: true });
  
  // Set Pino as the logger
  app.useLogger(app.get(Logger));
  
  const configService = app.get(ConfigService);
  const logger = app.get(Logger);

  // Security
  app.use(helmet());
  app.getHttpAdapter().getInstance().disable('x-powered-by');
  app.use(cookieParser());
  // Behind reverse proxies (e.g., Nginx) to ensure correct IPs and secure cookies
  if (configService.get('TRUST_PROXY', 'false') === 'true') {
    const httpAdapter = app.getHttpAdapter();
    const instance: any = httpAdapter.getInstance();
    if (instance?.set) {
      instance.set('trust proxy', 1);
    }
  }
  
  // CORS
  app.enableCors({
    origin: configService.get('CORS_ORIGIN', 'http://localhost:3000'),
    credentials: true,
  });

  // Global validation pipe
  app.useGlobalPipes(
    new ValidationPipe({
      transform: true,
      whitelist: true,
      forbidNonWhitelisted: true,
    }),
  );

  // Global exception filter
  app.useGlobalFilters(new GlobalExceptionFilter());

  // Ensure proper shutdown for Prisma/Redis and logger flush
  app.enableShutdownHooks();
  const shutdown = async (signal: string) => {
    try {
      logger.warn(`Received ${signal}. Shutting down gracefully...`);
      await app.close();
      if (typeof (logger as any).flush === 'function') {
        await (logger as any).flush();
      }
    } catch (err) {
      // eslint-disable-next-line no-console
      console.error('Error during shutdown', err);
    } finally {
      process.exit(0);
    }
  };
  process.on('SIGINT', () => shutdown('SIGINT'));
  process.on('SIGTERM', () => shutdown('SIGTERM'));

  // Global prefix
  app.setGlobalPrefix('api');

  // Swagger documentation
  if (configService.get('NODE_ENV') !== 'production') {
    const config = new DocumentBuilder()
      .setTitle('Customer Portal API')
      .setDescription('Backend for Frontend API for customer portal')
      .setVersion('1.0')
      .addBearerAuth()
      .addCookieAuth('auth-cookie')
      .build();
    
    const document = SwaggerModule.createDocument(app, config);
    SwaggerModule.setup('api/docs', app, document);
  }

  const port = Number(configService.get('BFF_PORT', 4000));
  
  await app.listen(port);
  
  logger.log(`🚀 BFF API running on: http://localhost:${port}/api`);
  if (configService.get('NODE_ENV') !== 'production') {
    logger.log(`📚 API Documentation: http://localhost:${port}/api/docs`);
  }
}

bootstrap();