/**
 * EmailSorter Backend Server
 * Main entry point
 */

import 'dotenv/config'
import express from 'express'
import cors from 'cors'
import { fileURLToPath } from 'url'
import { dirname, join } from 'path'

// Config & Middleware
import { config, validateConfig } from './config/index.mjs'
import { errorHandler, asyncHandler, NotFoundError, ValidationError } from './middleware/errorHandler.mjs'
import { respond } from './utils/response.mjs'
import { logger, log } from './middleware/logger.mjs'
import { limiters } from './middleware/rateLimit.mjs'

// Routes
import oauthRoutes from './routes/oauth.mjs'
import emailRoutes from './routes/email.mjs'
import stripeRoutes from './routes/stripe.mjs'
import apiRoutes from './routes/api.mjs'
import analyticsRoutes from './routes/analytics.mjs'

const __filename = fileURLToPath(import.meta.url)
const __dirname = dirname(__filename)

// Validate configuration
validateConfig()

// Create Express app
const app = express()

// Trust proxy (for rate limiting behind reverse proxy)
app.set('trust proxy', 1)

// Request ID middleware
app.use((req, res, next) => {
  req.id = Math.random().toString(36).substring(2, 15)
  res.setHeader('X-Request-ID', req.id)
  next()
})

// CORS
app.use(cors(config.cors))

// Request logging
app.use(logger({
  skip: (req) => req.path === '/api/health' || req.path.startsWith('/assets'),
}))

// Rate limiting
app.use('/api', limiters.api)

// Static files
app.use(express.static(join(__dirname, '..', 'public')))

// Body parsing (BEFORE routes, AFTER static)
// Note: Stripe webhook needs raw body, handled in stripe routes
app.use('/api', express.json({ limit: '1mb' }))
app.use('/api', express.urlencoded({ extended: true }))

// Health check (no rate limit)
app.get('/api/health', (req, res) => {
  res.json({
    success: true,
    data: {
      status: 'healthy',
      timestamp: new Date().toISOString(),
      version: process.env.npm_package_version || '1.0.0',
      environment: config.nodeEnv,
      uptime: Math.floor(process.uptime()),
    },
  })
})

// API Routes
app.use('/api/oauth', oauthRoutes)
app.use('/api/email', emailRoutes)
app.use('/api/subscription', stripeRoutes)
app.use('/api/analytics', analyticsRoutes)
app.use('/api', apiRoutes)

// Preferences endpoints (inline for simplicity)
import { userPreferences } from './services/database.mjs'

app.get('/api/preferences', asyncHandler(async (req, res) => {
  const { userId } = req.query
  if (!userId) throw new ValidationError('userId ist erforderlich')
  
  const prefs = await userPreferences.getByUser(userId)
  respond.success(res, prefs?.preferences || {
    vipSenders: [],
    blockedSenders: [],
    customRules: [],
    priorityTopics: [],
  })
}))

app.post('/api/preferences', asyncHandler(async (req, res) => {
  const { userId, ...preferences } = req.body
  if (!userId) throw new ValidationError('userId ist erforderlich')
  
  await userPreferences.upsert(userId, preferences)
  respond.success(res, null, 'Einstellungen gespeichert')
}))

// Legacy Stripe webhook endpoint
app.use('/stripe', stripeRoutes)

// 404 handler for API routes
app.use('/api/*', (req, res, next) => {
  next(new NotFoundError('Endpoint'))
})

// SPA fallback for non-API routes
app.get('*', (req, res) => {
  res.sendFile(join(__dirname, '..', 'public', 'index.html'))
})

// Global error handler (must be last)
app.use(errorHandler)

// Graceful shutdown
let server

function gracefulShutdown(signal) {
  log.info(`${signal} empfangen, Server wird heruntergefahren...`)

  server.close(() => {
    log.info('HTTP Server geschlossen')
    process.exit(0)
  })

  // Force close after 10 seconds
  setTimeout(() => {
    log.error('Erzwungenes Herunterfahren')
    process.exit(1)
  }, 10000)
}

process.on('SIGTERM', () => gracefulShutdown('SIGTERM'))
process.on('SIGINT', () => gracefulShutdown('SIGINT'))

// Handle uncaught errors
process.on('uncaughtException', (err) => {
  log.error('Uncaught Exception:', { error: err.message, stack: err.stack })
  process.exit(1)
})

process.on('unhandledRejection', (reason, promise) => {
  log.error('Unhandled Rejection:', { reason, promise })
})

// Start server
server = app.listen(config.port, () => {
  console.log('')
  log.success(`Server gestartet auf Port ${config.port}`)
  log.info(`Frontend URL: ${config.frontendUrl}`)
  log.info(`Environment: ${config.nodeEnv}`)
  console.log('')
  console.log(`  🌐 API:      http://localhost:${config.port}/api`)
  console.log(`  💚 Health:   http://localhost:${config.port}/api/health`)
  console.log('')
})

export default app