// /app.js — Main Express Application Entry Point
'use strict';

const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const rateLimit = require('express-rate-limit');
const mongoose = require('mongoose');

const config = require('./config/config');
const connectDB = require('./config/db');
const logger = require('./utils/logger');
const notFoundHandler = require('./middlewares/notFoundHandler');
const globalErrorHandler = require('./middlewares/globalErrorHandler');

// ── Route imports ─────────────────────────────────────────────────────────────
const authRoutes = require('./components/auth/authRoutes');
const userRoutes = require('./components/users/userRoutes');
const professorRoutes = require('./components/professors/professorRoutes');
const courseRoutes = require('./components/courses/courseRoutes');
const classRoutes = require('./components/classes/classRoutes');
const sessionRoutes = require('./components/sessions/sessionRoutes');
const paymentRoutes = require('./components/payments/paymentRoutes');
const roleRoutes = require('./components/roles/roleRoutes');
const notificationRoutes = require('./components/notifications/notificationRoutes');
const certificateRoutes = require('./components/certificates/certificateRoutes');
const documentRoutes = require('./components/documents/documentRoutes');
const fileRoutes = require('./components/files/fileRoutes');
const dashboardRoutes = require('./components/dashboard/dashboardRoutes');
const activityLogRoutes = require('./components/activityLogs/activityLogRoutes');
const contactInquiryRoutes = require('./components/contactInquiries/contactInquiryRoutes');
const expenseRoutes = require('./components/expenses/expenseRoutes');
const financialReportRoutes = require('./components/financialReports/financialReportRoutes');
const activityLogger = require('./middlewares/activityLogger');

const app = express();

// ── Security & Middleware ─────────────────────────────────────────────────────
app.use(helmet());
app.use(cors({
  origin: config.CORS_ORIGIN,
  credentials: true
}));
app.use(express.json({ limit: '10mb' }));
app.use(express.urlencoded({ extended: true, limit: '10mb' }));
app.use(activityLogger);

// Global rate limiter
const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 300,
  standardHeaders: true,
  legacyHeaders: false,
  message: { status: 'error', message: 'Too many requests. Please try again later.' }
});
app.use('/api', limiter);

// ── Routes ────────────────────────────────────────────────────────────────────
app.get('/api/health', (req, res) => {
  const dbStates = {
    0: 'disconnected',
    1: 'connected',
    2: 'connecting',
    3: 'disconnecting',
    99: 'uninitialized'
  };

  const dbStateCode = mongoose.connection.readyState;
  const dbStatus = dbStates[dbStateCode] || 'unknown';
  const isHealthy = dbStateCode === 1;

  res.status(isHealthy ? 200 : 503).json({
    status: isHealthy ? 'healthy' : 'unhealthy',
    timestamp: new Date().toISOString(),
    uptime: process.uptime(),
    services: {
      database: dbStatus
    },
    environment: config.NODE_ENV
  });
});

const seedDatabase = require('./seed');
const seedRoutes = require('./components/seed/seedRoutes');
const dataImportRoutes = require('./components/dataImport/dataImportRoutes');
const settingRoutes = require('./components/settings/settingRoutes');

app.use('/api/auth', authRoutes);
app.use('/api/users', userRoutes);
app.use('/api/professors', professorRoutes);
app.use('/api/courses', courseRoutes);
app.use('/api/classes', classRoutes);
app.use('/api/sessions', sessionRoutes);
app.use('/api/payments', paymentRoutes);
app.use('/api/roles', roleRoutes);
app.use('/api/notifications', notificationRoutes);
app.use('/api/certificates', certificateRoutes);
app.use('/api/documents', documentRoutes);
app.use('/api/files', fileRoutes);
app.use('/api/dashboard', dashboardRoutes);
app.use('/api/activity-logs', activityLogRoutes);
app.use('/api/contact-inquiries', contactInquiryRoutes);
app.use('/api/expenses', expenseRoutes);
app.use('/api/financial-reports', financialReportRoutes);
const pendingStudentRoutes = require('./components/pendingStudents/pendingStudentRoutes');
const waitlistRoutes = require('./components/waitlist/waitlistRoutes');
app.use('/api/pending-students', pendingStudentRoutes);
app.use('/api/waitlist', waitlistRoutes);
const employeeTimingRoutes = require('./components/employeeTimings/employeeTimingRoutes');
app.use('/api/employee-timings', employeeTimingRoutes);
app.use('/api/seed', seedRoutes);
app.use('/api/data-import', dataImportRoutes);
app.use('/api/settings', settingRoutes);

// ── Error Handlers ────────────────────────────────────────────────────────────
app.use(notFoundHandler);
app.use(globalErrorHandler);

// ── Server startup ────────────────────────────────────────────────────────────
const PORT = config.PORT || 3000;

const startServer = async () => {
  await connectDB();

  if (config.NODE_ENV === 'production') {
    logger.info('Running production bootstrap (roles + SuperAdmin from env)');
    await seedDatabase({ disconnectOnComplete: false });
  }

  const { ensureAppBuckets } = require('./utils/s3Client');
  await ensureAppBuckets();

  const registerEventListeners = require('./events/eventListeners');
  const { startPaymentReminderJob } = require('./jobs/paymentReminderJob');
  const { startNotificationRetryJob } = require('./jobs/notificationRetryJob');
  const { startTempBucketCleanupJob } = require('./jobs/tempBucketCleanupJob');
  const { startClassReminderJob } = require('./jobs/classReminderJob');

  registerEventListeners();
  startPaymentReminderJob();
  startNotificationRetryJob();
  startTempBucketCleanupJob();
  startClassReminderJob();

  app.listen(PORT, () => {
    logger.info(`Gameno API listening on http://localhost:${PORT} [${config.NODE_ENV}]`);
  });
};

startServer().catch(err => {
  logger.error('Failed to start server:', err);
  process.exit(1);
});

module.exports = app;