const express = require('express');
const { protect } = require('../middleware/auth');
const database = require('../config/database');
const logger = require('../utils/logger');

const router = express.Router();

// Get dashboard overview
router.get('/dashboard', protect, async (req, res) => {
  try {
    // Get total devices
    const [deviceCount] = await database.query('SELECT COUNT(*) as count FROM devices');
    
    // Get online devices
    const [onlineDevices] = await database.query("SELECT COUNT(*) as count FROM devices WHERE status = 'online'");
    
    // Get total alerts in last 24h
    const [alerts24h] = await database.query(
      'SELECT COUNT(*) as count FROM alerts WHERE created_at >= DATE_SUB(NOW(), INTERVAL 24 HOUR)'
    );
    
    // Get critical alerts
    const [criticalAlerts] = await database.query(
      "SELECT COUNT(*) as count FROM alerts WHERE severity = 'critical' AND status = 'active'"
    );
    
    const overview = {
      total_devices: deviceCount.count,
      online_devices: onlineDevices.count,
      offline_devices: deviceCount.count - onlineDevices.count,
      alerts_24h: alerts24h.count,
      critical_alerts: criticalAlerts.count,
      uptime_percentage: deviceCount.count > 0 ? ((onlineDevices.count / deviceCount.count) * 100).toFixed(2) : 0
    };
    
    res.json({
      success: true,
      data: overview
    });
  } catch (error) {
    logger.error('Get dashboard overview error:', error);
    res.status(500).json({
      success: false,
      message: 'Failed to get dashboard overview'
    });
  }
});

// Get device performance metrics
router.get('/performance', protect, async (req, res) => {
  try {
    const { period = '24h' } = req.query;
    
    let timeFilter;
    switch (period) {
      case '1h':
        timeFilter = 'DATE_SUB(NOW(), INTERVAL 1 HOUR)';
        break;
      case '24h':
        timeFilter = 'DATE_SUB(NOW(), INTERVAL 24 HOUR)';
        break;
      case '7d':
        timeFilter = 'DATE_SUB(NOW(), INTERVAL 7 DAY)';
        break;
      default:
        timeFilter = 'DATE_SUB(NOW(), INTERVAL 24 HOUR)';
    }
    
    // Get data points count
    const [dataPoints] = await database.query(
      `SELECT COUNT(*) as count FROM device_data WHERE created_at >= ${timeFilter}`
    );
    
    // Get average data size
    const [avgDataSize] = await database.query(
      `SELECT AVG(JSON_LENGTH(raw_data)) as avg_size FROM device_data WHERE created_at >= ${timeFilter}`
    );
    
    const performance = {
      period,
      data_points: dataPoints.count,
      avg_data_size: avgDataSize.avg_size || 0,
      data_rate_per_hour: period === '1h' ? dataPoints.count : Math.round(dataPoints.count / 24)
    };
    
    res.json({
      success: true,
      data: performance
    });
  } catch (error) {
    logger.error('Get performance metrics error:', error);
    res.status(500).json({
      success: false,
      message: 'Failed to get performance metrics'
    });
  }
});

module.exports = router;