const express = require('express');
const router = express.Router();
const Joi = require('joi');
const { validateRequest } = require('../middleware/validation');
const { Heartbeat, Device, DroneDetection } = require('../models');
const AlertService = require('../services/alertService');
const DroneTrackingService = require('../services/droneTrackingService');

// Initialize services
const alertService = new AlertService();
const droneTracker = new DroneTrackingService();

// Handle movement alerts from the tracking service
droneTracker.on('movement_alert', (alertData) => {
  const { io } = require('../index');
  if (io) {
    // Emit to dashboard with detailed movement information
    io.emitToDashboard('drone_movement_alert', {
      ...alertData,
      timestamp: new Date().toISOString()
    });
    
    // Emit to specific device room
    io.emitToDevice(alertData.deviceId, 'drone_movement_alert', {
      ...alertData,
      timestamp: new Date().toISOString()
    });
    
    console.log(`🚨 Movement Alert: ${alertData.analysis.description} (Drone ${alertData.droneId})`);
  }
});

// Unified schema that accepts both heartbeat and detection payloads
const detectorSchema = Joi.object({
  // Heartbeat fields
  type: Joi.string().valid('heartbeat').when('device_id', { 
    not: Joi.exist(), 
    then: Joi.required() 
  }),
  key: Joi.string().when('type', { 
    is: 'heartbeat', 
    then: Joi.required() 
  }),
  
  // Optional heartbeat fields (from original heartbeat route)
  signal_strength: Joi.number().integer().optional(),
  battery_level: Joi.number().integer().min(0).max(100).optional(),
  temperature: Joi.number().optional(),
  uptime: Joi.number().integer().min(0).optional(),
  memory_usage: Joi.number().integer().min(0).max(100).optional(),
  firmware_version: Joi.string().optional(),
  
  // Detection fields
  device_id: Joi.number().integer().when('type', { 
    not: 'heartbeat', 
    then: Joi.required() 
  }),
  geo_lat: Joi.number().min(-90).max(90).when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  geo_lon: Joi.number().min(-180).max(180).when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  device_timestamp: Joi.number().integer().min(0).when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  drone_type: Joi.number().integer().min(0).when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  rssi: Joi.number().when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  freq: Joi.number().when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  drone_id: Joi.number().integer().when('device_id', { 
    is: Joi.exist(), 
    then: Joi.required() 
  }),
  
  // Optional detection fields
  confidence_level: Joi.number().min(0).max(1).optional(),
  signal_duration: Joi.number().integer().min(0).optional()
}).or('type', 'device_id'); // Must have either type (heartbeat) or device_id (detection)

// POST /api/detectors - Unified endpoint for heartbeats and detections
router.post('/', validateRequest(detectorSchema), async (req, res) => {
  try {
    // Determine if this is a heartbeat or detection based on payload
    if (req.body.type === 'heartbeat') {
      return await handleHeartbeat(req, res);
    } else if (req.body.device_id) {
      return await handleDetection(req, res);
    } else {
      return res.status(400).json({
        success: false,
        error: 'Invalid payload: must be either heartbeat or detection format'
      });
    }
  } catch (error) {
    console.error('Error in detectors endpoint:', error);
    res.status(500).json({
      success: false,
      error: 'Internal server error'
    });
  }
});

// Handle heartbeat payload
async function handleHeartbeat(req, res) {
  const { type, key, device_id, ...heartbeatData } = req.body;
  
  console.log(`💓 Heartbeat received from device key: ${key}`);
  
  // If device_id is not provided, try to find device by key
  let deviceId = device_id;
  if (!deviceId) {
    // Try to extract device ID from key or use key as identifier
    const keyMatch = key.match(/device[_-]?(\d+)/i);
    deviceId = keyMatch ? parseInt(keyMatch[1]) : key.hashCode();
  }
  
  // Ensure device exists or create it
  const [device] = await Device.findOrCreate({
    where: { id: deviceId },
    defaults: {
      id: deviceId,
      name: `Device ${deviceId}`,
      last_heartbeat: new Date()
    }
  });

  // Update device's last heartbeat
  await device.update({ last_heartbeat: new Date() });

  // Create heartbeat record with all optional fields
  const heartbeat = await Heartbeat.create({
    device_id: deviceId,
    device_key: key,
    ...heartbeatData,
    received_at: new Date()
  });

  // Emit real-time update via Socket.IO (from original heartbeat route)
  req.io.emit('device_heartbeat', {
    device_id: deviceId,
    device_key: key,
    timestamp: heartbeat.received_at,
    status: 'online',
    ...heartbeatData
  });

  console.log(`✅ Heartbeat recorded for device ${deviceId}`);

  return res.status(201).json({
    success: true,
    data: heartbeat,
    message: 'Heartbeat recorded successfully'
  });
}

// Handle detection payload
async function handleDetection(req, res) {
  const detectionData = req.body;
  
  console.log(`🚁 Drone detection received from device ${detectionData.device_id}: drone_id=${detectionData.drone_id}, type=${detectionData.drone_type}, rssi=${detectionData.rssi}`);

  // Ensure device exists or create it (from original detection route)
  const [device] = await Device.findOrCreate({
    where: { id: detectionData.device_id },
    defaults: {
      id: detectionData.device_id,
      geo_lat: detectionData.geo_lat || 0,
      geo_lon: detectionData.geo_lon || 0,
      last_heartbeat: new Date()
    }
  });

  // Create detection record
  const detection = await DroneDetection.create({
    ...detectionData,
    server_timestamp: new Date()
  });

  // Process detection through tracking service for movement analysis (from original)
  const movementAnalysis = droneTracker.processDetection({
    ...detectionData,
    server_timestamp: detection.server_timestamp
  });

  // Emit real-time update via Socket.IO with movement analysis (from original)
  req.io.emit('drone_detection', {
    id: detection.id,
    device_id: detection.device_id,
    drone_id: detection.drone_id,
    drone_type: detection.drone_type,
    rssi: detection.rssi,
    freq: detection.freq,
    geo_lat: detection.geo_lat,
    geo_lon: detection.geo_lon,
    server_timestamp: detection.server_timestamp,
    confidence_level: detection.confidence_level,
    signal_duration: detection.signal_duration,
    movement_analysis: movementAnalysis,
    device: {
      id: device.id,
      name: device.name,
      geo_lat: device.geo_lat,
      geo_lon: device.geo_lon
    }
  });

  // Process alerts asynchronously (from original)
  alertService.processAlert(detection, req.io).catch(error => {
    console.error('Alert processing error:', error);
  });

  console.log(`✅ Detection recorded and alert processing initiated for detection ${detection.id}`);

  return res.status(201).json({
    success: true,
    data: {
      ...detection.toJSON(),
      movement_analysis: movementAnalysis
    },
    message: 'Drone detection recorded successfully'
  });
}

// Helper function for string hashing (if key is not numeric)
String.prototype.hashCode = function() {
  let hash = 0;
  if (this.length === 0) return hash;
  for (let i = 0; i < this.length; i++) {
    const char = this.charCodeAt(i);
    hash = ((hash << 5) - hash) + char;
    hash = hash & hash; // Convert to 32bit integer
  }
  return Math.abs(hash);
};

module.exports = router;