weather_alert_service.py

import requests
import json
from datetime import datetime, timedelta
from typing import Dict, List, Optional
import logging
from models import WeatherAlert, Farm, db

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class WeatherAlertService:
    """Service for generating weather-based alerts for farms"""
    
    def __init__(self, weather_api_key: str):
        self.weather_api_key = weather_api_key
        self.base_url = "http://api.openweathermap.org/data/2.5"
        
    def check_and_generate_alerts(self, farm_id: int) -> List[Dict]:
        """Check weather conditions for a farm and generate alerts if needed"""
        try:
            farm = Farm.query.get(farm_id)
            if not farm or not farm.latitude or not farm.longitude:
                logger.warning(f"Farm {farm_id} not found or coordinates missing")
                return []
            
            # Get current weather and forecast
            current_weather = self._get_current_weather(farm.latitude, farm.longitude)
            forecast = self._get_weather_forecast(farm.latitude, farm.longitude)
            
            alerts = []
            
            # Check for various weather conditions
            alerts.extend(self._check_rain_alerts(farm, current_weather, forecast))
            alerts.extend(self._check_temperature_alerts(farm, current_weather, forecast))
            alerts.extend(self._check_wind_alerts(farm, current_weather, forecast))
            alerts.extend(self._check_humidity_alerts(farm, current_weather, forecast))
            
            # Save alerts to database
            for alert_data in alerts:
                existing = WeatherAlert.query.filter_by(
                    farm_id=farm_id,
                    alert_type=alert_data['alert_type'],
                    is_active=True
                ).first()
                
                if not existing:
                    alert = WeatherAlert(
                        farm_id=farm_id,
                        alert_type=alert_data['alert_type'],
                        severity=alert_data['severity'],
                        title=alert_data['title'],
                        message=alert_data['message'],
                        recommended_action=alert_data['recommended_action'],
                        weather_data=json.dumps(alert_data.get('weather_data', {})),
                        expires_at=datetime.now() + timedelta(hours=24)
                    )
                    db.session.add(alert)
            
            db.session.commit()
            return alerts
            
        except Exception as e:
            logger.error(f"Error generating weather alerts for farm {farm_id}: {str(e)}")
            return []
    
    def _get_current_weather(self, lat: float, lon: float) -> Dict:
        """Get current weather data"""
        try:
            url = f"{self.base_url}/weather"
            params = {
                'lat': lat,
                'lon': lon,
                'appid': self.weather_api_key,
                'units': 'metric'
            }
            response = requests.get(url, params=params, timeout=10)
            response.raise_for_status()
            return response.json()
        except Exception as e:
            logger.error(f"Error fetching current weather: {str(e)}")
            return {}
    
    def _get_weather_forecast(self, lat: float, lon: float) -> Dict:
        """Get 5-day weather forecast"""
        try:
            url = f"{self.base_url}/forecast"
            params = {
                'lat': lat,
                'lon': lon,
                'appid': self.weather_api_key,
                'units': 'metric'
            }
            response = requests.get(url, params=params, timeout=10)
            response.raise_for_status()
            return response.json()
        except Exception as e:
            logger.error(f"Error fetching weather forecast: {str(e)}")
            return {}
    
    def _check_rain_alerts(self, farm: Farm, current: Dict, forecast: Dict) -> List[Dict]:
        """Check for rain-related alerts"""
        alerts = []
        
        # Heavy rain alert
        if current.get('rain', {}).get('1h', 0) > 10:  # More than 10mm/hour
            alerts.append({
                'alert_type': 'heavy_rain',
                'severity': 'high',
                'title': 'Heavy Rain Alert',
                'message': f'Heavy rainfall detected at {farm.farm_name}. Current rate: {current["rain"]["1h"]:.1f}mm/hour',
                'recommended_action': 'Ensure proper drainage, protect harvested crops, avoid field operations',
                'weather_data': current
            })
        
        # Forecast rain alert
        forecast_list = forecast.get('list', [])
        for item in forecast_list[:8]:  # Next 24 hours
            if item.get('rain', {}).get('3h', 0) > 15:  # More than 15mm in 3 hours
                alerts.append({
                    'alert_type': 'rain_forecast',
                    'severity': 'medium',
                    'title': 'Heavy Rain Expected',
                    'message': f'Heavy rain expected at {farm.farm_name} in the next 24 hours',
                    'recommended_action': 'Prepare drainage, postpone irrigation, cover sensitive crops',
                    'weather_data': item
                })
                break
        
        return alerts
    
    def _check_temperature_alerts(self, farm: Farm, current: Dict, forecast: Dict) -> List[Dict]:
        """Check for temperature-related alerts"""
        alerts = []
        
        temp = current.get('main', {}).get('temp', 0)
        
        # Heat wave alert
        if temp > 40:
            alerts.append({
                'alert_type': 'heat_wave',
                'severity': 'high',
                'title': 'Extreme Heat Alert',
                'message': f'Very high temperature at {farm.farm_name}: {temp:.1f}°C',
                'recommended_action': 'Increase irrigation frequency, provide shade for livestock, avoid midday work',
                'weather_data': current
            })
        
        # Cold wave alert
        elif temp < 5:
            alerts.append({
                'alert_type': 'cold_wave',
                'severity': 'high',
                'title': 'Cold Wave Alert',
                'message': f'Very low temperature at {farm.farm_name}: {temp:.1f}°C',
                'recommended_action': 'Protect crops from frost, cover sensitive plants, check irrigation pipes',
                'weather_data': current
            })
        
        return alerts
    
    def _check_wind_alerts(self, farm: Farm, current: Dict, forecast: Dict) -> List[Dict]:
        """Check for wind-related alerts"""
        alerts = []
        
        wind_speed = current.get('wind', {}).get('speed', 0) * 3.6  # Convert m/s to km/h
        
        if wind_speed > 50:  # Strong winds
            alerts.append({
                'alert_type': 'strong_wind',
                'severity': 'medium',
                'title': 'Strong Wind Alert',
                'message': f'Strong winds at {farm.farm_name}: {wind_speed:.1f} km/h',
                'recommended_action': 'Secure loose structures, check support for tall crops, avoid spraying',
                'weather_data': current
            })
        
        return alerts
    
    def _check_humidity_alerts(self, farm: Farm, current: Dict, forecast: Dict) -> List[Dict]:
        """Check for humidity-related alerts"""
        alerts = []
        
        humidity = current.get('main', {}).get('humidity', 0)
        
        # High humidity - disease risk
        if humidity > 85:
            alerts.append({
                'alert_type': 'high_humidity',
                'severity': 'medium',
                'title': 'Disease Risk Alert',
                'message': f'High humidity at {farm.farm_name}: {humidity}% - Increased disease risk',
                'recommended_action': 'Monitor crops for fungal diseases, improve ventilation, reduce watering',
                'weather_data': current
            })
        
        return alerts
    
    def get_weather_alerts(self, latitude: float, longitude: float) -> List[Dict]:
        """
        Get weather alerts for a location
        
        Args:
            latitude: Farm latitude
            longitude: Farm longitude
            
        Returns:
            List of weather alert dictionaries
        """
        try:
            # Get current weather and forecast for this location
            current_weather = self._get_current_weather(latitude, longitude)
            forecast = self._get_weather_forecast(latitude, longitude)
            
            alerts = []
            
            # Generate alerts based on current conditions
            if current_weather:
                # Temperature alerts
                temp = current_weather.get('main', {}).get('temp', 0)
                if temp > 40:
                    alerts.append({
                        'alert_type': 'extreme_heat',
                        'severity': 'high',
                        'title': 'Extreme Heat Warning',
                        'message': f'Very high temperature: {temp}°C. Protect crops from heat stress.',
                        'recommendations': 'Increase irrigation, provide shade, harvest early morning',
                        'created_at': datetime.now().isoformat(),
                        'is_active': True
                    })
                elif temp < 5:
                    alerts.append({
                        'alert_type': 'frost_warning',
                        'severity': 'high',
                        'title': 'Frost Warning', 
                        'message': f'Low temperature: {temp}°C. Risk of frost damage.',
                        'recommendations': 'Cover sensitive crops, use frost protection methods',
                        'created_at': datetime.now().isoformat(),
                        'is_active': True
                    })
                
                # Rain alerts
                rain = current_weather.get('rain', {}).get('1h', 0)
                if rain > 10:
                    alerts.append({
                        'alert_type': 'heavy_rain',
                        'severity': 'medium',
                        'title': 'Heavy Rain Alert',
                        'message': f'Heavy rainfall: {rain}mm/hr. Check drainage systems.',
                        'recommendations': 'Ensure proper drainage, avoid field operations',
                        'created_at': datetime.now().isoformat(),
                        'is_active': True
                    })
                
                # Wind alerts
                wind_speed = current_weather.get('wind', {}).get('speed', 0) * 3.6  # Convert m/s to km/h
                if wind_speed > 50:
                    alerts.append({
                        'alert_type': 'strong_wind',
                        'severity': 'medium',
                        'title': 'Strong Wind Warning',
                        'message': f'Strong winds: {wind_speed:.1f} km/h. Risk of crop damage.',
                        'recommendations': 'Secure equipment, check for crop lodging',
                        'created_at': datetime.now().isoformat(),
                        'is_active': True
                    })
                
                # Humidity alerts
                humidity = current_weather.get('main', {}).get('humidity', 0)
                if humidity > 85:
                    alerts.append({
                        'alert_type': 'high_humidity',
                        'severity': 'medium',
                        'title': 'High Humidity Alert',
                        'message': f'High humidity: {humidity}%. Increased disease risk.',
                        'recommendations': 'Monitor for fungal diseases, improve ventilation',
                        'created_at': datetime.now().isoformat(),
                        'is_active': True
                    })
            
            # Check forecast for upcoming conditions
            if forecast and 'list' in forecast:
                for item in forecast['list'][:8]:  # Check next 24 hours
                    forecast_temp = item.get('main', {}).get('temp', 0)
                    forecast_rain = item.get('rain', {}).get('3h', 0)
                    
                    if forecast_temp > 42:
                        alerts.append({
                            'alert_type': 'upcoming_heat',
                            'severity': 'medium',
                            'title': 'Upcoming Heat Wave',
                            'message': f'High temperature expected: {forecast_temp}°C',
                            'recommendations': 'Prepare heat protection measures, plan irrigation',
                            'created_at': datetime.now().isoformat(),
                            'is_active': True
                        })
                        break  # Only add one forecast alert
                    
                    if forecast_rain > 15:
                        alerts.append({
                            'alert_type': 'upcoming_rain',
                            'severity': 'medium',
                            'title': 'Heavy Rain Expected',
                            'message': f'Heavy rain forecast: {forecast_rain}mm',
                            'recommendations': 'Postpone spraying, check drainage systems',
                            'created_at': datetime.now().isoformat(),
                            'is_active': True
                        })
                        break  # Only add one forecast alert
            
            return alerts
            
        except Exception as e:
            logger.error(f"Error getting weather alerts: {str(e)}")
            return []
    
    def get_active_alerts(self, farm_id: int) -> List[WeatherAlert]:
        """Get all active alerts for a farm"""
        return WeatherAlert.query.filter_by(
            farm_id=farm_id,
            is_active=True
        ).filter(
            WeatherAlert.expires_at > datetime.now()
        ).order_by(WeatherAlert.created_at.desc()).all()
    
    def mark_alert_sent(self, alert_id: int):
        """Mark an alert as sent"""
        alert = WeatherAlert.query.get(alert_id)
        if alert:
            alert.is_sent = True
            db.session.commit()