// Real API hook for Critical Alerts using backend forecast alerts
import { useState, useCallback, useEffect } from 'react';
import { useForecast } from '../api';
import { useTenantId } from './useTenantId';

export interface RealAlert {
  id: string;
  type: 'stock' | 'weather' | 'order' | 'production' | 'system';
  severity: 'high' | 'medium' | 'low';
  title: string;
  description: string;
  action?: string;
  time: string;
}

export const useRealAlerts = () => {
  const [alerts, setAlerts] = useState<RealAlert[]>([]);
  const [isLoading, setIsLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const { tenantId } = useTenantId();
  const { getForecastAlerts, acknowledgeForecastAlert } = useForecast();

  // Transform backend forecast alerts to frontend alert format
  const transformForecastAlert = (alert: any): RealAlert => {
    // Map alert types
    let type: RealAlert['type'] = 'system';
    if (alert.alert_type?.includes('stock') || alert.alert_type?.includes('demand')) {
      type = 'stock';
    } else if (alert.alert_type?.includes('weather')) {
      type = 'weather';
    } else if (alert.alert_type?.includes('production')) {
      type = 'production';
    }

    // Map severity
    let severity: RealAlert['severity'] = 'medium';
    if (alert.severity === 'critical' || alert.severity === 'high') {
      severity = 'high';
    } else if (alert.severity === 'low') {
      severity = 'low';
    }

    // Generate user-friendly title and description
    let title = alert.message;
    let description = alert.message;
    
    if (alert.alert_type?.includes('high_demand')) {
      title = 'Alta Demanda Prevista';
      description = `Se prevé alta demanda. ${alert.message}`;
    } else if (alert.alert_type?.includes('low_confidence')) {
      title = 'Predicción Incierta';
      description = `Baja confianza en predicción. ${alert.message}`;
    } else if (alert.alert_type?.includes('stock_risk')) {
      title = 'Riesgo de Desabastecimiento';
      description = `Posible falta de stock. ${alert.message}`;
    }

    return {
      id: alert.id,
      type,
      severity,
      title,
      description,
      action: 'Ver detalles',
      time: new Date(alert.created_at).toLocaleTimeString('es-ES', { 
        hour: '2-digit', 
        minute: '2-digit' 
      })
    };
  };

  // Load real alerts from backend
  const loadAlerts = useCallback(async () => {
    if (!tenantId) return;

    setIsLoading(true);
    setError(null);

    try {
      // Get forecast alerts from backend
      const forecastAlerts = await getForecastAlerts(tenantId);
      
      // Filter only active alerts
      const activeAlerts = forecastAlerts.filter(alert => alert.is_active);
      
      // Transform to frontend format
      const transformedAlerts = activeAlerts.map(transformForecastAlert);
      
      // Sort by severity and time (most recent first)
      transformedAlerts.sort((a, b) => {
        // First by severity (high > medium > low)
        const severityOrder = { high: 3, medium: 2, low: 1 };
        const severityDiff = severityOrder[b.severity] - severityOrder[a.severity];
        if (severityDiff !== 0) return severityDiff;
        
        // Then by time (most recent first)
        return b.time.localeCompare(a.time);
      });

      setAlerts(transformedAlerts.slice(0, 3)); // Show max 3 alerts in dashboard
    } catch (error) {
      console.error('Error loading alerts:', error);
      setError(error instanceof Error ? error.message : 'Failed to load alerts');
      
      // Fallback to sample alerts based on common scenarios
      setAlerts(generateFallbackAlerts());
    } finally {
      setIsLoading(false);
    }
  }, [tenantId, getForecastAlerts]);

  // Handle alert acknowledgment
  const handleAlertAction = useCallback(async (alertId: string) => {
    if (!tenantId) return;

    try {
      await acknowledgeForecastAlert(tenantId, alertId);
      // Remove acknowledged alert from local state
      setAlerts(prev => prev.filter(alert => alert.id !== alertId));
    } catch (error) {
      console.error('Error acknowledging alert:', error);
    }
  }, [tenantId, acknowledgeForecastAlert]);

  // Generate fallback alerts when API fails
  const generateFallbackAlerts = (): RealAlert[] => {
    const now = new Date();
    const timeString = now.toLocaleTimeString('es-ES', { hour: '2-digit', minute: '2-digit' });

    return [
      {
        id: 'fallback-1',
        type: 'stock',
        severity: 'high',
        title: 'Stock Bajo de Croissants',
        description: 'Se prevé alta demanda este fin de semana',
        action: 'Aumentar producción',
        time: timeString
      }
    ];
  };

  // Load alerts on mount and when tenant changes
  useEffect(() => {
    loadAlerts();
    
    // Refresh alerts every 5 minutes
    const interval = setInterval(loadAlerts, 5 * 60 * 1000);
    
    return () => clearInterval(interval);
  }, [loadAlerts]);

  return {
    alerts,
    isLoading,
    error,
    onAlertAction: handleAlertAction,
    reload: loadAlerts,
    clearError: () => setError(null),
  };
};