package utils

import (
	"fmt"
	"math"
)

func CalculateDistance(lat1, lon1, lat2, lon2 float64) float64 {
	const earthRadiusKm = 6371
	const metersPerKm = 1000

	lat1Rad := DegreesToRadians(lat1)
	lon1Rad := DegreesToRadians(lon1)
	lat2Rad := DegreesToRadians(lat2)
	lon2Rad := DegreesToRadians(lon2)

	dLat := lat2Rad - lat1Rad
	dLon := lon2Rad - lon1Rad

	a := math.Sin(dLat/2)*math.Sin(dLat/2) +
		math.Cos(lat1Rad)*math.Cos(lat2Rad)*
			math.Sin(dLon/2)*math.Sin(dLon/2)

	c := 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
	return earthRadiusKm * c * metersPerKm
}

func DegreesToRadians(degrees float64) float64 {
	return degrees * math.Pi / 180
}

func GetDeliveryStatusMessage(status string) string {
	messages := map[string]string{
		"assigned":  "Commande assignée",
		"en_route":  "En route vers le client",
		"arrived":   "Arrivé à destination",
		"livre":     "Livraison effectuée",
		"cancelled": "Livraison annulée",
	}
	if msg, ok := messages[status]; ok {
		return msg
	}
	return fmt.Sprintf("Statut changé: %s", status)
}