/**
 * Created by VoidArtanis on 11/2/2017
 */

package shared

import "math"

const (
	RoleAdmin   string = "admin"
	RoleProUser string = "pro-user"
)

func DistanceKm(lat1 float64, lng1 float64, lat2 float64, lng2 float64) float64 {
	radlat1 := float64(math.Pi * lat1 / 180)
	radlat2 := float64(math.Pi * lat2 / 180)

	theta := float64(lng1 - lng2)
	radtheta := float64(math.Pi * theta / 180)

	dist := math.Sin(radlat1)*math.Sin(radlat2) + math.Cos(radlat1)*math.Cos(radlat2)*math.Cos(radtheta)
	if dist > 1 {
		dist = 1
	}

	dist = math.Acos(dist)
	dist = dist * 180 / math.Pi
	dist = dist * 60 * 1.1515

	return dist * 1.609344
}