package common

import "net"

// BroadcastAddr returns the last address in the given network, or the broadcast address.
func BroadcastAddr(n *net.IPNet) net.IP {
	// The golang net package doesn't make it easy to calculate the broadcast address. :(
	var broadcast net.IP
	if len(n.IP) == 4 {
		broadcast = net.ParseIP("0.0.0.0").To4()
	} else {
		broadcast = net.ParseIP("::")
	}
	for i := 0; i < len(n.IP); i++ {
		broadcast[i] = n.IP[i] | ^n.Mask[i]
	}
	return broadcast
}

//  http://play.golang.org/p/m8TNTtygK0
func IncreaseIP(ip net.IP) {
	for j := len(ip) - 1; j >= 0; j-- {
		ip[j]++
		if ip[j] > 0 {
			break
		}
	}
}

// IsIPv6 check if given ip is IPv6
func IsIPv6(address string) bool {
	ip := net.ParseIP(address)
	if ip == nil {
		return false
	}
	return ip.To4() == nil
}