package util

import (
	"net"
	"regexp"
)

// Parses an IPv4 or IPv6 address with an optional port on the end. Returns
// match groups for the addresses. The first match is the IPv6 address and the
// second the IPv4 address.
var ipRegexp = regexp.MustCompile(`(?:\[([0-9a-f:]+)\]|(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}))(?::\d+)?`)

func ParseIP(s string) net.IP {
	ips := ipRegexp.FindStringSubmatch(s)
	if ips == nil {
		return nil
	}

	if v6, v4 := ips[1], ips[2]; v6 != "" {
		return net.ParseIP(v6)
	} else {
		return net.ParseIP(v4)
	}
}