package opts
 
 import (

 	"fmt"

 	"net"
 )
 

 // IPOpt holds an IP. It is used to store values from CLI flags.

 type IPOpt struct {

 	*net.IP
 }
 

 // NewIPOpt creates a new IPOpt from a reference net.IP and a
 // string representation of an IP. If the string is not a valid
 // IP it will fallback to the specified reference.

 func NewIPOpt(ref *net.IP, defaultVal string) *IPOpt {
 	o := &IPOpt{

 		IP: ref,
 	}
 	o.Set(defaultVal)
 	return o
 }
 

 // Set sets an IPv4 or IPv6 address from a given string. If the given

 // string is not parsable as an IP address it returns an error.

 func (o *IPOpt) Set(val string) error {

 	ip := net.ParseIP(val)
 	if ip == nil {

 		return fmt.Errorf("%s is not an ip address", val)

 	}

 	*o.IP = ip

 	return nil
 }
 

 // String returns the IP address stored in the IPOpt. If stored IP is a

 // nil pointer, it returns an empty string.
 func (o *IPOpt) String() string {

 	if *o.IP == nil {
 		return ""
 	}

 	return o.IP.String()

 }

 
 // Type returns the type of the option
 func (o *IPOpt) Type() string {
 	return "ip"
 }