package flags

import (

"fmt"

"net"

"github.com/spf13/pflag"

)

type cidrFlag struct {

value string

}

// Ensure the implementation satisfies the expected interface

var _ pflag.Value = &cidrFlag{}

// CIDRFlag returns a flag which must be a valid CIDR.

func CIDRFlag() *cidrFlag {

return &cidrFlag{}

}

func (f *cidrFlag) String() string {

return f.value

}

func (f *cidrFlag) Set(value string) error {

if value == "" {

return fmt.Errorf("value cannot be empty")

}

err := validateCIDR(value)

if err != nil {

return err

}

f.value = value

return nil

}

func (f *cidrFlag) Type() string {

return "string"

}

func validateCIDR(value string) error {

_, _, err := net.ParseCIDR(value)

if err != nil {

return fmt.Errorf("parse %s as CIDR: %w", value, err)

}

return nil

}