package netpol

import (
	"fmt"
	"regexp"
	"strconv"
)

func validateNodePortRange(nodePortOption string) (string, error) {
	nodePortValidator := regexp.MustCompile(`^([0-9]+)[:-]([0-9]+)$`)
	if matched := nodePortValidator.MatchString(nodePortOption); !matched {
		return "", fmt.Errorf("failed to parse node port range given: '%s' please see specification in help text", nodePortOption)
	}
	matches := nodePortValidator.FindStringSubmatch(nodePortOption)
	if len(matches) != 3 {
		return "", fmt.Errorf("could not parse port number from range given: '%s'", nodePortOption)
	}
	port1, err := strconv.ParseUint(matches[1], 10, 16)
	if err != nil {
		return "", fmt.Errorf("could not parse first port number from range given: '%s'", nodePortOption)
	}
	port2, err := strconv.ParseUint(matches[2], 10, 16)
	if err != nil {
		return "", fmt.Errorf("could not parse second port number from range given: '%s'", nodePortOption)
	}
	if port1 >= port2 {
		return "", fmt.Errorf("port 1 is greater than or equal to port 2 in range given: '%s'", nodePortOption)
	}
	return fmt.Sprintf("%d:%d", port1, port2), nil
}