package utils

import (
	"strings"

	"github.com/pkg/errors"
)

// SplitHost returns hostname into domain and subdomain strings.
// For example:
//  "some.subdomain.example.com" → ("some.subdomain", "example.com", nil)
//  "example.com" → ("", "example.com", nil)
func SplitHost(host string) (subdomain string, domain string, err error) {
	subdomains := strings.Split(host, ".")

	if len(subdomains) >= 3 {
		domain = strings.Join(subdomains[len(subdomains)-2:], ".")
		subdomain = strings.Join(subdomains[:len(subdomains)-2], ".")
	} else if len(subdomains) == 2 {
		domain = strings.Join(subdomains, ".")
	} else {
		err = errors.New("invalid domain")
	}
	return subdomain, domain, err
}