package hostname

// functions to import and export the protobuf
// data to and from config files

import (
	"bytes"
	"fmt"
	"os"
	"os/exec"
	"strings"
)

func osGetHostname() (string, error) {
	host, err := os.Hostname()
	if err != nil {
		return host, fmt.Errorf("failed to get hostname: %w", err)
	}

	domain, err := getDomainName()
	if err != nil || domain == "" {
		return host, err
	}

	return fmt.Sprintf("%s.%s", host, domain), nil
}

// getDomainName executes the 'domainname' command and returns its output.
func getDomainName() (string, error) {
	cmd := exec.Command("domainname")
	var out bytes.Buffer
	cmd.Stdout = &out
	if err := cmd.Run(); err != nil {
		return "", fmt.Errorf("failed to execute 'domainname': %w", err)
	}
	domain := strings.TrimSpace(out.String())
	if domain == "(none)" {
		return "", ErrorDomainNameMisconfigured
	}

	return domain, nil
}