package thumbs

import (
	"fmt"
	"os"
	"os/user"
	"strconv"
	"syscall"
)

// ownerOf is "root:render 0660" for a device node, the thing to say when it cannot be opened.
func ownerOf(st os.FileInfo) string {
	sys, ok := st.Sys().(*syscall.Stat_t)
	if !ok {
		return ""
	}
	u := strconv.Itoa(int(sys.Uid))
	if x, err := user.LookupId(u); err == nil {
		u = x.Username
	}
	g := strconv.Itoa(int(sys.Gid))
	if x, err := user.LookupGroupId(g); err == nil {
		g = x.Name
	}
	return fmt.Sprintf("%s:%s %04o", u, g, st.Mode().Perm())
}