package fileops

import (
	"io/fs"
	"os"

	"golang.org/x/sys/windows"
)

func preserveFileMetadata(file *os.File, target string, _ fs.FileInfo) error {
	sd, err := windows.GetNamedSecurityInfo(target, windows.SE_FILE_OBJECT,
		windows.OWNER_SECURITY_INFORMATION|windows.DACL_SECURITY_INFORMATION)
	if err != nil {
		return err
	}
	owner, _, err := sd.Owner()
	if err != nil {
		return err
	}
	dacl, _, err := sd.DACL()
	if err != nil {
		return err
	}
	control, _, err := sd.Control()
	if err != nil {
		return err
	}
	flags := windows.SECURITY_INFORMATION(windows.DACL_SECURITY_INFORMATION | windows.UNPROTECTED_DACL_SECURITY_INFORMATION)
	if control&windows.SE_DACL_PROTECTED != 0 {
		flags = windows.DACL_SECURITY_INFORMATION | windows.PROTECTED_DACL_SECURITY_INFORMATION
	}
	// The initial temp owner is already the current process user. Avoid asking
	// for an unnecessary owner change on ordinary non-elevated saves.
	user, err := windows.GetCurrentProcessToken().GetTokenUser()
	if err != nil {
		return err
	}
	if owner != nil && !owner.Equals(user.User.Sid) {
		flags |= windows.OWNER_SECURITY_INFORMATION
	} else {
		owner = nil
	}
	return windows.SetNamedSecurityInfo(file.Name(), windows.SE_FILE_OBJECT, flags, owner, nil, dacl, nil)
}