//go:build windows

package store

import (
	"os"

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

func acquireInstanceLock(path string) (func() error, error) {
	if err := ensurePrivateFile(path); err != nil {
		return nil, err
	}
	file, err := os.OpenFile(path, os.O_RDWR, 0)
	if err != nil {
		return nil, err
	}
	var overlapped windows.Overlapped
	err = windows.LockFileEx(windows.Handle(file.Fd()), windows.LOCKFILE_EXCLUSIVE_LOCK|windows.LOCKFILE_FAIL_IMMEDIATELY, 0, 1, 0, &overlapped)
	if err != nil {
		_ = file.Close()
		return nil, ErrAlreadyOpen
	}
	return func() error {
		unlockErr := windows.UnlockFileEx(windows.Handle(file.Fd()), 0, 1, 0, &overlapped)
		closeErr := file.Close()
		if unlockErr != nil {
			return unlockErr
		}
		return closeErr
	}, nil
}