// Copyright 2026 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

//go:build windows

package lock

import (
	"errors"
	"os"

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

// tryLock opens (creating if needed) the lock file and takes a non-blocking
// exclusive lock on it via LockFileEx. The returned release closes the file,
// which drops the lock; Windows also drops it when the process exits.
func tryLock(path string) (func() error, error) {
	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0o600)
	if err != nil {
		return nil, err
	}
	handle := windows.Handle(f.Fd())
	overlapped := new(windows.Overlapped)
	if err := windows.LockFileEx(handle, windows.LOCKFILE_EXCLUSIVE_LOCK|windows.LOCKFILE_FAIL_IMMEDIATELY, 0, 1, 0, overlapped); err != nil {
		_ = f.Close()
		if errors.Is(err, windows.ERROR_LOCK_VIOLATION) {
			return nil, ErrLocked
		}
		return nil, err
	}
	return func() error {
		_ = windows.UnlockFileEx(handle, 0, 1, 0, overlapped)
		return f.Close()
	}, nil
}