//go:build windows

package fileops

import (
	"errors"
	"fmt"
	"os"

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

func syncDirectory(path string) error {
	pathPointer, err := windows.UTF16PtrFromString(path)
	if err != nil {
		return err
	}
	directory, err := windows.CreateFile(
		pathPointer,
		windows.GENERIC_WRITE,
		windows.FILE_SHARE_READ|windows.FILE_SHARE_WRITE|windows.FILE_SHARE_DELETE,
		nil,
		windows.OPEN_EXISTING,
		windows.FILE_FLAG_BACKUP_SEMANTICS,
		0,
	)
	if err != nil {
		return err
	}
	defer func() { _ = windows.CloseHandle(directory) }()

	err = windows.FlushFileBuffers(directory)
	// Windows filesystems may reject flushing a directory handle even when it
	// was opened correctly. Report documented unavailable forms explicitly so
	// callers do not confuse visible replacement with a durable one.
	if errors.Is(err, windows.ERROR_INVALID_FUNCTION) ||
		errors.Is(err, windows.ERROR_INVALID_HANDLE) ||
		errors.Is(err, windows.ERROR_NOT_SUPPORTED) {
		return fmt.Errorf("%w for %q: %w", ErrDirectorySyncUnsupported, path, err)
	}
	return err
}

func syncDirectoryFile(directory *os.File, path string) error {
	err := directory.Sync()
	if errors.Is(err, windows.ERROR_INVALID_FUNCTION) ||
		errors.Is(err, windows.ERROR_INVALID_HANDLE) ||
		errors.Is(err, windows.ERROR_NOT_SUPPORTED) {
		return fmt.Errorf("%w for %q: %w", ErrDirectorySyncUnsupported, path, err)
	}
	return err
}