// Copyright 2013 @atotto. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// +build windows

package clipboard

import (
	"errors"
	"syscall"
	"unsafe"

	"github.com/lxn/win"
)

func readAll() (string, error) {
	if !win.OpenClipboard(0) {
		return "", errors.New("OpenClipboard")
	}
	defer win.CloseClipboard()
	hMem := win.HGLOBAL(win.GetClipboardData(win.CF_UNICODETEXT))
	if hMem == 0 {
		return "", errors.New("GetClipboardData")
	}
	p := win.GlobalLock(hMem)
	if p == nil {
		return "", errors.New("GlobalLock()")
	}
	defer win.GlobalUnlock(hMem)
	text := win.UTF16PtrToString((*uint16)(p))
	return text, nil
}

func writeAll(text string) error {
	if !win.OpenClipboard(0) {
		return errors.New("OpenClipboard")
	}
	defer win.CloseClipboard()
	utf16, err := syscall.UTF16FromString(text)
	if err != nil {
		return err
	}
	hMem := win.GlobalAlloc(win.GMEM_MOVEABLE, uintptr(len(utf16)*2))
	if hMem == 0 {
		return errors.New("GlobalAlloc")
	}
	p := win.GlobalLock(hMem)
	if p == nil {
		return errors.New("GlobalLock()")
	}
	win.MoveMemory(p, unsafe.Pointer(&utf16[0]), uintptr(len(utf16)*2))
	win.GlobalUnlock(hMem)
	if 0 == win.SetClipboardData(win.CF_UNICODETEXT, win.HANDLE(hMem)) {
		// We need to free hMem.
		defer win.GlobalFree(hMem)
		return errors.New("SetClipboardData")
	}
	// The system now owns the memory referred to by hMem.
	return nil
}