package win32api

import (
	"errors"
	"syscall"
	"unsafe"
)

func Keybd_event(keyname string, keydown bool) error {
	var key int
	var down uintptr
	if !keydown {
		down = KEYEVENTF_KEYUP
	}
	switch keyname {
	case "shift":
		key = VK_SHIFT
	case "lshift":
		key = VK_LSHIFT
	case "rshift":
		key = VK_RSHIFT
	case "a":
		key = VK_A
	}
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	keyevent, err := syscall.GetProcAddress(syscall.Handle(user32), "keybd_event")
	if err != nil {
		return errors.New("Can't Load Keybd_event API")
	}
	syscall.Syscall6(keyevent, 4, uintptr(key), uintptr(key), down, 0, 0, 0)
	return nil
}

func Keybd_event_origin(key, keyenv, down, extra uintptr) error {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	keyevent, err := syscall.GetProcAddress(syscall.Handle(user32), "keybd_event")
	if err != nil {
		return errors.New("Can't Load Keybd_event API")
	}
	syscall.Syscall6(keyevent, 4, key, keyenv, down, extra, 0, 0)
	return nil
}

func OpenClipboard(hWnd HWND) error {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	oc, err := syscall.GetProcAddress(syscall.Handle(user32), "OpenClipboard")
	if err != nil {
		return errors.New("Can't Load OpenClipboard API")
	}
	if hWnd != 0 {
		if r, _, errno := syscall.Syscall(oc, 1, uintptr(hWnd), 0, 0); r == 0 {
			return error(errno)
		}
		return nil
	}
	if r, _, errno := syscall.Syscall(oc, 1, 0, 0, 0); r == 0 {
		return error(errno)
	}
	return nil
}

func CloseClipboard() error {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	cc, err := syscall.GetProcAddress(syscall.Handle(user32), "CloseClipboard")
	if err != nil {
		return errors.New("Can't Load CloseClipboard API")
	}
	if r, _, errno := syscall.Syscall(cc, 0, 0, 0, 0); r == 0 {
		return error(errno)
	}
	return nil
}

func GetClipboardData(uFormat DWORD) (HGLOBAL, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	gcd, err := syscall.GetProcAddress(syscall.Handle(user32), "GetClipboardData")
	if err != nil {
		return 0, errors.New("Can't Load GetClipboardData API")
	}
	r, _, errno := syscall.Syscall(gcd, 1, uintptr(uFormat), 0, 0)
	if r == 0 {
		return 0, error(errno)
	}
	return HGLOBAL(r), nil
}

func EnumClipboardFormats(uFormat DWORD) (DWORD, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	ecf, err := syscall.GetProcAddress(syscall.Handle(user32), "EnumClipboardFormats")
	if err != nil {
		return 0, errors.New("Can't Load EnumClipboardFormats API")
	}
	r, _, errno := syscall.Syscall(ecf, 1, uintptr(uFormat), 0, 0)
	if r == 0 {
		if errno == 0 {
			return 0, nil
		}
		return 0, error(errno)
	}
	return DWORD(r), nil
}

func EnumAllClipboardFormats() ([]DWORD, error) {
	var formats []DWORD
	var current DWORD
	for {
		format, err := EnumClipboardFormats(current)
		if err != nil {
			return nil, err
		}
		if format == 0 {
			break
		}
		formats = append(formats, format)
		current = format
	}
	return formats, nil
}

func GetClipboardFormatName(uFormat DWORD) (string, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return "", errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	gcfn, err := syscall.GetProcAddress(syscall.Handle(user32), "GetClipboardFormatNameW")
	if err != nil {
		return "", errors.New("Can't Load GetClipboardFormatName API")
	}
	var buffer [256]uint16
	r, _, errno := syscall.Syscall6(gcfn, 3, uintptr(uFormat), uintptr(unsafe.Pointer(&buffer)), uintptr(len(buffer)), 0, 0, 0)
	if r == 0 {
		return "", error(errno)
	}
	return syscall.UTF16ToString(buffer[:]), nil
}

func RegisterClipboardFormat(lpszFormat string) DWORD {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0
	}
	defer syscall.FreeLibrary(user32)
	rcf, err := syscall.GetProcAddress(syscall.Handle(user32), "RegisterClipboardFormatW")
	if err != nil {
		return 0
	}
	r, _, _ := syscall.Syscall(rcf, 1, uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpszFormat))), 0, 0)
	return DWORD(r)
}

func EmptyClipboard() error {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	ec, err := syscall.GetProcAddress(syscall.Handle(user32), "EmptyClipboard")
	if err != nil {
		return errors.New("Can't Load EmptyClipboard API")
	}
	if r, _, errno := syscall.Syscall(ec, 0, 0, 0, 0); r == 0 {
		return error(errno)
	}
	return nil
}

func CountClipboardFormats() (int, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	ccf, err := syscall.GetProcAddress(syscall.Handle(user32), "CountClipboardFormats")
	if err != nil {
		return 0, errors.New("Can't Load CountClipboardFormats API")
	}
	r, _, errno := syscall.Syscall(ccf, 0, 0, 0, 0)
	if r == 0 {
		if errno == 0 {
			return 0, nil
		}
		return 0, error(errno)
	}
	return int(r), nil
}

func GetClipboardOwner() (HWND, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	gco, err := syscall.GetProcAddress(syscall.Handle(user32), "GetClipboardOwner")
	if err != nil {
		return 0, errors.New("Can't Load GetClipboardOwner API")
	}
	r, _, errno := syscall.Syscall(gco, 0, 0, 0, 0)
	if r == 0 {
		if errno == 0 {
			return 0, nil
		}
		return 0, error(errno)
	}
	return HWND(r), nil
}

func GetUpdatedClipboardFormats(lpuiFormats unsafe.Pointer, cFormats int, pcFormats unsafe.Pointer) (int, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	gucf, err := syscall.GetProcAddress(syscall.Handle(user32), "GetUpdatedClipboardFormats")
	if err != nil {
		return 0, errors.New("Can't Load GetUpdatedClipboardFormats API")
	}
	r, _, errno := syscall.Syscall(gucf, 3, uintptr(lpuiFormats), uintptr(cFormats), uintptr(pcFormats))
	if r == 0 {
		return 0, error(errno)
	}
	return int(r), nil
}

type updatedClipboardFormatsFunc func(lpuiFormats unsafe.Pointer, cFormats int, pcFormats unsafe.Pointer) (int, error)

func getUpdatedClipboardFormatsAll(fetch updatedClipboardFormatsFunc) ([]DWORD, error) {
	if fetch == nil {
		fetch = GetUpdatedClipboardFormats
	}
	for size := 32; ; {
		formats := make([]uint32, size)
		var count uint32
		_, err := fetch(unsafe.Pointer(&formats[0]), len(formats), unsafe.Pointer(&count))
		if err != nil {
			if errors.Is(err, syscall.ERROR_INSUFFICIENT_BUFFER) {
				nextSize := size * 2
				if count > uint32(size) {
					nextSize = int(count)
				}
				size = nextSize
				continue
			}
			return nil, err
		}
		if count > uint32(len(formats)) {
			size = int(count)
			continue
		}
		res := make([]DWORD, 0, int(count))
		for i := 0; i < int(count); i++ {
			res = append(res, DWORD(formats[i]))
		}
		return res, nil
	}
}

func GetUpdatedClipboardFormatsAll() ([]DWORD, error) {
	return getUpdatedClipboardFormatsAll(GetUpdatedClipboardFormats)
}

func IsClipboardFormatAvailable(uFormat DWORD) (bool, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return false, err
	}
	defer syscall.FreeLibrary(user32)
	icfa, err := syscall.GetProcAddress(syscall.Handle(user32), "IsClipboardFormatAvailable")
	if err != nil {
		return false, err
	}
	r, _, _ := syscall.Syscall(icfa, 1, uintptr(uFormat), 0, 0)
	return r != 0, nil
}

func AddClipboardFormatListener(hWnd HWND) (bool, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return false, err
	}
	defer syscall.FreeLibrary(user32)
	acfl, err := syscall.GetProcAddress(syscall.Handle(user32), "AddClipboardFormatListener")
	if err != nil {
		return false, err
	}
	r, _, errno := syscall.Syscall(acfl, 1, uintptr(hWnd), 0, 0)
	if r == 0 {
		if errno != 0 {
			return false, error(errno)
		}
		return false, syscall.EINVAL
	}
	return true, nil
}

func RemoveClipboardFormatListener(hWnd HWND) (bool, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return false, err
	}
	defer syscall.FreeLibrary(user32)
	rcfl, err := syscall.GetProcAddress(syscall.Handle(user32), "RemoveClipboardFormatListener")
	if err != nil {
		return false, err
	}
	r, _, errno := syscall.Syscall(rcfl, 1, uintptr(hWnd), 0, 0)
	if r == 0 {
		if errno != 0 {
			return false, error(errno)
		}
		return false, syscall.EINVAL
	}
	return true, nil
}

func SetClipboardData(uFormat DWORD, hMem HGLOBAL) (HGLOBAL, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	scd, err := syscall.GetProcAddress(syscall.Handle(user32), "SetClipboardData")
	if err != nil {
		return 0, errors.New("Can't Load SetClipboardData API")
	}
	r, _, errno := syscall.Syscall(scd, 2, uintptr(uFormat), uintptr(hMem), 0)
	if r == 0 {
		return 0, error(errno)
	}
	return HGLOBAL(r), nil
}

func SetClipboardViewer(hWndNewViewer HWND) (HWND, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	scv, err := syscall.GetProcAddress(syscall.Handle(user32), "SetClipboardViewer")
	if err != nil {
		return 0, errors.New("Can't Load SetClipboardViewer API")
	}
	r, _, errno := syscall.Syscall(scv, 1, uintptr(hWndNewViewer), 0, 0)
	if r == 0 {
		if errno == 0 {
			return 0, nil
		}
		return 0, error(errno)
	}
	return HWND(r), nil
}

func GetClipboardSequenceNumber() (DWORD, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	gcsn, err := syscall.GetProcAddress(syscall.Handle(user32), "GetClipboardSequenceNumber")
	if err != nil {
		return 0, errors.New("Can't Load GetClipboardSequenceNumber API")
	}
	r, _, errno := syscall.Syscall(gcsn, 0, 0, 0, 0)
	if r == 0 {
		return 0, error(errno)
	}
	return DWORD(r), nil
}

func CreateWindowEx(dwExStyle DWORD, lpClassName, lpWindowName string, dwStyle DWORD, x, y, nWidth, nHeight int, hWndParent HWND, hMenu HMENU, hInstance HINSTANCE, lpParam unsafe.Pointer) (HWND, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	cwe, err := syscall.GetProcAddress(syscall.Handle(user32), "CreateWindowExW")
	if err != nil {
		return 0, errors.New("Can't Load CreateWindowEx API")
	}
	r, _, errno := syscall.Syscall12(cwe, 12, uintptr(dwExStyle), uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpClassName))), uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpWindowName))), uintptr(dwStyle), uintptr(x), uintptr(y), uintptr(nWidth), uintptr(nHeight), uintptr(hWndParent), uintptr(hMenu), uintptr(hInstance), uintptr(lpParam))
	if r == 0 {
		return 0, error(errno)
	}
	return HWND(r), nil
}

func DestroyWindow(hWnd HWND) (bool, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return false, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	dw, err := syscall.GetProcAddress(syscall.Handle(user32), "DestroyWindow")
	if err != nil {
		return false, errors.New("Can't Load DestroyWindow API")
	}
	r, _, errno := syscall.Syscall(dw, 1, uintptr(hWnd), 0, 0)
	if r == 0 {
		if errno != 0 {
			return false, error(errno)
		}
		return false, syscall.EINVAL
	}
	return true, nil
}

func GetMessage(lpMsg *MSG, hWnd HWND, wMsgFilterMin, wMsgFilterMax DWORD) (DWORD, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, errors.New("Can't Load User32 API")
	}
	defer syscall.FreeLibrary(user32)
	gm, err := syscall.GetProcAddress(syscall.Handle(user32), "GetMessageW")
	if err != nil {
		return 0, errors.New("Can't Load GetMessage API")
	}
	r, _, errno := syscall.Syscall6(gm, 4, uintptr(unsafe.Pointer(lpMsg)), uintptr(hWnd), uintptr(wMsgFilterMin), uintptr(wMsgFilterMax), 0, 0)
	if int32(r) == -1 {
		return 0, error(errno)
	}
	return DWORD(r), nil
}

func TranslateMessage(lpMsg *MSG) (bool, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return false, err
	}
	defer syscall.FreeLibrary(user32)
	proc, err := syscall.GetProcAddress(syscall.Handle(user32), "TranslateMessage")
	if err != nil {
		return false, err
	}
	r, _, _ := syscall.Syscall(proc, 1, uintptr(unsafe.Pointer(lpMsg)), 0, 0)
	return r != 0, nil
}

func DispatchMessage(lpMsg *MSG) (LRESULT, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, err
	}
	defer syscall.FreeLibrary(user32)
	proc, err := syscall.GetProcAddress(syscall.Handle(user32), "DispatchMessageW")
	if err != nil {
		return 0, err
	}
	r, _, _ := syscall.Syscall(proc, 1, uintptr(unsafe.Pointer(lpMsg)), 0, 0)
	return LRESULT(r), nil
}

func DefWindowProc(hWnd HWND, uMsg UINT, wParam WPARAM, lParam LPARAM) LRESULT {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0
	}
	defer syscall.FreeLibrary(user32)
	proc, err := syscall.GetProcAddress(syscall.Handle(user32), "DefWindowProcW")
	if err != nil {
		return 0
	}
	r, _, _ := syscall.Syscall6(proc, 4, uintptr(hWnd), uintptr(uMsg), uintptr(wParam), uintptr(lParam), 0, 0)
	return LRESULT(r)
}

func PostMessage(hWnd HWND, msg UINT, wParam WPARAM, lParam LPARAM) (bool, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return false, err
	}
	defer syscall.FreeLibrary(user32)
	proc, err := syscall.GetProcAddress(syscall.Handle(user32), "PostMessageW")
	if err != nil {
		return false, err
	}
	r, _, errno := syscall.Syscall6(proc, 4, uintptr(hWnd), uintptr(msg), uintptr(wParam), uintptr(lParam), 0, 0)
	if r == 0 {
		if errno != 0 {
			return false, error(errno)
		}
		return false, syscall.EINVAL
	}
	return true, nil
}

func PostQuitMessage(nExitCode int) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return
	}
	defer syscall.FreeLibrary(user32)
	proc, err := syscall.GetProcAddress(syscall.Handle(user32), "PostQuitMessage")
	if err != nil {
		return
	}
	syscall.Syscall(proc, 1, uintptr(nExitCode), 0, 0)
}

func RegisterClassEx(lpWndClass *WNDCLASSEX) (uint16, error) {
	user32, err := syscall.LoadLibrary("user32.dll")
	if err != nil {
		return 0, err
	}
	defer syscall.FreeLibrary(user32)
	proc, err := syscall.GetProcAddress(syscall.Handle(user32), "RegisterClassExW")
	if err != nil {
		return 0, err
	}
	r, _, err := syscall.Syscall(proc, 1, uintptr(unsafe.Pointer(lpWndClass)), 0, 0)
	if r == 0 {
		return 0, err
	}
	return uint16(r), nil
}

func OpenInputDesktop(dwFlags DWORD, fInherit bool, dwDesiredAccess DWORD) (HDESK, error) {
	proc, err := getProcAddr("user32.dll", "OpenInputDesktop")
	if err != nil {
		return 0, err
	}
	inherit := uintptr(0)
	if fInherit {
		inherit = 1
	}
	r, _, errno := syscall.Syscall(proc, 3, uintptr(dwFlags), inherit, uintptr(dwDesiredAccess))
	if r == 0 {
		if errno != 0 {
			return 0, error(errno)
		}
		return 0, syscall.EINVAL
	}
	return HDESK(r), nil
}

func CloseDesktop(hDesktop HDESK) error {
	proc, err := getProcAddr("user32.dll", "CloseDesktop")
	if err != nil {
		return err
	}
	r, _, errno := syscall.Syscall(proc, 1, uintptr(hDesktop), 0, 0)
	if r == 0 {
		if errno != 0 {
			return error(errno)
		}
		return syscall.EINVAL
	}
	return nil
}

func SwitchDesktop(hDesktop HDESK) error {
	proc, err := getProcAddr("user32.dll", "SwitchDesktop")
	if err != nil {
		return err
	}
	r, _, errno := syscall.Syscall(proc, 1, uintptr(hDesktop), 0, 0)
	if r == 0 {
		if errno != 0 {
			return error(errno)
		}
		return syscall.EINVAL
	}
	return nil
}

func GetThreadDesktop(dwThreadId DWORD) (HDESK, error) {
	proc, err := getProcAddr("user32.dll", "GetThreadDesktop")
	if err != nil {
		return 0, err
	}
	r, _, errno := syscall.Syscall(proc, 1, uintptr(dwThreadId), 0, 0)
	if r == 0 {
		if errno != 0 {
			return 0, error(errno)
		}
		return 0, syscall.EINVAL
	}
	return HDESK(r), nil
}

func SetThreadDesktop(hDesktop HDESK) error {
	proc, err := getProcAddr("user32.dll", "SetThreadDesktop")
	if err != nil {
		return err
	}
	r, _, errno := syscall.Syscall(proc, 1, uintptr(hDesktop), 0, 0)
	if r == 0 {
		if errno != 0 {
			return error(errno)
		}
		return syscall.EINVAL
	}
	return nil
}

func GetDesktopWindow() HWND {
	proc, err := getProcAddr("user32.dll", "GetDesktopWindow")
	if err != nil {
		return 0
	}
	r, _, _ := syscall.Syscall(proc, 0, 0, 0, 0)
	return HWND(r)
}

func GetShellWindow() HWND {
	proc, err := getProcAddr("user32.dll", "GetShellWindow")
	if err != nil {
		return 0
	}
	r, _, _ := syscall.Syscall(proc, 0, 0, 0, 0)
	return HWND(r)
}

func GetForegroundWindow() HWND {
	proc, err := getProcAddr("user32.dll", "GetForegroundWindow")
	if err != nil {
		return 0
	}
	r, _, _ := syscall.Syscall(proc, 0, 0, 0, 0)
	return HWND(r)
}

func GetWindowThreadProcessId(hWnd HWND) (DWORD, DWORD, error) {
	proc, err := getProcAddr("user32.dll", "GetWindowThreadProcessId")
	if err != nil {
		return 0, 0, err
	}
	var processID DWORD
	r, _, errno := syscall.Syscall(proc, 2, uintptr(hWnd), uintptr(unsafe.Pointer(&processID)), 0)
	threadID := DWORD(r)
	if threadID == 0 {
		if errno != 0 {
			return 0, processID, error(errno)
		}
		return 0, processID, syscall.EINVAL
	}
	return threadID, processID, nil
}

func GetWindowText(hWnd HWND) (string, error) {
	lenProc, err := getProcAddr("user32.dll", "GetWindowTextLengthW")
	if err != nil {
		return "", err
	}
	textProc, err := getProcAddr("user32.dll", "GetWindowTextW")
	if err != nil {
		return "", err
	}

	n, _, _ := syscall.Syscall(lenProc, 1, uintptr(hWnd), 0, 0)
	size := uint32(n) + 1
	if size < 2 {
		size = 2
	}
	buf := make([]uint16, size)
	r, _, errno := syscall.Syscall(textProc, 3, uintptr(hWnd), uintptr(unsafe.Pointer(&buf[0])), uintptr(size))
	if r == 0 {
		if errno != 0 {
			return "", error(errno)
		}
		return "", nil
	}
	return syscall.UTF16ToString(buf[:r]), nil
}