#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE Instance, HINSTANCE PrevInstance, LPSTR CmdLine, int CmdShow) {
    TCHAR winClsName[] = _T("MyWinCls");
    TCHAR Title[] = _T("Current Kb Layout");

    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);
    wcex.style = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc = WndProc;
    wcex.cbClsExtra = 0;
    wcex.cbWndExtra = 0;
    wcex.hInstance = Instance;
    wcex.hIcon = LoadIcon(Instance, MAKEINTRESOURCE(IDI_APPLICATION));
    wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wcex.lpszMenuName = NULL;
    wcex.lpszClassName = winClsName;
    wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));

    if (!RegisterClassEx(&wcex)) {
        MessageBox(NULL, _T("Call to RegisterClassEx failed!"), Title, NULL);
        return 1;
    }

    HWND wnd = CreateWindow(winClsName, Title, WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 300, 100, NULL, NULL, Instance, NULL);

    ShowWindow(wnd, CmdShow);
    UpdateWindow(wnd);

    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND wnd, UINT message, WPARAM wparam, LPARAM lparam) {
    switch (message) {
    case WM_PAINT: {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(wnd, &ps);
        TCHAR lang[] = _T("OTHER");
        switch (LOWORD(GetKeyboardLayout(GetWindowThreadProcessId(wnd, NULL)))) {
        case 1033:
            wsprintf(lang, _T("%s"), _T("EN"));
            break;
        case 1049:
            wsprintf(lang, _T("%s"), _T("RU"));
            break;
        }
        TextOut(hdc, 5, 5, lang, _tcslen(lang));
        EndPaint(wnd, &ps);
        break;
    }
    case WM_INPUTLANGCHANGE:
        InvalidateRect(wnd, NULL, TRUE);
        UpdateWindow(wnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(wnd, message, wparam, lparam);
        break;
    }
    return 0;
}