#include <Windows.h>

LPCWSTR g_szClassName = L"MainWindowClass";

/*Define Section*/
/*Buttons*/
#define BUTTON_01 1
/*Buttons - End*/
/*Define Section - End*/

/*Void Zone*/
void checkIfComputerIsOpened()
{
    LPCWSTR Computer = L"Computador";
    HWND computer = FindWindow(NULL, Computer);

    if (computer == NULL)
    {
        LPCWSTR ComputerError = L"Computer is not opened!";
        LPCWSTR ComputerError_Caption = L"Error";
        MessageBox(NULL, ComputerError, ComputerError_Caption, MB_OK | MB_ICONERROR);
    }
    else
    {
        LPCWSTR ComputerError = L"Computer is opened!";
        LPCWSTR ComputerError_Caption = L"Congrats";
        MessageBox(NULL, ComputerError, ComputerError_Caption, MB_OK | MB_ICONINFORMATION);
    }
}
/*Void Zone - End*/

LRESULT CALLBACK WndProc(HWND hwnd, UINT Msg, WPARAM wParam , LPARAM lParam)
{
    switch (Msg)
    {
    case WM_CREATE:
    {
                      /*Button01*/
                      LPCWSTR button01_ID = L"BUTTON";
                      LPCWSTR button01_text = L"Verify";
                      HWND button01 = CreateWindowEx(NULL, button01_ID, button01_text, BS_DEFPUSHBUTTON | WS_VISIBLE | WS_BORDER | WS_CHILD, 100, 50, 70, 30, hwnd, (HMENU)BUTTON_01, NULL, NULL);
                      /*Button01-End*/
    }
        break;
    case WM_COMMAND:
    {
                       switch (wParam)
                       {
                       case BUTTON_01:
                           checkIfComputerIsOpened();
                           break;
                       }
    }
        break;
    case WM_CLOSE:
        DestroyWindow(hwnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hwnd, Msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASSEX wc;
    MSG msg;
    HWND hwnd;

    ZeroMemory(&wc, sizeof(wc));

    wc.style = 0;
    wc.lpszMenuName = NULL;
    wc.lpszClassName = g_szClassName;
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInstance;
    wc.hIconSm = LoadIcon(NULL, IDC_ICON);
    wc.hIcon = LoadIcon(NULL, IDC_ICON);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.cbWndExtra = 0;
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.cbClsExtra = 0;

    if (!RegisterClassEx(&wc))
    {
        LPCWSTR Error01 = L"Could not register class";
        LPCWSTR Error01_Caption = L"Error";
        MessageBox(NULL, Error01, Error01_Caption, MB_OK | MB_ICONERROR);
    }

    LPCWSTR WindowTitle = L"TUTORIAL!!!";

    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE, g_szClassName, WindowTitle, WS_OVERLAPPEDWINDOW , CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInstance, NULL);

    if (hwnd == NULL)
    {
        LPCWSTR Error02 = L"Could not create window!";
        LPCWSTR Error02_Caption = L"Error";
        MessageBox(NULL, Error02, Error02_Caption, MB_OK | MB_ICONERROR);
    }

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

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

    return msg.wParam;
}