focus.exe

#include <Windows.h>
#include <time.h>
#include <stdio.h>

#pragma warning(disable: 4996)

int main(int argc, char* argv[])
{
    HWND hWnd = 0;
    DWORD lastProcessId = 0;
    WCHAR processImageName[260];
    WCHAR msg[128];
    time_t Time;

    while (1)
    {
        HWND hCurrentWnd;

        do
        {
            Sleep(0x64u);
            hCurrentWnd = GetForegroundWindow();
        } while (hCurrentWnd == hWnd);

        hWnd = hCurrentWnd;

        if (hWnd)
        {
            DWORD dwProcessId;

            GetWindowThreadProcessId(hWnd, &dwProcessId);
            CloseHandle(hWnd);

            if (dwProcessId != lastProcessId)
            {
                HANDLE process;

                lastProcessId = dwProcessId;
                process = OpenProcess(0x1000u, 0, dwProcessId);

                if (process)
                {
                    DWORD lpDwSize = 260;

                    if (!QueryFullProcessImageNameW(process, 0, processImageName, &lpDwSize))
                    {
                        processImageName[0] = L'\0';
                    }

                    time(&Time);

                    wsprintfW(msg, L"%s", _wasctime(localtime(&Time)));
                    wprintf(L"%lu:%s | %s", dwProcessId, processImageName, msg);

                    CloseHandle(process);
                }
                else
                {
                    time(&Time);

                    wsprintfW(msg, L"%s", _wasctime(localtime(&Time)));
                    wprintf(L"%lu:Could not open process | %s", dwProcessId, msg);
                }
            }
        }
        else
        {
            time(&Time);

            wsprintfW(msg, L"%s", _wasctime(localtime(&Time)));
            wprintf(L"No foreground application | %s", msg);
        }
    }
}