AutoHotKey script replacement in C for multi-monitor window maximization (Windows only)

multi-monitor-window-maximization.c

// Compile with: cl /O2 /GL src\main.c

#include "stdbool.h"
// #include "stdio.h"
#include "windows.h"
#include "winuser.h"

#pragma comment( lib, "user32.lib")

bool altPressed = false;
bool controlPressed = false;
bool shiftPressed = false;
bool winkeyPressed = false;

LRESULT WINAPI hookProc(_In_ int nCode, _In_ WPARAM wParam, _In_ LPARAM lParam);

int WINAPI WinMain(HINSTANCE _hInstance, HINSTANCE _hPrevInstance, LPSTR _lpCmdLine, int _nCmdShow)
{
    int returnCode = 0;
    // Ensures only one instance of application can run at one time
    HANDLE globalMutexHandle = CreateMutex(NULL, true, "multi-monitor-window-maximization");
    if (globalMutexHandle == NULL) {
        returnCode = -1;
        goto exit;
    }
    DWORD lastErrorAfterMutexCreationAttempt = GetLastError();
    if (lastErrorAfterMutexCreationAttempt == ERROR_ALREADY_EXISTS) {
        returnCode = -2;
        goto cleanup;
    } if (lastErrorAfterMutexCreationAttempt == ERROR_INVALID_HANDLE) {
        returnCode = -3;
        goto cleanup;
    }

    HHOOK hook = SetWindowsHookEx(WH_KEYBOARD_LL, (HOOKPROC)&hookProc, NULL, 0);
    if (hook == NULL) {
        // printf("Exited with code : %u", GetLastError());
        returnCode = -4;
        goto cleanup;
    }

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

    UnhookWindowsHookEx(hook);
 cleanup:
    ReleaseMutex(globalMutexHandle);
    CloseHandle(globalMutexHandle);
 exit:
    return returnCode;
}

void changeWindowPosition(int x, int y, int width, int height) {
    HWND foreground = GetForegroundWindow();
    if (foreground == NULL) {
        // printf("No active window to maximize.\n");
        return;
    }

    int _wasPreviouslyVisibleP = ShowWindow(foreground, SW_RESTORE);

    int _wasWindowResizedP = SetWindowPos(foreground, HWND_NOTOPMOST,
                                          x, y, width, height,
                                          SWP_ASYNCWINDOWPOS);

    // if (wasWindowResizedP == 0) {
    //     printf("Failed to change window size and/or position\n");
    // }
}

void superMaximizeCurrentWindow() {
    changeWindowPosition(0, 0, 2560, 2520);
}

void ultraMaximizeCurrentWindow() {
    changeWindowPosition(0, 0, 4000, 2520);
}

void superLeftMaximizeCurrentWindow() {
    changeWindowPosition(0, 0, 1280, 2520);
}

void superRightMaximizeCurrentWindow() {
    changeWindowPosition(1280, 0, 1280, 2520);
}

bool detectAndActivateShortcut(DWORD vkCode)
{
    if (winkeyPressed && shiftPressed) {
        switch (vkCode) {
        case VK_UP:
            if (controlPressed) {
                ultraMaximizeCurrentWindow();
            } else {
                superMaximizeCurrentWindow();
            }
            return true;
        case VK_LEFT:
            superLeftMaximizeCurrentWindow();
            return true;
        case VK_RIGHT:
            superRightMaximizeCurrentWindow();
            return true;
        default:
            break;
        }
    }
    return false;
}

LRESULT WINAPI hookProc(_In_ int nCode, _In_ WPARAM wParam, _In_ LPARAM lParam)
{
    if(nCode < 0)
        return CallNextHookEx(NULL, nCode, wParam, lParam);
    bool activated = false;
    KBDLLHOOKSTRUCT* hookStruct = (KBDLLHOOKSTRUCT*) lParam;
    if(wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN)
    {
        // printf("Pressed : %d\n", hookStruct->vkCode);

        switch (hookStruct->vkCode) {
        case VK_LSHIFT: // 0xA1 Left Shift Key
        case VK_RSHIFT: // 0xA2 Rigth Shift Key
            shiftPressed = true;
        //     printf("Shift pressed");
            break;
        case VK_LCONTROL: // 0xA3 Left Control Key
        case VK_RCONTROL: // 0xA4 Left Control Key
            controlPressed = true;
            break;
        case VK_LMENU: // 0xA5 Left Alt Key
        case VK_RMENU: // 0xA6 Right Alt Key
            altPressed = true;
            break;
        case VK_LWIN: // 0x5B Windows key
        case VK_RWIN: // 0x5C Windows key
            winkeyPressed = true;
            break;
        case VK_SHIFT: // 0x10 Shift Key
            shiftPressed = true;
        //     printf("Shift pressed");
            break;
        case VK_CONTROL: // 0x11 Control Key
            controlPressed = true;
            break;
        case VK_MENU: // 0x12 Alt Key
            altPressed = true;
            break;
        default:
            activated = detectAndActivateShortcut(hookStruct->vkCode);
            break;
        }
    }
    else if(wParam == WM_KEYUP || wParam == WM_SYSKEYUP)
    {
        // printf("Released : %d\n", hookStruct->vkCode);

        switch (hookStruct->vkCode) {
        case VK_LSHIFT: // 0xA1 Left Shift Key
        case VK_RSHIFT: // 0xA2 Rigth Shift Key
            shiftPressed = false;
        //     printf("Shift released");
            break;
        case VK_LCONTROL: // 0xA3 Left Control Key
        case VK_RCONTROL: // 0xA4 Left Control Key
            controlPressed = false;
            break;
        case VK_LMENU: // 0xA5 Left Alt Key
        case VK_RMENU: // 0xA6 Right Alt Key
            altPressed = false;
            break;
        case VK_LWIN: // 0x5B Windows key
        case VK_RWIN: // 0x5C Windows key
            winkeyPressed = false;
            break;
        case VK_SHIFT: // 0x10 Shift Key
            shiftPressed = false;
        //     printf("Shift released");
            break;
        case VK_CONTROL: // 0x11 Control Key
            controlPressed = false;
            break;
        case VK_MENU: // 0x12 Alt Key
            altPressed = false;
            break;
        default:
            break;
        }
    }
    if (activated) {
        return -1;
    } else {
        return CallNextHookEx(NULL, (activated ? -1 : nCode), wParam, lParam);
    }
}