#include "KeyboardInputWindows.h"
#include <Windows.h>
#include "../../logging.h"

namespace advsettings {

void fillKiStruct(INPUT& ip, WORD scanCode, bool keyup) {
    ip.type = INPUT_KEYBOARD;
    ip.ki.wVk = scanCode;
    if (keyup) {
        ip.ki.dwFlags = KEYEVENTF_KEYUP;
    } else {
        ip.ki.dwFlags = 0;
    }
    ip.ki.wScan = 0;
    ip.ki.dwExtraInfo = 0;
    ip.ki.time = 0;
};

void sendKeyboardInputRaw(int inputCount, LPINPUT input) {
    if ((inputCount > 0) && !SendInput(static_cast<UINT>(inputCount), input, sizeof(INPUT))) {
        char *err;
        auto errCode = GetLastError();
        if (!FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
                nullptr,
                errCode,
                MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // default language
                (LPTSTR)&err,
                0,
                nullptr)){
            LOG(ERROR) << "Error calling SendInput(): Could not get error message (" << errCode << ")";
        } else {
            LOG(ERROR) << "Error calling SendInput(): " << err;
        }
    }
}

void KeyboardInputWindows::sendKeyboardInput(QString input)
{
    int len = input.length();
    if (len > 0) {
        LPINPUT ips = new INPUT[static_cast<unsigned int>(len) * 5 + 3];
        int ii = 0;
        bool shiftPressed = false;
        bool ctrlPressed = false;
        bool altPressed = false;
        for (int i = 0; i < len; i++) {
            short tmp = VkKeyScan(input.at(i).toLatin1());
            WORD c = tmp & 0xFF;
            short shiftState = tmp >> 8;
            bool isShift = shiftState & 1;
            bool isCtrl = shiftState & 2;
            bool isAlt = shiftState & 4;
            if (isShift && !shiftPressed) {
                fillKiStruct(ips[ii++], VK_SHIFT, false);
                shiftPressed = true;
            } else if (!isShift && shiftPressed) {
                fillKiStruct(ips[ii++], VK_SHIFT, true);
                shiftPressed = false;
            }
            if (isCtrl && !ctrlPressed) {
                fillKiStruct(ips[ii++], VK_CONTROL, false);
                ctrlPressed = true;
            } else if (!isCtrl && ctrlPressed) {
                fillKiStruct(ips[ii++], VK_CONTROL, true);
                ctrlPressed = false;
            }
            if (isAlt && !altPressed) {
                fillKiStruct(ips[ii++], VK_MENU, false);
                altPressed = true;
            } else if (!isAlt && altPressed) {
                fillKiStruct(ips[ii++], VK_MENU, true);
                altPressed = false;
            }
            fillKiStruct(ips[ii++], c, false);
            fillKiStruct(ips[ii++], c, true);
        }
        if (shiftPressed) {
            fillKiStruct(ips[ii++], VK_SHIFT, true);
            shiftPressed = false;
        }
        if (ctrlPressed) {
            fillKiStruct(ips[ii++], VK_CONTROL, true);
            ctrlPressed = false;
        }
        if (altPressed) {
            fillKiStruct(ips[ii++], VK_MENU, true);
            altPressed = false;
        }

        sendKeyboardInputRaw(ii, ips);
        delete ips;
    }
}

void KeyboardInputWindows::sendKeyboardEnter()
{
    LPINPUT ips = new INPUT[2];
    fillKiStruct(ips[0], VK_RETURN, false);
    fillKiStruct(ips[1], VK_RETURN, true);

    sendKeyboardInputRaw(2, ips);
    delete ips;
}

void KeyboardInputWindows::sendKeyboardBackspace(int count)
{
    if (count > 0) {
        // We ensure that count is nonnegative, therefore safe cast.
        LPINPUT ips = new INPUT[static_cast<unsigned int>(count) * 2];
        for (int i = 0; i < count; i++) {
            fillKiStruct(ips[2 * i], VK_BACK, false);
            fillKiStruct(ips[2 * i + 1], VK_BACK, true);
        }

        sendKeyboardInputRaw(count * 2, ips);
        delete ips;
    }
}

void KeyboardInputWindows::sendKeyboardAltTab()
{
    LPINPUT ips = new INPUT[4];
    // VK_MENU is alt
    fillKiStruct(ips[0], VK_MENU, false);
    fillKiStruct(ips[1], VK_TAB, false);
    fillKiStruct(ips[2], VK_TAB, true);
    fillKiStruct(ips[3], VK_MENU, true);

    sendKeyboardInputRaw(4, ips);
    delete ips;
}

}