/** @file
 *
 * VBoxControl - Guest Additions Utility
 *
 * Copyright (C) 2006-2007 innotek GmbH
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License as published by the Free Software Foundation,
 * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
 * distribution. VirtualBox OSE is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY of any kind.
 */

#include <windows.h>
#include <stdio.h>
#include <stdarg.h>
#include <malloc.h>

void printHelp()
{
    printf("VBoxControl   getvideoacceleration\n"
           "\n"
           "VBoxControl   setvideoacceleration <on|off>\n"
           "\n"
           "VBoxControl   listcustommodes\n"
           "\n"
           "VBoxControl   addcustommode <width> <height> <bpp>\n"
           "\n"
           "VBoxControl   removecustommode <width> <height> <bpp>\n"
           "\n"
           "VBoxControl   setvideomode <width> <height> <bpp> <screen>\n");
}

#if defined(DEBUG) || defined(LOG_ENABLED)
#define dprintf(a) do { int err = GetLastError (); printf a; SetLastError (err); } while (0)
#else
#define dprintf(a) do {} while (0)
#endif /* DEBUG */

LONG (WINAPI * gpfnChangeDisplaySettingsEx)(LPCTSTR lpszDeviceName, LPDEVMODE lpDevMode, HWND hwnd, DWORD dwflags, LPVOID lParam);

static unsigned nextAdjacentRectXP (RECTL *paRects, unsigned nRects, unsigned iRect)
{
    unsigned i;
    for (i = 0; i < nRects; i++)
    {
        if (paRects[iRect].right == paRects[i].left)
        {
            return i;
        }
    }
    return ~0;
}

static unsigned nextAdjacentRectXN (RECTL *paRects, unsigned nRects, unsigned iRect)
{
    unsigned i;
    for (i = 0; i < nRects; i++)
    {
        if (paRects[iRect].left == paRects[i].right)
        {
            return i;
        }
    }
    return ~0;
}

static unsigned nextAdjacentRectYP (RECTL *paRects, unsigned nRects, unsigned iRect)
{
    unsigned i;
    for (i = 0; i < nRects; i++)
    {
        if (paRects[iRect].bottom == paRects[i].top)
        {
            return i;
        }
    }
    return ~0;
}

unsigned nextAdjacentRectYN (RECTL *paRects, unsigned nRects, unsigned iRect)
{
    unsigned i;
    for (i = 0; i < nRects; i++)
    {
        if (paRects[iRect].top == paRects[i].bottom)
        {
            return i;
        }
    }
    return ~0;
}

void resizeRect(RECTL *paRects, unsigned nRects, unsigned iPrimary, unsigned iResized, int NewWidth, int NewHeight)
{
    RECTL *paNewRects = (RECTL *)alloca (sizeof (RECTL) * nRects);
    memcpy (paNewRects, paRects, sizeof (RECTL) * nRects);
    paNewRects[iResized].right += NewWidth - (paNewRects[iResized].right - paNewRects[iResized].left);
    paNewRects[iResized].bottom += NewHeight - (paNewRects[iResized].bottom - paNewRects[iResized].top);
    
    /* Verify all pairs of originally adjacent rectangles for all 4 directions. 
     * If the pair has a "good" delta (that is the first rectangle intersects the second)
     * at a direction and the second rectangle is not primary one (which can not be moved),
     * move the second rectangle to make it adjacent to the first one.
     */
    
    /* X positive. */
    unsigned iRect;
    for (iRect = 0; iRect < nRects; iRect++)
    {
        /* Find the next adjacent original rect in x positive direction. */
        unsigned iNextRect = nextAdjacentRectXP (paRects, nRects, iRect);
        dprintf(("next %d -> %d\n", iRect, iNextRect));
        
        if (iNextRect == ~0 || iNextRect == iPrimary)
        {
            continue;
        }
        
        /* Check whether there is an X intesection between these adjacent rects in the new rectangles
         * and fix the intersection if delta is "good".
         */
        int delta = paNewRects[iRect].right - paNewRects[iNextRect].left;
        
        if (delta > 0)
        {
            dprintf(("XP intersection right %d left %d, diff %d\n",
                     paNewRects[iRect].right, paNewRects[iNextRect].left,
                     delta));
            
            paNewRects[iNextRect].left += delta;
            paNewRects[iNextRect].right += delta;
        }
    }
    
    /* X negative. */
    for (iRect = 0; iRect < nRects; iRect++)
    {
        /* Find the next adjacent original rect in x negative direction. */
        unsigned iNextRect = nextAdjacentRectXN (paRects, nRects, iRect);
        dprintf(("next %d -> %d\n", iRect, iNextRect));
        
        if (iNextRect == ~0 || iNextRect == iPrimary)
        {
            continue;
        }
        
        /* Check whether there is an X intesection between these adjacent rects in the new rectangles
         * and fix the intersection if delta is "good".
         */
        int delta = paNewRects[iRect].left - paNewRects[iNextRect].right;
        
        if (delta < 0)
        {
            dprintf(("XN intersection left %d right %d, diff %d\n",
                     paNewRects[iRect].left, paNewRects[iNextRect].right,
                     delta));
            
            paNewRects[iNextRect].left += delta;
            paNewRects[iNextRect].right += delta;
        }
    }
    
    /* Y positive (in the computer sence, top->down). */
    for (iRect = 0; iRect < nRects; iRect++)
    {
        /* Find the next adjacent original rect in y positive direction. */
        unsigned iNextRect = nextAdjacentRectYP (paRects, nRects, iRect);
        dprintf(("next %d -> %d\n", iRect, iNextRect));
        
        if (iNextRect == ~0 || iNextRect == iPrimary)
        {
            continue;
        }
        
        /* Check whether there is an Y intesection between these adjacent rects in the new rectangles
         * and fix the intersection if delta is "good".
         */
        int delta = paNewRects[iRect].bottom - paNewRects[iNextRect].top;
        
        if (delta > 0)
        {
            dprintf(("YP intersection bottom %d top %d, diff %d\n",
                     paNewRects[iRect].bottom, paNewRects[iNextRect].top,
                     delta));
            
            paNewRects[iNextRect].top += delta;
            paNewRects[iNextRect].bottom += delta;
        }
    }
    
    /* Y negative (in the computer sence, down->top). */
    for (iRect = 0; iRect < nRects; iRect++)
    {
        /* Find the next adjacent original rect in x negative direction. */
        unsigned iNextRect = nextAdjacentRectYN (paRects, nRects, iRect);
        dprintf(("next %d -> %d\n", iRect, iNextRect));
        
        if (iNextRect == ~0 || iNextRect == iPrimary)
        {
            continue;
        }
        
        /* Check whether there is an Y intesection between these adjacent rects in the new rectangles
         * and fix the intersection if delta is "good".
         */
        int delta = paNewRects[iRect].top - paNewRects[iNextRect].bottom;
        
        if (delta < 0)
        {
            dprintf(("YN intersection top %d bottom %d, diff %d\n",
                     paNewRects[iRect].top, paNewRects[iNextRect].bottom,
                     delta));
            
            paNewRects[iNextRect].top += delta;
            paNewRects[iNextRect].bottom += delta;
        }
    }
    
    memcpy (paRects, paNewRects, sizeof (RECTL) * nRects);
    return;
}

/* Returns TRUE to try again. */
static BOOL ResizeDisplayDevice(ULONG Id, DWORD Width, DWORD Height, DWORD BitsPerPixel)
{
    BOOL fModeReset = (Width == 0 && Height == 0 && BitsPerPixel == 0);
    
    DISPLAY_DEVICE DisplayDevice;

    ZeroMemory(&DisplayDevice, sizeof(DisplayDevice));
    DisplayDevice.cb = sizeof(DisplayDevice);
    
    /* Find out how many display devices the system has */
    DWORD NumDevices = 0;
    DWORD i = 0;
    while (EnumDisplayDevices (NULL, i, &DisplayDevice, 0))
    { 
        dprintf(("[%d] %s\n", i, DisplayDevice.DeviceName));

        if (DisplayDevice.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE)
        {
            dprintf(("Found primary device. err %d\n", GetLastError ()));
            NumDevices++;
        }
        else if (!(DisplayDevice.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER))
        {
            
            dprintf(("Found secondary device. err %d\n", GetLastError ()));
            NumDevices++;
        }
        
        ZeroMemory(&DisplayDevice, sizeof(DisplayDevice));
        DisplayDevice.cb = sizeof(DisplayDevice);
        i++;
    }
    
    dprintf(("Found total %d devices. err %d\n", NumDevices, GetLastError ()));
    
    if (NumDevices == 0 || Id >= NumDevices)
    {
        dprintf(("Requested identifier %d is invalid. err %d\n", Id, GetLastError ()));
        return FALSE;
    }
    
    DISPLAY_DEVICE *paDisplayDevices = (DISPLAY_DEVICE *)alloca (sizeof (DISPLAY_DEVICE) * NumDevices);
    DEVMODE *paDeviceModes = (DEVMODE *)alloca (sizeof (DEVMODE) * NumDevices);
    RECTL *paRects = (RECTL *)alloca (sizeof (RECTL) * NumDevices);
    
    /* Fetch information about current devices and modes. */
    DWORD DevNum = 0;
    DWORD DevPrimaryNum = 0;
    
    ZeroMemory(&DisplayDevice, sizeof(DISPLAY_DEVICE));
    DisplayDevice.cb = sizeof(DISPLAY_DEVICE);
    
    i = 0;
    while (EnumDisplayDevices (NULL, i, &DisplayDevice, 0))
    { 
        dprintf(("[%d(%d)] %s\n", i, DevNum, DisplayDevice.DeviceName));
        
        BOOL bFetchDevice = FALSE;

        if (DisplayDevice.StateFlags & DISPLAY_DEVICE_PRIMARY_DEVICE)
        {
            dprintf(("Found primary device. err %d\n", GetLastError ()));
            DevPrimaryNum = DevNum;
            bFetchDevice = TRUE;
        }
        else if (!(DisplayDevice.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER))
        {
            
            dprintf(("Found secondary device. err %d\n", GetLastError ()));
            bFetchDevice = TRUE;
        }
        
        if (bFetchDevice)
        {
            if (DevNum >= NumDevices)
            {
                dprintf(("%d >= %d\n", NumDevices, DevNum));
                return FALSE;
            }
        
            paDisplayDevices[DevNum] = DisplayDevice;
            
            ZeroMemory(&paDeviceModes[DevNum], sizeof(DEVMODE));
            paDeviceModes[DevNum].dmSize = sizeof(DEVMODE);
            if (!EnumDisplaySettings((LPSTR)DisplayDevice.DeviceName,
                 ENUM_REGISTRY_SETTINGS, &paDeviceModes[DevNum]))
            {
                dprintf(("EnumDisplaySettings err %d\n", GetLastError ()));
                return FALSE;
            }
            
            dprintf(("%dx%d at %d,%d\n",
                    paDeviceModes[DevNum].dmPelsWidth,
                    paDeviceModes[DevNum].dmPelsHeight,
                    paDeviceModes[DevNum].dmPosition.x,
                    paDeviceModes[DevNum].dmPosition.y));
                    
            paRects[DevNum].left   = paDeviceModes[DevNum].dmPosition.x;
            paRects[DevNum].top    = paDeviceModes[DevNum].dmPosition.y;
            paRects[DevNum].right  = paDeviceModes[DevNum].dmPosition.x + paDeviceModes[DevNum].dmPelsWidth;
            paRects[DevNum].bottom = paDeviceModes[DevNum].dmPosition.y + paDeviceModes[DevNum].dmPelsHeight;
            DevNum++;
        }
        
        ZeroMemory(&DisplayDevice, sizeof(DISPLAY_DEVICE));
        DisplayDevice.cb = sizeof(DISPLAY_DEVICE);
        i++;
    }
    
    if (Width == 0)
    {
        Width = paRects[Id].right - paRects[Id].left;
    }

    if (Height == 0)
    {
        Height = paRects[Id].bottom - paRects[Id].top;
    }

    /* Check whether a mode reset or a change is requested. */
    if (   !fModeReset
        && paRects[Id].right - paRects[Id].left == Width
        && paRects[Id].bottom - paRects[Id].top == Height
        && paDeviceModes[Id].dmBitsPerPel == BitsPerPixel)
    {
        dprintf(("VBoxDisplayThread : already at desired resolution.\n"));
        return FALSE;
    }

    resizeRect(paRects, NumDevices, DevPrimaryNum, Id, Width, Height);
#ifdef dprintf
    for (i = 0; i < NumDevices; i++)
    {
        dprintf(("[%d]: %d,%d %dx%d\n",
                i, paRects[i].left, paRects[i].top,
                paRects[i].right - paRects[i].left,
                paRects[i].bottom - paRects[i].top));
    }
#endif /* dprintf */
    
    /* Without this, Windows will not ask the miniport for its
     * mode table but uses an internal cache instead.
     */
    DEVMODE tempDevMode;
    ZeroMemory (&tempDevMode, sizeof (tempDevMode));
    tempDevMode.dmSize = sizeof(DEVMODE);
    EnumDisplaySettings(NULL, 0xffffff, &tempDevMode);

    /* Assign the new rectangles to displays. */
    for (i = 0; i < NumDevices; i++)
    {
        paDeviceModes[i].dmPosition.x = paRects[i].left;
        paDeviceModes[i].dmPosition.y = paRects[i].top;
        paDeviceModes[i].dmPelsWidth  = paRects[i].right - paRects[i].left;
        paDeviceModes[i].dmPelsHeight = paRects[i].bottom - paRects[i].top;
        
        paDeviceModes[i].dmFields = DM_POSITION | DM_PELSHEIGHT | DM_PELSWIDTH;
        
        if (   i == Id
            && BitsPerPixel != 0)
        {
            paDeviceModes[i].dmFields |= DM_BITSPERPEL;
            paDeviceModes[i].dmBitsPerPel = BitsPerPixel;
        }
        dprintf(("calling pfnChangeDisplaySettingsEx %x\n", gpfnChangeDisplaySettingsEx));     
        gpfnChangeDisplaySettingsEx((LPSTR)paDisplayDevices[i].DeviceName, 
                 &paDeviceModes[i], NULL, CDS_NORESET | CDS_UPDATEREGISTRY, NULL); 
        dprintf(("ChangeDisplaySettings position err %d\n", GetLastError ()));
    }
    
    /* A second call to ChangeDisplaySettings updates the monitor. */
    LONG status = ChangeDisplaySettings(NULL, 0); 
    dprintf(("ChangeDisplaySettings update status %d\n", status));
    if (status == DISP_CHANGE_SUCCESSFUL || status == DISP_CHANGE_BADMODE)
    {
        /* Successfully set new video mode or our driver can not set the requested mode. Stop trying. */
        return FALSE;
    }

    /* Retry the request. */
    return TRUE;
}

void handleSetVideoMode(int argc, char *argv[])
{
    if (argc != 3 && argc != 4)
    {
        printf("Error: not enough parameters!\n");
        return;
    }

    DWORD xres = atoi(argv[0]);
    DWORD yres = atoi(argv[1]);
    DWORD bpp  = atoi(argv[2]);
    DWORD scr  = 0;

    if (argc == 4)
    {
        scr = atoi(argv[3]);
    }

    HMODULE hUser = GetModuleHandle("USER32");

    if (hUser)
    {
        *(uintptr_t *)&gpfnChangeDisplaySettingsEx = (uintptr_t)GetProcAddress(hUser, "ChangeDisplaySettingsExA");
        dprintf(("VBoxService: pChangeDisplaySettingsEx = %p\n", gpfnChangeDisplaySettingsEx));
        
        if (gpfnChangeDisplaySettingsEx)
        {
            /* The screen index is 0 based in the ResizeDisplayDevice call. */
            scr = scr > 0? scr - 1: 0;
            
            /* Horizontal resolution must be a multiple of 8, round down. */
            xres &= ~0x7;

            ResizeDisplayDevice(scr, xres, yres, bpp);
        }
    }
}

HKEY getVideoKey(bool writable)
{
    HKEY hkeyDeviceMap = 0;
    HKEY hkeyVideo = 0;
    LONG status;

    status = RegOpenKeyExA(HKEY_LOCAL_MACHINE, "HARDWARE\\DEVICEMAP\\VIDEO", 0, KEY_READ, &hkeyDeviceMap);
    if ((status != ERROR_SUCCESS) || !hkeyDeviceMap)
    {
        printf("Error opening video device map registry key!\n");
        return 0;
    }
    char szVideoLocation[256];
    DWORD dwKeyType;
    szVideoLocation[0] = 0;
    DWORD len = sizeof(szVideoLocation);
    status = RegQueryValueExA(hkeyDeviceMap, "\\Device\\Video0", NULL, &dwKeyType, (LPBYTE)szVideoLocation, &len);
    /*
     * This value will start with a weird value: \REGISTRY\Machine
     * Make sure this is true.
     */
    if (   (status == ERROR_SUCCESS)
        && (dwKeyType == REG_SZ)
        && (_strnicmp(szVideoLocation, "\\REGISTRY\\Machine", 17) == 0))
    {
        /* open that branch */
        status = RegOpenKeyExA(HKEY_LOCAL_MACHINE, &szVideoLocation[18], 0, KEY_READ | (writable ? KEY_WRITE : 0), &hkeyVideo);
    }
    else
    {
        printf("Error opening registry key '%s'\n", &szVideoLocation[18]);
    }
    RegCloseKey(hkeyDeviceMap);
    return hkeyVideo;
}

void handleGetVideoAcceleration(int argc, char *argv[])
{
    ULONG status;
    HKEY hkeyVideo = getVideoKey(false);

    if (hkeyVideo)
    {
        /* query the actual value */
        DWORD fAcceleration = 1;
        DWORD len = sizeof(fAcceleration);
        DWORD dwKeyType;
        status = RegQueryValueExA(hkeyVideo, "EnableVideoAccel", NULL, &dwKeyType, (LPBYTE)&fAcceleration, &len);
        if (status != ERROR_SUCCESS)
            printf("Video acceleration: default\n");
        else
            printf("Video acceleration: %s\n", fAcceleration ? "on" : "off");
        RegCloseKey(hkeyVideo);
    }
}

void handleSetVideoAcceleration(int argc, char *argv[])
{
    ULONG status;
    HKEY hkeyVideo;

    /* must have exactly one argument: the new offset */
    if (   (argc != 1)
        || (   strcmp(argv[0], "on")
            && strcmp(argv[0], "off")))
    {
        printf("Error: invalid video acceleration status!\n");
        return;
    }

    hkeyVideo = getVideoKey(true);

    if (hkeyVideo)
    {
        int fAccel = 0;
        if (!strcmp(argv[0], "on"))
            fAccel = 1;
        /* set a new value */
        status = RegSetValueExA(hkeyVideo, "EnableVideoAccel", 0, REG_DWORD, (LPBYTE)&fAccel, sizeof(fAccel));
        if (status != ERROR_SUCCESS)
        {
            printf("Error %d writing video acceleration status!\n", status);
        }
        RegCloseKey(hkeyVideo);
    }
}

#define MAX_CUSTOM_MODES 128

/* the table of custom modes */
struct
{
    DWORD xres;
    DWORD yres;
    DWORD bpp;
} customModes[MAX_CUSTOM_MODES] = {0};

void getCustomModes(HKEY hkeyVideo)
{
    ULONG status;
    int curMode = 0;

    /* null out the table */
    memset(customModes, 0, sizeof(customModes));

    do
    {
        char valueName[20];
        DWORD xres, yres, bpp = 0;
        DWORD dwType;
        DWORD dwLen = sizeof(DWORD);

        sprintf(valueName, "CustomMode%dWidth", curMode);
        status = RegQueryValueExA(hkeyVideo, valueName, NULL, &dwType, (LPBYTE)&xres, &dwLen);
        if (status != ERROR_SUCCESS)
            break;
        sprintf(valueName, "CustomMode%dHeight", curMode);
        status = RegQueryValueExA(hkeyVideo, valueName, NULL, &dwType, (LPBYTE)&yres, &dwLen);
        if (status != ERROR_SUCCESS)
            break;
        sprintf(valueName, "CustomMode%dBPP", curMode);
        status = RegQueryValueExA(hkeyVideo, valueName, NULL, &dwType, (LPBYTE)&bpp, &dwLen);
        if (status != ERROR_SUCCESS)
            break;

        /* check if the mode is OK */
        if (   (xres > (1 << 16))
            && (yres > (1 << 16))
            && (   (bpp != 16)
                || (bpp != 24)
                || (bpp != 32)))
            break;

        /* add mode to table */
        customModes[curMode].xres = xres;
        customModes[curMode].yres = yres;
        customModes[curMode].bpp  = bpp;

        ++curMode;

        if (curMode >= MAX_CUSTOM_MODES)
            break;
    } while(1);
}

void writeCustomModes(HKEY hkeyVideo)
{
    ULONG status;
    int tableIndex = 0;
    int modeIndex = 0;

    /* first remove all values */
    for (int i = 0; i < MAX_CUSTOM_MODES; i++)
    {
        char valueName[20];
        sprintf(valueName, "CustomMode%dWidth", i);
        RegDeleteValueA(hkeyVideo, valueName);
        sprintf(valueName, "CustomMode%dHeight", i);
        RegDeleteValueA(hkeyVideo, valueName);
        sprintf(valueName, "CustomMode%dBPP", i);
        RegDeleteValueA(hkeyVideo, valueName);
    }

    do
    {
        if (tableIndex >= MAX_CUSTOM_MODES)
            break;

        /* is the table entry present? */
        if (   (!customModes[tableIndex].xres)
            || (!customModes[tableIndex].yres)
            || (!customModes[tableIndex].bpp))
        {
            tableIndex++;
            continue;
        }

        printf("writing mode %d (%dx%dx%d)\n", modeIndex, customModes[tableIndex].xres, customModes[tableIndex].yres, customModes[tableIndex].bpp);
        char valueName[20];
        sprintf(valueName, "CustomMode%dWidth", modeIndex);
        status = RegSetValueExA(hkeyVideo, valueName, 0, REG_DWORD, (LPBYTE)&customModes[tableIndex].xres,
                                sizeof(customModes[tableIndex].xres));
        sprintf(valueName, "CustomMode%dHeight", modeIndex);
        RegSetValueExA(hkeyVideo, valueName, 0, REG_DWORD, (LPBYTE)&customModes[tableIndex].yres,
                       sizeof(customModes[tableIndex].yres));
        sprintf(valueName, "CustomMode%dBPP", modeIndex);
        RegSetValueExA(hkeyVideo, valueName, 0, REG_DWORD, (LPBYTE)&customModes[tableIndex].bpp,
                       sizeof(customModes[tableIndex].bpp));

        modeIndex++;
        tableIndex++;

    } while(1);

}

void handleListCustomModes(int argc, char *argv[])
{
    if (argc != 0)
    {
        printf("Error: too many parameters!");
        return;
    }

    HKEY hkeyVideo = getVideoKey(false);

    if (hkeyVideo)
    {
        getCustomModes(hkeyVideo);
        for (int i = 0; i < (sizeof(customModes) / sizeof(customModes[0])); i++)
        {
            if (   !customModes[i].xres
                || !customModes[i].yres
                || !customModes[i].bpp)
                continue;

            printf("Mode: %d x %d x %d\n",
                   customModes[i].xres, customModes[i].yres, customModes[i].bpp);
        }
        RegCloseKey(hkeyVideo);
    }
}

void handleAddCustomMode(int argc, char *argv[])
{
    if (argc != 3)
    {
        printf("Error: not enough parameters!\n");
        return;
    }

    DWORD xres = atoi(argv[0]);
    DWORD yres = atoi(argv[1]);
    DWORD bpp  = atoi(argv[2]);

    /** @todo better check including xres mod 8 = 0! */
    if (   (xres > (1 << 16))
        && (yres > (1 << 16))
        && (   (bpp != 16)
            || (bpp != 24)
            || (bpp != 32)))
    {
        printf("Error: invalid mode specified!\n");
        return;
    }

    HKEY hkeyVideo = getVideoKey(true);

    if (hkeyVideo)
    {
        getCustomModes(hkeyVideo);
        for (int i = 0; i < MAX_CUSTOM_MODES; i++)
        {
            /* item free? */
            if (!customModes[i].xres)
            {
                customModes[i].xres = xres;
                customModes[i].yres = yres;
                customModes[i].bpp  = bpp;
                break;
            }
        }
        writeCustomModes(hkeyVideo);
        RegCloseKey(hkeyVideo);
    }
}

void handleRemoveCustomMode(int argc, char *argv[])
{
    if (argc != 3)
    {
        printf("Error: not enough parameters!\n");
        return;
    }

    DWORD xres = atoi(argv[0]);
    DWORD yres = atoi(argv[1]);
    DWORD bpp  = atoi(argv[2]);

    HKEY hkeyVideo = getVideoKey(true);

    if (hkeyVideo)
    {
        getCustomModes(hkeyVideo);
        for (int i = 0; i < MAX_CUSTOM_MODES; i++)
        {
            /* correct item? */
            if (   (customModes[i].xres == xres)
                && (customModes[i].yres == yres)
                && (customModes[i].bpp  == bpp))
            {
printf("found mode at index %d\n", i);
                memset(&customModes[i], 0, sizeof(customModes[i]));
                break;
            }
        }
        writeCustomModes(hkeyVideo);
        RegCloseKey(hkeyVideo);
    }
}


/**
 * Main function
 */
int main(int argc, char *argv[])
{
    if (argc < 2)
    {
        printHelp();
        return 1;
    }

    /* determine which command */
    if (strcmp(argv[1], "getvideoacceleration") == 0)
    {
        handleGetVideoAcceleration(argc - 2, &argv[2]);
    }
    else if (strcmp(argv[1], "setvideoacceleration") == 0)
    {
        handleSetVideoAcceleration(argc - 2, &argv[2]);
    }
    else if (strcmp(argv[1], "listcustommodes") == 0)
    {
        handleListCustomModes(argc - 2, &argv[2]);
    }
    else if (strcmp(argv[1], "addcustommode") == 0)
    {
        handleAddCustomMode(argc - 2, &argv[2]);
    }
    else if (strcmp(argv[1], "removecustommode") == 0)
    {
        handleRemoveCustomMode(argc - 2, &argv[2]);
    }
    else if (strcmp(argv[1], "setvideomode") == 0)
    {
        handleSetVideoMode(argc - 2, &argv[2]);
    }
    else
    {
        printHelp();
        return 1;
    }

    return 0;
}