Rough implemtation of the install button of fontview

gistfile1.c

static LRESULT
MainWnd_OnInstall(HWND hwnd)
{
  DWORD fontExists;
	HKEY hKey;
	LPWSTR subKey = L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Fonts";
	WCHAR szDestDir[256];

	/* First, we have to find out if the font still exists. */
	fontExists = GetFileAttributesW(g_fileName);
	if (fontExists != 0xFFFFFFFF) /* If the file does not exist */
	{
		ErrorMsgBox(0, IDS_ERROR, IDS_ERROR_NOFONT, g_fileName);
		return -1;
	}
	// Prepare the Registry Key
	LONG res = RegOpenKeyExW(HKEY_LOCAL_MACHINE, subKey, 0, KEY_ALL_ACCESS, &hKey);
	
	if(res != ERROR_SUCCESS)
	{
		MessageBoxW(hwnd, L"There is a corruption in the Registry.", L"Registry Fault", MB_OK);
		RegCloseKey(hKey);
		return -1;
	}

/* 
Prepare the final directory string
*/
	
	WCHAR filename[256];
	wcscpy(filename, g_fileName);
	UINT i;
	for(i=wcslen(filename);;i--)
	{
		if(filename[i]==L'\\')
		{
			i++;
			break;
		}
	}
	LPWSTR fileExt;
	UINT j;
	for(j=i;j<=wcslen(filename);j++)
	{
		wcscat(fileExt,(LPWSTR)&filename[j]);
	};
	/* Or Maybe \\WINDOWS\\Fonts ?*/
	swprintf(szDestDir, L"%%windir%%\\Fonts\\%s", fileExt);
    
	// Check if already exists. 
	DWORD exists = GetFileAttributesW(szDestDir);
	if (exists == 0xFFFFFFFF)
	{
		//To Register if the value is missing?
		MessageBoxW(hwnd,L"This font is already installed!", L"Already Installed", MB_OK);
		RegCloseKey(hKey);
		return 0;
	}
    
	/* Copy the file */
	if(!CopyFileW(filename, szDestDir, TRUE))
	{
		MessageBoxW(hwnd,L"Error with copying the font file.", L"File Error", MB_OK);
		RegCloseKey(hKey);
		return -1;
	}
		
	/* Register The Font */
	res = RegSetValueExW(hKey, g_ExtLogFontW.elfFullName, 0, REG_SZ, (LPBYTE)fileExt, wcslen(fileExt)+1);
	if(res != ERROR_SUCCESS)
	{
		MessageBoxW(hwnd, L"There is a corruption in the Registry.", L"Registry Fault", MB_OK);
		RegCloseKey(hKey);
		return -1;
	}
    
	/* if all of this goes correctly, message the user about success */
	
	MessageBox(hwnd, L"Font Installation Completed.", L"Success", MB_OK);
	
	// And to get rid of the below!
	//MessageBox(hwnd, TEXT("This function is unimplemented"), TEXT("Unimplemented"), MB_OK);
	// Close the key
	RegCloseKey(hKey);

	return 0;
}