_WIN32_CLIENT_RELEASES = {
    (5, 0): "2000",
    (5, 1): "XP",
    # Strictly, 5.2 client is XP 64-bit, but platform.py historically
    # has always called it 2003 Server
    (5, 2): "2003Server",
    (5, None): "post2003",
    
    (6, 0): "Vista",
    (6, 1): "7",
    (6, 2): "8",
    (6, 3): "8.1",
    (6, None): "post8.1",
    
    (10, 0): "10",
    (10, None): "post10",
}

# Server release name lookup will default to client names if necessary
_WIN32_SERVER_RELEASES = {
    (5, 2): "2003Server",
    
    (6, 0): "2008Server",
    (6, 1): "2008ServerR2",
    (6, 2): "2012Server",
    (6, 3): "2012ServerR2",
    (6, None): "post2012ServerR2",
}

def _get_real_winver(maj, min, build):
    if maj < 6 or (maj == 6 and min < 2):
        return maj, min, build
    
    from ctypes import (c_buffer, POINTER, byref, create_unicode_buffer,
                        Structure, WinDLL)
    from ctypes.wintypes import DWORD, HANDLE
    
    class VS_FIXEDFILEINFO(Structure):
        _fields_ = [
            ("dwSignature", DWORD),
            ("dwStrucVersion", DWORD),
            ("dwFileVersionMS", DWORD),
            ("dwFileVersionLS", DWORD),
            ("dwProductVersionMS", DWORD),
            ("dwProductVersionLS", DWORD),
            ("dwFileFlagsMask", DWORD),
            ("dwFileFlags", DWORD),
            ("dwFileOS", DWORD),
            ("dwFileType", DWORD),
            ("dwFileSubtype", DWORD),
            ("dwFileDateMS", DWORD),
            ("dwFileDateLS", DWORD),
        ]

    kernel32 = WinDLL('kernel32')
    version = WinDLL('version')

    # We will immediately double the length up to MAX_PATH, but the
    # path may be longer, so we retry until the returned string is
    # shorter than our buffer.
    name_len = actual_len = 130
    while actual_len == name_len:
        name_len *= 2
        name = create_unicode_buffer(name_len)
        actual_len = kernel32.GetModuleFileNameW(HANDLE(kernel32._handle),
                                                 name, len(name))
        if not actual_len:
            return maj, min, build

    size = version.GetFileVersionInfoSizeW(name, None)
    if not size:
        return maj, min, build

    ver_block = c_buffer(size)
    if (not version.GetFileVersionInfoW(name, None, size, ver_block) or
        not ver_block):
        return maj, min, build

    pvi = POINTER(VS_FIXEDFILEINFO)()
    if not version.VerQueryValueW(ver_block, "\\", byref(pvi), byref(DWORD())):
        return maj, min, build

    maj = pvi.contents.dwProductVersionMS >> 16
    min = pvi.contents.dwProductVersionMS & 0xFFFF
    build = pvi.contents.dwProductVersionLS >> 16
    
    return maj, min, build

def win32_ver(release='', version='', csd='', ptype=''):
    from sys import getwindowsversion
    try:
        from winreg import OpenKeyEx, QueryValueEx, CloseKey, HKEY_LOCAL_MACHINE
    except ImportError:
        from _winreg import OpenKeyEx, QueryValueEx, CloseKey, HKEY_LOCAL_MACHINE
    
    winver = getwindowsversion()
    maj, min, build = _get_real_winver(*winver[:3])
    version = '{0}.{1}.{2}'.format(maj, min, build)
    
    release = (_WIN32_CLIENT_RELEASES.get((maj, min)) or
               _WIN32_CLIENT_RELEASES.get((maj, None)) or
               release)
    
    # getwindowsversion() reflect the compatibility mode Python is
    # running under, and so the service pack value is only going to be
    # valid if the versions match.
    if winver[:2] == (maj, min):
        try:
            csd = 'SP{}'.format(winver.service_pack_major)
        except AttributeError:
            if csd[:13] == 'Service Pack ':
                csd = 'SP' + csd[13:]
    
    # VER_NT_SERVER = 3
    if getattr(winver, 'product_type', None) == 3:
        release = (_WIN32_SERVER_RELEASES.get((maj, min)) or
                   _WIN32_SERVER_RELEASES.get((maj, None)) or
                   release)

    key = None
    try:
        key = OpenKeyEx(HKEY_LOCAL_MACHINE,
                        r'SOFTWARE\Microsoft\Windows NT\CurrentVersion')
        ptype = QueryValueEx(key, 'CurrentType')[0]
    except:
        pass
    finally:
        if key:
            CloseKey(key)

    return release, version, csd, ptype

print(win32_ver())