import win32con
import sys
from ctypes import *

WNDPROC = WINFUNCTYPE(c_long, c_int, c_uint, c_int, c_int)

NULL            = c_int(0)

WM_PAINT        = win32con.WM_PAINT
WM_DESTROY      = win32con.WM_DESTROY
CS_HREDRAW      = win32con.CS_HREDRAW
CS_VREDRAW      = win32con.CS_VREDRAW
IDI_APPLICATION = win32con.IDI_APPLICATION
IDC_ARROW       = win32con.IDC_ARROW
WHITE_BRUSH     = win32con.WHITE_BRUSH
WS_OVERLAPPEDWINDOW = win32con.WS_OVERLAPPEDWINDOW
CW_USEDEFAULT   = win32con.CW_USEDEFAULT
SW_SHOWNORMAL   = win32con.SW_SHOWNORMAL
SW_SHOW         = win32con.SW_SHOW
SW_SHOWDEFAULT  = win32con.SW_SHOWDEFAULT

GetModuleHandle = windll.kernel32.GetModuleHandleA
BeginPaint      = windll.user32.BeginPaint
EndPaint        = windll.user32.EndPaint
PostQuitMessage = windll.user32.PostQuitMessage
DefWindowProc   = windll.user32.DefWindowProcA
CreateWindowEx  = windll.user32.CreateWindowExA
CreateWindowEx.argtypes = [c_int, c_char_p, c_char_p, c_int, c_int, c_int, c_int, c_int, c_int, c_int, c_int, c_int]
LoadIcon        = windll.user32.LoadIconA
LoadCursor      = windll.user32.LoadCursorA
RegisterClass   = windll.user32.RegisterClassA
ShowWindow      = windll.user32.ShowWindow
UpdateWindow    = windll.user32.UpdateWindow
GetMessage      = windll.user32.GetMessageA
TranslateMessage = windll.user32.TranslateMessage
DispatchMessage = windll.user32.DispatchMessageA
TextOut         = windll.gdi32.TextOutA
GetStockObject  = windll.gdi32.GetStockObject

class POINT(Structure):
    _fields_ = [('x', c_long),
                ('y', c_long)]
    
class MSG(Structure):
    _fields_ = [('hwnd', c_int),
                ('message', c_uint),
                ('wParam', c_int),
                ('lParam', c_int),
                ('time', c_int),
                ('pt', POINT)]

class WNDCLASS(Structure):
    _fields_ = [('style', c_uint),
                ('lpfnWndProc', WNDPROC),
                ('cbClsExtra', c_int),
                ('cbWndExtra', c_int),
                ('hInstance', c_int),
                ('hIcon', c_int),
                ('hCursor', c_int),
                ('hbrBackground', c_int),
                ('lpszMenuName', c_char_p),
                ('lpszClassName', c_char_p)]

class RECT(Structure):
    _fields_ = [('left', c_long),
                ('top', c_long),
                ('right', c_long),
                ('bottom', c_long)]

class PAINTSTRUCT(Structure):
    _fields_ = [('hdc', c_int),
                ('fErase', c_int),
                ('rcPaint', RECT),
                ('fRestore', c_int),
                ('fIncUpdate', c_int),
                ('rgbReserved', c_char * 32)]

def WndProc(hwnd, message, wParam, lParam):
    strMessage = "Hello, Win32 GUI(Python) World!"
    if message == WM_PAINT:
        ps = PAINTSTRUCT()
        hdc = BeginPaint( hwnd, byref(ps) )
        TextOut( hdc, 0, 0, strMessage, len(strMessage) )
        EndPaint( hwnd, byref(ps) )
        return 0
    elif message == WM_DESTROY:
        PostQuitMessage(0)
        return 0

    return DefWindowProc(hwnd, message, wParam, lParam)

def WinMain():
    wndclass               = WNDCLASS()
    wndclass.style         = CS_HREDRAW | CS_VREDRAW
    wndclass.lpfnWndProc   = WNDPROC(WndProc)
    wndclass.cbClsExtra    = 0
    wndclass.cbWndExtra    = 0
    wndclass.hInstance     = GetModuleHandle(0)
    wndclass.hIcon         = LoadIcon(0, IDI_APPLICATION)
    wndclass.hCursor       = LoadCursor(0, IDC_ARROW)
    wndclass.hbrBackground = GetStockObject(WHITE_BRUSH)
    wndclass.lpszMenuName  = 0
    wndclass.lpszClassName = "helloWindow"
    
    RegisterClass(byref(wndclass))

    hwnd = CreateWindowEx(
        0,
        wndclass.lpszClassName,
        "Hello, World!",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        640,
        480,
        0,
        0,
        wndclass.hInstance,
        0)

    ShowWindow(hwnd, SW_SHOWDEFAULT)
    UpdateWindow(hwnd)

    msg = MSG()
    pMsg = pointer(msg)
    
    while GetMessage( pMsg, NULL, 0, 0 ) != 0:
        TranslateMessage(pMsg)
        DispatchMessage(pMsg)

    return msg.wParam

if __name__=='__main__':
    sys.exit(WinMain())