WIP hexchat script that hooks its WndProc to listen to hibernate and wakeup messages

power.py

import ctypes
from ctypes import byref, c_int, c_long, c_int64, addressof, WINFUNCTYPE
from ctypes.wintypes import (
    HWND, DWORD, LPARAM, BOOL, WPARAM, LPDWORD, UINT, HINSTANCE, HHOOK
)
import os

# import hexchat

# script metadata
__module_name__ = "Power"
__module_version__ = "0.1.0"
__module_description__ = "Disconnect and reconnect all servers when Windows hibernates or resumes."


# ctypes aliases
NULL = None
FALSE = 0
TRUE = 1
LRESULT = c_long
LONG_PTR = c_int64  # (c_int32 on 32-bit arch/proc)


class CWPSTRUCT(ctypes.Structure):  # noqa
    _fields_ = [
        ('lParam', LPARAM),
        ('wParam', WPARAM),
        ('message', UINT),
        ('hwnd', HWND),
    ]

# function types for callbacks
# https://msdn.microsoft.com/en-us/library/windows/desktop/ms633498(v=vs.85).aspx
WNDENUMPROC = WINFUNCTYPE(BOOL, HWND, LPARAM)  # EnumWindowsProc
# WndProc = WINFUNCTYPE(c_int, HWND, c_int, WPARAM, LPARAM)
# https://msdn.microsoft.com/en-us/library/windows/desktop/ms644975%28v=vs.85%29.aspx
HOOKPROC = WINFUNCTYPE(LRESULT, c_int, WPARAM, LPARAM)
WNDPROC = WINFUNCTYPE(LRESULT, HWND, UINT, WPARAM, LPARAM)

user32 = ctypes.windll.user32
kernel32 = ctypes.windll.kernel32

# Win32API functions
# CallWindowProc = user32.CallWindowProcW

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms644974%28v=vs.85%29.aspx
CallNextHookEx = user32.CallNextHookEx
CallNextHookEx.argtypes = (HHOOK, c_int, WPARAM, LPARAM)
CallNextHookEx.restype = LRESULT

CallWindowProc = user32.CallWindowProcW
CallWindowProc.argtypes = (WNDPROC, HWND, UINT, WPARAM, LPARAM)
CallWindowProc.restype = LRESULT

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms633497(v=vs.85).aspx
EnumWindows = user32.EnumWindows
EnumWindows.argtypes = (WNDENUMPROC, LPARAM)
EnumWindows.restype = BOOL

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms683183%28v=vs.85%29.aspx
GetCurrentThreadId = kernel32.GetCurrentThreadId
GetCurrentThreadId.argtypes = ()
GetCurrentThreadId.restype = DWORD

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms633515%28v=vs.85%29.aspx
GetWindow = user32.GetWindow
GetWindow.argtypes = (HWND, UINT)
GetWindow.restype = (HWND)

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms633585%28v=vs.85%29.aspx
GetWindowLongPtr = user32.GetWindowLongPtrW
GetWindowLongPtr.argtypes = (HWND, c_int)
GetWindowLongPtr.restype = LONG_PTR

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms633522(v=vs.85).aspx
GetWindowThreadProcessId = user32.GetWindowThreadProcessId
GetWindowThreadProcessId.argtypes = (HWND, LPDWORD)
GetWindowThreadProcessId.restype = DWORD

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms633530(v=vs.85).aspx
IsWindowVisible = user32.IsWindowVisible
IsWindowVisible.argtypes = (HWND,)
IsWindowVisible.restype = BOOL

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms644898%28v=vs.85%29.aspx
SetWindowLongPtr = user32.SetWindowLongPtrW
SetWindowLongPtr.argtypes = (HWND, c_int, LONG_PTR)
SetWindowLongPtr.restype = LONG_PTR

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms644990%28v=vs.85%29.aspx
SetWindowsHookEx = user32.SetWindowsHookExW
SetWindowsHookEx.argtypes = (c_int, HOOKPROC, HINSTANCE, DWORD)
SetWindowsHookEx.restype = HHOOK

# https://msdn.microsoft.com/en-us/library/windows/desktop/ms644993%28v=vs.85%29.aspx
UnhookWindowsHookEx = user32.UnhookWindowsHookEx
UnhookWindowsHookEx.argtypes = (HHOOK,)
UnhookWindowsHookEx.restype = BOOL

# Win32API constants
GWLP_WNDPROC = -4
GW_OWNER = 4
WH_GETMESSAGE = 3
WH_CALLWNDPROC = 4


def get_main_window_handle(pid):
    """Get a process's main window handle.

    Algorithm loosely based on http://stackoverflow.com/a/21767578.
    """
    handle = None

    @WNDENUMPROC
    def enum_windows_proc(hwnd, lparam):
        nonlocal handle
        wnd_pid = DWORD()
        GetWindowThreadProcessId(hwnd, byref(wnd_pid))
        if pid == wnd_pid.value:
            # print("hwnd:", hwnd)
            # print("owner:", GetWindow(hwnd, GW_OWNER))
            if GetWindow(hwnd, GW_OWNER) is None and IsWindowVisible(hwnd):
                # print("visible")
                handle = hwnd
                return FALSE  # stop enumeration
        return TRUE

    EnumWindows(enum_windows_proc, 0)
    return handle


@HOOKPROC
def call_wnd_proc(ncode, wparam, lparam):
    msg = CWPSTRUCT(lparam)  # TODO do this properly
    hexchat.prnt(ncode, wparam, msg.message, msg.wParam, msg.lParam)
    # if msg.message == WM_POWERBROADCAST:
    #     if msg.wParam == PBT_APMSUSPEND:
    #         pass
    #     elif msg.wParam == PBT_APMRESUMEAUTOMATIC:
    #         pass
    return CallNextHookEx(None, ncode, wparam, lparam)


old_wnd_proc = None


@WNDPROC
def wnd_proc(hwnd, msg, wparam, lparam):
    print(msg, wparam, lparam)
    # if msg == WM_POWERBROADCAST:
    #     if wparam== PBT_APMSUSPEND:
    #         pass
    #     elif wparam == PBT_APMRESUMEAUTOMATIC:
    #         pass
    return CallWindowProc(old_wnd_proc, hwnd, msg, wparam, lparam)


def main():
    global old_wnd_proc

    hc_pid = os.getpid()  # 2804
    hwnd = get_main_window_handle(hc_pid)
    # hwnd = hexchat.get_info("win_ptr")  # fixed on 2016-02-18
    print("hwnd", hwnd)

    old_wnd_proc = GetWindowLongPtr(hwnd, GWLP_WNDPROC)
    if not old_wnd_proc:
        print("cannot get old WndProc")
        return
    print("old_wnd_proc", old_wnd_proc)

    print("wnd_proc", wnd_proc)
    print("addr", ctypes.addressof(wnd_proc))
    result = SetWindowLongPtr(hwnd, GWLP_WNDPROC, addressof(wnd_proc))
    if not result:
        print("cannot set new WndProc")
        return

    # hhook = SetWindowsHookEx(WH_CALLWNDPROC, call_wnd_proc, None, GetCurrentThreadId())
    # if not hhook:
    #     print("error registering hook")
    #     return

    def unload_cb(_):
        # UnhookWindowsHookEx(hhook)
        SetWindowLongPtr(hwnd, GWLP_WNDPROC, old_wnd_proc)
        print(__module_name__, __module_version__, "unloaded")

    hexchat.hook_unload(unload_cb)
    print(__module_name__, __module_version__, "loaded")


if __name__ == '__main__':
    main()