from ctypes import wintypes, windll, create_unicode_buffer, WINFUNCTYPE
from typing import Optional, Dict
import sys

from zope import interface
from interfaces import desktopEvent
import win32api
import win32gui
import win32con
from zope import component
from interfaces.message import IMessage, Debug
from consumer import Mapping

# This code tries to hook the Focus changes events with the callback method.

# The types of events we want to listen for, and the names we'll use for
# them in the log output. Pick from
# http://msdn.microsoft.com/en-us/library/windows/desktop/dd318066(v=vs.85).aspx
WINEVENT_OUTOFCONTEXT = 0x0000

eventTypes = {
    #win32con.EVENT_SYSTEM_FOREGROUND: "Foreground",
    win32con.EVENT_OBJECT_FOCUS: "Focus",
    win32con.EVENT_OBJECT_NAMECHANGE: "NameChange",
    win32con.EVENT_OBJECT_SHOW: "Show",
    #win32con.EVENT_SYSTEM_DIALOGSTART: "Dialog",
    #win32con.EVENT_SYSTEM_CAPTURESTART: "Capture",
    #win32con.EVENT_SYSTEM_MINIMIZEEND: "UnMinimize"
}

WinEventProcType = WINFUNCTYPE(
    None,
    wintypes.HANDLE,
    wintypes.DWORD,
    wintypes.HWND,
    wintypes.LONG,
    wintypes.LONG,
    wintypes.DWORD,
    wintypes.DWORD
)

def setHook(WinEventProc, eventType):
    """ Register the hook foo being notified when the window change
    """
    return windll.user32.SetWinEventHook(
        eventType,
        eventType,
        0,
        WinEventProc,
        0,
        0,
        WINEVENT_OUTOFCONTEXT
    )

@interface.implementer(desktopEvent.IDesktop)
class Listener(object):

    def __init__(self, mapping: Dict[str, str]):
        self.WinEventProc = WinEventProcType(self.callback)
        self.mapping = mapping

    def getForegroundWindowTitle(self) -> Optional[str]:
        """ Get the window title name.
            Example found from https://stackoverflow.com/a/58355052
            See the function in the winuser librarry :
            https://learn.microsoft.com/en-us/windows/win32/api/winuser/
        """
        hWnd = windll.user32.GetForegroundWindow()
        length = windll.user32.GetWindowTextLengthW(hWnd)
        buf = create_unicode_buffer(length + 1)
        windll.user32.GetWindowTextW(hWnd, buf, length + 1)

        # 1-liner alternative: return buf.value if buf.value else None
        if buf.value:
            return buf.value
        else:
            return None


    def callback(self, hWinEventHook, event, hwnd, idObject, idChild, dwEventThread,
             dwmsEventTime) -> None:

        if hwnd is None:
            return
        match_event = event in (win32con.EVENT_OBJECT_FOCUS,
                                win32con.EVENT_OBJECT_NAMECHANGE)
        if not match_event:
            return

        # Loop until we found the main window
        parent = windll.user32.GetParent(hwnd)
        while parent != 0:
            hwnd = parent
            parent = windll.user32.GetParent(hwnd)

        is_foreground = (hwnd == windll.user32.GetForegroundWindow())
        if not is_foreground:
            return

        length = windll.user32.GetWindowTextLengthW(hwnd)
        title = create_unicode_buffer(length + 1)
        windll.user32.GetWindowTextW(hwnd, title, length + 1)
        if title.value is None:
            return
        title = str(title.value).lower().strip()
        if title == "":
            return

        for pattern, code in self.mapping.items():
            if pattern == "default":
                continue
            if pattern in title:
                for key in code.keys():
                    print(f"Mapping '{title}' to {key}")
                component.handle(Mapping((code, None)))
                return
        # Get the default mapping to apply if there is any defined
        # This only applies when the window raising the event is the main
        # window
        print(f"Mapping '{title}' to default")
        component.handle(Mapping(("default", None)))

    def start(self) -> None:
        self.hookIDs = [setHook(self.WinEventProc, et) for et in eventTypes.keys()]
        if not any(self.hookIDs):
            print('SetWinEventHook failed')
            sys.exit(1)

    def stop(self) -> None:
        for hook in self.hookIDs:
            windll.user32.UnhookWinEvent(hook)