# Required for the window title name
from ctypes import wintypes, windll, create_unicode_buffer, WINFUNCTYPE
from typing import Optional, Dict

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

# 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], queue):
        self.WinEventProc = WinEventProcType(self.callback)
        self.mapping = mapping
        self.queue = queue

    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

        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()
        if title == "":
            return
        for pattern, code in self.mapping.items():
            if pattern == "default":
                continue
            if pattern in title:
                self.queue.put ( (code, None) )
                return
        print("Matching '%s' to default" % title)
        # Get the default mapping to apply if there is any defined
        default = self.mapping.get("default", None)
        if default is not None:
            self.queue.put ( (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)