try:
    import Xlib.X
    import Xlib.protocol.event
except ImportError:
    pass


class TargetEngine:
    Primary = -1
    All = -3


class EngineAction:

    def __init__(self, target_engine_index):
        self._target_engine_index = target_engine_index

    def execute_on_window(self, extended_controls, xkeyevent, engine_window):
        raise Exception('abstract method')

    def execute(self, extended_controls, xkeyevent):
        if self._target_engine_index == TargetEngine.Primary:
            target_windows = [extended_controls.primary_engine_window]
        elif self._target_engine_index == TargetEngine.All:
            target_windows = extended_controls.engine_windows
        else:
            target_windows = extended_controls.engine_windows_by_target_index.get(
                self._target_engine_index,
                [],
            )
        for target_window in target_windows:
            self.execute_on_window(extended_controls, xkeyevent, target_window)


class SelectGagAction(EngineAction):

    def __init__(self, target_engine_index, factor_x, factor_y):
        super().__init__(
            target_engine_index=target_engine_index,
        )
        self._button = Xlib.X.Button1
        self._factor_x = factor_x
        self._factor_y = factor_y

    def execute_on_window(self, extended_controls, xkeyevent, engine_window):
        engine_geometry = engine_window.get_geometry()
        smaller_dimension = min(engine_geometry.width, engine_geometry.height)
        attr = dict(
            window=engine_window,
            detail=self._button,
            state=xkeyevent.state,
            event_x=int(engine_geometry.width / 2
                        + smaller_dimension * self._factor_x),
            event_y=int(engine_geometry.height / 2
                        + smaller_dimension * self._factor_y),
            # apparently root_x & root_y do not need to correspond with event_x/y.
            # attributes are still required to be set.
            root_x=0,  # xkeyevent.root_x,
            root_y=0,  # xkeyevent.root_y,
            child=xkeyevent.child,
            root=xkeyevent.root,
            time=xkeyevent.time,  # X.CurrentTime
            same_screen=xkeyevent.same_screen,
        )
        if isinstance(xkeyevent, Xlib.protocol.event.KeyPress):
            e = Xlib.protocol.event.ButtonPress(**attr)
        else:
            e = Xlib.protocol.event.ButtonRelease(**attr)
        engine_window.send_event(e)


class RewriteKeyEventAction(EngineAction):

    def __init__(self, target_engine_index, keysym=None):
        super().__init__(
            target_engine_index=target_engine_index,
        )
        self._keysym = keysym

    def execute_on_window(self, extended_controls, xkeyevent, engine_window):
        engine_window.send_event(type(xkeyevent)(
            window=engine_window,
            detail=extended_controls.xdisplay.keysym_to_keycode(self._keysym)
                if self._keysym else xkeyevent.detail,
            state=xkeyevent.state,
            root_x=xkeyevent.root_x,
            root_y=xkeyevent.root_y,
            event_x=xkeyevent.event_x,
            event_y=xkeyevent.event_y,
            child=xkeyevent.child,
            root=xkeyevent.root,
            time=xkeyevent.time,  # X.CurrentTime
            same_screen=xkeyevent.same_screen,
        ))


class ForwardKeyEventAction(RewriteKeyEventAction):

    def __init__(self):
        super().__init__(
            keysym=None,
            target_engine_index=TargetEngine.Primary,
        )


class ToggleExtendedControlsAction:

    def execute(self, extended_controls, xkeyevent):
        if isinstance(xkeyevent, Xlib.protocol.event.KeyPress):
            extended_controls.toggle()