"""
    find and loads the ui objects
"""
import os

from PySide2.QtUiTools      import QUiLoader
from PySide2.QtCore         import QFile, QObject
from PySide2                import QtWidgets
from typing                 import Any

class DynamicLoader(QObject):
    """
    the parent class of all the run time loadable widgets
    """

    canMaximize = True
    isVisible = False
    menu_name = 'Dynamic Loader'

    def __init__(self, location: str):
        super().__init__(None)
        self.location = location
        self.loader = QUiLoader()
        self.__load_ui()
        self._init_loader()
        self._init_widgets()
        self._init_connections()

    def _init_loader(self):
        """
        Virtual method to be implemented in the child class and should be called in order
        Main purpose is to find/create the widgets objects in this method
        :return: None
        """
        raise NotImplementedError()

    def _init_widgets(self):
        """
        Virtual method to be implemented in the child class and should be called in order
        Main purpose is to setup/initialize widgets properties in this method
        :return: None
        """
        raise NotImplementedError()

    def _init_connections(self):
        """
        Virtual method to be implemented in the child class and should be called in order
        Main purpose is to initial the widgets signal/slots connections in this method
        :return: None
        """
        raise NotImplementedError()

    def __load_ui(self):
        """
        loads the ui file of the GUI at run time
        :return: none
        """
        ui_file = QFile(self.location + "/interface.ui")
        ui_file.open(QFile.ReadOnly)
        self.window = self.loader.load(ui_file)
        # assert if the ui file can't be loaded
        error = self.loader.errorString()
        assert len(error) == 0, error
        ui_file.close()

    def show(self):
        """
        shows the main container window
        :return: none
        """
        self.window.show()

    def find_widget(self, child_type, child_name: str):
            """
            finds a child in the loaded ui and returns the reference to it if found
            otherwise quits the application
            :param child_type: (var) type of the child
            :param child_name: (str) name of the child
            :return: (QtWidgets.QWidget) reference to the child
            """
            child = self.window.findChild(child_type, child_name)
            assert child is not None, "child name '{}' with type '{}' can't be found.".format(child_name, child_type)
            return child