#!/usr/bin/python

import sys

try:
    from gi.repository import Gtk
except ImportError:
    print('Cannot Import Gtk')
    sys.exit(1)


class GUI():
    # Initialize GUI
    def __init__(self):
        # Build from .glade file
        self.builder = Gtk.Builder()
        self.builder.add_from_file('CalculatorGUI.glade')

        # Create and connect signals
        signalHandler = {
        'on_main_window_destroy': Gtk.main_quit,
        'on_button_quit_clicked': self.on_button_quit_clicked,
        'on_button_about_clicked': self.on_button_about_clicked,
        'on_button_add_clicked': self.on_button_add_clicked,
        'about_response':self.about_response
        }
        self.builder.connect_signals(signalHandler)

        # Create main window object.
        self.main_window = self.builder.get_object('main_window')

        # Create tags to entries for easy acces
        self.first_number = self.builder.get_object('entry_first_number')
        self.second_number = self.builder.get_object('entry_second_number')
        self.result_label = self.builder.get_object('label_result')
        self.image_warning = self.builder.get_object('image_warning')
        self.label_warning = self.builder.get_object('label_warning')
        self.about_dialog = self.builder.get_object('aboutdialog')

    # Confirm and exit when Quit button is clicked.
    def on_button_quit_clicked(self, widget):
        confirmation_dialog = Gtk.MessageDialog(parent = None,
                                                flags = Gtk.DialogFlags.DESTROY_WITH_PARENT,
                                                type = Gtk.MessageType.QUESTION,
                                                buttons = Gtk.ButtonsType.YES_NO,
                                                message_format =
                                                'Are you sure you want to quit?')
        print('Quit confirmation dialog is running.')
        confirmation_response = confirmation_dialog.run()
        if confirmation_response == Gtk.ResponseType.YES:
            print('You have clicked on YES, quiting..')
            Gtk.main_quit()
        elif confirmation_response == Gtk.ResponseType.NO:
            print('You have clicked on NO')
        confirmation_dialog.destroy()
        print('Quit confirmation dialog is destroyed.')

    # Show About dialog when button is clicked.
    def on_button_about_clicked(self, widget):
        self.about_dialog.present()
        print('About dialog opened.')

    # About dialog "response" signal.
    def about_response(self, widget, response_id, user_data=None):
        # self.about_dialog.destroy()
        print(widget, response_id, user_data)
        print('About dialog closed.')

    # Perform addition when button is clicked.
    def on_button_add_clicked(self, widget):
        print('Adding two numbers..')
        try:
            first_number = float(self.first_number.get_text())
            second_number = float(self.second_number.get_text())
            result = first_number + second_number
            print('First number is: {0}. Second Number is: {1}.\nResult is: {2}.'
                    . format(first_number, second_number, result))
            self.result_label.set_text('{:.10g}'.format(result))
            self.image_warning.hide()
            self.label_warning.hide()
        except ValueError:
            print('Could not convert strings to integers in entries.')
            self.label_warning.set_text('Could not convert strings to integers in entries.')
            self.image_warning.show()
            self.label_warning.show()
        except:
            print('Could not do the addition; ' + str(sys.exc_info()[1]))
            self.label_warning.set_text('Could not do the addition.')
            self.image_warning.show()
            self.label_warning.show()



# Main function
def main():
    myGUI = GUI()
    myGUI.main_window.show_all()

    Gtk.main()

    print ('Program Finished!')

# If the program is not imported as a module, then run.
if __name__ == '__main__':
    main()