main.py

from kivy.config import Config
from kivymd.app import MDApp
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.core.window import Window

Window.size = (560, 810)
Config.set('kivy', 'keyboard_mode', 'systemanddock')

import matplotlib.pyplot as plt


def calculation_percents(months: int, start_deposit: float, percent: float, monthly_refill: float):
    """
    Calculate compound interest from parameters:
    :param months: input by user number of months
    :param start_deposit:input by user sum of start deposit
    :param percent:input by user year deposit percent
    :param monthly_refill:input by user monthly amount added
    :return: dictionary with all calculation for showing in app
    """
    sum_list = []
    muns_list = []
    add_sum = start_deposit

    for month in range(months):
        month_sum = add_sum * (1 + percent / 12)
        sum_list.append(month_sum)
        add_sum = month_sum + monthly_refill
        muns_list.append(month)
        print(add_sum)

    final_deposit = str(round(add_sum, 2))
    all_add_sum = str(start_deposit + monthly_refill * months)
    get_percents = str(round((float(final_deposit) - (float(all_add_sum))), 2))
    tax = str(round((float(get_percents) * 0.195), 2))
    net_profit = str(round((float(get_percents) - float(tax)), 2))

    return {"final_deposit": final_deposit,
            "get_percents": get_percents,
            "all_add_sum": all_add_sum,
            "tax": tax,
            "net_profit": net_profit,
            "muns_list": muns_list,
            "sum_list": sum_list}


def build_graph(muns_list: list, sum_list: list):
    """
    Build graph from input date
    :param muns_list: returned list of number of month from calculation_percents
    :param sum_list: returned list of monthly increased sum from calculation_percents
    as result save graph in png file
    """
    plt.bar(muns_list, sum_list)
    plt.xlabel('Месяци инвистирования')
    plt.ylabel('Сумма депозита')
    plt.savefig('culc_graph.png')


class StartWindow(Screen):
    """
    Starting window in app
    """
    pass


class MainWindow(Screen):
    """
    Main window in app with input and output aria
    """

    def calculation(self):
        """
        get input data from kv file and convert in number
        then call calculation_percents and return result in main window
        :return:
        """
        try:
            months = int(self.muns_input.text)
            start_deposit = float(self.start_input.text)
            percent = float(self.year_percent_input.text) / 100
            monthly_refill = float(self.add_input.text)
        except:
            months = 1
            start_deposit = 1
            percent = 1
            monthly_refill = 1

        calc = calculation_percents(months, start_deposit, percent, monthly_refill)

        self.final_deposit.text = calc.get('final_deposit')
        self.get_percents.text = calc.get('get_percents')
        self.all_add_sum.text = calc.get('all_add_sum')
        self.tax.text = calc.get('tax')
        self.net_profit.text = calc.get('net_profit')

        build_graph(calc.get('muns_list'), calc.get('sum_list'))
        # image = "culc_graph.png"
        # GraphWindow().graph_img = Image(source=image)

    @staticmethod
    def change_graph():
        """
        reload graph image
        """
        GraphWindow().reload_graph()


class InfoWindow(Screen):
    # TODO add some useful information
    pass


class GraphWindow(Screen):
    """
    window with graph image
    """
    img_graph = "culc_graph.png"

    def reload_graph(self):
        # image = "culc_graph.png"
        # self.graph_img = Image(sourse=image)
        print(self.graph_img.source)
        self.graph_img.reload()


class WindowManager(ScreenManager):
    pass


class MyApp(MDApp):
    """
    main class of working app
    """
    def build(self):
        self.theme_cls.theme_style = 'Light'
        with open("my.kv") as f:
            kv_file = Builder.load_string(f.read())
        return kv_file


app = MyApp()

if __name__ == '__main__':
    app.run()

"""
Box Layout - вертикально ореентированый (виджеты один под другим) и горизонтально ореентированый (виджеты в строку)
Grid Layout - расположение виджетов в сетку
Stack Layout - размещает виджеты в столбик/строку пока они помещаються на екран
Anchor Layout - фиксация виджета в определенном месте
Page Layout - размещение елементов конроля на разных страницах
Float Layout - указание абсолютных координат выджетов
Relative Layout
Scatter Layout - мультитач
"""