main.py

from kivy.lang import Builder
from kivy.metrics import dp
from kivy.core.text import LabelBase
from kivymd.app import MDApp
from kivymd.uix.widget import MDWidget
from kivymd.uix.dialog import MDDialog
from kivymd.uix.button import MDFlatButton
from kivymd.uix.menu import MDDropdownMenu
from kivymd.uix.transition import MDSlideTransition
from kivymd.toast import toast
from json import dump,load
from pylatexenc.latex2text import LatexNodes2Text as LT
import re

# importing font for math expressions
LabelBase.register(
    name="DejaVu",
    fn_regular="DejaVuSansCondensed.ttf"
)

# Main Class
class MainBaseApp(MDApp):
    # method to make dropdown menus
    def make_dropdown(self,names,funcs,caller):
        items = [{"viewclass":"OneLineListItem","text": i,"halign": "center","height": dp(54),"on_release": j}for i,j in zip(names,funcs)]
        menu = MDDropdownMenu(
            caller=caller,
            items=items,
            width_mult=2.5
        )
        return menu
    # method to switch themes
## TODO: add this (full) to settings screen
    def decide_colors(self,style):
        if style == "Dark":
            res = ["Dark","DeepOrange","#070707","#bcbcbc","#a3a3a380","#f0f0f080"]
        else:
            res = ["Light","Green","#e8e8e8","#303030","#363636","#07070780"]
        return res
    # method to reset converter screens
    # (is needed)
    # this may go on settings as :
    #Switch: Keep result from different conversions
    def init_convers(self,which):
        self.current = self.convs[which]
        a = [i for i in self.current.keys()]
        self.screen.ids.first.text = a[0]
        self.screen.ids.second.text = a[0]
        self.screen.ids.input_label.text = "0"
        self.screen.ids.output_label.text = "0"

        self.first_menu = self.make_dropdown(
            self.current.keys(),
            [lambda x=i:self.change_label(x,1)for i in self.current],
            self.screen.ids.first
        )
        self.second_menu = self.make_dropdown(
            self.current.keys(),
            [lambda x=i:self.change_label(x,0)for i in self.current],
            self.screen.ids.second
        )
    # initializing the class
    def __init__(self, **kwargs):
        # check the main buttons layout
        self.main_switched = False
        # latex engine
        self.lt = LT()
        # setting up parent class (is needed)
        super().__init__(**kwargs)
        # default theme (the only point responsible for theming)
        self.colors = self.decide_colors("Darky")
        # loading the file responsible for the hierarchy of widgets
        self.screen = Builder.load_file("main.kv")
        self.theme_cls.theme_style = self.colors[0]
        self.theme_cls.primary_palette = self.colors[1]
        # loading conversion coefficients
        with open('conversions.json','r') as f:
            self.convs = load(f)
        self.exit_dialog = None
        # default screen (changable)
        self.curr_main = "main_scr"
        self.exit_menu = self.make_dropdown(
            ["Cilësimet","Rreth","Dil"],
            [
                lambda x="Settings":self.menu_callback(x),
                lambda x="About":self.menu_callback(x),
                lambda x="Quit":self.menu_callback(x)
            ],
            self.screen.ids.menu_caller)

    # this is needed (builds up the whole program)
    def build(self):
        return self.screen
    # method to response `exit_menu` events
    def menu_callback(self,call):
        if call=="Settings":
            self.root.ids.my_toolbar.opacity = 0
            self.root.ids.my_toolbar.disabled = True
            self.change_screen("settings_scr")
        if call=="About":
            self.root.ids.my_toolbar.opacity = 0
            self.root.ids.my_toolbar.disabled = True
            self.change_screen("about_scr")
        if call=="Quit":
            self.dialog()
        self.exit_menu.dismiss()
    # method to change screens (prime ones)
    # also applying effects
    def change_screen(self,screen):
        color = self.colors[4]
        current = self.root.ids.manager.current
        if screen == "main_scr":
            self.root.ids.main_btn.icon_color = self.theme_cls.primary_color
            self.root.ids.conv_btn.icon_color = color
            self.root.ids.curr_btn.icon_color = color
            if current=="about_scr":
                self.root.ids.my_toolbar.opacity = 1
                self.root.ids.my_toolbar.disabled = False
            if current=="settings_scr":
                self.root.ids.my_toolbar.opacity = 1
                self.root.ids.my_toolbar.disabled = False
        elif screen == "converter_scr":
            self.root.ids.main_btn.icon_color = color
            self.root.ids.conv_btn.icon_color = self.theme_cls.primary_color
            self.root.ids.curr_btn.icon_color = color
        elif screen == "currency_scr":
            self.root.ids.main_btn.icon_color = color
            self.root.ids.conv_btn.icon_color = color
            self.root.ids.curr_btn.icon_color = self.theme_cls.primary_color
        self.root.ids.manager.current = screen
    # this also changes screens, but is used only for converters
    # TODO: add statements to change on unpure conversions
    def change_screen1(self,t):
        if t=="bases":
            self.root.ids.manager.current = "bases-convy"
            self.screen.ids.bases_first.text = "dec"
            self.screen.ids.bases_second.text = "dec"
            self.bases_first_menu = self.make_dropdown(
            ["Binar","Oktal","Decimal","Hexadecimal"],
            [lambda x=i:self.change_label(x,1)for i in ["bin","oct","dec","hex"]],
            self.screen.ids.bases_first
        )
            self.bases_second_menu = self.make_dropdown(
            ["Binar","Oktal","Decimal","Hexadecimal"],
            [lambda x=i:self.change_label(x,0)for i in ["bin","oct","dec","hex"]],
            self.screen.ids.bases_second
        )
        else:
            self.init_convers(t)
            self.root.ids.manager.current = "convy"
    # this shows a toast
    # TODO: fond a use for it
    def show_toast(self,text):
        toast(text)
    # inserting values from buttons to input labels
    def insert_value(self,val):
        d = self.screen.ids.manager.current
        print(d,val)
        if d=="main_scr":
            c = self.root.ids.the_input.text
            if c=='0' and val!='.':
                self.root.ids.the_input.text = val
            else:
                z = ([1,0][len(i)>2]for i in (i.split('.')for i in re.split('[^0-9.-]',c)))
                if not all(z):
                    return
                self.root.ids.the_input.text = c+val
        elif d=="convy":
            c = self.root.ids.input_label.text
            if c=='0' and val!='.':
                self.root.ids.input_label.text = val
            else:
                z = ([1,0][len(i)>2]for i in (i.split('.')for i in re.split('[^0-9.-]',c)))
                if not all(z):
                    return
                self.root.ids.input_label.text = c+val
        elif d=="bases-convy":
            c = self.root.ids.bases_input_label.text
            if c == "0":
                self.root.ids.bases_input_label.text = val
            else:
                self.root.ids.bases_input_label.text = c+val
    # the `C` button functionality
    def clear_input(self):
        c = self.root.ids.manager.current
        if c == "main_scr":
            self.root.ids.the_input.text = "0"
        elif c == "convy":
            self.root.ids.input_label.text = "0"
            self.root.ids.output_label.text = "0"
        elif c == "bases-convy":
            self.root.ids.bases_input_label.text = "0"
            self.root.ids.bases_output_label.text = "0"
    # this pops one char from inputs
    def backspace(self):
        c = self.root.ids.manager.current
        if c == "main_scr":
            d = self.root.ids.the_input.text
            self.root.ids.the_input.text = d[:-1] if len(d)>1 else "0"
        elif c == "convy":
            d = self.root.ids.input_label.text
            self.root.ids.input_label.text = d[:-1] if len(d)>1 else "0"
        elif c == "bases-convy":
            d = self.root.ids.bases_input_label.text
            self.root.ids.bases_input_label.text = d[:-1] if len(d)>1 else "0"

    # here I am using `eval` because there cannot be vulnerabilities using numbers only
    # P.S. I may be wrong
    def evaluate(self):
        c = self.root.ids.the_input.text
        try:
            r = eval(c)
            self.root.ids.the_input.text = f'{r:,}'
        except:
            pass
    # this is the `exit_dialog` formation
    def dialog(self):
        def dfunc(n):
            if n:
                exit()
            else:
                self.exit_dialog.dismiss(force=True)
            self.exit_dialog = None
        if not self.exit_dialog:
            self.exit_dialog = MDDialog(text="Të dal tani ?",buttons=[MDFlatButton(text="ANULLO",theme_text_color="Custom",text_color=self.theme_cls.primary_color,on_release=lambda x:dfunc(0)),MDFlatButton(text="PO",theme_text_color="Custom",text_color=self.theme_cls.primary_color,on_release=lambda x:dfunc(1))],radius=[20,20,20,20])
            self.exit_dialog.open()
    # converting pure units (convert screen only)
    def convert(self):
        fromUnit = self.screen.ids.first.text
        toUnit = self.screen.ids.second.text
        f = self.current[fromUnit]
        t = self.current[toUnit]
        # here I do two operations without considering the types of units
        # so they can be the same, one-way or impossibe conversions
        r = str((float(self.screen.ids.input_label.text)/f)*t)
        self.screen.ids.output_label.text = r

    # this is used to convert a number from given base to another
    def conv_bases(self):
        n = self.screen.ids.bases_input_label.text
        f = self.screen.ids.bases_first.text
        t = self.screen.ids.bases_second.text
        a={"bin":2,"oct":8,"dec":10,"hex":16}.get(f,10)
        b={"bin":bin,"oct":oct,"dec":int,"hex":hex}.get(t,int)
        try:
            to_dec = int(n,a)
            to_other = str((lambda x:x(to_dec))(b))
        except Exception as e:
            self.show_toast(e)
            return
        if any(to_other.count(i)for i in'box'):
            to_other = to_other[2:]
        self.screen.ids.bases_output_label.text = to_other
    # used to adapt menus' texts upon unit choosing
    def change_label(self,unit,w):
        if self.root.ids.manager.current!="bases-convy":
            if w:
                self.screen.ids.first.text = unit
                self.first_menu.dismiss()
            else:
                self.screen.ids.second.text = unit
                self.second_menu.dismiss()
        else:
            if w:
                self.screen.ids.bases_first.text = unit
                self.bases_first_menu.dismiss()
            else:
                self.screen.ids.bases_second.text = unit
                self.bases_second_menu.dismiss()

if __name__ in ["__main__","__android__"]:
    MainBaseApp().run()