#~~~~imports~~~~
import PySimpleGUI as sg

import pathlib

WIN_W = 90
WIN_H = 25
#~~~~layout~~~~
# settings
menu_def = [['File', ['New    Ctrl+N', 'Open...    Ctrl+O', 'Save    Ctrl+S','Save As...', '---', 'Exit'  ]],
                ['Edit', ['Undo    Ctrl+Z', 'Paste    Ctrl+V'], ],
                ['Help', '  About memopad   '], ]

# the layout its self
layout = [[sg.Menu(menu_def)],
          [sg.Multiline(font=('Consolas', 12), size=(WIN_W, WIN_H), key='_BODY_')]]

# reading the window
window = sg.Window('untitled - memopad', layout=layout, element_padding=(0, 0), margins=(0, 0), resizable=True, return_keyboard_events=True, finalize=True)
window['_BODY_'].expand(expand_x=True, expand_y=True)

#~~~~defs~~~~
def new_file():
    '''Reset body and info bar, and clear filename variable'''
    window['_BODY_'].update(value='')
    window.TKroot.title('untitled - memopad')
    file = None
    return file

def open_file():
    '''Open file and update the infobar'''
    filepath = sg.popup_get_file('Open', no_window=True)
    filename = filepath.split('/')
    if filename:
        try:
            file = pathlib.Path(filepath)
            window['_BODY_'].update(value=file.read_text())
            window.TKroot.title(filename[-1] + '- memopad')
            return file
        except:
            pass

def save_file(file):
    '''Save file instantly if already open; otherwise use `save-as` popup'''
    try:
        if file:
            file.write_text(values.get('_BODY_'))
        else:
            save_file_as()

def save_file_as():
    '''Save new file or save existing file with another name'''
    filename = sg.popup_get_file('Save As', save_as=True, no_window=True)
    try:
        if filename:
            file = pathlib.Path(filepath)
            file.write_text(values.get('_BODY_'))
            filename = filepath.split('/')
            window.TKroot.title(filename[-1] + '- memopad')
            return file
    except:
        pass

def about_me():
    '''A short, pithy quote'''
    sg.popup_no_wait('"All great things have small beginnings" - Peter Senge')

#~~~event loop~~~~
while True:
    event, values = window.read()
    if event in (None, 'Exit'):
        break

    if event in ('New    Ctrl+N', 'n:78'):
        file = new_file()

    if event in ('Open...    Ctrl+O', 'o:79'):
        file = open_file()

    if event in ('Save    Ctrl+S', 's:83'):
        save_file(file)

    if event in ('Save As...',):
        file = save_file_as()

    if event in ('  About memopad   ',):
        about_me()