terminal-emulator/terminal/__main__.py

import keyboard
import os

TEXT_REGULAR = '\033[38;5;2m'
TEXT_HIGHLIGHTED = '\033[38;5;0m\033[48;5;2m'
RESET_CODE = '\033[2;0;0m'


class Text:
    def __init__(self, text: str):
        self.text = text
        self.prefix = TEXT_REGULAR
        self.suffix = RESET_CODE

    def highlight(self):
        self.prefix = TEXT_HIGHLIGHTED
        return self

    def regular(self):
        self.prefix = TEXT_REGULAR
        return self

    def draw_at(self, line: int, col: int):
        position = f'\033[{int(line)};{int(col)}f'
        print(f'{position}{self.prefix}{self.text}{self.suffix}', end='\r')


class Menu:
    def __init__(self, title: str, options: dict):
        self.title = f'[{title}]'
        self.options = options
        self.selected = 0

    def next(self):
        self.selected += 1
        if self.selected > len(self.options) - 1:
            self.selected = 0

    def prev(self):
        self.selected -= 1
        if self.selected < 0:
            self.selected = len(self.options) - 1

    def draw(self):
        term_dims = os.get_terminal_size()
        title_start = int((term_dims.columns / 2) - (len(self.title) / 2))
        Text(self.title).draw_at(1, title_start)

        for i, k in enumerate(self.options):
            if i == self.selected:
                Text(k).highlight().draw_at(i + 2, 1)
            else:
                Text(k).draw_at(i + 2, 1)


def main():
    os.system('clear')
    os.system('stty -echo')

    menu = Menu('Test Menu', {
        'Option 1:': 'opt',
        'Option 2:': 'opt2',
        'Option 3:': 'opt3'
    })
    menu.draw()
    while True:
        pressed_key = keyboard.read_event()
        if pressed_key.event_type == 'down':
            if pressed_key.name == 'j':
                menu.next()
            elif pressed_key.name == 'k':
                menu.prev()
        menu.draw()


if __name__ == '__main__':
    main()