Česká Televize (ČT) teletext terminal viewer

teletext.py

#!/bin/env python3

import time, json
import termbox as TB
from urllib.request import urlopen

try:
    with urlopen(f"https://api-teletext.ceskatelevize.cz/teletext-api/v2/text/?t={int(time.time())}") as f:
        tt_json = f.read().decode('utf-8')
        pages = json.loads(tt_json)['data']
except Exception as err:
    print('Error fetching teletext.')
    print()
    print(err)
    quit()

class Viewer:
    def __init__(self, page=100):
        self.page = str(page)
        self.subpage_i = 0

    def get_subpage_codes(self):
        try:
            return pages[self.page]['subpages']
        except KeyError:
            return []

    def get_text(self):
        try:
            if self.get_subpage_codes():    # If there are subpages
                text = pages[self.page]['text'][self.page + self.get_subpage_codes()[self.subpage_i]]
            else:
                text = pages[self.page]['text'][self.page]

            return text.replace('<pre>', '').replace('</pre>', '')
        except KeyError:
            return "Page not found."

    def next_subpage(self):
        if (not self.get_subpage_codes()) or (self.subpage_i == len(self.get_subpage_codes()) - 1):
            self.page = str(int(self.page) + 1)
            self.subpage_i = 0
        else:
            self.subpage_i += 1

    def prev_subpage(self):
        if (not self.get_subpage_codes()) or (self.subpage_i == 0):
            self.page = str(int(self.page) - 1)
            self.subpage_i = len(self.get_subpage_codes()) - 1
        else:
            self.subpage_i -= 1

    def run(self):
        tb = TB.Termbox()
        buffer = ''
        history = []

        while True:
            tb.clear()

            # Draw UI
            for x in range(0, tb.width()):
                tb.change_cell(x, tb.height() - 1, ord(' '), TB.BLACK, TB.WHITE)

            tb_print(tb, tb.width() - 10, tb.height() - 1, f'Page {self.page}' + (f'.{self.subpage_i}' if self.get_subpage_codes() else ''), TB.BLACK, TB.WHITE)
            tb_print(tb, 0, tb.height() - 1, '[   ]', TB.BLACK, TB.WHITE)
            tb_print(tb, 1, tb.height() - 1, (' ' * (3 - len(buffer))) + buffer[-3:], TB.BLACK, TB.WHITE)

            # Draw text
            text = self.get_text()
            w, h = len(text.splitlines()[0]), len(text.splitlines())

            tb_print(tb, (tb.width() - w) // 2, (tb.height() - h) // 2, text, TB.WHITE, TB.DEFAULT)

            tb.present()

            # Wait for events
            match tb.poll_event():
                case (TB.EVENT_KEY, 'q', *args):
                    break;
                case (TB.EVENT_KEY, c, *args) if str(c).isdigit():
                    buffer += c;
                case (TB.EVENT_KEY, _, TB.KEY_BACKSPACE, *args) | (TB.EVENT_KEY, _, TB.KEY_BACKSPACE2, *args):
                    buffer = buffer[:-1]
                case (TB.EVENT_KEY, _, TB.KEY_ENTER, *args):
                    self.page = buffer
                    history.append(buffer)  # Add to history
                    self.subpage_i = 0
                    buffer = ''
                case (TB.EVENT_KEY, _, TB.KEY_ARROW_LEFT, TB.MOD_ALT, *args):
                    if history:
                        self.page = history.pop()
                        self.subpage_i = 0

                case (TB.EVENT_KEY, '[', *args):
                    self.page = str(int(self.page) - 1)
                    self.subpage_i = 0
                case (TB.EVENT_KEY, ']', *args):
                    self.page = str(int(self.page) + 1)
                    self.subpage_i = 0
                case (TB.EVENT_KEY, _, TB.KEY_ARROW_RIGHT, *args):
                    self.next_subpage()
                case (TB.EVENT_KEY, _, TB.KEY_ARROW_LEFT, *args):
                    self.prev_subpage()

        tb.close()

def tb_print(tb, x, y, text, fg, bg):
    cx, cy = x, y

    for c in text:
        if c == '\n':
            cx = x
            cy += 1
            continue

        tb.change_cell(cx, cy, ord(c), fg, bg)
        cx += 1

if __name__ == '__main__':
    v = Viewer()
    v.run()