fix(edu): review findings for checker.py i18n — group chat language via resolve_lang/chat: keys (default uk), weekday normalization with _norm_day + logging, drop dead translation keys, html.escape, single lang lookup, distinct whitelist emoji

edu_master/webinar-checker/checker.py

@@ -6,6 +6,7 @@ import re
 import tempfile
 import time
 from datetime import datetime, timedelta
+from html import escape
 
 import redis
 from playwright.async_api import async_playwright
@@ -55,6 +56,9 @@ KEY_SUBSCRIBERS = 'bot:subscribers'
 KEY_PHPSESSID = 'EDU_PHPSESSID'
 KEY_WEBINAR_HISTORY = 'bot:webinar_history'  # Stores last 3 webinars
 
+# Marker shown by the site when there are no active online lessons
+NO_WEBINAR_MARKER = 'Жодного онлайн уроку зараз'
+
 # Initialize Redis
 try:
     redis_client = redis.Redis(host=REDIS_HOST, port=REDIS_PORT, decode_responses=True)
@@ -83,7 +87,7 @@ TRANSLATIONS = {
         'usage_adduser': 'Использование: /adduser [user_id]',
         'usage_removeuser': 'Использование: /removeuser [user_id]',
         'whitelist_enabled': '✅ Белый список включен',
-        'whitelist_disabled': '✅ Белый список отключен',
+        'whitelist_disabled': '🚫 Белый список отключен',
         'whitelist_title': '📋 <b>Белый список:</b>\n',
         'subscribers_title': '👥 <b>Подписчики:</b>\n',
         'empty': 'Пусто',
@@ -99,12 +103,44 @@ TRANSLATIONS = {
         'webinar_found': '🎓 <b>Новый вебинар!</b>\n\n',
         'webinar_item': '📌 <b>{name}</b>\n🔗 https://edu.edu.vn.ua{url}',
         'select_language': '🌐 <b>Выберите язык / Оберіть мову / Select language:</b>',
-        'language_changed': '✅ Язык изменен на русский',
+        'language_changed': '✅ Язык изменен на {lang}',
         'flag_ru': '🇷🇺 Русский',
         'flag_uk': '🇺🇦 Українська',
         'flag_en': '🇬🇧 English',
         'history_cleared': '✅ История вебинаров очищена',
         'history_clear_failed': '❌ Ошибка при очистке истории',
+        'today': '📌 Сегодня',
+        'tomorrow': '📌 Завтра',
+        'week': '📅 Эта неделя',
+        'month': '📅 Весь месяц',
+        'no_events': 'Нет событий',
+        'no_lessons': 'Нет уроков',
+        'free_period': 'Свободно',
+        'unsubscribed': '🔕 Вы отписались от уведомлений.',
+        'diary_title': '📅 <b>Дневник</b> — выберите период:',
+        'diary_week_title': '📅 <b>Неделя {start} – {end}</b>',
+        'schedule_title': '📅 <b>{weekday} — {class_num} класс</b>',
+        'loading_diary': '🔄 Загружаю дневник...',
+        'diary_load_failed': '❌ Не удалось загрузить дневник.',
+        'diary_no_session': '❌ Не удалось загрузить дневник. Нет сессии или ошибка.',
+        'diary_next_month': '❌ Данные за следующий месяц недоступны. Перейдите на сайт.',
+        'schedule_load_failed': '❌ Не удалось загрузить расписание.',
+        'class_not_set': '❌ Класс не настроен. Используйте /setclass.',
+        'class_not_found': '❌ Классы не найдены в расписании.',
+        'select_class': '🎒 <b>Выберите класс</b> — сохранится и больше не спросится:',
+        'admin_class_not_set': '⚠️ Администратор еще не настроил класс для этой группы. Используйте /setclass 11',
+        'loading_schedule': '🔄 Загружаю расписание...',
+        'invalid_class_num': '❌ Неверный номер класса.',
+        'class_saved': '✅ Класс <b>{class_num}</b> сохранен.',
+        'admin_only_msg': '⚠️ Только администратор может настроить класс для группы.',
+        'truncation': '\n\n✂️ ...(обрезано)',
+        'day_mon': 'Пн',
+        'day_tue': 'Вт',
+        'day_wed': 'Ср',
+        'day_thu': 'Чт',
+        'day_fri': 'Пт',
+        'day_sat': 'Сб',
+        'day_sun': 'Вс',
     },
     'uk': {
         'welcome': "👋 Привіт, {name}!\n\nЯ бот-сповіщувач про вебінари. Я повідомлятиму вас, коли з'явиться новий вебінар.\nВи підписані на сповіщення.",
@@ -122,7 +158,7 @@ TRANSLATIONS = {
         'usage_adduser': 'Використання: /adduser [user_id]',
         'usage_removeuser': 'Використання: /removeuser [user_id]',
         'whitelist_enabled': '✅ Білий список увімкнено',
-        'whitelist_disabled': '✅ Білий список вимкнено',
+        'whitelist_disabled': '🚫 Білий список вимкнено',
         'whitelist_title': '📋 <b>Білий список:</b>\n',
         'subscribers_title': '👥 <b>Підписники:</b>\n',
         'empty': 'Порожньо',
@@ -138,12 +174,44 @@ TRANSLATIONS = {
         'webinar_found': '🎓 <b>Новий вебінар!</b>\n\n',
         'webinar_item': '📌 <b>{name}</b>\n🔗 https://edu.edu.vn.ua{url}',
         'select_language': '🌐 <b>Виберіть мову / Выберите язык / Select language:</b>',
-        'language_changed': '✅ Мову змінено на українську',
+        'language_changed': '✅ Мову змінено на {lang}',
         'flag_ru': '🇷🇺 Русский',
         'flag_uk': '🇺🇦 Українська',
         'flag_en': '🇬🇧 English',
         'history_cleared': '✅ Історія вебінарів очищена',
         'history_clear_failed': '❌ Помилка при очищенні історії',
+        'today': '📌 Сьогодні',
+        'tomorrow': '📌 Завтра',
+        'week': '📅 Цей тиждень',
+        'month': '📅 Весь місяць',
+        'no_events': 'Немає подій',
+        'no_lessons': 'Немає уроків',
+        'free_period': 'Вільно',
+        'unsubscribed': '🔕 Ви відписалися від сповіщень.',
+        'diary_title': '📅 <b>Щоденник</b> — виберіть період:',
+        'diary_week_title': '📅 <b>Тиждень {start} – {end}</b>',
+        'schedule_title': '📅 <b>{weekday} — {class_num} клас</b>',
+        'loading_diary': '🔄 Завантажую щоденник...',
+        'diary_load_failed': '❌ Не вдалося завантажити щоденник.',
+        'diary_no_session': '❌ Не вдалося завантажити щоденник. Немає сесії або помилка.',
+        'diary_next_month': '❌ Дані за наступний місяць недоступні. Перейдіть на сайт.',
+        'schedule_load_failed': '❌ Не вдалося завантажити розклад.',
+        'class_not_set': '❌ Клас не налаштовано. Використайте /setclass.',
+        'class_not_found': '❌ Класи не знайдені в розкладі.',
+        'select_class': '🎒 <b>Оберіть клас</b> — збережеться і більше не питатиметься:',
+        'admin_class_not_set': '⚠️ Адміністратор ще не налаштував клас для цієї групи. Використайте /setclass 11',
+        'loading_schedule': '🔄 Завантажую розклад...',
+        'invalid_class_num': '❌ Невірний номер класу.',
+        'class_saved': '✅ Клас <b>{class_num}</b> збережено.',
+        'admin_only_msg': '⚠️ Тільки адміністратор може налаштувати клас для групи.',
+        'truncation': '\n\n✂️ ...(обрізано)',
+        'day_mon': 'Пн',
+        'day_tue': 'Вт',
+        'day_wed': 'Ср',
+        'day_thu': 'Чт',
+        'day_fri': 'Пт',
+        'day_sat': 'Сб',
+        'day_sun': 'Нд',
     },
     'en': {
         'welcome': '👋 Hello, {name}!\n\nI am the Webinar Checker Bot. I will notify you when a new webinar appears.\nYou have been subscribed to notifications.',
@@ -161,7 +229,7 @@ TRANSLATIONS = {
         'usage_adduser': 'Usage: /adduser [user_id]',
         'usage_removeuser': 'Usage: /removeuser [user_id]',
         'whitelist_enabled': '✅ Whitelist Enabled',
-        'whitelist_disabled': '✅ Whitelist Disabled',
+        'whitelist_disabled': '🚫 Whitelist Disabled',
         'whitelist_title': '📋 <b>Whitelist:</b>\n',
         'subscribers_title': '👥 <b>Subscribers:</b>\n',
         'empty': 'Empty',
@@ -177,22 +245,57 @@ TRANSLATIONS = {
         'webinar_found': '🎓 <b>New webinar found!</b>\n\n',
         'webinar_item': '📌 <b>{name}</b>\n🔗 https://edu.edu.vn.ua{url}',
         'select_language': '🌐 <b>Select language / Виберіть мову / Выберите язык:</b>',
-        'language_changed': '✅ Language changed to English',
+        'language_changed': '✅ Language changed to {lang}',
         'flag_ru': '🇷🇺 Русский',
         'flag_uk': '🇺🇦 Українська',
         'flag_en': '🇬🇧 English',
         'history_cleared': '✅ Webinar history cleared',
         'history_clear_failed': '❌ Error clearing history',
+        'today': '📌 Today',
+        'tomorrow': '📌 Tomorrow',
+        'week': '📅 This week',
+        'month': '📅 Whole month',
+        'no_events': 'No events',
+        'no_lessons': 'No lessons',
+        'free_period': 'Free',
+        'unsubscribed': '🔕 You have unsubscribed from notifications.',
+        'diary_title': '📅 <b>Diary</b> — choose a period:',
+        'diary_week_title': '📅 <b>Week {start} – {end}</b>',
+        'schedule_title': '📅 <b>{weekday} — {class_num} class</b>',
+        'loading_diary': '🔄 Loading diary...',
+        'diary_load_failed': '❌ Failed to load diary.',
+        'diary_no_session': '❌ Failed to load diary. No session or error.',
+        'diary_next_month': '❌ Next month data is not available. Please visit the website.',
+        'schedule_load_failed': '❌ Failed to load schedule.',
+        'class_not_set': '❌ Class is not set. Use /setclass.',
+        'class_not_found': '❌ No classes found in the schedule.',
+        'select_class': '🎒 <b>Choose a class</b> — it will be saved and not asked again:',
+        'admin_class_not_set': '⚠️ Admin has not set a class for this group yet. Use /setclass 11',
+        'loading_schedule': '🔄 Loading schedule...',
+        'invalid_class_num': '❌ Invalid class number.',
+        'class_saved': '✅ Class <b>{class_num}</b> saved.',
+        'admin_only_msg': '⚠️ Only an admin can set the class for this group.',
+        'truncation': '\n\n✂️ ...(truncated)',
+        'day_mon': 'Mon',
+        'day_tue': 'Tue',
+        'day_wed': 'Wed',
+        'day_thu': 'Thu',
+        'day_fri': 'Fri',
+        'day_sat': 'Sat',
+        'day_sun': 'Sun',
     },
 }
 
 # --- Language Helper Functions ---
 
 
+LANG_NAME_MAP = {'ru': 'Русский', 'uk': 'Українська', 'en': 'English'}
+
+
 def get_user_language(user_id: int) -> str:
-    """Get user's preferred language from Redis. Default: Ukrainian."""
+    """Get user's preferred language from Redis. Default: English."""
     lang = redis_client.get(f'user:{user_id}:language')
-    return lang if lang in ['ru', 'uk', 'en'] else 'uk'
+    return lang if lang in ['ru', 'uk', 'en'] else 'en'
 
 
 def set_user_language(user_id: int, lang: str):
@@ -203,23 +306,87 @@ def set_user_language(user_id: int, lang: str):
 
 
 def t(user_id: int, key: str, **kwargs) -> str:
-    """Translate message for user with optional formatting."""
+    """Translate message for user with optional formatting.
+
+    Fallback chain: user lang → en → uk → ru, otherwise return the key.
+    """
     lang = get_user_language(user_id)
-    message = TRANSLATIONS.get(lang, TRANSLATIONS['uk']).get(key, key)
+    message = None
+    for fallback in (lang, 'en', 'uk', 'ru'):
+        message = TRANSLATIONS.get(fallback, {}).get(key)
+        if message is not None:
+            break
+    if message is None:
+        return key
     if kwargs:
         return message.format(**kwargs)
     return message
 
 
-def get_language_keyboard():
+def _tr(lang: str, key: str, **kwargs) -> str:
+    """Translate by explicit lang code (for format_* helpers).
+
+    Fallback chain: lang → en → uk → ru, otherwise return the key.
+    """
+    message = None
+    for fallback in (lang, 'en', 'uk', 'ru'):
+        message = TRANSLATIONS.get(fallback, {}).get(key)
+        if message is not None:
+            break
+    if message is None:
+        return key
+    if kwargs:
+        return message.format(**kwargs)
+    return message
+
+
+def get_chat_language(chat_id: int) -> str:
+    """Get group chat language from Redis. Default: Ukrainian."""
+    lang = redis_client.get(f'chat:{chat_id}:language')
+    return lang if lang in ['ru', 'uk', 'en'] else 'uk'
+
+
+def set_chat_language(chat_id: int, lang: str):
+    """Save group chat language preference to Redis."""
+    if lang in ['ru', 'uk', 'en']:
+        redis_client.set(f'chat:{chat_id}:language', lang)
+        logger.info(f'Chat {chat_id} language set to {lang}')
+
+
+def resolve_lang(chat, user_id=None) -> str:
+    """Resolve effective language: private → user lang, groups → chat lang (default 'uk')."""
+    chat_id = getattr(chat, 'id', chat)
+    chat_type = getattr(chat, 'type', None)
+    if chat_type is None:
+        try:
+            is_private = int(chat_id) > 0
+        except (TypeError, ValueError):
+            is_private = True
+        if is_private:
+            uid = user_id if user_id is not None else chat_id
+            return get_user_language(int(uid))
+        return get_chat_language(int(chat_id))
+    if chat_type in (ChatType.PRIVATE, 'private'):
+        uid = user_id if user_id is not None else chat_id
+        return get_user_language(int(uid))
+    return get_chat_language(chat_id)
+
+
+def t_chat(chat, user_id, key: str, **kwargs) -> str:
+    """Translate using chat-resolved language (private → user, groups → chat 'uk' default)."""
+    return _tr(resolve_lang(chat, user_id), key, **kwargs)
+
+
+def get_language_keyboard(user_id: int | None = None):
     """Generate language selection keyboard."""
+    lang = get_user_language(user_id) if user_id is not None else 'en'
     keyboard = [
         [
-            InlineKeyboardButton('🇷🇺 Русский', callback_data='lang_ru'),
+            InlineKeyboardButton(_tr(lang, 'flag_ru'), callback_data='lang_ru'),
-            InlineKeyboardButton('🇺🇦 Українська', callback_data='lang_uk'),
+            InlineKeyboardButton(_tr(lang, 'flag_uk'), callback_data='lang_uk'),
         ],
         [
-            InlineKeyboardButton('🇬🇧 English', callback_data='lang_en'),
+            InlineKeyboardButton(_tr(lang, 'flag_en'), callback_data='lang_en'),
         ],
     ]
     return InlineKeyboardMarkup(keyboard)
@@ -272,38 +439,51 @@ def get_admin_keyboard(user_id: int):
 
 # --- Diary Functions ---
 
-SCHEDULE_WEEKDAYS_FULL = ['Понеділок', 'Вівторок', 'Середа', 'Четвер', "П'ятниця", 'Субота', 'Неділя']
+SCHEDULE_WEEKDAYS_FULL = {
+    'uk': ['Понеділок', 'Вівторок', 'Середа', 'Четвер', "П'ятниця", 'Субота', 'Неділя'],
+    'ru': ['Понедельник', 'Вторник', 'Среда', 'Четверг', 'Пятница', 'Суббота', 'Воскресенье'],
+    'en': ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'],
+}
+# Canonical weekday names used in callback_data and schedule lookup (site language).
+SCHEDULE_WEEKDAYS_CANONICAL = SCHEDULE_WEEKDAYS_FULL['uk']
 SCHEDULE_CACHE_TTL = 18000  # 5 hours
 
-DIARY_MONTH_NAMES = [
-    '',
-    'Січня',
-    'Лютого',
-    'Березня',
-    'Квітня',
-    'Травня',
-    'Червня',
-    'Липня',
-    'Серпня',
-    'Вересня',
-    'Жовтня',
-    'Листопада',
-    'Грудня',
-]
 
-DIARY_WEEKDAYS_SHORT = ['Пн', 'Вт', 'Ср', 'Чт', 'Пт', 'Сб', 'Нд']
+def _norm_day(s):
+    """Normalize weekday name for tolerant matching (case, spaces, apostrophes)."""
+    if not isinstance(s, str):
+        return ''
+    s = s.strip().casefold()
+    for _q in ('\u2019', '\u2018', '\u02bc', '`'):
+        s = s.replace(_q, "'")
+    s = re.sub(r'\s+', ' ', s)
+    return s.strip()
 
 
-def get_diary_keyboard():
+_SCHEDULE_WEEKDAYS_CANONICAL_NORM = [_norm_day(d) for d in SCHEDULE_WEEKDAYS_CANONICAL]
+
+DIARY_WEEKDAYS_SHORT = {
+    'uk': ['Пн', 'Вт', 'Ср', 'Чт', 'Пт', 'Сб', 'Нд'],
+    'ru': ['Пн', 'Вт', 'Ср', 'Чт', 'Пт', 'Сб', 'Вс'],
+    'en': ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'],
+}
+
+
+def get_diary_keyboard(user_id: int | None = None):
     today = datetime.now()
+    lang = get_user_language(user_id) if user_id is not None else 'en'
+    today_label = _tr(lang, 'today')
+    tomorrow_label = _tr(lang, 'tomorrow')
+    week_label = _tr(lang, 'week')
+    month_label = _tr(lang, 'month')
     keyboard = [
         [
-            InlineKeyboardButton(f'📌 Сьогодні ({today.day}.{today.month:02d})', callback_data='diary_today'),
+            InlineKeyboardButton(f'{today_label} ({today.day}.{today.month:02d})', callback_data='diary_today'),
-            InlineKeyboardButton('📌 Завтра', callback_data='diary_tomorrow'),
+            InlineKeyboardButton(tomorrow_label, callback_data='diary_tomorrow'),
         ],
         [
-            InlineKeyboardButton('📅 Цей тиждень', callback_data='diary_week'),
+            InlineKeyboardButton(week_label, callback_data='diary_week'),
-            InlineKeyboardButton('📅 Весь місяць', callback_data='diary_month'),
+            InlineKeyboardButton(month_label, callback_data='diary_month'),
         ],
     ]
     return InlineKeyboardMarkup(keyboard)
@@ -416,41 +596,44 @@ def _parse_diary_month(text: str) -> str:
     return text.strip()
 
 
-def format_diary_day(data: dict, day_num: int) -> str:
+def format_diary_day(data: dict, day_num: int, lang: str = 'en') -> str:
     days = data.get('days', {})
     month_str = _parse_diary_month(data.get('monthFullText', ''))
     day_data = days.get(str(day_num))
     lines = [f'📅 <b>{day_num} {month_str}</b>', '─' * 18]
     if not day_data or not day_data.get('events'):
-        lines.append('Немає подій')
+        lines.append(_tr(lang, 'no_events'))
     else:
         for e in day_data['events']:
-            lines.append(f'📌 {e}')
+            lines.append(f'📌 {escape(e)}')
     lines.append(f'\n🔗 {DIARY_URL}')
     return '\n'.join(lines)
 
 
-def format_diary_week(data: dict, today: datetime) -> str:
+def format_diary_week(data: dict, today: datetime, lang: str = 'en') -> str:
     days = data.get('days', {})
     _parse_diary_month(data.get('monthFullText', ''))
     monday = today - timedelta(days=today.weekday())
     sunday = monday + timedelta(days=6)
-    lines = [f'📅 <b>Тиждень {monday.day}.{monday.month} – {sunday.day}.{sunday.month}</b>\n']
+    start = f'{monday.day}.{monday.month}'
+    end = f'{sunday.day}.{sunday.month}'
+    short = DIARY_WEEKDAYS_SHORT.get(lang, DIARY_WEEKDAYS_SHORT['en'])
+    lines = [_tr(lang, 'diary_week_title', start=start, end=end) + '\n']
     for i in range(7):
         d = monday + timedelta(days=i)
         day_data = days.get(str(d.day))
-        lines.append(f'─ <b>{DIARY_WEEKDAYS_SHORT[i]} {d.day}.{d.month}</b> ─')
+        lines.append(f'─ <b>{short[i]} {d.day}.{d.month}</b> ─')
         if not day_data or not day_data.get('events'):
-            lines.append('Немає подій\n')
+            lines.append(_tr(lang, 'no_events') + '\n')
         else:
             for e in day_data['events']:
-                lines.append(f'📌 {e}')
+                lines.append(f'📌 {escape(e)}')
             lines.append('')
     lines.append(f'🔗 {DIARY_URL}')
     return '\n'.join(lines)
 
 
-def format_diary_month(data: dict) -> str:
+def format_diary_month(data: dict, lang: str = 'en') -> str:
     days = data.get('days', {})
     month_str = _parse_diary_month(data.get('monthFullText', ''))
     lines = [f'📅 <b>{month_str}</b>\n']
@@ -460,10 +643,10 @@ def format_diary_month(data: dict) -> str:
         weekday = day_data.get('weekday', '')
         lines.append(f'─ <b>{weekday} {day_num}</b> ─')
         if not events:
-            lines.append('Немає подій\n')
+            lines.append(_tr(lang, 'no_events') + '\n')
         else:
             for e in events:
-                lines.append(f'📌 {e}')
+                lines.append(f'📌 {escape(e)}')
             lines.append('')
     lines.append(f'🔗 {DIARY_URL}')
     return '\n'.join(lines)
@@ -486,26 +669,37 @@ async def _get_diary_data(context: ContextTypes.DEFAULT_TYPE) -> dict | None:
 # --- Schedule Functions ---
 
 
-def get_schedule_day_keyboard():
+def get_schedule_day_keyboard(user_id: int | None = None):
+    lang = get_user_language(user_id) if user_id is not None else 'en'
+    full = SCHEDULE_WEEKDAYS_FULL.get(lang, SCHEDULE_WEEKDAYS_FULL['en'])
     today = datetime.now()
     tomorrow = today + timedelta(days=1)
+    today_label = _tr(lang, 'today')
+    tomorrow_label = _tr(lang, 'tomorrow')
+    short_keys = ['day_mon', 'day_tue', 'day_wed', 'day_thu', 'day_fri', 'day_sat', 'day_sun']
     keyboard = [
         [
-            InlineKeyboardButton(f'📌 Сьогодні ({SCHEDULE_WEEKDAYS_FULL[today.weekday()]})', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[today.weekday()]}'),
+            InlineKeyboardButton(
-            InlineKeyboardButton(f'📌 Завтра ({SCHEDULE_WEEKDAYS_FULL[tomorrow.weekday()]})', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[tomorrow.weekday()]}'),
+                f'{today_label} ({full[today.weekday()]})',
+                callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[today.weekday()]}',
+            ),
+            InlineKeyboardButton(
+                f'{tomorrow_label} ({full[tomorrow.weekday()]})',
+                callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[tomorrow.weekday()]}',
+            ),
         ],
         [
-            InlineKeyboardButton('Пн', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[0]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[0]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[0]}'),
-            InlineKeyboardButton('Вт', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[1]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[1]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[1]}'),
-            InlineKeyboardButton('Ср', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[2]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[2]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[2]}'),
         ],
         [
-            InlineKeyboardButton('Чт', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[3]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[3]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[3]}'),
-            InlineKeyboardButton('Пт', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[4]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[4]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[4]}'),
-            InlineKeyboardButton('Сб', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[5]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[5]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[5]}'),
         ],
         [
-            InlineKeyboardButton('Нд', callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_FULL[6]}'),
+            InlineKeyboardButton(_tr(lang, short_keys[6]), callback_data=f'schedule_day_{SCHEDULE_WEEKDAYS_CANONICAL[6]}'),
         ],
     ]
     return InlineKeyboardMarkup(keyboard)
@@ -563,7 +757,7 @@ def _parse_schedule_cell(cell_html: str) -> list:
 
 def _parse_schedule_html(table_html: str) -> dict:
     """Parse schedule HTML table into {classes: [...], weekdays: {day: [...]}}."""
-    result = {'classes': [], 'weekdays': {}}
+    result = {'classes': [], 'weekdays': {}, 'weekday_norm': {}}
     row_matches = re.finditer(r'<tr([^>]*)>(.*?)</tr>', table_html, re.DOTALL)
 
     current_day = None
@@ -578,6 +772,7 @@ def _parse_schedule_html(table_html: str) -> dict:
                 day_text = re.sub(r'<[^>]+>', '', cells[0]).strip()
                 current_day = day_text
                 result['weekdays'][current_day] = []
+                result['weekday_norm'][_norm_day(day_text)] = current_day
                 classes_header = []
                 for cell in cells[1:]:
                     cls = re.sub(r'<[^>]+>', '', cell).strip()
@@ -654,6 +849,7 @@ async def fetch_schedule_data(phpsessid: str) -> dict | None:
                         f.write(table_html)
 
                     data = _parse_schedule_html(table_html)
+                    logger.info(list(data['weekdays'].keys()))
                     logger.info(f'Schedule parsed: {len(data["weekdays"])} days, classes={data["classes"]}')
 
                     return data
@@ -685,17 +881,28 @@ async def _get_schedule_data(context: ContextTypes.DEFAULT_TYPE) -> dict | None:
     return data
 
 
-def format_schedule_day(data: dict, weekday: str, class_num) -> str:
+def format_schedule_day(data: dict, weekday: str, class_num, lang: str = 'en') -> str:
     days = data.get('weekdays', {})
-    entries = days.get(weekday, [])
+    norm_map = data.get('weekday_norm') or {_norm_day(k): k for k in days}
+    norm = _norm_day(weekday)
+    day_key = norm_map.get(norm)
+    if day_key is None:
+        logger.warning(f'Schedule weekday not matched: {weekday!r}')
+    entries = days.get(day_key, []) if day_key is not None else []
     try:
         class_key = int(class_num)
     except (TypeError, ValueError):
         class_key = class_num
-    lines = [f'📅 <b>{weekday} — {class_num} клас</b>', '─' * 20]
+    try:
+        idx = _SCHEDULE_WEEKDAYS_CANONICAL_NORM.index(norm)
+        display_weekday = SCHEDULE_WEEKDAYS_FULL.get(lang, SCHEDULE_WEEKDAYS_FULL['en'])[idx]
+    except ValueError:
+        logger.warning(f'Schedule weekday not in canonical list: {weekday!r}')
+        display_weekday = weekday
+    lines = [_tr(lang, 'schedule_title', weekday=display_weekday, class_num=class_num), '─' * 20]
 
     if not entries:
-        lines.append('Немає уроків')
+        lines.append(_tr(lang, 'no_lessons'))
     else:
         for entry in entries:
             time_str = entry.get('time', '').replace(' ', '–')
@@ -703,13 +910,13 @@ def format_schedule_day(data: dict, weekday: str, class_num) -> str:
 
             lessons = entry.get('classes', {}).get(class_key, [])
             if not lessons:
-                lines.append('  Вільно')
+                lines.append(f'  {_tr(lang, "free_period")}')
             else:
                 for i, lesson in enumerate(lessons):
-                    note_part = f' ({lesson["note"]})' if lesson.get('note') else ''
+                    note_part = f' ({escape(lesson["note"])})' if lesson.get('note') else ''
-                    lines.append(f'  📌 <b>{lesson["subject"]}</b>{note_part}')
+                    lines.append(f'  📌 <b>{escape(lesson["subject"])}</b>{note_part}')
                     if lesson.get('teacher'):
-                        lines.append(f'  {lesson["teacher"]}')
+                        lines.append(f'  {escape(lesson["teacher"])}')
                     if i < len(lessons) - 1:
                         lines.append('  ──')
 
@@ -734,10 +941,10 @@ async def start(update: Update, _context: ContextTypes.DEFAULT_TYPE):
     # Add to subscribers (Chat ID!)
     redis_client.sadd(KEY_SUBSCRIBERS, chat.id)
 
-    msg = t(chat.id, 'welcome', name=user.first_name)
+    msg = t_chat(chat, user.id, 'welcome', name=escape(user.first_name))
 
     if user.id == ADMIN_ID and chat.type == 'private':
-        msg += t(chat.id, 'welcome_admin')
+        msg += t_chat(chat, user.id, 'welcome_admin')
         await update.message.reply_text(msg, parse_mode='HTML', reply_markup=get_admin_keyboard(user.id))
     else:
         await update.message.reply_text(msg, parse_mode='HTML')
@@ -746,11 +953,11 @@ async def start(update: Update, _context: ContextTypes.DEFAULT_TYPE):
 async def help_command(update: Update, _context: ContextTypes.DEFAULT_TYPE):
     """Handle /help command."""
     user_id = update.effective_user.id
-    chat_id = update.effective_chat.id
+    chat = update.effective_chat
-    msg = t(chat_id, 'help_title') + t(chat_id, 'help_commands')
+    msg = t_chat(chat, user_id, 'help_title') + t_chat(chat, user_id, 'help_commands')
 
     if user_id == ADMIN_ID and update.effective_chat.type == 'private':
-        msg += t(chat_id, 'help_admin')
+        msg += t_chat(chat, user_id, 'help_admin')
         await update.message.reply_text(msg, parse_mode='HTML', reply_markup=get_admin_keyboard(user_id))
     else:
         await update.message.reply_text(msg, parse_mode='HTML')
@@ -762,19 +969,13 @@ async def stop_command(update: Update, context: ContextTypes.DEFAULT_TYPE):
     chat = update.effective_chat
 
     # Permission check: Whitelisted user OR Group Admin
+    lang = resolve_lang(chat, user.id)
     if not (is_whitelisted(user.id) or await is_group_admin(update, context)):
-        await update.message.reply_text(t(chat.id, 'access_denied'))  # Or specific "admin only" message
+        await update.message.reply_text(_tr(lang, 'access_denied'))  # Or specific "admin only" message
         return
 
     redis_client.srem(KEY_SUBSCRIBERS, chat.id)
-    await update.message.reply_text(
+    await update.message.reply_text(_tr(lang, 'unsubscribed'))
-        t(chat.id, 'whitelist_disabled')
-        .replace(' whitelist', ' notifications')
-        .replace('Білий список', 'Сповіщення')
-        .replace('Белый список', 'Уведомления')
-        if chat.id
-        else 'Unsubscribed'
-    )
 
 
 async def language_command(update: Update, context: ContextTypes.DEFAULT_TYPE):
@@ -787,7 +988,7 @@ async def language_command(update: Update, context: ContextTypes.DEFAULT_TYPE):
         return
 
     await update.message.reply_text(
-        t(chat.id, 'select_language'), parse_mode='HTML', reply_markup=get_language_keyboard()
+        t_chat(chat, user.id, 'select_language'), parse_mode='HTML', reply_markup=get_language_keyboard()
     )
 
 
@@ -860,7 +1061,7 @@ async def diary_command(update: Update, _context: ContextTypes.DEFAULT_TYPE):
         await update.message.reply_text(t(user.id, 'access_denied'))
         return
     await update.message.reply_text(
-        '📅 <b>Щоденник</b> — виберіть період:', parse_mode='HTML', reply_markup=get_diary_keyboard()
+        t(user.id, 'diary_title'), parse_mode='HTML', reply_markup=get_diary_keyboard(user.id)
     )
 
 
@@ -870,48 +1071,49 @@ async def diary_callback(update: Update, context: ContextTypes.DEFAULT_TYPE):
     await query.answer()
 
     if user_id != ADMIN_ID and not is_whitelisted(user_id):
-        await query.edit_message_text('⛔ Доступ заборонено.')
+        await query.edit_message_text(t(user_id, 'access_denied'))
         return
 
     data = query.data
     if data == 'diary_refresh':
         context.user_data.pop('diary_cache', None)
-        await query.edit_message_text('🔄 Завантажую щоденник...')
+        await query.edit_message_text(t(user_id, 'loading_diary'))
         diary_data = await _get_diary_data(context)
         if not diary_data:
-            await query.edit_message_text('❌ Не вдалося завантажити щоденник. Немає сесії або помилка.')
+            await query.edit_message_text(t(user_id, 'diary_no_session'))
             return
         await query.edit_message_text(
-            '📅 <b>Щоденник</b> — виберіть період:', parse_mode='HTML', reply_markup=get_diary_keyboard()
+            t(user_id, 'diary_title'), parse_mode='HTML', reply_markup=get_diary_keyboard(user_id)
         )
         return
 
-    await query.edit_message_text('🔄 Завантажую щоденник...')
+    await query.edit_message_text(t(user_id, 'loading_diary'))
     diary_data = await _get_diary_data(context)
     if not diary_data:
-        await query.edit_message_text('❌ Не вдалося завантажити щоденник.')
+        await query.edit_message_text(t(user_id, 'diary_load_failed'))
         return
 
     today = datetime.now()
+    lang = get_user_language(user_id)
     if data == 'diary_today':
-        text = format_diary_day(diary_data, today.day)
+        text = format_diary_day(diary_data, today.day, lang=lang)
     elif data == 'diary_tomorrow':
         tomorrow = today + timedelta(days=1)
         if tomorrow.day < today.day:
-            text = '❌ Дані за наступний місяць недоступні. Перейдіть на сайт.'
+            text = t(user_id, 'diary_next_month')
         else:
-            text = format_diary_day(diary_data, tomorrow.day)
+            text = format_diary_day(diary_data, tomorrow.day, lang=lang)
     elif data == 'diary_week':
-        text = format_diary_week(diary_data, today)
+        text = format_diary_week(diary_data, today, lang=lang)
     elif data == 'diary_month':
-        text = format_diary_month(diary_data)
+        text = format_diary_month(diary_data, lang=lang)
     else:
         return
 
     if len(text) > 4096:
-        text = text[:4090] + '\n\n✂️ ...(обрізано)'
+        text = text[:4090] + t(user_id, 'truncation')
 
-    await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_diary_keyboard())
+    await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_diary_keyboard(user_id))
 
 
 # --- Schedule Command Handlers ---
@@ -921,28 +1123,29 @@ async def _schedule_text_for(context, chat, user_id, weekday) -> tuple:
     """Load schedule data and render one weekday for the stored class."""
     schedule_data = await _get_schedule_data(context)
     if not schedule_data:
-        return None, '❌ Не вдалося завантажити розклад.'
+        return None, t(user_id, 'schedule_load_failed')
     class_num = _get_chat_class(chat, user_id)
     if not class_num:
-        return None, '❌ Клас не налаштовано. Використайте /setclass.'
+        return None, t(user_id, 'class_not_set')
-    text = format_schedule_day(schedule_data, weekday, class_num)
+    text = format_schedule_day(schedule_data, weekday, class_num, lang=get_user_language(user_id))
     if len(text) > 4096:
-        text = text[:4090] + '\n\n✂️ ...(обрізано)'
+        text = text[:4090] + t(user_id, 'truncation')
     return text, None
 
 
 async def _show_class_picker(update, context) -> bool:
     """Fetch classes from schedule and render the class-picker keyboard."""
+    user_id = update.effective_user.id
     schedule_data = await _get_schedule_data(context)
     if not schedule_data:
-        await update.message.reply_text('❌ Не вдалося завантажити розклад.')
+        await update.message.reply_text(t(user_id, 'schedule_load_failed'))
         return False
     classes = schedule_data.get('classes', [])
     if not classes:
-        await update.message.reply_text('❌ Класи не знайдені в розкладі.')
+        await update.message.reply_text(t(user_id, 'class_not_found'))
         return False
     await update.message.reply_text(
-        '🎒 <b>Оберіть клас</b> — збережеться і більше не питатиметься:',
+        t(user_id, 'select_class'),
         parse_mode='HTML',
         reply_markup=get_schedule_class_keyboard(classes),
     )
@@ -960,19 +1163,19 @@ async def schedule_command(update: Update, context: ContextTypes.DEFAULT_TYPE):
 
     if not stored_class:
         if chat.type != 'private' and not await is_group_admin(update, context):
-            await update.message.reply_text('⚠️ Адміністратор ще не налаштував клас для цієї групи. Використайте /setclass 11')
+            await update.message.reply_text(t(user.id, 'admin_class_not_set'))
             return
         await _show_class_picker(update, context)
         return
 
-    await update.message.reply_text('🔄 Завантажую розклад...')
+    await update.message.reply_text(t(user.id, 'loading_schedule'))
     today = datetime.now()
-    weekday = SCHEDULE_WEEKDAYS_FULL[today.weekday()]
+    weekday = SCHEDULE_WEEKDAYS_CANONICAL[today.weekday()]
     text, err = await _schedule_text_for(context, chat, user.id, weekday)
     if err:
         await update.message.reply_text(err)
         return
-    await update.message.reply_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard())
+    await update.message.reply_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard(user.id))
 
 
 async def setclass_command(update: Update, context: ContextTypes.DEFAULT_TYPE):
@@ -990,10 +1193,10 @@ async def setclass_command(update: Update, context: ContextTypes.DEFAULT_TYPE):
         try:
             class_num = int(context.args[0])
         except ValueError:
-            await update.message.reply_text('❌ Невірний номер класу.')
+            await update.message.reply_text(t(user.id, 'invalid_class_num'))
             return
         _set_chat_class(chat, user.id, class_num)
-        await update.message.reply_text(f'✅ Клас <b>{class_num}</b> збережено.')
+        await update.message.reply_text(t(user.id, 'class_saved', class_num=class_num), parse_mode='HTML')
         return
 
     await _show_class_picker(update, context)
@@ -1005,7 +1208,7 @@ async def schedule_callback(update: Update, context: ContextTypes.DEFAULT_TYPE):
     await query.answer()
 
     if user_id != ADMIN_ID and not is_whitelisted(user_id):
-        await query.edit_message_text('⛔ Доступ заборонено.')
+        await query.edit_message_text(t(user_id, 'access_denied'))
         return
 
     data = query.data
@@ -1015,46 +1218,50 @@ async def schedule_callback(update: Update, context: ContextTypes.DEFAULT_TYPE):
         try:
             class_num = int(class_num_str)
         except ValueError:
-            await query.edit_message_text('❌ Невірний номер класу.')
+            await query.edit_message_text(t(user_id, 'invalid_class_num'))
             return
 
         chat = update.effective_chat
         if chat.type != 'private' and not await is_group_admin(update, context):
-            await query.edit_message_text('⚠️ Тільки адміністратор може налаштувати клас для групи.')
+            await query.edit_message_text(t(user_id, 'admin_only_msg'))
             return
 
         _set_chat_class(chat, user_id, class_num)
-        await query.edit_message_text('🔄 Завантажую розклад...')
+        await query.edit_message_text(t(user_id, 'loading_schedule'))
 
         today = datetime.now()
-        weekday = SCHEDULE_WEEKDAYS_FULL[today.weekday()]
+        weekday = SCHEDULE_WEEKDAYS_CANONICAL[today.weekday()]
         text, err = await _schedule_text_for(context, chat, user_id, weekday)
         if err:
             await query.edit_message_text(err)
             return
-        await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard())
+        await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard(user_id))
         return
 
     if data.startswith('schedule_day_'):
         weekday = data[len('schedule_day_'):]
-        await query.edit_message_text('🔄 Завантажую розклад...')
+        try:
+            _SCHEDULE_WEEKDAYS_CANONICAL_NORM.index(_norm_day(weekday))
+        except ValueError:
+            logger.warning(f'Schedule callback weekday not in canonical list: {weekday!r}')
+        await query.edit_message_text(t(user_id, 'loading_schedule'))
         text, err = await _schedule_text_for(context, query.message.chat, user_id, weekday)
         if err:
             await query.edit_message_text(err)
             return
-        await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard())
+        await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard(user_id))
         return
 
     if data == 'schedule_refresh':
         context.user_data.pop('schedule_cache', None)
-        await query.edit_message_text('🔄 Завантажую розклад...')
+        await query.edit_message_text(t(user_id, 'loading_schedule'))
         today = datetime.now()
-        weekday = SCHEDULE_WEEKDAYS_FULL[today.weekday()]
+        weekday = SCHEDULE_WEEKDAYS_CANONICAL[today.weekday()]
         text, err = await _schedule_text_for(context, query.message.chat, user_id, weekday)
         if err:
             await query.edit_message_text(err)
             return
-        await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard())
+        await query.edit_message_text(text, parse_mode='HTML', reply_markup=get_schedule_day_keyboard(user_id))
         return
 
 
@@ -1103,17 +1310,31 @@ async def admin_callback(update: Update, context: ContextTypes.DEFAULT_TYPE):
             await query.message.reply_text(t(user_id, 'check_completed', count=result))
 
 
-async def language_callback(update: Update, _context: ContextTypes.DEFAULT_TYPE):
+async def language_callback(update: Update, context: ContextTypes.DEFAULT_TYPE):
     """Handle language selection button clicks."""
     query = update.callback_query
     user_id = query.from_user.id
+    chat = update.effective_chat
     data = query.data
 
     if data.startswith('lang_'):
         lang = data.split('_')[1]
-        set_user_language(user_id, lang)
+        is_private = chat is None or getattr(chat, 'type', 'private') in (ChatType.PRIVATE, 'private')
-        await query.answer()
+        if is_private:
-        await query.edit_message_text(t(user_id, 'language_changed'), parse_mode='HTML')
+            set_user_language(user_id, lang)
+            await query.answer()
+            await query.edit_message_text(
+                t(user_id, 'language_changed', lang=LANG_NAME_MAP.get(lang, lang)), parse_mode='HTML'
+            )
+        else:
+            if not await is_group_admin(update, context):
+                await query.answer(t_chat(chat, user_id, 'admin_only'), show_alert=True)
+                return
+            set_chat_language(chat.id, lang)
+            await query.answer()
+            await query.edit_message_text(
+                _tr(lang, 'language_changed', lang=LANG_NAME_MAP.get(lang, lang)), parse_mode='HTML'
+            )
 
 
 # --- Webinar Checking Job ---
@@ -1198,7 +1419,7 @@ async def check_webinars_job(context: ContextTypes.DEFAULT_TYPE):
                     content = await page.content()
 
                     # Check if "no webinar" message is present
-                    if 'Жодного онлайн уроку зараз' not in content:
+                    if NO_WEBINAR_MARKER not in content:
                         logger.info('!!! WEBINAR FOUND !!!')
 
                         # Extract webinar details from table rows
@@ -1209,7 +1430,7 @@ async def check_webinars_job(context: ContextTypes.DEFAULT_TYPE):
                             row = rows.nth(i)
                             text = await row.inner_text()
 
-                            if 'Жодного онлайн уроку зараз' not in text:
+                            if NO_WEBINAR_MARKER not in text:
                                 # Extract name (topic) from first column
                                 name_elem = row.locator('td').nth(0)
                                 name = await name_elem.inner_text()
@@ -1289,9 +1510,9 @@ async def check_webinars_job(context: ContextTypes.DEFAULT_TYPE):
                     # Build message in user's language
                     # sub_id comes from redis set as string, convert to int for translation lookup
                     webinar_items = '\n\n'.join(
-                        [t(int(sub_id), 'webinar_item', name=w['name'], url=w['url']) for w in new_webinars]
+                        [t_chat(int(sub_id), int(sub_id), 'webinar_item', name=escape(w['name']), url=escape(w['url'])) for w in new_webinars]
                     )
-                    message = t(int(sub_id), 'webinar_found') + webinar_items
+                    message = t_chat(int(sub_id), int(sub_id), 'webinar_found') + webinar_items
 
                     await context.bot.send_message(chat_id=sub_id, text=message, parse_mode='HTML')
                     logger.info(f'Notification sent to {sub_id}')