refactor: streamline configuration loading and enhance admin checks

- Refactored the configuration loading in `config.py` to utilize a single source of truth through the `Settings` class, improving maintainability and clarity.
- Introduced the `is_admin_for_telegram_user` function in `repository.py` to centralize admin checks based on usernames and phone numbers.
- Updated command handlers to use the new admin check function, ensuring consistent access control across the application.
- Enhanced error handling in the `error_handler` to log exceptions when sending error replies to users, improving debugging capabilities.
- Improved the handling of user phone updates in `repository.py` to ensure proper normalization and validation of phone numbers.

duty_teller/config.py

@@ -119,42 +119,23 @@ class Settings:
         )
 
 
-# Module-level vars: no validation on import; entry point must check BOT_TOKEN when needed.
-BOT_TOKEN = os.getenv("BOT_TOKEN") or ""
-DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///data/duty_teller.db")
-MINI_APP_BASE_URL = os.getenv("MINI_APP_BASE_URL", "").rstrip("/")
-HTTP_PORT = int(os.getenv("HTTP_PORT", "8080"))
+# Single source of truth: load once at import; entry point must check BOT_TOKEN when needed.
+_settings = Settings.from_env()
 
-_raw_allowed = os.getenv("ALLOWED_USERNAMES", "").strip()
-ALLOWED_USERNAMES = {
-    s.strip().lstrip("@").lower() for s in _raw_allowed.split(",") if s.strip()
-}
-
-_raw_admin = os.getenv("ADMIN_USERNAMES", "").strip()
-ADMIN_USERNAMES = {
-    s.strip().lstrip("@").lower() for s in _raw_admin.split(",") if s.strip()
-}
-
-ALLOWED_PHONES = _parse_phone_list(os.getenv("ALLOWED_PHONES", ""))
-ADMIN_PHONES = _parse_phone_list(os.getenv("ADMIN_PHONES", ""))
-
-MINI_APP_SKIP_AUTH = os.getenv("MINI_APP_SKIP_AUTH", "").strip() in ("1", "true", "yes")
-INIT_DATA_MAX_AGE_SECONDS = int(os.getenv("INIT_DATA_MAX_AGE_SECONDS", "0"))
-
-_raw_cors = os.getenv("CORS_ORIGINS", "").strip()
-CORS_ORIGINS = (
-    [_o.strip() for _o in _raw_cors.split(",") if _o.strip()]
-    if _raw_cors and _raw_cors != "*"
-    else ["*"]
-)
-
-EXTERNAL_CALENDAR_ICS_URL = os.getenv("EXTERNAL_CALENDAR_ICS_URL", "").strip()
-DUTY_DISPLAY_TZ = (
-    os.getenv("DUTY_DISPLAY_TZ", "Europe/Moscow").strip() or "Europe/Moscow"
-)
-DEFAULT_LANGUAGE = _normalize_default_language(
-    os.getenv("DEFAULT_LANGUAGE", "en").strip()
-)
+BOT_TOKEN = _settings.bot_token
+DATABASE_URL = _settings.database_url
+MINI_APP_BASE_URL = _settings.mini_app_base_url
+HTTP_PORT = _settings.http_port
+ALLOWED_USERNAMES = _settings.allowed_usernames
+ADMIN_USERNAMES = _settings.admin_usernames
+ALLOWED_PHONES = _settings.allowed_phones
+ADMIN_PHONES = _settings.admin_phones
+MINI_APP_SKIP_AUTH = _settings.mini_app_skip_auth
+INIT_DATA_MAX_AGE_SECONDS = _settings.init_data_max_age_seconds
+CORS_ORIGINS = _settings.cors_origins
+EXTERNAL_CALENDAR_ICS_URL = _settings.external_calendar_ics_url
+DUTY_DISPLAY_TZ = _settings.duty_display_tz
+DEFAULT_LANGUAGE = _settings.default_language
 
 
 def is_admin(username: str) -> bool: