import logging
from aiogram.exceptions import TelegramAPIError, TelegramBadRequest, TelegramForbiddenError

logger = logging.getLogger(__name__)

# Errors that mean the user is definitively NOT in the chat
_NOT_MEMBER_PHRASES = (
    "user not found",
    "participant not found",
    "user_not_participant",
    "chat not found",
    "bot was kicked",
    "bot is not a member",
)

# Errors that mean we simply can't verify (privacy / anonymous mode) - allow through
_UNVERIFIABLE_PHRASES = (
    "user_id_invalid",
    "have no rights",
    "not enough rights",
    "administrators only",
)


async def check_membership(chat_id: int, user_id: int) -> bool:
    """Check if a user is an active member of a Telegram chat.

    Returns True when membership is confirmed OR when the check cannot be
    performed due to anonymous/privacy settings (bot has admin rights but
    Telegram hides the member - treat as verified to avoid false rejections).
    """
    from app.bot.router import bot

    try:
        member = await bot.get_chat_member(chat_id, user_id)
        return member.status in ("member", "administrator", "creator", "restricted")
    except TelegramBadRequest as e:
        msg = str(e).lower()
        if any(p in msg for p in _NOT_MEMBER_PHRASES):
            return False
        if any(p in msg for p in _UNVERIFIABLE_PHRASES):
            logger.debug("Membership unverifiable for user %s in chat %s (%s) - allowing", user_id, chat_id, e)
            return True
        # Unknown bad request - conservative deny
        logger.warning("getChatMember bad request for user %s in chat %s: %s", user_id, chat_id, e)
        return False
    except TelegramForbiddenError as e:
        # Bot removed from chat or no rights at all
        logger.warning("getChatMember forbidden for chat %s: %s", chat_id, e)
        return False
    except TelegramAPIError as e:
        logger.warning("getChatMember error for user %s in chat %s: %s", user_id, chat_id, e)
        return False