#  cobaltgram - Telegram MTProto API Client Library for Python
#  Copyright (C) 2017-present Dan <https://github.com/delivrance>
#
#  This file is part of cobaltgram.
#
#  cobaltgram is free software: you can redistribute it and/or modify
#  it under the terms of the GNU Lesser General Public License as published
#  by the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  cobaltgram is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU Lesser General Public License for more details.
#
#  You should have received a copy of the GNU Lesser General Public License
#  along with cobaltgram.  If not, see <http://www.gnu.org/licenses/>.

import logging
from typing import Union

import cobaltgram
from cobaltgram import raw

log = logging.getLogger(__name__)


class GetChatHistoryCount:
    async def get_chat_history_count(
        self: "cobaltgram.Client",
        chat_id: Union[int, str]
    ) -> int:
        """Get the total count of messages in a chat.

        .. note::

            Due to Telegram latest internal changes, the server can't reliably find anymore the total count of messages
            a **private** or a **basic group** chat has with a single method call. To overcome this limitation, cobaltgram
            has to iterate over all the messages. Channels and supergroups are not affected by this limitation.

        .. include:: /_includes/usable-by/users.rst

        Parameters:
            chat_id (``int`` | ``str``):
                Unique identifier (int) or username (str) of the target chat.

        Returns:
            ``int``: On success, the chat history count is returned.

        Example:
            .. code-block:: python

                await app.get_chat_history_count(chat_id)
        """

        peer = await self.resolve_peer(chat_id)

        # https://t.me/tdlibchat/189410
        ranges = await self.invoke(raw.functions.messages.GetSplitRanges())
        total = 0

        for split_range in ranges:
            r = await self.invoke(
                raw.functions.InvokeWithMessagesRange(
                    range=split_range,
                    query=raw.functions.messages.GetHistory(
                        peer=peer,
                        offset_id=0,
                        offset_date=0,
                        add_offset=0,
                        limit=1,
                        max_id=0,
                        min_id=0,
                        hash=0
                    )
                )
            )
            if isinstance(r, raw.types.messages.Messages):
                total += len(r.messages)
            else:
                total += r.count

        return total
