# Show chat activity statistics
# Copyright © 2022 https://t.me/nalinor

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program 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 General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# meta developer: @nalinormods
# requires: matplotlib

from contextlib import suppress
from io import BytesIO
from typing import Awaitable

import matplotlib.pyplot as plt
from telethon import TelegramClient
from telethon.hints import EntityLike
from telethon.tl.custom import Message
from telethon.tl.functions.channels import JoinChannelRequest
from telethon.tl.types import MessageEmpty

from .. import loader, utils


# noinspection PyCallingNonCallable,PyAttributeOutsideInit
# pylint: disable=not-callable,attribute-defined-outside-init,invalid-name
@loader.tds
class MsgRateMod(loader.Module):
    """Show chat activity, counted in MpH (messages per hour)"""

    strings = {
        "name": "MsgRate",
        "author": "@nalinormods",
        "channels_only": "🚫 <b>This command can be executed only in groups and channels</b>",
        "unable_first_msg": "🚫 <b>Unable to retrieve first message</b>",
        "mph_for": "🔢 <b>MpH for {title}: {count}</b>",
        "chat_small": "🚫 <b>Messaging history of this chat is too small</b>",
        "calculating": "🕑 <b>Calculating, please wait..</b>",
        "messages_count": "Messages count",
        "average_mph": "Average messages per hour",
        "stats_for_chat": "MpH stats for chat {title}",
    }

    strings_ru = {
        "_cls_doc": "Показывает активность чата в MpH (кол-во сообщений в час)",
        "_cmd_doc_msgrate": "<айди чата/юзернейм/текущий> — Показать MpH чата",
        "_cmd_doc_msgstat": "<r|g|b> <айди чата/юзернейм/текущий> — Показать статистику MpH чата",
        "channels_only": "🚫 <b>Эта команда может быть выполнена только в группах и каналах</b>",
        "unable_first_msg": "🚫 <b>Не удаётся получить первое сообщение чата</b>",
        "mph_for": "🔢 <b>MpH для {title}: {count}</b>",
        "chat_small": "🚫 <b>История сообщений этого чата слишком мала</b>",
        "calculating": "🕑 <b>Рассчитываем, пожалуйста, подождите..</b>",
        "messages_count": "Количество сообщений",
        "average_mph": "Среднее кол-во сообщений в час",
        "stats_for_chat": "Статистика MpH для чата {title}",
    }

    async def client_ready(self, client: TelegramClient, _):
        """client_ready hook"""
        self.client = client

        await client(JoinChannelRequest(channel=self.strings("author")))

    @staticmethod
    def calc_mph(msg1: Message, msg2: Message) -> float:
        """Calculates MpH value for range between two messages"""
        count = msg2.id - msg1.id
        hours = (msg2.date - msg1.date).total_seconds() / 3600

        return round(count / (hours or 1), 3)

    @staticmethod
    def get_chat_id(message: Message) -> int:
        """Get chat_id from given message"""
        args = utils.get_args(message)
        if args and len(args[-1]) > 3:
            chat_id = args[-1]
            with suppress(ValueError):
                chat_id = int(chat_id)
        else:
            chat_id = message.chat_id

        return chat_id

    def get_last_msg(
        self, chat_id: EntityLike, reverse: bool = False
    ) -> Awaitable[Message]:
        """Gets last or first message in chat"""
        return self.client.iter_messages(chat_id, limit=1, reverse=reverse).__anext__()

    async def msgratecmd(self, message: Message):
        """<chat id/username/current> — Show MpH for chat"""
        chat_id = self.get_chat_id(message)
        last_msg = await self.get_last_msg(chat_id)

        if not last_msg.is_channel:
            return await utils.answer(message, self.strings("channels_only"))

        if (reply := await message.get_reply_message()) and chat_id == message.chat_id:
            msg = reply
        else:
            msg = await self.get_last_msg(chat_id, reverse=True)

        await utils.answer(
            message,
            self.strings("mph_for").format(
                title=(await last_msg.get_chat()).title,
                count=self.calc_mph(msg, last_msg),
            ),
        )

    async def msgstatcmd(self, message: Message):
        """<r|g|b> <chat id/username/current> — Show chat MpH statistics"""
        chat_id = self.get_chat_id(message)
        last_msg = await self.get_last_msg(chat_id)

        if not last_msg.is_channel:
            return await utils.answer(message, self.strings("channels_only"))

        if last_msg.id <= 200:
            return await utils.answer(message, self.strings("chat_small"))

        m = await utils.answer(message, self.strings("calculating"))
        if isinstance(m, list):
            m = m[0]

        messages = list(
            filter(
                lambda msg: msg and not isinstance(msg, MessageEmpty),
                await self.client.get_messages(
                    chat_id,
                    ids=[int(last_msg.id / 200) * count + 1 for count in range(200)],
                ),
            )
        )

        fig = plt.figure()

        x = [msg.id for msg in messages[:-1]]
        y = [
            self.calc_mph(first, second)
            for first, second
            in zip(messages, messages[1:])
        ]

        plt.xlabel(self.strings("messages_count"))
        plt.ylabel(self.strings("average_mph"))
        plt.plot(x, y, "r")

        plt.title(
            self.strings("stats_for_chat").format(
                title=(await last_msg.get_chat()).title
            )
        )

        stream = BytesIO()
        stream.name = "stats.png"
        await utils.run_sync(plt.savefig, stream)
        stream.seek(0)
        plt.close(fig)

        await self.client.send_file(
            message.chat_id,
            stream,
            reply_to=message.reply_to_msg_id,
        )
        await m.delete()