# Pyrogram - Telegram MTProto API Client Library for Python
# Copyright (C) 2017-2018 Dan Tès <https://github.com/delivrance>
#
# This file is part of Pyrogram.
#
# Pyrogram 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.
#
# Pyrogram 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 Pyrogram.  If not, see <http://www.gnu.org/licenses/>.

import asyncio
import logging
from collections import OrderedDict

import pyrogram
from pyrogram.api import types
from ..handlers import CallbackQueryHandler, MessageHandler, RawUpdateHandler, UserStatusHandler, DeletedMessagesHandler

log = logging.getLogger(__name__)


class Dispatcher:
    NEW_MESSAGE_UPDATES = (
        types.UpdateNewMessage,
        types.UpdateNewChannelMessage
    )

    EDIT_MESSAGE_UPDATES = (
        types.UpdateEditMessage,
        types.UpdateEditChannelMessage
    )

    DELETE_MESSAGES_UPDATES = (
        types.UpdateDeleteMessages,
        types.UpdateDeleteChannelMessages
    )

    CALLBACK_QUERY_UPDATES = (
        types.UpdateBotCallbackQuery,
        types.UpdateInlineBotCallbackQuery
    )

    MESSAGE_UPDATES = NEW_MESSAGE_UPDATES + EDIT_MESSAGE_UPDATES

    def __init__(self, client, workers: int):
        self.client = client
        self.workers = workers

        self.update_worker_tasks = []
        self.updates_queue = asyncio.Queue()
        self.groups = OrderedDict()

        async def message_parser(update, users, chats):
            return await pyrogram.Message._parse(self.client, update.message, users, chats), MessageHandler

        async def deleted_messages_parser(update, users, chats):
            return pyrogram.Messages._parse_deleted(self.client, update), DeletedMessagesHandler

        async def callback_query_parser(update, users, chats):
            return await pyrogram.CallbackQuery._parse(self.client, update, users), CallbackQueryHandler

        async def user_status_parser(update, users, chats):
            return pyrogram.UserStatus._parse(self.client, update.status, update.user_id), UserStatusHandler

        self.update_parsers = {
            Dispatcher.MESSAGE_UPDATES: message_parser,
            Dispatcher.DELETE_MESSAGES_UPDATES: deleted_messages_parser,
            Dispatcher.CALLBACK_QUERY_UPDATES: callback_query_parser,
            (types.UpdateUserStatus,): user_status_parser
        }

        self.update_parsers = {key: value for key_tuple, value in self.update_parsers.items() for key in key_tuple}

    async def start(self):
        for i in range(self.workers):
            self.update_worker_tasks.append(
                asyncio.ensure_future(self.update_worker())
            )

        log.info("Started {} UpdateWorkerTasks".format(self.workers))

    async def stop(self):
        for i in range(self.workers):
            self.updates_queue.put_nowait(None)

        for i in self.update_worker_tasks:
            await i

        self.update_worker_tasks.clear()

        log.info("Stopped {} UpdateWorkerTasks".format(self.workers))

    def add_handler(self, handler, group: int):
        if group not in self.groups:
            self.groups[group] = []
            self.groups = OrderedDict(sorted(self.groups.items()))

        self.groups[group].append(handler)

    def remove_handler(self, handler, group: int):
        if group not in self.groups:
            raise ValueError("Group {} does not exist. Handler was not removed.".format(group))

        self.groups[group].remove(handler)

    async def update_worker(self):
        while True:
            update = await self.updates_queue.get()

            if update is None:
                break

            try:
                users = {i.id: i for i in update[1]}
                chats = {i.id: i for i in update[2]}
                update = update[0]

                parser = self.update_parsers.get(type(update), None)

                if parser is None:
                    continue

                parsed_update, handler_type = await parser(update, users, chats)

                for group in self.groups.values():
                    try:
                        for handler in group:
                            args = None

                            if isinstance(handler, RawUpdateHandler):
                                args = (update, users, chats)
                            elif isinstance(handler, handler_type):
                                if handler.check(parsed_update):
                                    args = (parsed_update,)

                            if args is None:
                                continue

                            try:
                                await handler.callback(self.client, *args)
                            except StopIteration:
                                raise
                            except Exception as e:
                                log.error(e, exc_info=True)

                            break
                    except StopIteration:
                        break
            except Exception as e:
                log.error(e, exc_info=True)