# 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 logging
import threading
from collections import OrderedDict
from queue import Queue
from threading import Thread

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.workers_list = []
        self.updates_queue = Queue()
        self.groups = OrderedDict()

        self.update_parsers = {
            Dispatcher.MESSAGE_UPDATES:
                lambda upd, usr, cht: (pyrogram.Message.parse(self.client, upd.message, usr, cht), MessageHandler),

            Dispatcher.DELETE_MESSAGES_UPDATES:
                lambda upd, usr, cht: (pyrogram.Messages.parse_deleted(self.client, upd), DeletedMessagesHandler),

            Dispatcher.CALLBACK_QUERY_UPDATES:
                lambda upd, usr, cht: (pyrogram.CallbackQuery.parse(self.client, upd, usr), CallbackQueryHandler),

            (types.UpdateUserStatus,):
                lambda upd, usr, cht: (
                    pyrogram.UserStatus.parse(self.client, upd.status, upd.user_id), UserStatusHandler
                )
        }

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

    def start(self):
        for i in range(self.workers):
            self.workers_list.append(
                Thread(
                    target=self.update_worker,
                    name="UpdateWorker#{}".format(i + 1)
                )
            )

            self.workers_list[-1].start()

    def stop(self):
        for _ in range(self.workers):
            self.updates_queue.put(None)

        for worker in self.workers_list:
            worker.join()

        self.workers_list.clear()

    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)

    def update_worker(self):
        name = threading.current_thread().name
        log.debug("{} started".format(name))

        while True:
            update = 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 = parser(update, users, chats)

                for group in self.groups.values():
                    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:
                            handler.callback(self.client, *args)
                        except Exception as e:
                            log.error(e, exc_info=True)
                        finally:
                            break
            except Exception as e:
                log.error(e, exc_info=True)

        log.debug("{} stopped".format(name))