# This file is based on TLSharp
# https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/TelegramClient.cs
import platform

import utils
import network.authenticator
from network import MtProtoSender, TcpTransport
from errors import *

from tl import Session
from tl.types import InputPeerUser, InputPeerEmpty
from tl.functions import InvokeWithLayerRequest, InitConnectionRequest
from tl.functions.help import GetConfigRequest
from tl.functions.auth import CheckPhoneRequest, SendCodeRequest, SignInRequest
from tl.functions.messages import GetDialogsRequest, SendMessageRequest


class TelegramClient:
    def __init__(self, session_user_id, layer, api_id=None, api_hash=None):
        if api_id is None or api_hash is None:
            raise PermissionError('Your API ID or Hash are invalid. Please read "Requirements" on README.md')

        self.api_id = api_id
        self.api_hash = api_hash

        self.layer = layer

        self.session = Session.try_load_or_create_new(session_user_id)
        self.transport = TcpTransport(self.session.server_address, self.session.port)

        # These will be set later
        self.dc_options = None
        self.sender = None
        self.phone_code_hash = None

    def connect(self, reconnect=False):
        if not self.session.auth_key or reconnect:
            self.session.auth_key, self.session.time_offset = network.authenticator.do_authentication(self.transport)
            self.session.save()

        self.sender = MtProtoSender(self.transport, self.session)
        self.sender.add_update_handler(self.on_update)

        # Always init connection by using the latest layer, not only when not reconnecting (as in original TLSharp's)
        # Otherwise, the server thinks that were using the oldest layer!
        # (Note that this is mainly untested, but it seems like it since some errors point in that direction)
        request = InvokeWithLayerRequest(layer=self.layer,
                                         query=InitConnectionRequest(api_id=self.api_id,
                                                                     device_model=platform.node(),
                                                                     system_version=platform.system(),
                                                                     app_version='0.1',
                                                                     lang_code='en',
                                                                     query=GetConfigRequest()))

        self.sender.send(request)
        self.sender.receive(request)

        # Result is a Config TLObject
        self.dc_options = request.result.dc_options

        return True

    def reconnect_to_dc(self, dc_id):
        if self.dc_options is None or not self.dc_options:
            raise ConnectionError("Can't reconnect. Stabilise an initial connection first.")

        # dc is a DcOption TLObject
        dc = next(dc for dc in self.dc_options if dc.id == dc_id)

        self.transport.close()
        self.transport = TcpTransport(dc.ip_address, dc.port)
        self.session.server_address = dc.ip_address
        self.session.port = dc.port
        self.session.save()

        self.connect(reconnect=True)

    def is_user_authorized(self):
        return self.session.user is not None

    def is_phone_registered(self, phone_number):
        assert self.sender is not None, 'Not connected!'

        request = CheckPhoneRequest(phone_number)
        self.sender.send(request)
        self.sender.receive(request)

        # Result is an Auth.CheckedPhone
        return request.result.phone_registered

    def send_code_request(self, phone_number):
        request = SendCodeRequest(phone_number, self.api_id, self.api_hash)
        completed = False
        while not completed:
            try:
                self.sender.send(request)
                self.sender.receive(request)
                completed = True
                if request.result:
                    self.phone_code_hash = request.result.phone_code_hash

            except InvalidDCError as error:
                self.reconnect_to_dc(error.new_dc)

    def make_auth(self, phone_number, code):
        if not self.phone_code_hash:
            raise ValueError('Please make sure you have called send_code_request first!')

        request = SignInRequest(phone_number, self.phone_code_hash, code)
        self.sender.send(request)
        self.sender.receive(request)

        # Result is an Auth.Authorization TLObject
        self.session.user = request.result.user
        self.session.save()

        return self.session.user

    def get_dialogs(self):
        request = GetDialogsRequest(offset_date=0,
                                    offset_id=0,
                                    offset_peer=InputPeerEmpty(),
                                    limit=20)

        self.sender.send(request)
        self.sender.receive(request)

        print(request.result)

    def send_message(self, user, message):
        peer = InputPeerUser(user.id, user.access_hash)
        request = SendMessageRequest(peer, message, utils.generate_random_long())

        self.sender.send(request)
        self.sender.receive(request)

    def on_update(self, tlobject):
        """This method is fired when there are updates from Telegram.
        Add your own implementation below, or simply override it!"""
        print('We have an update: {}'.format(str(tlobject)))