# -*- coding: utf-8 -*-

"""
The MIT License (MIT)

Copyright (c) 2015 Rapptz

Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
"""

from . import endpoints
from .user import User
from .channel import Channel, PrivateChannel
from .server import Server
from .message import Message
from .invite import Invite
from .object import Object
from .errors import *
from .state import ConnectionState
from . import utils

import asyncio
import aiohttp
import websockets

import logging, traceback
import sys, time, re, json

log = logging.getLogger(__name__)
request_logging_format = '{method} {response.url} has returned {response.status}'
request_success_log = '{response.url} with {json} received {data}'

def to_json(obj):
    return json.dumps(obj, separators=(',', ':'), ensure_ascii=True)

class Client:
    """Represents a client connection that connects to Discord.
    This class is used to interact with the Discord WebSocket and API.

    A number of options can be passed to the :class:`Client`.

    Parameters
    ----------
    max_messages : Optional[int]
        The maximum number of messages to store in :attr:`messages`.
        This defaults to 5000. Passing in `None` or a value of ``<= 0``
        will use the default instead of the passed in value.
    loop : Optional[event loop].
        The `event loop`_ to use for asynchronous operations. Defaults to ``None``,
        in which case the default event loop is used via ``asyncio.get_event_loop()``.

    Attributes
    -----------
    user : Optional[:class:`User`]
        Represents the connected client. None if not logged in.
    servers : list of :class:`Server`
        The servers that the connected client is a member of.
    private_channels : list of :class:`PrivateChannel`
        The private channels that the connected client is participating on.
    messages : deque_ of :class:`Message`
        A deque_ of :class:`Message` that the client has received from all
        servers and private messages. The number of messages stored in this
        deque is controlled by the ``max_messages`` parameter.
    email : Optional[str]
        The email used to login. This is only set if login is successful,
        otherwise it's None.
    gateway : Optional[str]
        The websocket gateway the client is currently connected to. Could be None.
    loop
        The `event loop`_ that the client uses for HTTP requests and websocket operations.

    .. _deque: https://docs.python.org/3.4/library/collections.html#collections.deque
    .. _event loop: https://docs.python.org/3/library/asyncio-eventloops.html
    """
    def __init__(self, *, loop=None, **options):
        self.ws = None
        self.token = None
        self.gateway = None
        self.loop = asyncio.get_event_loop() if loop is None else loop

        max_messages = options.get('max_messages')
        if max_messages is None or max_messages <= 0:
            max_messages = 5000

        self.connection = ConnectionState(self.dispatch, max_messages)
        self.session = aiohttp.ClientSession(loop=self.loop)
        self.headers = {
            'content-type': 'application/json',
        }
        self._closed = False

    def _resolve_mentions(self, content, mentions):
        if isinstance(mentions, list):
            return [user.id for user in mentions]
        elif mentions == True:
            return re.findall(r'<@(\d+)>', content)
        else:
            return []

    def _resolve_invite(self, invite):
        if isinstance(invite, Invite) or isinstance(invite, Object):
            return invite.id
        else:
            rx = r'(?:https?\:\/\/)?discord\.gg\/(.+)'
            m = re.match(rx, invite)
            if m:
                return m.group(1)
        return invite

    def _resolve_destination(self, destination):
        if isinstance(destination, (Channel, PrivateChannel, Server)):
            return destination.id
        elif isinstance(destination, User):
            found = utils.find(lambda pm: pm.user == destination, self.private_channels)
            if found is None:
                # Couldn't find the user, so start a PM with them first.
                self.start_private_message(destination)
                channel_id = self.private_channels[-1].id
                return channel_id
            else:
                return found.id
        elif isinstance(destination, Object):
            return destination.id
        else:
            raise InvalidArgument('Destination must be Channel, PrivateChannel, User, or Object')

    # Compatibility shim
    def __getattr__(self, name):
        if name in ('user', 'email', 'servers', 'private_channels', 'messages'):
            return getattr(self.connection, name)
        else:
            msg = "'{}' object has no attribute '{}'"
            raise AttributeError(msg.format(self.__class__, name))

    # Compatibility shim
    def __setattr__(self, name, value):
        if name in ('user', 'email', 'servers', 'private_channels',
                    'messages'):
            return setattr(self.connection, name, value)
        else:
            object.__setattr__(self, name, value)

    @property
    def is_logged_in(self):
        """bool: Indicates if the client has logged in successfully."""
        return self._is_logged_in

    @asyncio.coroutine
    def _get_gateway(self):
        resp = yield from self.session.get(endpoints.GATEWAY, headers=self.headers)
        if resp.status != 200:
            raise GatewayNotFound()
        data = yield from resp.json()
        return data.get('url')

    @asyncio.coroutine
    def _run_event(self, event, *args, **kwargs):
        try:
            yield from getattr(self, event)(*args, **kwargs)
        except Exception as e:
            yield from self.on_error(event, *args, **kwargs)

    def dispatch(self, event, *args, **kwargs):
        log.debug('Dispatching event {}'.format(event))
        method = 'on_' + event
        handler = 'handle_' + event

        if hasattr(self, handler):
            getattr(self, handler)(*args, **kwargs)

        if hasattr(self, method):
            utils.create_task(self._run_event(method, *args, **kwargs), loop=self.loop)

    def get_channel(self, id):
        """Returns a :class:`Channel` or :class:`PrivateChannel` with the following ID. If not found, returns None."""
        return self.connection.get_channel(id)

    @asyncio.coroutine
    def login(self, email, password):
        """|coro|

        Logs in the client with the specified credentials.

        Parameters
        ----------
        email : str
            The email used to login.
        password : str
            The password used to login.

        Raises
        ------
        LoginFailure
            The wrong credentials are passed.
        HTTPException
            An unknown HTTP related error occurred,
            usually when it isn't 200 or the known incorrect credentials
            passing status code.
        """
        payload = {
            'email': email,
            'password': password
        }

        data = to_json(payload)
        resp = yield from self.session.post(endpoints.LOGIN, data=data, headers=self.headers)
        log.debug(request_logging_format.format(method='POST', response=resp))
        if resp.status == 400:
            raise LoginFailure('Improper credentials have been passed.')
        elif resp.status != 200:
            data = yield from resp.json()
            raise HTTPException(resp, data.get('message'))

        log.info('logging in returned status code {}'.format(resp.status))
        self.email = email

        body = yield from resp.json()
        self.token = body['token']
        self.headers['authorization'] = self.token
        self._is_logged_in = True

    @asyncio.coroutine
    def keep_alive_handler(self, interval):
        while not self._closed:
            payload = {
                'op': 1,
                'd': int(time.time())
            }

            msg = 'Keeping websocket alive with timestamp {}'
            log.debug(msg.format(payload['d']))
            yield from self.ws.send(to_json(payload))
            yield from asyncio.sleep(interval)

    @asyncio.coroutine
    def on_error(self, event_method, *args, **kwargs):
        """|coro|

        The default error handler provided by the client.

        By default this prints to ``sys.stderr`` however it could be
        overridden to have a different implementation.
        Check :func:`discord.on_error` for more details.
        """
        print('Ignoring exception in {}'.format(event_method), file=sys.stderr)
        traceback.print_exc()

    def received_message(self, msg):
        log.debug('WebSocket Event: {}'.format(msg))
        self.dispatch('socket_response', msg)

        op = msg.get('op')
        data = msg.get('d')

        if op != 0:
            log.info('Unhandled op {}'.format(op))
            return

        event = msg.get('t')

        if event == 'READY':
            interval = data['heartbeat_interval'] / 1000.0
            self.keep_alive = utils.create_task(self.keep_alive_handler(interval), loop=self.loop)

        if event in ('READY', 'MESSAGE_CREATE', 'MESSAGE_DELETE',
                     'MESSAGE_UPDATE', 'PRESENCE_UPDATE', 'USER_UPDATE',
                     'CHANNEL_DELETE', 'CHANNEL_UPDATE', 'CHANNEL_CREATE',
                     'GUILD_MEMBER_ADD', 'GUILD_MEMBER_REMOVE',
                     'GUILD_MEMBER_UPDATE', 'GUILD_CREATE', 'GUILD_DELETE',
                     'GUILD_ROLE_CREATE', 'GUILD_ROLE_DELETE', 'TYPING_START',
                     'GUILD_ROLE_UPDATE', 'VOICE_STATE_UPDATE'):
            parser = 'parse_' + event.lower()
            if hasattr(self.connection, parser):
                getattr(self.connection, parser)(data)
        else:
            log.info("Unhandled event {}".format(event))

    @asyncio.coroutine
    def _make_websocket(self):
        if not self.is_logged_in:
            raise ClientException('You must be logged in to connect')

        self.gateway = yield from self._get_gateway()
        self.ws = yield from websockets.connect(self.gateway)
        self.ws.max_size = None
        log.info('Created websocket connected to {0.gateway}'.format(self))
        payload = {
            'op': 2,
            'd': {
                'token': self.token,
                'properties': {
                    '$os': sys.platform,
                    '$browser': 'discord.py',
                    '$device': 'discord.py',
                    '$referrer': '',
                    '$referring_domain': ''
                },
                'v': 3
            }
        }

        yield from self.ws.send(to_json(payload))
        log.info('sent the initial payload to create the websocket')

    @asyncio.coroutine
    def connect(self):
        """|coro|

        Creates a websocket connection and connects to the websocket listen
        to messages from discord.

        This function is implemented using a while loop in the background.
        If you need to run this event listening in another thread then
        you should run it in an executor or schedule the coroutine to
        be executed later using ``loop.create_task``.

        This function throws :exc:`ClientException` if called before
        logging in via :meth:`login`.
        """
        yield from self._make_websocket()

        while not self._closed:
            msg = yield from self.ws.recv()
            if msg is None:
                yield from self.ws.close()
                self._closed = True
                self.keep_alive.cancel()
                break

            self.received_message(json.loads(msg))

    def event(self, coro):
        """A decorator that registers an event to listen to.

        You can find more info about the events on the :ref:`documentation below <discord-api-events>`.

        The events must be a |corourl|_, if not, :exc:`ClientException` is raised.

        Example: ::

            @client.event
            @asyncio.coroutine
            def on_ready():
                print('Ready!')
        """

        if not asyncio.iscoroutinefunction(coro):
            raise ClientException('event registered must be a coroutine function')

        setattr(self, coro.__name__, coro)
        log.info('{0.__name__} has successfully been registered as an event'.format(coro))
        return coro

    @asyncio.coroutine
    def start_private_message(self, user):
        """|coro|

        Starts a private message with the user. This allows you to
        :meth:`send_message` to the user.

        Note
        -----
        This method should rarely be called as :meth:`send_message`
        does it automatically for you.

        Parameters
        -----------
        user : :class:`User`
            The user to start the private message with.

        Raises
        ------
        HTTPException
            The request failed.
        """

        if not isinstance(user, User):
            raise TypeError('user argument must be a User')

        payload = {
            'recipient_id': user.id
        }

        r = requests.post('{}/{}/channels'.format(endpoints.USERS, self.user.id), json=payload, headers=self.headers)
        log.debug(request_logging_format.format(response=r))
        utils._verify_successful_response(r)
        data = r.json()
        log.debug(request_success_log.format(response=r, json=payload, data=data))
        self.private_channels.append(PrivateChannel(id=data['id'], user=user))

    @asyncio.coroutine
    def send_message(self, destination, content, *, mentions=True, tts=False):
        """|coro|

        Sends a message to the destination given with the content given.

        The destination could be a :class:`Channel`, :class:`PrivateChannel` or :class:`Server`.
        For convenience it could also be a :class:`User`. If it's a :class:`User` or :class:`PrivateChannel`
        then it sends the message via private message, otherwise it sends the message to the channel.
        If the destination is a :class:`Server` then it's equivalent to calling
        :meth:`Server.get_default_channel` and sending it there. If it is a :class:`Object`
        instance then it is assumed to be the destination ID.

        .. versionchanged:: 0.9.0
            ``str`` being allowed was removed and replaced with :class:`Object`.

        The content must be a type that can convert to a string through ``str(content)``.

        The mentions must be either an array of :class:`User` to mention or a boolean. If
        ``mentions`` is ``True`` then all the users mentioned in the content are mentioned, otherwise
        no one is mentioned. Note that to mention someone in the content, you should use :meth:`User.mention`.

        Parameters
        ------------
        destination
            The location to send the message.
        content
            The content of the message to send.
        mentions
            A list of :class:`User` to mention in the message or a boolean. Ignored for private messages.
        tts : bool
            Indicates if the message should be sent using text-to-speech.

        Raises
        --------
        HTTPException
            Sending the message failed.
        InvalidArgument
            The destination parameter is invalid.

        Returns
        ---------
        :class:`Message`
            The message that was sent.
        """

        channel_id = self._resolve_destination(destination)

        content = str(content)
        mentions = self._resolve_mentions(content, mentions)

        url = '{base}/{id}/messages'.format(base=endpoints.CHANNELS, id=channel_id)
        payload = {
            'content': content,
            'mentions': mentions
        }

        if tts:
            payload['tts'] = True

        resp = yield from self.session.post(url, data=to_json(payload), headers=self.headers)
        log.debug(request_logging_format.format(method='POST', response=resp))
        yield from utils._verify_successful_response(resp)
        data = yield from resp.json()
        log.debug(request_success_log.format(response=resp, json=payload, data=data))
        channel = self.get_channel(data.get('channel_id'))
        message = Message(channel=channel, **data)
        return message