import os
import logging
import gevent
from Crypto.Hash import SHA
from eventemitter import EventEmitter
from steam.enums.emsg import EMsg
from steam.enums import EResult, EOSType, EPersonaState
from steam.core.msg import MsgProto
from steam.core.cm import CMClient
from steam import SteamID
from steam.client.features import FeatureBase

logger = logging.getLogger("SteamClient")


class SteamClient(EventEmitter, FeatureBase):
    """
    Implementation of Steam client based on ``gevent``

    See `gevent-eventmitter <https://github.com/rossengeorgiev/gevent-eventemitter>`_
    for details on how to work with events.
    """
    current_jobid = 0
    credential_location = None  #: location for sentry
    username = None  #: username when logged on
    _logger = logger

    def __init__(self):
        self.cm = CMClient()

        # register listners
        self.cm.on(None, self._handle_cm_events)
        self.on(EMsg.ClientLogOnResponse, self._handle_logon)
        self.on(EMsg.ClientUpdateMachineAuth, self._handle_update_machine_auth)
        self.on("disconnected", self._handle_disconnect)

        #: indicates logged on status. Listen to ``logged_on`` when change to ``True``
        self.logged_on = False

        super(SteamClient, self).__init__()

    def __repr__(self):
        return "<%s() %s>" % (self.__class__.__name__,
                              'online' if self.connected else 'offline',
                              )

    def emit(self, event, *args):
        if event is not None:
            logger.debug("Emit event: %s" % repr(event))
        super(SteamClient, self).emit(event, *args)

    def set_credential_location(self, path):
        """
        Sets folder location for sentry files

        Needs to be set explicitly for sentries to be created.
        """
        self.credential_location = path

    @property
    def steam_id(self):
        """
        ``steam.steamid.SteamID`` of the current logged on user.
        Points to invalid user, if not logged on.
        """
        return self.cm.steam_id

    @property
    def connected(self):
        """
        Monitor ``connected`` and ``disconnected`` events for when this changes.
        """
        return self.cm.connected

    def connect(self):
        """
        Initiate connection
        """
        self.cm.connect()

    def disconnect(self):
        """
        Close connection
        """
        self.cm.disconnect()

    def _handle_cm_events(self, event, *args):
        self.emit(event, *args)

        if isinstance(event, EMsg):
            message = args[0]

            if message.proto:
                jobid = message.header.jobid_target
            else:
                jobid = message.header.targetJobID

            if jobid not in (-1, 18446744073709551615):
                self.emit("job_%d" % jobid, *args)

    def _handle_disconnect(self):
        self.username = None
        self.logged_on = False
        self.current_jobid = 0

    def _handle_logon(self, msg):
        result = EResult(msg.body.eresult)

        if result == EResult.OK:
            self.logged_on = True
            self.set_persona(EPersonaState.Online)
            self.emit("logged_on")
            return

        # CM kills the connection on error anyway
        self.disconnect()

        if result in (EResult.AccountLogonDenied,
                      EResult.InvalidLoginAuthCode,
                      EResult.AccountLoginDeniedNeedTwoFactor,
                      EResult.TwoFactorCodeMismatch,
                      ):

            is_2fa = (result in (EResult.AccountLoginDeniedNeedTwoFactor,
                                 EResult.TwoFactorCodeMismatch,
                                 ))

            if is_2fa:
                code_mismatch = (result == EResult.TwoFactorCodeMismatch)
            else:
                code_mismatch = (result == EResult.InvalidLoginAuthCode)

            self.emit("auth_code_required", is_2fa, code_mismatch)
        else:
            self.emit("error", result)

    def _handle_update_machine_auth(self, message):
        ok = self.store_sentry(self.username, message.body.bytes)

        if ok:
            resp = MsgProto(EMsg.ClientUpdateMachineAuthResponse)

            resp.header.jobid_target = message.header.jobid_source

            resp.body.filename = message.body.filename
            resp.body.eresult = EResult.OK
            resp.body.sha_file = SHA.new(message.body.bytes).digest()
            resp.body.getlasterror = 0
            resp.body.offset = message.body.offset
            resp.body.cubwrote = message.body.cubtowrite

            self.send(resp)

    def send(self, message):
        """
        Send a message to CM

        :param message: a message instance
        :type message: :class:`steam.core.msg.Msg`, :class:`steam.core.msg.MsgProto`
        """
        if not self.connected:
            raise RuntimeError("Cannot send message while not connected")

        self.cm.send_message(message)

    def send_job(self, message):
        """
        Send a message as a job

        .. note::
            Not all messages are jobs, you'll have to find out which are which

        :param message: a message instance
        :type message: :class:`steam.core.msg.Msg`, :class:`steam.core.msg.MsgProto`
        :return: ``jobid`` event identifier
        :rtype: :class:`str`

        To catch the response just listen for the ``jobid`` event.

        .. code:: python

            jobid = steamclient.send_job(my_message)

            resp = steamclient.wait_event(jobid, timeout=15)
            if resp:
                (message,) = resp

            @steamclient.once(jobid)
            def handle_response(message):
                pass

        """
        jobid = self.current_jobid = (self.current_jobid + 1) % 4294967295

        if message.proto:
            message.header.jobid_source = jobid
        else:
            message.header.sourceJobID = jobid

        self.send(message)

        return "job_%d" % jobid

    def _pre_login(self):
        if self.logged_on:
            logger.debug("Trying to login while logged on???")
            raise RuntimeError("Already logged on")

        if not self.connected:
            self.connect()

        if not self.cm.channel_secured:
            self.wait_event("channel_secured")

    def _get_sentry_path(self, username):
        if self.credential_location is not None:
            return os.path.join(self.credential_location,
                                "%s_sentry.bin" % username
                                 )
        return None

    def get_sentry(self, username):
        """
        Returns contents of sentry file for the given username

        .. note::
            returns ``None`` if :attr:`credential_location` is not set, or file is not found/inaccessible

        :param username: username
        :type username: :class:`str`
        :return: sentry file contents, or ``None``
        :rtype: :class:`bytes`, :class:`None`
        """
        filepath = self._get_sentry_path(username)

        if filepath and os.path.isfile(filepath):
            try:
                with open(filepath, 'r') as f:
                    return f.read()
            except IOError as e:
                logger.error("get_sentry: %s" % str(e))

        return None

    def store_sentry(self, username, sentry_bytes):
        """
        Store sentry bytes under a username

        :param username: username
        :type username: :class:`str`
        :return: Whenver the operation succeed
        :rtype: :class:`bool`
        """
        filepath = self._get_sentry_path(username)
        if filepath:
            try:
                with open(filepath, 'w') as f:
                    f.write(sentry_bytes)
                return True
            except IOError as e:
                logger.error("store_sentry: %s" % str(e))

        return False

    def login(self, username, password, auth_code=None, two_factor_code=None):
        """
        Login as a specific user

        :param username: username
        :type username: :class:`str`
        :param password: password
        :type password: :class:`str`
        :param auth_code: email authentication code
        :type auth_code: :class:`str`
        :param two_factor_code: 2FA authentication code
        :type two_factor_code: :class:`str`

        .. note::
            Failure to login will result in the server dropping the connection, ``error`` event is fired

        ``auth_code_required`` event is fired when 2FA or Email code is needed.
        Here is example code of how to handle the situation.

        .. code:: python

            @steamclient.on('auth_code_required')
            def auth_code_prompt(is_2fa, code_mismatch):
                if is_2fa:
                    code = raw_input("Enter 2FA Code: ")
                    steamclient.login(username, password, two_factor_code=code)
                else:
                    code = raw_input("Enter Email Code: ")
                    steamclient.login(username, password, auth_code=code)

        Codes are required every time a user logins if sentry is not setup.
        See :meth:`set_credential_location`
        """
        logger.debug("Attempting login")

        self._pre_login()

        self.username = username

        message = MsgProto(EMsg.ClientLogon)
        message.header.steamid = SteamID(type='Individual', universe='Public')
        message.body.protocol_version = 65575
        message.body.client_package_version = 1771
        message.body.client_os_type = EOSType.Win10
        message.body.client_language = "english"

        message.body.account_name = username
        message.body.password = password

        sentry = self.get_sentry(username)
        if sentry is None:
            message.body.eresult_sentryfile = EResult.FileNotFound
        else:
            message.body.eresult_sentryfile = EResult.OK
            message.body.sha_sentryfile = SHA.new(sentry).digest()

        if auth_code:
            message.body.auth_code = auth_code
        if two_factor_code:
            message.body.two_factor_code = two_factor_code

        self.send(message)

    def anonymous_login(self):
        """
        Login as anonymous user
        """
        logger.debug("Attempting Anonymous login")

        self._pre_login()

        message = MsgProto(EMsg.ClientLogon)
        message.header.steamid = SteamID(type='AnonUser', universe='Public')
        message.body.protocol_version = 65575
        self.send(message)

    def logout(self):
        """
        Logout from steam. Doesn't nothing if not logged on upon calling :meth:`logout`

        .. note::
            The server will drop the connection immediatelly upon logout.
        """
        if self.logged_on:
            self.logged_on = False
            self.send(MsgProto(EMsg.ClientLogOff))
            self.wait_event('disconnected')

    def run_forever(self):
        """
        Transfer control the gevent event loop

        This is useful when the application is setup and ment to run for a long time
        """
        while True:
            gevent.sleep(300)