import logging

from hashlib import sha1
from uuid import uuid4

from sleekxmpp.plugins.xep_0065 import stanza

from sleekxmpp.plugins.base import base_plugin
from sleekxmpp.xmlstream.handler import Callback
from sleekxmpp.xmlstream.matcher import StanzaPath
from sleekxmpp.thirdparty.socks import socksocket, PROXY_TYPE_SOCKS5

# Registers the sleekxmpp logger
log = logging.getLogger(__name__)


class XEP_0065(base_plugin):
    """
    XEP-0065 Socks5 Bytestreams
    """

    description = "Socks5 Bytestreams"
    dependencies = set(['xep_0030', ])
    xep = '0065'
    name = 'xep_0065'

    # A dict contains for each SID, the proxy thread currently
    # running.
    proxies = {}

    def plugin_init(self):
        """ Initializes the xep_0065 plugin and all event callbacks.
        """

        # Shortcuts to access to the xep_0030 plugin.
        self.disco = self.xmpp['xep_0030']

        # Handler for the streamhost stanza.
        self.xmpp.registerHandler(
            Callback('Socks5 Bytestreams',
                     StanzaPath('iq@type=set/socks/streamhost'),
                     self._handle_streamhost))

        # Handler for the streamhost-used stanza.
        self.xmpp.registerHandler(
            Callback('Socks5 Bytestreams',
                     StanzaPath('iq@type=result/socks/streamhost-used'),
                     self._handle_streamhost_used))

    def get_socket(self, sid):
        """ Returns the socket associated to the SID.
        """

        proxy = self.proxies.get(sid)
        if proxy:
            return proxy

    def handshake(self, to, streamer=None):
        """ Starts the handshake to establish the socks5 bytestreams
        connection.
        """

        # Discovers the proxy.
        self.streamer = streamer or self.discover_proxy()

        # Requester requests network address from the proxy.
        streamhost = self.get_network_address(self.streamer)
        self.proxy_host = streamhost['socks']['streamhost']['host']
        self.proxy_port = streamhost['socks']['streamhost']['port']

        # Generates the SID for this new handshake.
        sid = uuid4().hex

        # Requester initiates S5B negotation with Target by sending
        # IQ-set that includes the JabberID and network address of
        # StreamHost as well as the StreamID (SID) of the proposed
        # bytestream.
        iq = self.xmpp.Iq(sto=to, stype='set')
        iq['socks']['sid'] = sid
        iq['socks']['streamhost']['jid'] = self.streamer
        iq['socks']['streamhost']['host'] = self.proxy_host
        iq['socks']['streamhost']['port'] = self.proxy_port

        # Sends the new IQ.
        return iq.send()

    def discover_proxy(self):
        """ Auto-discovers (using XEP 0030) the available bytestream
        proxy on the XMPP server.

        Returns the JID of the proxy.
        """

        # Gets all disco items.
        disco_items = self.disco.get_items(self.xmpp.server)

        for item in disco_items['disco_items']['items']:
            # For each items, gets the disco info.
            disco_info = self.disco.get_info(item[0])

            # Gets and verifies if the identity is a bytestream proxy.
            identities = disco_info['disco_info']['identities']
            for identity in identities:
                if identity[0] == 'proxy' and identity[1] == 'bytestreams':
                    # Returns when the first occurence is found.
                    return '%s' % disco_info['from']

    def get_network_address(self, streamer):
        """ Gets the streamhost information of the proxy.

        streamer : The jid of the proxy.
        """

        iq = self.xmpp.Iq(sto=streamer, stype='get')
        iq['socks']  # Adds the query eleme to the iq.

        return iq.send()

    def _handle_streamhost(self, iq):
        """ Handles all streamhost stanzas.
        """

        # Registers the streamhost info.
        self.streamer = iq['socks']['streamhost']['jid']
        self.proxy_host = iq['socks']['streamhost']['host']
        self.proxy_port = iq['socks']['streamhost']['port']

        # Sets the SID, the requester and the target.
        sid = iq['socks']['sid']
        requester = '%s' % iq['from']
        target = '%s' % self.xmpp.boundjid

        # Next the Target attempts to open a standard TCP socket on
        # the network address of the Proxy.
        self.proxy = self._connect_proxy(sid, requester, target,
                                         self.proxy_host, self.proxy_port)

        # Registers the new proxy to the proxies dict.
        self.proxies[sid] = self.proxy

        # Replies to the incoming iq with a streamhost-used stanza.
        res_iq = iq.reply()
        res_iq['socks']['sid'] = sid
        res_iq['socks']['streamhost-used']['jid'] = self.streamer

        # Sends the IQ
        return res_iq.send()

    def _handle_streamhost_used(self, iq):
        """ Handles all streamhost-used stanzas.
        """

        # Sets the SID, the requester and the target.
        sid = iq['socks']['sid']
        requester = '%s' % self.xmpp.boundjid
        target = '%s' % iq['from']

        # The Requester will establish a connection to the SOCKS5
        # proxy in the same way the Target did.
        self.proxy = self._connect_proxy(sid, requester, target,
                                         self.proxy_host, self.proxy_port)

        # Registers the new thread in the proxy_thread dict.
        self.proxies[sid] = self.proxy

        # Requester sends IQ-set to StreamHost requesting that StreamHost
        # activate the bytestream associated with the StreamID.
        self.activate(iq['socks']['sid'], target)

    def activate(self, sid, to):
        """ IQ-set to StreamHost requesting that StreamHost activate
        the bytestream associated with the StreamID.
        """

        # Creates the activate IQ.
        act_iq = self.xmpp.Iq(sto=self.streamer, stype='set')
        act_iq['socks']['sid'] = sid
        act_iq['socks']['activate'] = to

        # Send the IQ.
        act_iq.send()

    def deactivate(self, sid):
        """ Closes the Proxy thread associated to this SID.
        """

        proxy = self.proxies.get(sid)
        if proxy:
            proxy.s.close()
            del self.proxies[sid]

    def close(self):
        """ Closes all Proxy threads.
        """

        for sid, proxy in self.proxies.items():
            proxy.close()
            del self.proxies[sid]

    def send(self, sid, data):
        """ Sends the data over the Proxy socket associated to the
        SID.
        """

        proxy = self.get_socket(sid)
        if proxy:
            proxy.sendall(data)

    def _connect_proxy(self, sid, requester, target, proxy, proxy_port):
        """ Establishes a connection between the client and the server-side
        Socks5 proxy.

        sid        : The StreamID. <str>
        requester  : The JID of the requester. <str>
        target     : The JID of the target. <str>
        proxy_host : The hostname or the IP of the proxy. <str>
        proxy_port : The port of the proxy. <str> or <int>
        """

        # Because the xep_0065 plugin uses the proxy_port as string,
        # the Proxy class accepts the proxy_port argument as a string
        # or an integer. Here, we force to use the port as an integer.
        proxy_port = int(proxy_port)

        # Creates the socks5 proxy socket
        sock = socksocket()
        sock.setproxy(PROXY_TYPE_SOCKS5, proxy, port=proxy_port)

        # The hostname MUST be SHA1(SID + Requester JID + Target JID)
        # where the output is hexadecimal-encoded (not binary).
        digest = sha1()
        digest.update(sid)  # SID
        digest.update(requester)  # Requester JID
        digest.update(target)  # Target JID

        # Computes the digest in hex.
        dest = '%s' % digest.hexdigest()

        # The port MUST be 0.
        sock.connect((dest, 0))
        log.info('Socket connected.')

        # Send the XMPP event.
        self.xmpp.event('socks_connected', sid)

        return sock