"""
    IRC client, dispatching irker messages.
"""

from twisted.internet import reactor, interfaces, protocol, defer, error
from twisted.words.protocols import irc

from twisted.internet import endpoints

from twisted.python import log

PORT = 6667

def url2endpoint (reactor, url) :
    """
        Turn given urlparse URL into an endpoint.

        Raises KeyError on unknown scheme.
    """

    SCHEMES = {
            'irc':      lambda : endpoints.TCP4ClientEndpoint(reactor, url.hostname, url.port or PORT),
    }
    
    return SCHEMES[url.scheme]()

def normalize (name) :
    """
        Normalize a channel/nickname for comparisons in IRC.
    """

    return name.lower()

class IRCError (Exception) :
    """
        A handled protocol error.
    """

    pass

class IRCChannel (object) :
    """
        A joined channel on an IRC server.
    """

    ENCODING = 'utf-8'

    def __init__ (self, client, channel, encoding=ENCODING) :
        self.client = client
        self.channel = channel

        self.encoding = encoding

    def encode (self, unicode) :
        if unicode :
            return unicode.encode(self.encoding)
        else :
            return None

    def privmsg (self, *msgs) :
        for msg in msgs :
            # XXX: encode
            self.client.msg(self.channel, self.encode(msg))

    def notice (self, *msgs) :
        for msg in msgs :
            self.client.notice(self.channel, self.encode(msg))

    def part (self, msg=None) :
        """
            Remove channel from our list of channels.
        """

        self.client.leave(self.channel, self.encode(msg))

    def errback (self, failure) :
        """
            Fail any pending requests.
        """

        log.msg('IRCChannel.errback', self, failure)

    def __str__ (self) :
        return self.client.url(self.channel)

class IRCClient (irc.IRCClient) :
    """
        A connection to an IRC server with a specific, requested nickname.

        Joins to channels.
    """

    performLogin = False

    def __init__ (self, factory) :
        self.factory = factory
        
        self.nickname = None
        self.hostname = None

        self._registering = None
        self._channels = { }

        # TODO: smarter/configurable queueing?
        self.lineRate = 1.0

    def connectionMade (self) :
        self.hostname = self.transport.getPeer().host
        self.transport.logPrefix = self.logPrefix

        log.msg("connectionMade", self, self.transport)
        irc.IRCClient.connectionMade(self)

    def sendLine (self, line) :
        irc.IRCClient.sendLine(self, line)

        log.msg(">>>", line)

    def lineReceived (self, line) :
        log.msg("<<<", line)

        irc.IRCClient.lineReceived(self, line)
        
    ## Register
    def register (self, nickname, username=None, password=None) :
        """
            Register to the server, choosing a nickname based on the given nickname.

            Returns a Deferred that callbacks with our actual nickname once we have registered, or errbacks with an IRCError.
        """

        if self._registering :
            raise Exception("register: already registering")

        self.username = username
        self.password = password
        
        log.msg("register", nickname)
        irc.IRCClient.register(self, nickname)

        # defer
        d = self._registering = defer.Deferred()

        return d
    
    # irc_ERR_NICKNAMEINUSE
    # alterCollidedNick
    # irc_ERR_ERRONEUSNICKNAME

    def irc_ERR_PASSWDMISMATCH (self, prefix, params) :
        err = IRCError('ERR_PASSWDMISMATCH')
        log.err(err)
        self._registering.errback(err)

    def irc_RPL_WELCOME (self, prefix, params) :
        self.hostname = prefix
        irc.IRCClient.irc_RPL_WELCOME(self, prefix, params)

    def signedOn (self) :
        log.msg("signedOn", self.nickname)
        irc.IRCClient.signedOn(self)
        
        # defer
        d = self._registering

        if not d :
            raise Exception("signedOn: not registering?")

        self._registering = None

        d.callback(self.nickname)
    
    ## Channels
    def join (self, channel, key=None) :
        """
            Join the given channel.

            Returns a deferred that callbacks with the IRCChannel once joined, or errbacks.
        """

        irc.IRCClient.join(self, channel, key=key)

        d = self._channels[normalize(channel)] = defer.Deferred()

        return d

    # ERR_CHANNELISFULL
    # ERR_INVITEONLYCHAN
    # ERR_BANNEDFROMCHAN
    # ERR_BADCHANNELKEY
    
    def _close_channel (self, channel) :
        """
            Remove channel from our list of channels.

            TODO: purge queued messages for channel?
        """

        del self._channels[normalize(channel)]

    def left (self, channel) :
        log.msg('IRCClient.left', channel)

        self._close_channel(channel)

    def kickedFrom (self, channel, kicker, message) :
        log.msg('IRCClient.kicked', channel, kicker, message)
        
        self._close_channel(channel)

    def joined (self, channel) :
        """
            Have joined given channel.
        """
        
        lookup = normalize(channel)

        d = self._channels[lookup]
        channel = self._channels[lookup] = IRCChannel(self, channel)
        d.callback(channel)

    @defer.inlineCallbacks
    def channel (self, channel, key=None) :
        """
            Defer a joined IRCChannel.
        """

        lookup = normalize(channel)
        
        log.msg('IRCClient.channel', lookup, channel)

        if lookup not in self._channels :
            channel = yield self.join(channel, key)
        else :
            # wait or get
            yield self._channels[lookup]

        channel = self._channels[lookup]

        log.msg('IRCClient.channel', lookup, channel)
        
        defer.returnValue(channel)

    ## 
    def irc_ERR_CANNOTSENDTOCHAN (self, prefix, params) :
        nick, channel, error = params

        log.err(IRCError(channel, error))

    ## Quit
    def irc_ERROR (self, prefix, params) :
        msg, = params
        error = IRCError(None, msg)

        log.err(error)

        if self._registering :
            self._registering.errback(error)
            self._registering = None

    def connectionLost (self, reason) :
        irc.IRCClient.connectionLost(self, reason)
        log.err(reason)

        if self._registering :
            self._registering.errback(reason)
            self._registering = None
        
        # unregister channels
        for channel in self._channels :
            # errback Deferred or IRCChannel
            self._channels[channel].errback(reason)
        
        self._channels = { }

        # unregister client
        self.factory.clientLost(self)
    
    ## Logging
    def url (self, target=None) :
        """
            Format as URL.
        """

        if not self.transport : return 'IRC'
        
        # XXX: no isinstance() support
        if interfaces.ITCPTransport.providedBy(self.transport) :
            scheme = 'irc'
        else :
            # TODO: ssl?
            scheme = None
        
        peer = self.transport.getPeer()

        if peer.port == PORT :
            peer = "{irc.hostname}".format(irc=self, peer=peer)
        else :
            peer = "{irc.hostname}:{peer.port}".format(irc=self, peer=peer)

        if target :
            path = str(target)
        else :
            path = None
        
        return ''.join(part for part in (
            scheme, '://' if scheme else None,
            self.nickname, '@' if self.nickname else None,
            peer,
            '/' if path else None, path
        ) if part)

    __str__ = url
    logPrefix = url

class IRCFactory (protocol.ClientFactory) :
    """
        Manage Clients and Targets
    """

    NICKNAME = 'irker'

    def __init__ (self, nickname=NICKNAME, username=None) :
        # default nickname
        self.nickname = nickname
        self.username = username

        # (scheme, host, port, nick) -> IRCClient
        self.clients = {}
    
    def buildProtocol (self, addr) :
        return IRCClient(self)

    def clientLost (self, client) :
        """
            Given IRCClient is no more.
        """

        log.msg("IRCFactory.clientLost", client)
        
        # remove from our clients
        self.clients = dict((k, c) for k, c in self.clients.iteritems() if c != client)

    @defer.inlineCallbacks
    def connect (self, url) :
        """
            Defer a connected, registered Client for given URL.
        """
        
        endpoint = url2endpoint(reactor, url)

        log.msg('IRCFactory.connect', url, ':', endpoint)
        
        # connect
        try :
            client = yield endpoint.connect(self)
        
        except error.ConnectError as ex :
            log.err(ex, ': '.join(str(x) for x in ('IRCFactory.connect', url, endpoint)))
            raise
        
        else :
            log.msg('IRCFactory.connect', url, ':', endpoint, ':', client)
        
        # register
        try :
            nickname = yield client.register(url.username or self.nickname, 
                    username    = self.username,
                    password    = url.password, 
            )

        except Exception as ex :
            log.err("register", ex)
            raise
        
        log.msg('IRCFactory.connect', url, ':', endpoint, ':', client, ':', nickname)

        # okay!
        defer.returnValue(client)

    @defer.inlineCallbacks
    def client (self, url) :
        """
            Return IRCClient for given URL.
        """

        lookup = (url.scheme, url.hostname, url.port, url.username)

        if lookup not in self.clients :
            # deferred for connect
            connect = self.clients[lookup] = self.connect(url)
            
            try :
                # wait on deferred, and then store IRCClient
                self.clients[lookup] = yield connect

            except Exception as ex :
                # failed, remove the attempted connect
                del self.clients[lookup]
                raise

        else :
            # wait for result, if deferred
            # XXX: this yields None, since the first inlineCallbacks yielding on the deferred returns None in its callback
            yield self.clients[lookup]
        
        # connected client
        client = self.clients.get(lookup)

        if client :
            log.msg('IRCFactory.client', url, ":", client)

            defer.returnValue(client)
        else :
            log.msg('IRCFactory.client', url, ": client connect failed")
            
            # XXX: get failure from first yield's errback... except inlineCallbacks drops it and goes to callback with None <_<
            raise Exception("Client connect failed")

    @defer.inlineCallbacks
    def target (self, url) :
        """
            Return IRCChannel for given URL.
        """

        client = yield self.client(url)
        
        channel = '#' + url.path.lstrip('/')
        channel = yield client.channel(channel)
        
        log.msg('IRCFactory.target', url, ":", channel)

        defer.returnValue(channel)

    @defer.inlineCallbacks
    def privmsg (self, url, *msg) :
        """
            Dispatch given messages to given target.
        """

        target = yield self.target(url)
        
        log.msg('IRCFactory.privmsg', url, ":", target, ':', *msg)

        target.privmsg(*msg)