import cPickle

import traceback

from cubicweb.server.server import QuitEvent

class ZMQRepositoryServer(object):

    def __init__(self, repository):

        """make the repository available as a PyRO object"""

        self.address = None

        self.repo = repository

        self.socket = None

        self.stream = None

        self.loop = None

        # event queue

        self.events = []

    def connect(self, address):

        self.address = address

    def run(self):

        """enter the service loop"""

        # start repository looping tasks

        self.socket = ctx.socket(zmq.REP)

        self.loop = ioloop.IOLoop()

        self.stream = zmq.eventloop.zmqstream.ZMQStream(self.socket, io_loop=self.loop)

        self.stream.bind(self.address)

        self.info('ZMQ server bound on: %s', self.address)

        self.stream.on_recv(self.process_cmds)

        try:

            self.loop.start()

        except zmq.ZMQError:

            self.warning('ZMQ event loop killed')

        self.quit()

    def trigger_events(self):

        """trigger ready events"""

        for event in self.events[:]:

            if event.is_ready():

                self.info('starting event %s', event)

                event.fire(self)

                try:

                    event.update()

                except Finished:

                    self.events.remove(event)

    def process_cmd(self, cmd):

        """Delegate the given command to the repository.

        ``cmd`` is a list of (method_name, args, kwargs)

        where ``args`` is a list of positional arguments

        and ``kwargs`` is a dictionnary of named arguments.

        >>> rset = delegate_to_repo(["execute", [sessionid], {'rql': rql}])

        :note1: ``kwargs`` may be ommited

            >>> rset = delegate_to_repo(["execute", [sessionid, rql]])

        :note2: both ``args`` and ``kwargs`` may be omitted

            >>> schema = delegate_to_repo(["get_schema"])

            >>> schema = delegate_to_repo("get_schema") # also allowed

        """

        cmd = cPickle.loads(cmd)

        if not cmd:

            raise AttributeError('function name required')

        if isinstance(cmd, basestring):

            cmd = [cmd]

        if len(cmd) < 2:

            cmd.append(())

        if len(cmd) < 3:

            cmd.append({})

        cmd  = list(cmd) + [(), {}]

        funcname, args, kwargs = cmd[:3]

        result = getattr(self.repo, funcname)(*args, **kwargs)

        return result

    def process_cmds(self, cmds):

        """Callback intended to be used with ``on_recv``.

        Call ``delegate_to_repo`` on each command and send a pickled of

        each result recursively.

        Any exception are catched, pickled and sent.

        """

        try:

            for cmd in cmds:

                result = self.process_cmd(cmd)

                self.send_data(result)

        except Exception, exc:

            traceback.print_exc()

            self.send_data(exc)

    def send_data(self, data):

        self.socket.send_pyobj(data)

    def quit(self, shutdown_repo=False):

        """stop the server"""

        self.info('Quitting ZMQ server')

        try:

            self.loop.stop()

            self.stream.on_recv(None)

            self.stream.close()

        except Exception, e:

            print e

            pass

        if shutdown_repo and not self.repo.shutting_down:

            event = QuitEvent()

            event.fire(self)

    # server utilitities ######################################################

    def install_sig_handlers(self):

        """install signal handlers"""

        import signal

        self.info('installing signal handlers')

        signal.signal(signal.SIGINT, lambda x, y, s=self: s.quit(shutdown_repo=True))

        signal.signal(signal.SIGTERM, lambda x, y, s=self: s.quit(shutdown_repo=True))

    # these are overridden by set_log_methods below

    # only defining here to prevent pylint from complaining

    @classmethod

    def info(cls, msg, *a, **kw):

        pass

set_log_methods(ZMQRepositoryServer, getLogger('cubicweb.zmq.repo'))