from functools import partial

from twisted.python import log

from twisted.internet.defer import inlineCallbacks, returnValue, maybeDeferred, Deferred

from ..error import NoRouteForTask, RejectRecipient

from ..model.offer import offers

from ..model.job import exJobs

from .pool  import taskPool

class Task:

    '''one single part of a job.

    a task is one message to one recipient

    '''

    def __init__(self, recipient, job):

        self.recipient = recipient

        self.job = job

        self.status = None

        self.error = False

    def setStatus(self,status):

        self.status = status

        return status

    def setError(self, error):

        self.status = error

        self.error = True

        return error

    def start(self):

        self.d = Deferred()

        self.d.addCallback(self.setStatus)

        self.d.addCallback(partial(self.job.setStatus,self))

        self.d.addErrback(self.setError)

        self.d.addErrback(partial(self.job.setError,self))

        taskPool.run(self._run)

        return self.d

    def _run(self):

        os= iter(self.job.offers)

        def n():

            try:

                offer = os.next()

                d = maybeDeferred(offers[offer],self.recipient,self.job.message)

                d.addCallback(self.d.callback)

                d.addErrback(addErr,offer)

                d.addErrback(self.d.errback)

                return d

            except StopIteration:

                self.d.errback(NoRouteForTask())

        def addErr(failure, offer):

            if not isinstance(failure.value, RejectRecipient):  

                log.err(_why="Job(%s): Send to '%s' failed via '%s'"%(self.job.dbjob, self.recipient, offer),_stuff=failure)

            n()

        n()

@inlineCallbacks

def createJob(user,recipients, msg, offers, info=None):

    job = yield exJobs.create(user, recipients, msg, offers, info)

    for r in recipients:

        task = Task(r,job)

        job.addTask(task)

        task.start()

    returnValue(job)