from functools import partial
from twisted.internet import defer
from twisted.internet.defer import inlineCallbacks, returnValue 

from ..error import NoRoute, 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

    def start(self):
        self.d = taskPool.run(self._run)
        self.d.addCallback(partial(self.job.setStatus,self))
        self.d.addErrback(partial(self.job.setError,self))
        return self.d

    @inlineCallbacks
    def _run(self):
        for offer in self.job.offers:
            try:
                ret = yield (offers[offer].send(self.recipient,self.job.message))
                returnValue(ret)
            except RejectRecipient:
                continue
        else:
            raise NoRoute()


def createJob(user,recipients, msg, offers, info=None):
    d = defer.maybeDeferred(exJobs.create,user, recipients, msg, offers, info)
    def _(job):
        for r in recipients:
            task = Task(r,job)
            job.addTask(task)
            task.start()
        return job
    d.addCallback(_)
    return d