from django.contrib.contenttypes.models import ContentType
from django.core.urlresolvers import reverse
from django.db import models
from django.utils.datastructures import SortedDict
from django.utils.translation import ugettext as _
from django.utils.translation import ugettext_lazy, ugettext_noop

from openslides.agenda.models import Item, Speaker
from openslides.core.models import Tag
from openslides.config.api import config
from openslides.poll.models import (BaseOption, BasePoll, BaseVote,
                                    CollectDefaultVotesMixin,
                                    PublishPollMixin)
from openslides.projector.api import get_active_object, update_projector
from openslides.projector.models import RelatedModelMixin, SlideMixin
from openslides.utils.exceptions import OpenSlidesError
from openslides.utils.models import AbsoluteUrlMixin
from openslides.utils.utils import html_strong
from openslides.users.models import User


class AssignmentCandidate(RelatedModelMixin, models.Model):
    """
    Many2Many table between an assignment and the candidates.
    """
    assignment = models.ForeignKey("Assignment")
    person = models.ForeignKey(User, db_index=True)
    elected = models.BooleanField(default=False)
    blocked = models.BooleanField(default=False)

    class Meta:
        unique_together = ("assignment", "person")

    def __str__(self):
        return str(self.person)

    def get_related_model(self):
        """
        Returns the assignment
        """
        return self.assignment


class Assignment(SlideMixin, AbsoluteUrlMixin, models.Model):
    slide_callback_name = 'assignment'

    STATUS = (
        ('sea', ugettext_lazy('Searching for candidates')),
        ('vot', ugettext_lazy('Voting')),
        ('fin', ugettext_lazy('Finished')),
    )

    name = models.CharField(max_length=100, verbose_name=ugettext_lazy("Name"))
    description = models.TextField(null=True, blank=True, verbose_name=ugettext_lazy("Description"))
    posts = models.PositiveSmallIntegerField(verbose_name=ugettext_lazy("Number of available posts"))
    poll_description_default = models.CharField(
        max_length=79, null=True, blank=True,
        verbose_name=ugettext_lazy("Default comment on the ballot paper"))
    status = models.CharField(max_length=3, choices=STATUS, default='sea')
    tags = models.ManyToManyField(Tag, blank=True)

    class Meta:
        permissions = (
            ('can_see_assignment', ugettext_noop('Can see elections')),  # TODO: Add plural s to the codestring
            ('can_nominate_other', ugettext_noop('Can nominate another person')),
            ('can_nominate_self', ugettext_noop('Can nominate oneself')),
            ('can_manage_assignment', ugettext_noop('Can manage elections')),  # TODO: Add plural s also to the codestring
        )
        ordering = ('name',)
        verbose_name = ugettext_noop('Election')

    def __str__(self):
        return self.name

    def get_absolute_url(self, link='detail'):
        if link == 'detail':
            url = reverse('assignment_detail', args=[str(self.pk)])
        elif link == 'update':
            url = reverse('assignment_update', args=[str(self.pk)])
        elif link == 'delete':
            url = reverse('assignment_delete', args=[str(self.pk)])
        else:
            url = super(Assignment, self).get_absolute_url(link)
        return url

    def get_slide_context(self, **context):
        context.update({
            'polls': self.poll_set.filter(published=True),
            'vote_results': self.vote_results(only_published=True)})
        return super(Assignment, self).get_slide_context(**context)

    def set_status(self, status):
        status_dict = dict(self.STATUS)
        if status not in status_dict:
            raise ValueError(_('%s is not a valid status.') % html_strong(status))
        if self.status == status:
            raise ValueError(
                _('The election status is already %s.') % html_strong(status_dict[status]))
        self.status = status
        self.save()

    def run(self, candidate, person=None):
        """
        run for a vote
        candidate: The user who will be a candidate
        person: The user who chooses the candidate
        """
        # TODO: don't make any permission checks here.
        #       Use other Exceptions
        if self.is_candidate(candidate):
            raise NameError(_('<b>%s</b> is already a candidate.') % candidate)
        if not person.has_perm("assignment.can_manage_assignment") and self.status != 'sea':
            raise NameError(_('The candidate list is already closed.'))
        candidature = self.assignment_candidates.filter(person=candidate)
        if candidature and candidate != person and \
                not person.has_perm("assignment.can_manage_assignment"):
            # if the candidature is blocked and anotherone tries to run the
            # candidate
            raise NameError(
                _('%s does not want to be a candidate.') % candidate)
        elif candidature:
            candidature[0].blocked = False
            candidature[0].save()
        else:
            AssignmentCandidate(assignment=self, person=candidate).save()

    def delrun(self, candidate, blocked=True):
        """
        stop running for a vote
        """
        try:
            candidature = self.assignment_candidates.get(person=candidate)
        except AssignmentCandidate.DoesNotExist:
            raise Exception(_('%s is no candidate') % candidate)

        if not candidature.blocked:
            if blocked:
                candidature.blocked = True
                candidature.save()
            else:
                candidature.delete()
        else:
            candidature.delete()

    def is_candidate(self, person):
        """
        return True, if person is a candidate.
        """
        try:
            return self.assignment_candidates.filter(person=person).exclude(blocked=True).exists()
        except AttributeError:
            return False

    def is_blocked(self, person):
        """
        return True, if the person is blockt for candidature.
        """
        return self.assignment_candidates.filter(person=person).filter(blocked=True).exists()

    @property
    def assignment_candidates(self):
        return AssignmentCandidate.objects.filter(assignment=self)

    @property
    def candidates(self):
        return self.get_participants(only_candidate=True)

    @property
    def elected(self):
        return self.get_participants(only_elected=True)

    def get_participants(self, only_elected=False, only_candidate=False):
        candidates = self.assignment_candidates.exclude(blocked=True)

        assert not (only_elected and only_candidate)

        if only_elected:
            candidates = candidates.filter(elected=True)

        if only_candidate:
            candidates = candidates.filter(elected=False)

        # TODO: rewrite this with a queryset
        participants = []
        for candidate in candidates.all():
            participants.append(candidate.person)
        return participants

    def set_elected(self, person, value=True):
        candidate = self.assignment_candidates.get(person=person)
        candidate.elected = value
        candidate.save()
        # update projector if assignment or assignmentpoll slide is active
        active_object = get_active_object()
        if (type(active_object) is type(self) and active_object.pk == self.pk) or \
           (type(active_object) is AssignmentPoll and active_object.assignment_id == self.pk):
            update_projector()

    def is_elected(self, person):
        return person in self.elected

    def gen_poll(self):
        """
        Creates an new poll for the assignment and adds all candidates to all
        lists of speakers of related agenda items.
        """
        if config['assignment_poll_vote_values'] == 'votes':
            yesnoabstain = False
        elif config['assignment_poll_vote_values'] == 'yesnoabstain':
            yesnoabstain = True
        else:
            # config['assignment_poll_vote_values'] == 'auto'
            # candidates <= available posts -> yes/no/abstain
            if len(self.candidates) <= (self.posts - len(self.elected)):
                yesnoabstain = True
            else:
                yesnoabstain = False

        poll = AssignmentPoll.objects.create(
            assignment=self,
            description=self.poll_description_default,
            yesnoabstain=yesnoabstain)
        poll.set_options([{'candidate': person} for person in self.candidates])

        items = Item.objects.filter(content_type=ContentType.objects.get_for_model(Assignment), object_id=self.pk)
        for item in items:
            someone_added = None
            for candidate in self.candidates:
                try:
                    someone_added = Speaker.objects.add(candidate, item)
                except OpenSlidesError:
                    # The Speaker is already on the list. Do nothing.
                    # TODO: Find a smart way not to catch the error concerning AnonymousUser.
                    pass
            if someone_added is not None:
                someone_added.check_and_update_projector()

        return poll

    def vote_results(self, only_published):
        """
        returns a table represented as a list with all candidates from all
        related polls and their vote results.
        """
        vote_results_dict = SortedDict()
        # All polls related to this assigment
        polls = self.poll_set.all()
        if only_published:
            polls = polls.filter(published=True)
        # All PollOption-Objects related to this assignment
        options = []
        for poll in polls:
            options += poll.get_options()

        for option in options:
            candidate = option.candidate
            if candidate in vote_results_dict:
                continue
            vote_results_dict[candidate] = []
            for poll in polls:
                votes = {}
                try:
                    # candidate related to this poll
                    poll_option = poll.get_options().get(candidate=candidate)
                    for vote in poll_option.get_votes():
                        votes[vote.value] = vote.print_weight()
                except AssignmentOption.DoesNotExist:
                    # candidate not in related to this poll
                    votes = None
                vote_results_dict[candidate].append(votes)
        return vote_results_dict

    def get_agenda_title(self):
        return self.name

    def get_agenda_title_supplement(self):
        return '(%s)' % _('Assignment')


class AssignmentVote(BaseVote):
    option = models.ForeignKey('AssignmentOption')


class AssignmentOption(BaseOption):
    poll = models.ForeignKey('AssignmentPoll')
    candidate = models.ForeignKey(User)
    vote_class = AssignmentVote

    def __str__(self):
        return str(self.candidate)


class AssignmentPoll(SlideMixin, RelatedModelMixin, CollectDefaultVotesMixin,
                     PublishPollMixin, AbsoluteUrlMixin, BasePoll):

    slide_callback_name = 'assignmentpoll'
    """Name of the callback for the slide system."""

    option_class = AssignmentOption
    assignment = models.ForeignKey(Assignment, related_name='poll_set')
    yesnoabstain = models.BooleanField(default=False)
    description = models.CharField(
        max_length=79, null=True, blank=True,
        verbose_name=ugettext_lazy("Comment on the ballot paper"))

    def __str__(self):
        return _("Ballot %d") % self.get_ballot()

    def get_absolute_url(self, link='update'):
        """
        Return an URL for the poll.

        The keyargument 'link' can be 'update' or 'delete'.
        """
        if link == 'update':
            url = reverse('assignmentpoll_update', args=[str(self.pk)])
        elif link == 'delete':
            url = reverse('assignmentpoll_delete', args=[str(self.pk)])
        else:
            url = super(AssignmentPoll, self).get_absolute_url(link)
        return url

    def get_assignment(self):
        return self.assignment

    def get_related_model(self):
        return self.assignment

    def get_vote_values(self):
        if self.yesnoabstain:
            return [ugettext_noop('Yes'), ugettext_noop('No'), ugettext_noop('Abstain')]
        else:
            return [ugettext_noop('Votes')]

    def get_ballot(self):
        return self.assignment.poll_set.filter(id__lte=self.id).count()

    def get_percent_base_choice(self):
        return config['assignment_poll_100_percent_base']

    def append_pollform_fields(self, fields):
        fields.append('description')
        super(AssignmentPoll, self).append_pollform_fields(fields)

    def get_slide_context(self, **context):
        return super(AssignmentPoll, self).get_slide_context(poll=self)