#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
    openslides.assignment.models
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Models for the assignment app.

    :copyright: 2011–2013 by OpenSlides team, see AUTHORS.
    :license: GNU GPL, see LICENSE for more details.
"""

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

from openslides.utils.person import PersonField
from openslides.utils.utils import html_strong
from openslides.config.api import config
from openslides.projector.models import SlideMixin, RelatedModelMixin
from openslides.poll.models import (
    BasePoll, CountInvalid, CountVotesCast, BaseOption, PublishPollMixin, BaseVote)


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

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

    def __unicode__(self):
        return unicode(self.person)

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


class Assignment(SlideMixin, 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"))
    polldescription = models.CharField(
        max_length=100, null=True, blank=True,
        verbose_name=ugettext_lazy("Comment on the ballot paper"))
    status = models.CharField(max_length=3, choices=STATUS, default='sea')

    class Meta:
        permissions = (
            ('can_see_assignment', ugettext_noop('Can see assignments')),  # 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 assignments')),  # TODO: Add plural s also to the codestring
        )
        ordering = ('name',)

    def __unicode__(self):
        return self.name

    def get_absolute_url(self, link='detail'):
        if link == 'detail' or link == 'view':
            return reverse('assignment_detail', args=[str(self.id)])
        if link == 'update' or link == 'update':
            return reverse('assignment_update', args=[str(self.id)])
        if link == 'delete':
            return reverse('assignment_delete', args=[str(self.id)])
        return super(Assignment, self).get_absolute_url(link)

    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 assignment 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)

        participants = []
        for candidate in candidates.all():
            participants.append(candidate.person)
        participants.sort(key=lambda person: person.sort_name)
        return participants
        #return candidates.values_list('person', flat=True)

    def set_elected(self, person, value=True):
        candidate = self.assignment_candidates.get(person=person)
        candidate.elected = value
        candidate.save()

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

    def gen_poll(self):
        poll = AssignmentPoll(assignment=self)
        poll.save()
        poll.set_options([{'candidate': person} for person in self.candidates])
        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()

        options.sort(key=lambda option: option.candidate.sort_name)

        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 = PersonField()
    vote_class = AssignmentVote

    def __unicode__(self):
        return unicode(self.candidate)


class AssignmentPoll(RelatedModelMixin, CountInvalid, CountVotesCast,
                     PublishPollMixin, BasePoll):
    option_class = AssignmentOption

    assignment = models.ForeignKey(Assignment, related_name='poll_set')
    yesnoabstain = models.NullBooleanField()

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

    @models.permalink
    def get_absolute_url(self, link='detail'):
        if link == 'view' or link == 'detail' or link == 'update':
            return ('assignment_poll_view', [str(self.pk)])
        if link == 'delete':
            return ('assignment_poll_delete', [str(self.pk)])

    def get_assignment(self):
        return self.assignment

    def get_related_model(self):
        return self.assignment

    def get_vote_values(self):
        if self.yesnoabstain is None:
            if config['assignment_poll_vote_values'] == 'votes':
                self.yesnoabstain = False
            elif config['assignment_poll_vote_values'] == 'yesnoabstain':
                self.yesnoabstain = True
            else:
                # candidates <= available posts -> yes/no/abstain
                if len(self.assignment.candidates) <= (self.assignment.posts - len(self.assignment.elected)):
                    self.yesnoabstain = True
                else:
                    self.yesnoabstain = False
            self.save()
        if self.yesnoabstain:
            return [ugettext_noop('Yes'), ugettext_noop('No'), ugettext_noop('Abstain')]
        else:
            return [ugettext_noop('Votes')]

    def append_pollform_fields(self, fields):
        CountInvalid.append_pollform_fields(self, fields)
        CountVotesCast.append_pollform_fields(self, fields)

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