from django.contrib import messages
from django.core.urlresolvers import reverse
from django.shortcuts import redirect
from django.utils.translation import ugettext as _
from django.utils.translation import ungettext
from reportlab.lib import colors
from reportlab.lib.units import cm
from reportlab.platypus import (PageBreak, Paragraph, SimpleDocTemplate, Spacer,
                                LongTable, Table, TableStyle)

from openslides.agenda.views import CreateRelatedAgendaItemView as _CreateRelatedAgendaItemView
from openslides.config.api import config
from openslides.users.models import Group, User  # TODO: remove this
from openslides.poll.views import PollFormView
from openslides.utils import rest_api
from openslides.utils.pdf import stylesheet
from openslides.utils.utils import html_strong
from openslides.utils.views import (CreateView, DeleteView, DetailView,
                                    ListView, PDFView, PermissionMixin,
                                    QuestionView, RedirectView,
                                    SingleObjectMixin, UpdateView, View)

from .forms import AssignmentForm, AssignmentRunForm
from .models import Assignment, AssignmentPoll
from .serializers import AssignmentFullSerializer, AssignmentShortSerializer


class AssignmentListView(ListView):
    """ListView for all Assignments"""
    required_permission = 'assignment.can_see_assignment'
    model = Assignment


class AssignmentDetail(DetailView):
    required_permission = 'assignment.can_see_assignment'
    model = Assignment
    form_class = AssignmentRunForm

    def get_context_data(self, *args, **kwargs):
        context = super(AssignmentDetail, self).get_context_data(*args, **kwargs)
        if self.request.method == 'POST':
            context['form'] = self.form_class(self.request.POST)
        else:
            context['form'] = self.form_class()
        polls = self.get_object().poll_set.all()
        if not self.request.user.has_perm('assignment.can_manage_assignment'):
            polls = self.get_object().poll_set.filter(published=True)
            vote_results = self.get_object().vote_results(only_published=True)
        else:
            polls = self.get_object().poll_set.all()
            vote_results = self.get_object().vote_results(only_published=False)

        blocked_candidates = [
            candidate.person for candidate in
            self.get_object().assignment_candidates.filter(blocked=True)]
        context['polls'] = polls
        context['vote_results'] = vote_results
        context['blocked_candidates'] = blocked_candidates
        context['user_is_candidate'] = self.get_object().is_candidate(self.request.user)
        return context

    def post(self, *args, **kwargs):
        if self.request.user.has_perm('assignment.can_nominate_other'):
            form = self.form_class(self.request.POST)
            if form.is_valid():
                user = form.cleaned_data['candidate']
                try:
                    self.get_object().run(user, self.request.user)
                except NameError as e:
                    messages.error(self.request, e)
                else:
                    messages.success(self.request, _(
                        "Candidate %s was nominated successfully.")
                        % html_strong(user))
        return super(AssignmentDetail, self).get(*args, **kwargs)


class AssignmentCreateView(CreateView):
    model = Assignment
    form_class = AssignmentForm
    required_permission = 'assignment.can_manage_assignment'


class AssignmentUpdateView(UpdateView):
    model = Assignment
    form_class = AssignmentForm
    required_permission = 'assignment.can_manage_assignment'


class AssignmentDeleteView(DeleteView):
    required_permission = 'assignment.can_manage_assignment'
    model = Assignment
    success_url_name = 'assignment_list'


class AssignmentSetStatusView(SingleObjectMixin, RedirectView):
    model = Assignment
    required_permission = 'assignment.can_manage_assignment'
    url_name = 'assignment_detail'

    def pre_redirect(self, *args, **kwargs):
        status = kwargs.get('status')
        if status is not None:
            try:
                self.get_object().set_status(status)
            except ValueError as e:
                messages.error(self.request, e)
            else:
                messages.success(
                    self.request,
                    _('Election status was set to: %s.') %
                    html_strong(self.get_object().get_status_display())
                )


class AssignmentRunView(SingleObjectMixin, PermissionMixin, View):
    model = Assignment
    required_permission = 'assignment.can_nominate_self'

    def get(self, *args, **kwargs):
        assignment = self.get_object()
        try:
            assignment.run(self.request.user, self.request.user)
        except NameError as e:
            messages.error(self.request, e)
        else:
            messages.success(
                self.request, _('You have set your candidature successfully.'))
        return redirect(reverse('assignment_detail', args=[assignment.pk]))


class AssignmentRunDeleteView(SingleObjectMixin, RedirectView):
    model = Assignment
    url_name = 'assignment_detail'

    def pre_redirect(self, *args, **kwargs):
        if self.get_object().status == 'sea' or self.request.user.has_perm(
                "assignment.can_manage_assignment"):
            try:
                self.get_object().delrun(self.request.user, blocked=True)
            except Exception as e:
                # TODO: only catch relevant exception
                messages.error(self.request, e)
            else:
                messages.success(self.request, _(
                    'You have withdrawn your candidature successfully. '
                    'You can not be nominated by other participants anymore.'))
        else:
            messages.error(self.request, _('The candidate list is already closed.'))


class AssignmentRunOtherDeleteView(SingleObjectMixin, QuestionView):
    model = Assignment
    required_permission = 'assignment.can_manage_assignment'

    def get_question_message(self):
        self._get_person_information()
        if not self.is_blocked:
            question = _("Do you really want to withdraw %s from the election?") % html_strong(self.person)
        else:
            question = _("Do you really want to unblock %s for the election?") % html_strong(self.person)
        return question

    def on_clicked_yes(self):
        self._get_person_information()
        try:
            self.get_object().delrun(self.person, blocked=False)
        except Exception as e:
            # TODO: only catch relevant exception
            self.error = e
        else:
            self.error = False

    def create_final_message(self):
        if self.error:
            messages.error(self.request, self.error)
        else:
            messages.success(self.request, self.get_final_message())

    def get_final_message(self):
        message = _("Candidate %s was withdrawn successfully.") % html_strong(self.person)
        if self.is_blocked:
            message = _("%s was unblocked successfully.") % html_strong(self.person)
        return message

    def _get_person_information(self):
        self.person = User.objects.get(pk=self.kwargs.get('user_id'))
        self.is_blocked = self.get_object().is_blocked(self.person)


class AssignmentViewSet(rest_api.viewsets.ModelViewSet):
    """
    API endpoint to retrieve, create, edit and delete assignments.
    """
    model = Assignment
    queryset = Assignment.objects.all()

    def check_permissions(self, request):
        """
        Calls self.permission_denied() if the requesting user has not the
        permission to see and in case of create, update or destroy requests
        the permission to manage and to see organizational items.
        """
        if (not request.user.has_perm('assignment.can_see_assignment') or
                (self.action in ('create', 'update', 'destroy') and not
                 request.user.has_perm('assignment.can_manage_assignment'))):
            self.permission_denied(request)

    def get_serializer_class(self):
        """
        Returns different serializer classes with respect to users permissions.
        """
        if self.request.user.has_perm('assignment.can_manage_assignment'):
            serializer_class = AssignmentFullSerializer
        else:
            serializer_class = AssignmentShortSerializer
        return serializer_class


class PollCreateView(SingleObjectMixin, RedirectView):
    model = Assignment
    required_permission = 'assignment.can_manage_assignment'
    url_name = 'assignment_detail'

    def pre_redirect(self, *args, **kwargs):
        self.get_object().gen_poll()
        messages.success(self.request, _("New ballot was successfully created."))


class PollUpdateView(PollFormView):
    poll_class = AssignmentPoll
    template_name = 'assignment/assignmentpoll_form.html'

    def get_context_data(self, **kwargs):
        context = super(PollUpdateView, self).get_context_data(**kwargs)
        self.assignment = self.poll.get_assignment()
        context['assignment'] = self.assignment
        context['poll'] = self.poll
        context['polls'] = self.assignment.poll_set.all()
        context['ballotnumber'] = self.poll.get_ballot()
        return context

    def get_success_url(self):
        return_url = ''
        if 'apply' not in self.request.POST:
            return_url = reverse('assignment_detail', args=[self.poll.assignment.id])
        return return_url


class SetPublishStatusView(SingleObjectMixin, RedirectView):
    model = AssignmentPoll
    required_permission = 'assignment.can_manage_assignment'
    url_name = 'assignment_detail'
    allow_ajax = True

    def get_ajax_context(self, **kwargs):
        return {'published': self.object.published}

    def pre_redirect(self, *args, **kwargs):
        try:
            poll = self.get_object()
        except self.model.DoesNotExist:
            messages.error(self.request, _('Ballot ID %d does not exist.') %
                           int(kwargs['poll_id']))
        else:
            if poll.published:
                poll.set_published(False)
            else:
                poll.set_published(True)


class SetElectedView(SingleObjectMixin, RedirectView):
    model = Assignment
    required_permission = 'assignment.can_manage_assignment'
    url_name = 'assignment_detail'
    allow_ajax = True

    def pre_redirect(self, *args, **kwargs):
        self.person = User.objects.get(pk=kwargs['user_id'])
        self.elected = kwargs['elected']
        self.get_object().set_elected(self.person, self.elected)

    def get_ajax_context(self, **kwargs):
        if self.elected:
            link = reverse('assignment_user_not_elected',
                           args=[self.get_object().id, self.person.person_id])
            text = _('not elected')
        else:
            link = reverse('assignment_user_elected',
                           args=[self.get_object().id, self.person.person_id])
            text = _('elected')
        return {'elected': self.elected, 'link': link, 'text': text}


class AssignmentPollDeleteView(DeleteView):
    """
    Delete an assignment poll object.
    """
    required_permission = 'assignment.can_manage_assignment'
    model = AssignmentPoll

    def pre_redirect(self, request, *args, **kwargs):
        self.set_assignment()
        super(AssignmentPollDeleteView, self).pre_redirect(request, *args, **kwargs)

    def pre_post_redirect(self, request, *args, **kwargs):
        self.set_assignment()
        super(AssignmentPollDeleteView, self).pre_post_redirect(request, *args, **kwargs)

    def set_assignment(self):
        self.assignment = self.get_object().assignment

    def get_redirect_url(self, **kwargs):
        return reverse('assignment_detail', args=[self.assignment.id])

    def get_final_message(self):
        return _('Ballot was successfully deleted.')


class AssignmentPDF(PDFView):
    required_permission = 'assignment.can_see_assignment'
    top_space = 0

    def get_filename(self):
        try:
            assignment_id = self.kwargs['pk']
            assignment = Assignment.objects.get(id=assignment_id)
            filename = u'%s-%s' % (
                _("Assignment"),
                assignment.name.replace(' ', '_'))
        except:
            filename = _("Elections")
        return filename

    def append_to_pdf(self, story):
        try:
            assignment_id = self.kwargs['pk']
        except KeyError:
            assignment_id = None
        if assignment_id is None:  # print all assignments
            title = config["assignment_pdf_title"]
            story.append(Paragraph(title, stylesheet['Heading1']))
            preamble = config["assignment_pdf_preamble"]
            if preamble:
                story.append(Paragraph(
                    "%s" % preamble.replace('\r\n', '<br/>'),
                    stylesheet['Paragraph']))
            story.append(Spacer(0, 0.75 * cm))
            assignments = Assignment.objects.all()
            if not assignments:  # No assignments existing
                story.append(Paragraph(
                    _("No assignments available."), stylesheet['Heading3']))
            else:  # Print all assignments
                # List of assignments
                for assignment in assignments:
                    story.append(Paragraph(
                        assignment.name, stylesheet['Heading3']))
                # Assignment details (each assignment on single page)
                for assignment in assignments:
                    story.append(PageBreak())
                    # append the assignment to the story-object
                    self.get_assignment(assignment, story)
        else:  # print selected assignment
            assignment = Assignment.objects.get(id=assignment_id)
            # append the assignment to the story-object
            self.get_assignment(assignment, story)

    def get_assignment(self, assignment, story):
        # title
        story.append(Paragraph(
            _("Election: %s") % assignment.name, stylesheet['Heading1']))
        story.append(Spacer(0, 0.5 * cm))

        # Filling table rows...
        data = []
        polls = assignment.poll_set.filter(published=True)
        # 1. posts
        data.append([
            Paragraph("%s:" %
                      _("Number of available posts"), stylesheet['Bold']),
            Paragraph(str(assignment.posts), stylesheet['Paragraph'])])

        # 2a. if no polls available print candidates
        if not polls:
            data.append([
                Paragraph("%s:<seqreset id='counter'>" %
                          _("Candidates"), stylesheet['Heading4']),
                []])
            for candidate in assignment.candidates:
                data.append([
                    [],
                    Paragraph("<seq id='counter'/>.&nbsp; %s" % candidate,
                              stylesheet['Signaturefield'])])
            if assignment.status == "sea":
                for x in range(0, 7):
                    data.append([
                        [],
                        Paragraph("<seq id='counter'/>.&nbsp; "
                                  "__________________________________________",
                                  stylesheet['Signaturefield'])])

        # 2b. if polls available print election result
        if polls:
            # Preparing
            vote_results = assignment.vote_results(only_published=True)
            data_votes = []

            # Left side
            cell = []
            cell.append(Paragraph(
                "%s:" % (_("Election result")), stylesheet['Heading4']))

            # Add table head row
            headrow = []
            headrow.append(_("Candidates"))
            for poll in polls:
                headrow.append("%s. %s" % (poll.get_ballot(), _("ballot")))
            data_votes.append(headrow)

            # Add result rows
            elected_candidates = list(assignment.elected)
            length = len(vote_results)
            for candidate, poll_list in vote_results.iteritems():
                row = []
                candidate_string = candidate.clean_name
                if candidate in elected_candidates:
                    candidate_string = "* " + candidate_string
                if candidate.name_suffix and length < 20:
                    candidate_string += "\n(%s)" % candidate.name_suffix
                row.append(candidate_string)
                for vote in poll_list:
                    if vote is None:
                        row.append('–')
                    elif 'Yes' in vote and 'No' in vote and 'Abstain' in vote:
                        row.append(
                            _("Y: %(YES)s\nN: %(NO)s\nA: %(ABSTAIN)s")
                            % {'YES': vote['Yes'], 'NO': vote['No'],
                               'ABSTAIN': vote['Abstain']})
                    elif 'Votes' in vote:
                        row.append(vote['Votes'])
                    else:
                        pass
                data_votes.append(row)

            # Add valid votes row
            footrow_one = []
            footrow_one.append(_("Valid votes"))
            votesvalid_is_used = False
            for poll in polls:
                footrow_one.append(poll.print_votesvalid())
                if poll.votesvalid is not None:
                    votesvalid_is_used = True
            if votesvalid_is_used:
                data_votes.append(footrow_one)

            # Add invalid votes row
            footrow_two = []
            footrow_two.append(_("Invalid votes"))
            votesinvalid_is_used = False
            for poll in polls:
                footrow_two.append(poll.print_votesinvalid())
                if poll.votesinvalid is not None:
                    votesinvalid_is_used = True
            if votesinvalid_is_used:
                data_votes.append(footrow_two)

            # Add votes cast row
            footrow_three = []
            footrow_three.append(_("Votes cast"))
            votescast_is_used = False
            for poll in polls:
                footrow_three.append(poll.print_votescast())
                if poll.votescast is not None:
                    votescast_is_used = True
            if votescast_is_used:
                data_votes.append(footrow_three)

            table_votes = Table(data_votes)
            table_votes.setStyle(
                TableStyle([
                    ('GRID', (0, 0), (-1, -1), 0.5, colors.grey),
                    ('VALIGN', (0, 0), (-1, -1), 'TOP'),
                    ('LINEABOVE', (0, 0), (-1, 0), 2, colors.black),
                    ('LINEABOVE', (0, 1), (-1, 1), 1, colors.black),
                    ('LINEBELOW', (0, -1), (-1, -1), 2, colors.black),
                    ('ROWBACKGROUNDS', (0, 1), (-1, -1), (colors.white, (.9, .9, .9)))
                ])
            )
            data.append([cell, table_votes])
            if elected_candidates:
                data.append(['', '* = ' + _('elected')])

        # table style
        data.append(['', ''])
        t = LongTable(data)
        t._argW[0] = 4.5 * cm
        t._argW[1] = 11 * cm
        t.setStyle(TableStyle([
            ('BOX', (0, 0), (-1, -1), 1, colors.black),
            ('VALIGN', (0, 0), (-1, -1), 'TOP')]))
        story.append(t)
        story.append(Spacer(0, 1 * cm))

        # election description
        story.append(
            Paragraph("%s" % assignment.description.replace('\r\n', '<br/>'),
                      stylesheet['Paragraph']))


class CreateRelatedAgendaItemView(_CreateRelatedAgendaItemView):
    """
    View to create and agenda item for an assignment.
    """
    model = Assignment


class AssignmentPollPDF(PDFView):
    required_permission = 'assignment.can_manage_assignment'
    top_space = 0

    def get(self, request, *args, **kwargs):
        self.poll = AssignmentPoll.objects.get(id=self.kwargs['poll_id'])
        return super().get(request, *args, **kwargs)

    def get_filename(self):
        filename = u'%s-%s_%s' % (
            _("Election"), self.poll.assignment.name.replace(' ', '_'),
            self.poll.get_ballot())
        return filename

    def get_template(self, buffer):
        return SimpleDocTemplate(
            buffer, topMargin=-6, bottomMargin=-6, leftMargin=0, rightMargin=0,
            showBoundary=False)

    def build_document(self, pdf_document, story):
        pdf_document.build(story)

    def append_to_pdf(self, story):
        circle = "*"  # = Unicode Character 'HEAVY LARGE CIRCLE' (U+2B55)
        cell = []
        cell.append(Spacer(0, 0.8 * cm))
        cell.append(Paragraph(
            _("Election") + ": " + self.poll.assignment.name,
            stylesheet['Ballot_title']))
        cell.append(Paragraph(
            self.poll.description or '',
            stylesheet['Ballot_subtitle']))
        options = self.poll.get_options()

        ballot_string = _("%d. ballot") % self.poll.get_ballot()
        candidate_string = ungettext(
            "%d candidate", "%d candidates", len(options)) % len(options)
        available_posts_string = ungettext(
            "%d available post", "%d available posts",
            self.poll.assignment.posts) % self.poll.assignment.posts
        cell.append(Paragraph(
            "%s, %s, %s" % (ballot_string, candidate_string, available_posts_string),
            stylesheet['Ballot_description']))
        cell.append(Spacer(0, 0.4 * cm))

        data = []
        # get ballot papers config values
        ballot_papers_selection = config["assignment_pdf_ballot_papers_selection"]
        ballot_papers_number = config["assignment_pdf_ballot_papers_number"]

        # set number of ballot papers
        if ballot_papers_selection == "NUMBER_OF_DELEGATES":
            try:
                if Group.objects.get(pk=3):
                    number = User.objects.filter(groups__pk=3).count()
            except Group.DoesNotExist:
                number = 0
        elif ballot_papers_selection == "NUMBER_OF_ALL_PARTICIPANTS":
            number = int(User.objects.count())
        else:  # ballot_papers_selection == "CUSTOM_NUMBER"
            number = int(ballot_papers_number)
        number = max(1, number)

        counter = 0
        cellcolumnA = []
        # Choose kind of ballot paper (YesNoAbstain or Yes)
        if self.poll.yesnoabstain:  # YesNoAbstain ballot: max 27 candidates
            for option in options:
                counter += 1
                candidate = option.candidate
                cell.append(Paragraph(
                    candidate.get_short_name(), stylesheet['Ballot_option_name_YNA']))
                if candidate.structure_level:
                    cell.append(Paragraph(
                        "(%s)" % candidate.structure_level,
                        stylesheet['Ballot_option_suffix_YNA']))
                else:
                    cell.append(Paragraph(
                        "&nbsp;", stylesheet['Ballot_option_suffix_YNA']))
                cell.append(Paragraph("<font name='circlefont' size='15'>%(circle)s</font> \
                    <font name='Ubuntu'>%(yes)s &nbsp;&nbsp;&nbsp;</font> \
                    <font name='circlefont' size='15'>%(circle)s</font> \
                    <font name='Ubuntu'>%(no)s &nbsp;&nbsp;&nbsp;</font> \
                    <font name='circlefont' size='15'>%(circle)s</font> \
                    <font name='Ubuntu'>%(abstain)s</font>" %
                            {'circle': circle,
                             'yes': _("Yes"),
                             'no': _("No"),
                             'abstain': _("Abstention")},
                            stylesheet['Ballot_option_circle_YNA']))
                if counter == 13:
                    cellcolumnA = cell
                    cell = []
                    cell.append(Spacer(0, 1.3 * cm))

            # print ballot papers
            for user in range(number // 2):
                if len(options) > 13:
                    data.append([cellcolumnA, cell])
                else:
                    data.append([cell, cell])
            rest = number % 2
            if rest:
                data.append([cell, ''])
            if len(options) <= 2:
                t = Table(data, 10.5 * cm, 7.42 * cm)
            elif len(options) <= 5:
                t = Table(data, 10.5 * cm, 14.84 * cm)
            else:
                t = Table(data, 10.5 * cm, 29.7 * cm)
        else:  # Yes ballot: max 46 candidates
            for option in options:
                counter += 1
                candidate = option.candidate
                cell.append(Paragraph("<font name='circlefont' size='15'>%s</font> \
                            <font name='Ubuntu'>%s</font>" %
                            (circle, candidate.clean_name), stylesheet['Ballot_option_name']))
                if candidate.structure_level:
                    cell.append(Paragraph(
                        "(%s)" % candidate.structure_level,
                        stylesheet['Ballot_option_suffix']))
                else:
                    cell.append(Paragraph(
                        "&nbsp;", stylesheet['Ballot_option_suffix']))
                if counter == 22:
                    cellcolumnA = cell
                    cell = []
                    cell.append(Spacer(0, 0.75 * cm))

            # print ballot papers
            for user in range(number // 2):
                if len(options) > 22:
                    data.append([cellcolumnA, cell])
                else:
                    data.append([cell, cell])
            rest = number % 2
            if rest:
                data.append([cell, ''])
            if len(options) <= 4:
                t = Table(data, 10.5 * cm, 7.42 * cm)
            elif len(options) <= 8:
                t = Table(data, 10.5 * cm, 14.84 * cm)
            else:
                t = Table(data, 10.5 * cm, 29.7 * cm)

        t.setStyle(TableStyle([
            ('GRID', (0, 0), (-1, -1), 0.25, colors.grey),
            ('VALIGN', (0, 0), (-1, -1), 'TOP')]))
        story.append(t)