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

    Models for the motion app.

    :copyright: 2011, 2012 by OpenSlides team, see AUTHORS.
    :license: GNU GPL, see LICENSE for more details.
"""

from datetime import datetime

from django.core.urlresolvers import reverse
from django.db import models
from django.db.models import Max
from django.dispatch import receiver
from django.utils.translation import pgettext
from django.utils.translation import ugettext_lazy as _, ugettext_noop, ugettext

from openslides.utils.utils import _propper_unicode
from openslides.utils.person import PersonField

from openslides.config.models import config
from openslides.config.signals import default_config_value

from openslides.poll.models import (BaseOption, BasePoll, CountVotesCast,
    CountInvalid, BaseVote)

from openslides.projector.api import register_slidemodel
from openslides.projector.models import SlideMixin

from openslides.agenda.models import Item


class MotionSupporter(models.Model):
    motion = models.ForeignKey("Motion")
    person = PersonField()


class Motion(models.Model, SlideMixin):
    prefix = "motion"
    STATUS = (
        ('pub', _('Published')),
        ('per', _('Permitted')),
        ('acc', _('Accepted')),
        ('rej', _('Rejected')),
        ('wit', _('Withdrawed')),
        ('adj', _('Adjourned')),
        ('noc', _('Not Concerned')),
        ('com', _('Commited a bill')),
        ('nop', _('Rejected (not authorized)')),
        ('rev', _('Needs Review')), # Where is this status used?
        #additional actions:
        # edit
        # delete
        # setnumber
        # support
        # unsupport
        # createitem
        # activateitem
        # genpoll
    )

    submitter = PersonField(verbose_name=_("Submitter"))
    number = models.PositiveSmallIntegerField(blank=True, null=True,
                                        unique=True)
    status = models.CharField(max_length=3, choices=STATUS, default='pub')
    permitted = models.ForeignKey('AVersion', related_name='permitted', \
                                  null=True, blank=True)
    log = models.TextField(blank=True, null=True)

    @property
    def last_version(self):
        """
        Return last version of the motion.
        """
        try:
            return AVersion.objects.filter(motion=self).order_by('id') \
                                   .reverse()[0]
        except IndexError:
            return None

    @property
    def public_version(self):
        """
        Return permitted, if the motion was permitted, else last_version
        """
        if self.permitted is not None:
            return self.permitted
        else:
            return self.last_version

    def accept_version(self, version, user = None):
        """
        accept a Version
        """
        self.permitted = version
        self.save(nonewversion=True)
        version.rejected = False
        version.save()
        self.writelog(_("Version %d authorized") % (version.aid, ),
            user)

    def reject_version(self, version, user = None):
        if version.id > self.permitted.id:
            version.rejected = True
            version.save()
            self.writelog(pgettext("Rejected means not authorized", "Version %d rejected")
                % (version.aid, ), user)
            return True
        return False

    @property
    def versions(self):
        """
        Return a list of all versions of the motion.
        """
        return AVersion.objects.filter(motion=self)

    @property
    def creation_time(self):
        """
        Return the time of the creation of the motion.
        """
        try:
            return self.versions[0].time
        except IndexError:
            return None

    @property
    def notes(self):
        """
        Return some information of the motion.
        """
        note = []
        if self.status == "pub" and not self.enough_supporters:
            note.append(ugettext("Searching for supporters."))
        if self.status == "pub" and self.permitted is None:
            note.append(ugettext("Not yet authorized."))
        elif self.unpermitted_changes and self.permitted:
            note.append(ugettext("Not yet authorized changes."))
        return note

    @property
    def unpermitted_changes(self):
        """
        Return True if the motion has unpermitted changes.

        The motion has unpermitted changes, if the permitted-version
        is not the lastone and the lastone is not rejected.
        TODO: rename the property in unchecked__changes
        """
        if (self.last_version != self.permitted
        and not self.last_version.rejected):
            return True
        else:
            return False

    @property
    def supporters(self):
        for object in self.motionsupporter_set.all():
            yield object.person

    def is_supporter(self, person):
        try:
            return self.motionsupporter_set.filter(person=person).exists()
        except AttributeError:
            return False

    @property
    def enough_supporters(self):
        """
        Return True, if the motion has enough supporters
        """
        min_supporters = int(config['motion_min_supporters'])
        if self.status == "pub":
            return self.count_supporters() >= min_supporters
        else:
            return True

    def count_supporters(self):
        return self.motionsupporter_set.count()

    @property
    def missing_supporters(self):
        """
        Return number of missing supporters
        """
        min_supporters = int(config['motion_min_supporters'])
        delta = min_supporters - self.count_supporters()
        if delta > 0:
            return delta
        else:
            return 0

    def save(self, user=None, nonewversion=False, trivial_change=False):
        """
        Save the Motion, and create a new AVersion if necessary
        """
        super(Motion, self).save()
        if nonewversion:
            return
        last_version = self.last_version
        fields = ["text", "title", "reason"]
        if last_version is not None:
            changed_fields = [f for f in fields
                if getattr(last_version, f) != getattr(self, f)]
            if not changed_fields:
                return  # No changes
        try:
            if trivial_change and last_version is not None:
                last_version.text = self.text
                last_version.title = self.title
                last_version.reason = self.reason
                last_version.save()

                meta = AVersion._meta
                field_names = [unicode(meta.get_field(f).verbose_name)
                    for f in changed_fields]

                self.writelog(_("Trivial changes to version %(version)d; "
                    "changed fields: %(changed_fields)s")
                    % dict(version = last_version.aid,
                        changed_fields = ", ".join(field_names)))
                return # Done

            version = AVersion(title=getattr(self, 'title', ''),
                       text=getattr(self, 'text', ''),
                       reason=getattr(self, 'reason', ''),
                       motion=self)
            version.save()
            self.writelog(_("Version %s created") % version.aid, user)
            is_manager = user.has_perm('motion.can_manage_motion')
        except AttributeError:
            is_manager = False

        supporters = self.motionsupporter_set.all()
        if (self.status == "pub"
        and supporters
        and not is_manager):
            supporters.delete()
            self.writelog(_("Supporters removed"), user)

    def reset(self, user):
        """
        Reset the motion.
        """
        self.status = "pub"
        self.permitted = None
        self.save()
        self.writelog(_("Status reseted to: %s") % (self.get_status_display()), user)

    def support(self, person):
        """
        Add a Supporter to the list of supporters of the motion.
        """
        if person == self.submitter:
            # TODO: Use own Exception
            raise NameError('Supporter can not be the submitter of a ' \
                            'motion.')
        if self.permitted is not None:
            # TODO: Use own Exception
            raise NameError('This motion is already permitted.')
        if not self.is_supporter(person):
            MotionSupporter(motion=self, person=person).save()
            self.writelog(_("Supporter: +%s") % (person))
        # TODO: Raise a precise exception for the view in else-clause

    def unsupport(self, person):
        """
        remove a supporter from the list of supporters of the motion
        """
        if self.permitted is not None:
            # TODO: Use own Exception
            raise NameError('This motion is already permitted.')
        try:
            object = self.motionsupporter_set.get(person=person).delete()
        except MotionSupporter.DoesNotExist:
            # TODO: Don't do nothing but raise a precise exception for the view
            pass
        else:
            self.writelog(_("Supporter: -%s") % (person))

    def set_number(self, number=None, user=None):
        """
        Set a number for ths motion.
        """
        if self.number is not None:
            # TODO: Use own Exception
            raise NameError('This motion has already a number.')
        if number is None:
            try:
                number = Motion.objects.aggregate(Max('number')) \
                            ['number__max'] + 1
            except TypeError:
                number = 1
        self.number = number
        self.save()
        self.writelog(_("Number set: %s") % (self.number), user)
        return self.number

    def permit(self, user=None):
        """
        Change the status of this motion to permit.
        """
        self.set_status(user, "per")
        aversion = self.last_version
        if self.number is None:
            self.set_number()
        self.permitted = aversion
        self.save()
        self.writelog(_("Version %s authorized") % (aversion.aid), user)
        return self.permitted

    def notpermit(self, user=None):
        """
        Change the status of this motion to 'not permitted (rejected)'.
        """
        self.set_status(user, "nop")
        #TODO: reject last version
        aversion = self.last_version
        #self.permitted = aversion
        if self.number is None:
            self.set_number()
        self.save()
        self.writelog(_("Version %s not authorized") % (self.last_version.aid), user)

    def set_status(self, user, status, force=False):
        """
        Set the status of the motion.
        """
        error = True
        for a, b in Motion.STATUS:
            if status == a:
                error = False
                break
        if error:
            #TODO: Use the Right Error
            raise NameError(_('%s is not a valid status.') % status)
        if self.status == status:
            #TODO: Use the Right Error
            raise NameError(_('The motion status is already \'%s.\'') \
                            % self.status)

        actions = []
        actions = self.get_allowed_actions(user)
        if status not in actions and not force:
            #TODO: Use the Right Error
            raise NameError(_(
                'The motion status is: \'%(currentstatus)s\'. '
                'You can not set the status to \'%(newstatus)s\'.') % {
                    'currentstatus': self.status,
                    'newstatus': status})

        oldstatus = self.get_status_display()
        self.status = status
        self.save()
        self.writelog(_("Status modified")+": %s -> %s" \
                      % (oldstatus, self.get_status_display()), user)

    def get_allowed_actions(self, user):
        """
        Return a list of all the allowed status.
        """
        actions = []

        # check if user allowed to withdraw an motion
        if  ((self.status == "pub"
          and self.number
          and user == self.submitter)
        or   (self.status == "pub"
          and self.number
          and user.has_perm("motion.can_manage_motion"))
        or   (self.status == "per"
          and user == self.submitter)
        or (self.status == "per"
          and user.has_perm("motion.can_manage_motion"))):
            actions.append("wit")
        #Check if the user can review the motion
        if  (self.status == "rev"
        and (self.submitter == user
          or user.has_perm("motion.can_manage_motion"))):
            actions.append("pub")

        # Check if the user can support and unspoort the motion
        if  (self.status == "pub"
          and user != self.submitter
          and not self.is_supporter(user)):
            actions.append("support")

        if self.status == "pub" and self.is_supporter(user):
            actions.append("unsupport")

        #Check if the user can edit the motion
        if (user == self.submitter \
          and (self.status in ('pub', 'per'))) \
        or user.has_perm("motion.can_manage_motion"):
            actions.append("edit")

        # Check if the user can delete the motion (admin, manager, owner)
        # reworked as requiered in #100
        if (user.has_perm("motion.can_delete_all_motions") or
           (user.has_perm("motion.can_manage_motion") and
               self.number is None) or
           (self.submitter == user and self.number is None)):
            actions.append("delete")

        #For the rest, all actions need the manage permission
        if not user.has_perm("motion.can_manage_motion"):
            return actions

        if self.status == "pub":
            actions.append("nop")
            actions.append("per")
            if self.number == None:
                actions.append("setnumber")

        if self.status == "per":
            actions.append("acc")
            actions.append("rej")
            actions.append("adj")
            actions.append("noc")
            actions.append("com")
            actions.append("genpoll")
            if self.unpermitted_changes:
                actions.append("permitversion")
                actions.append("rejectversion")

        return actions

    def delete(self, force=False):
        """
        Delete the motion. It is not possible, if the motion has
        allready a number
        """
        if self.number and not force:
            raise NameError('The motion has already a number. ' \
                            'You can not delete it.')


        for item in Item.objects.filter(related_sid=self.sid):
            item.delete()
        super(Motion, self).delete()

    def writelog(self, text, user=None):
        if not self.log:
            self.log = ""
        self.log += u"%s | %s" % (datetime.now().strftime("%d.%m.%Y %H:%M:%S"), _propper_unicode(text))
        if user is not None:
            self.log += u" (%s %s)" % (_("by"), _propper_unicode(user.username))
        self.log += "\n"
        self.save()

    def get_agenda_title(self):
        return self.public_version.title

    def get_agenda_title_supplement(self):
        number = self.number or '<i>[%s]</i>' % ugettext('no number')
        return '(%s %s)' % (ugettext('motion'), number)

    def __getattr__(self, name):
        """
        if name is title, text, reason or time,
            Return this attribute from the newest version of the motion
        """
        if name in ('title', 'text', 'reason', 'time', 'aid'):
            try:
                if name == 'aid':
                    return self.last_version.aid
                return self.last_version.__dict__[name]
            except TypeError:
                raise AttributeError(name)
            except AttributeError:
                raise AttributeError(name)
        raise AttributeError(name)

    def gen_poll(self, user=None):
        """
        Generates a poll object for the motion
        """
        poll = MotionPoll(motion=self)
        poll.save()
        poll.set_options()
        self.writelog(_("Poll created"), user)
        return poll

    @property
    def polls(self):
        return self.motionpoll_set.all()

    @property
    def results(self):
        return self.get_poll_results()

    def get_poll_results(self):
        """
        Return a list of voting results
        """
        results = []
        for poll in self.polls:
            for option in poll.get_options():
                if option.get_votes().exists():
                    results.append((option['Yes'], option['No'],
                        option['Abstain'], poll.print_votesinvalid(),
                        poll.print_votescast()))
        return results


    def slide(self):
        """
        return the slide dict
        """
        data = super(Motion, self).slide()
        data['motion'] = self
        data['title'] = self.title
        data['template'] = 'projector/Motion.html'
        return data

    def get_absolute_url(self, link='view'):
        if link == 'view':
            return reverse('motion_view', args=[str(self.id)])
        if link == 'edit':
            return reverse('motion_edit', args=[str(self.id)])
        if link == 'delete':
            return reverse('motion_delete', args=[str(self.id)])

    def __unicode__(self):
        try:
            return self.last_version.title
        except AttributeError:
            return "no title jet"

    class Meta:
        permissions = (
            ('can_see_motion', ugettext_noop("Can see motions")),
            ('can_create_motion', ugettext_noop("Can create motions")),
            ('can_support_motion', ugettext_noop("Can support motions")),
            ('can_manage_motion', ugettext_noop("Can manage motions")),
        )
        ordering = ('number',)


class AVersion(models.Model):
    title = models.CharField(max_length=100, verbose_name = _("Title"))
    text = models.TextField(verbose_name = _("Text"))
    reason = models.TextField(null=True, blank=True, verbose_name = _("Reason"))
    rejected = models.BooleanField() # = Not Permitted
    time = models.DateTimeField(auto_now=True)
    motion = models.ForeignKey(Motion)

    def __unicode__(self):
        return "%s %s" % (self.id, self.title)

    @property
    def aid(self):
        try:
            return self._aid
        except AttributeError:
            self._aid = AVersion.objects \
                .filter(motion=self.motion) \
                .filter(id__lte=self.id).count()
            return self._aid

register_slidemodel(Motion)


class MotionVote(BaseVote):
    option = models.ForeignKey('MotionOption')


class MotionOption(BaseOption):
    poll = models.ForeignKey('MotionPoll')
    vote_class = MotionVote


class MotionPoll(BasePoll, CountInvalid, CountVotesCast):
    option_class = MotionOption
    vote_values = [ugettext_noop('Yes'), ugettext_noop('No'),
        ugettext_noop('Abstain')]

    motion = models.ForeignKey(Motion)

    def get_motion(self):
        return self.motion

    def set_options(self):
        #TODO: maybe it is possible with .create() to call this without poll=self
        self.get_option_class()(poll=self).save()

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

    def get_absolute_url(self):
        return reverse('motion_poll_view', args=[self.id])

    def get_ballot(self):
        return self.motion.motionpoll_set.filter(id__lte=self.id).count()


@receiver(default_config_value, dispatch_uid="motion_default_config")
def default_config(sender, key, **kwargs):
    return {
        'motion_min_supporters': 0,
        'motion_preamble': _('The assembly may decide,'),
        'motion_pdf_ballot_papers_selection': 'CUSTOM_NUMBER',
        'motion_pdf_ballot_papers_number': '8',
        'motion_pdf_title': _('Motions'),
        'motion_pdf_preamble': '',
        'motion_allow_trivial_change': False,
    }.get(key)