# -*- coding:utf-8 -*
#
# Copyright 2016,2017
# - Skia <skia@libskia.so>
# - Sli <antoine@bartuccio.fr>
#
# Ce fichier fait partie du site de l'Association des Étudiants de l'UTBM,
# http://ae.utbm.fr.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License a published by the Free Software
# Foundation; either version 3 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Sofware Foundation, Inc., 59 Temple
# Place - Suite 330, Boston, MA 02111-1307, USA.
#
#

from django.db import models
from django.core import validators
from django.conf import settings
from django.utils.translation import ugettext_lazy as _
from django.core.exceptions import ValidationError
from django.db import transaction
from django.core.urlresolvers import reverse
from django.utils import timezone

from core.models import User, MetaGroup, Group, SithFile


# Create your models here.

class Club(models.Model):
    """
    The Club class, made as a tree to allow nice tidy organization
    """
    id = models.AutoField(primary_key=True, db_index=True)
    name = models.CharField(_('name'), max_length=64)
    parent = models.ForeignKey('Club', related_name='children', null=True, blank=True)
    unix_name = models.CharField(_('unix name'), max_length=30, unique=True,
                                 validators=[
        validators.RegexValidator(
            r'^[a-z0-9][a-z0-9._-]*[a-z0-9]$',
            _('Enter a valid unix name. This value may contain only '
              'letters, numbers ./-/_ characters.')
        ),
    ],
        error_messages={
        'unique': _("A club with that unix name already exists."),
    },
    )
    address = models.CharField(_('address'), max_length=254)
    # email = models.EmailField(_('email address'), unique=True) # This should, and will be generated automatically
    owner_group = models.ForeignKey(Group, related_name="owned_club",
                                    default=settings.SITH_GROUP_ROOT_ID)
    edit_groups = models.ManyToManyField(Group, related_name="editable_club", blank=True)
    view_groups = models.ManyToManyField(Group, related_name="viewable_club", blank=True)
    home = models.OneToOneField(SithFile, related_name='home_of_club', verbose_name=_("home"), null=True, blank=True,
                                on_delete=models.SET_NULL)

    class Meta:
        ordering = ['name', 'unix_name']

    def check_loop(self):
        """Raise a validation error when a loop is found within the parent list"""
        objs = []
        cur = self
        while cur.parent is not None:
            if cur in objs:
                raise ValidationError(_('You can not make loops in clubs'))
            objs.append(cur)
            cur = cur.parent

    def clean(self):
        self.check_loop()

    def _change_unixname(self, new_name):
        c = Club.objects.filter(unix_name=new_name).first()
        if c is None:
            if self.home:
                self.home.name = new_name
                self.home.save()
        else:
            raise ValidationError(_("A club with that unix_name already exists"))

    def make_home(self):
        if not self.home:
            home_root = SithFile.objects.filter(parent=None, name="clubs").first()
            root = User.objects.filter(username="root").first()
            if home_root and root:
                home = SithFile(parent=home_root, name=self.unix_name, owner=root)
                home.save()
                self.home = home
                self.save()

    def save(self, *args, **kwargs):
        with transaction.atomic():
            creation = False
            old = Club.objects.filter(id=self.id).first()
            if not old:
                creation = True
            else:
                if old.unix_name != self.unix_name:
                    self._change_unixname(self.unix_name)
            super(Club, self).save(*args, **kwargs)
            if creation:
                board = MetaGroup(name=self.unix_name + settings.SITH_BOARD_SUFFIX)
                board.save()
                member = MetaGroup(name=self.unix_name + settings.SITH_MEMBER_SUFFIX)
                member.save()
                subscribers = Group.objects.filter(name=settings.SITH_MAIN_MEMBERS_GROUP).first()
                self.make_home()
                self.home.edit_groups = [board]
                self.home.view_groups = [member, subscribers]
                self.home.save()

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse('club:club_view', kwargs={'club_id': self.id})

    def get_display_name(self):
        return self.name

    def is_owned_by(self, user):
        """
        Method to see if that object can be super edited by the given user
        """
        return user.is_in_group(settings.SITH_MAIN_BOARD_GROUP)

    def can_be_edited_by(self, user):
        """
        Method to see if that object can be edited by the given user
        """
        return self.has_rights_in_club(user)

    def can_be_viewed_by(self, user):
        """
        Method to see if that object can be seen by the given user
        """
        sub = User.objects.filter(pk=user.pk).first()
        if sub is None:
            return False
        return sub.is_subscribed

    _memberships = {}

    def get_membership_for(self, user):
        """
        Returns the current membership the given user
        """
        try:
            return Club._memberships[self.id][user.id]
        except:
            m = self.members.filter(user=user.id).filter(end_date=None).first()
            try:
                Club._memberships[self.id][user.id] = m
            except:
                Club._memberships[self.id] = {}
                Club._memberships[self.id][user.id] = m
            return m

    def has_rights_in_club(self, user):
        m = self.get_membership_for(user)
        return m is not None and m.role > settings.SITH_MAXIMUM_FREE_ROLE


class Membership(models.Model):
    """
    The Membership class makes the connection between User and Clubs

    Both Users and Clubs can have many Membership objects:
       - a user can be a member of many clubs at a time
       - a club can have many members at a time too

    A User is currently member of all the Clubs where its Membership has an end_date set to null/None.
    Otherwise, it's a past membership kept because it can be very useful to see who was in which Club in the past.
    """
    user = models.ForeignKey(User, verbose_name=_('user'), related_name="memberships", null=False, blank=False)
    club = models.ForeignKey(Club, verbose_name=_('club'), related_name="members", null=False, blank=False)
    start_date = models.DateField(_('start date'), default=timezone.now)
    end_date = models.DateField(_('end date'), null=True, blank=True)
    role = models.IntegerField(_('role'), choices=sorted(settings.SITH_CLUB_ROLES.items()),
                               default=sorted(settings.SITH_CLUB_ROLES.items())[0][0])
    description = models.CharField(_('description'), max_length=128, null=False, blank=True)

    def clean(self):
        sub = User.objects.filter(pk=self.user.pk).first()
        if sub is None or not sub.is_subscribed:
            raise ValidationError(_('User must be subscriber to take part to a club'))
        if Membership.objects.filter(user=self.user).filter(club=self.club).filter(end_date=None).exists():
            raise ValidationError(_('User is already member of that club'))

    def __str__(self):
        return self.club.name + ' - ' + self.user.username + ' - ' + str(settings.SITH_CLUB_ROLES[self.role]) + str(
            " - " + str(_('past member')) if self.end_date is not None else ""
        )

    def is_owned_by(self, user):
        """
        Method to see if that object can be super edited by the given user
        """
        return user.is_in_group(settings.SITH_MAIN_BOARD_GROUP)

    def can_be_edited_by(self, user):
        """
        Method to see if that object can be edited by the given user
        """
        if user.memberships:
            ms = user.memberships.filter(club=self.club, end_date=None).first()
            return (ms and ms.role >= self.role) or user.is_in_group(settings.SITH_MAIN_BOARD_GROUP)
        return user.is_in_group(settings.SITH_MAIN_BOARD_GROUP)

    def get_absolute_url(self):
        return reverse('club:club_members', kwargs={'club_id': self.club.id})


class Mailing(models.Model):
    """
    This class correspond to a mailing list
    Remember that mailing lists should be validated by UTBM
    """
    club = models.ForeignKey(Club, verbose_name=_('Club'), related_name="mailings", null=False, blank=False)
    email = models.EmailField(_('Email address'), unique=True)

    def is_owned_by(self, user):
        return user.is_in_group(self) or user.is_root or user.is_board_member

    def can_view(self, user):
        return self.club.has_rights_in_club(user)

    def delete(self):
        for sub in self.subscriptions.all():
            sub.delete()
        super(Mailing, self).delete()

    def __str__(self):
        return "%s - %s" % (self.club, self.email)


class MailingSubscription(models.Model):
    """
    This class makes the link between user and mailing list
    """
    mailing = models.ForeignKey(Mailing, verbose_name=_('Mailing'), related_name="subscriptions", null=False, blank=False)
    user = models.ForeignKey(User, verbose_name=_('User'), related_name="mailing_subscriptions", null=True, blank=True)
    email = models.EmailField(_('Email address'), blank=False, null=False)

    class Meta:
        unique_together = (('user', 'email', 'mailing'),)

    def clean(self):
        if not self.user and not self.email:
            raise ValidationError(_("At least user or email is required"))
        if self.user and not self.email:
            self.email = self.user.email
        super(MailingSubscription, self).clean()

    def is_owned_by(self, user):
        return self.mailing.club.has_rights_in_club(user) or user.is_root

    def can_be_edited_by(self, user):
        return self.is_owned_by(user) or (user is not None and user.id == self.user.id)

    def __str__(self):
        if self.user:
            user = str(self.user)
        else:
            user = _("Unregistered user")
        return "(%s) - %s : %s" % (self.mailing, user, self.email)