# Copyright (C) 2018-2020 by BDE ENS Paris-Saclay
# SPDX-License-Identifier: GPL-3.0-or-later

import datetime
import os

from django.conf import settings
from django.contrib.auth.models import User
from django.core.exceptions import ValidationError
from django.db import models
from django.template import loader
from django.urls import reverse, reverse_lazy
from django.utils.encoding import force_bytes
from django.utils.http import urlsafe_base64_encode
from django.utils.translation import gettext_lazy as _
from registration.tokens import email_validation_token
from note.models import MembershipTransaction


class Profile(models.Model):
    """
    An user profile

    We do not want to patch the Django Contrib :model:`auth.User`model;
    so this model add an user profile with additional information.

    """
    user = models.OneToOneField(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
    )
    phone_number = models.CharField(
        verbose_name=_('phone number'),
        max_length=50,
        blank=True,
        null=True,
    )
    section = models.CharField(
        verbose_name=_('section'),
        help_text=_('e.g. "1A0", "9A♥", "SAPHIRE"'),
        max_length=255,
        blank=True,
        null=True,
    )
    address = models.CharField(
        verbose_name=_('address'),
        max_length=255,
        blank=True,
        null=True,
    )
    paid = models.BooleanField(
        verbose_name=_("paid"),
        help_text=_("Tells if the user receive a salary."),
        default=False,
    )

    email_confirmed = models.BooleanField(
        verbose_name=_("email confirmed"),
        default=False,
    )

    registration_valid = models.BooleanField(
        verbose_name=_("registration valid"),
        default=False,
    )

    soge = models.BooleanField(
        verbose_name=_("Société générale"),
        help_text=_("Has the user ever be paid by the Société générale?"),
        default=False,
    )

    class Meta:
        verbose_name = _('user profile')
        verbose_name_plural = _('user profile')
        indexes = [models.Index(fields=['user'])]

    def get_absolute_url(self):
        return reverse('user_detail', args=(self.pk,))

    def send_email_validation_link(self):
        subject = "Activate your Note Kfet account"
        message = loader.render_to_string('registration/mails/email_validation_email.html',
                                          {
                                              'user': self.user,
                                              'domain': os.getenv("NOTE_URL", "note.example.com"),
                                              'token': email_validation_token.make_token(self.user),
                                              'uid': urlsafe_base64_encode(force_bytes(self.user.pk)).decode('UTF-8'),
                                          })
        self.user.email_user(subject, message)


class Club(models.Model):
    """
    A club is a group of people, whose membership is handle by their
    :model:`member.Membership`, and gives access to right defined by a :model:`member.Role`.
    """
    name = models.CharField(
        verbose_name=_('name'),
        max_length=255,
        unique=True,
    )
    email = models.EmailField(
        verbose_name=_('email'),
    )
    parent_club = models.ForeignKey(
        'self',
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        verbose_name=_('parent club'),
    )

    # Memberships

    # When set to False, the membership system won't be used.
    # Useful to create notes for activities or departments.
    require_memberships = models.BooleanField(
        default=True,
        verbose_name=_("require memberships"),
        help_text=_("Uncheck if this club don't require memberships."),
    )

    membership_fee_paid = models.PositiveIntegerField(
        default=0,
        verbose_name=_('membership fee (paid students)'),
    )

    membership_fee_unpaid = models.PositiveIntegerField(
        default=0,
        verbose_name=_('membership fee (unpaid students)'),
    )

    membership_duration = models.PositiveIntegerField(
        blank=True,
        null=True,
        verbose_name=_('membership duration'),
        help_text=_('The longest time (in days) a membership can last '
                    '(NULL = infinite).'),
    )

    membership_start = models.DateField(
        blank=True,
        null=True,
        verbose_name=_('membership start'),
        help_text=_('How long after January 1st the members can renew '
                    'their membership.'),
    )

    membership_end = models.DateField(
        blank=True,
        null=True,
        verbose_name=_('membership end'),
        help_text=_('How long the membership can last after January 1st '
                    'of the next year after members can renew their '
                    'membership.'),
    )

    def update_membership_dates(self):
        """
        This function is called each time the club detail view is displayed.
        Update the year of the membership dates.
        """
        if not self.membership_start:
            return

        today = datetime.date.today()

        if (today - self.membership_start).days >= 365:
            self.membership_start = datetime.date(self.membership_start.year + 1,
                                                  self.membership_start.month, self.membership_start.day)
            self.membership_end = datetime.date(self.membership_end.year + 1,
                                                self.membership_end.month, self.membership_end.day)
            self.save(force_update=True)

    def save(self, force_insert=False, force_update=False, using=None,
             update_fields=None):
        if not self.require_memberships:
            self.membership_fee_paid = 0
            self.membership_fee_unpaid = 0
            self.membership_duration = None
            self.membership_start = None
            self.membership_end = None
        super().save(force_insert, force_update, update_fields)

    class Meta:
        verbose_name = _("club")
        verbose_name_plural = _("clubs")

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse_lazy('member:club_detail', args=(self.pk,))


class Role(models.Model):
    """
    Role that an :model:`auth.User` can have in a :model:`member.Club`
    """
    name = models.CharField(
        verbose_name=_('name'),
        max_length=255,
        unique=True,
    )

    class Meta:
        verbose_name = _('role')
        verbose_name_plural = _('roles')

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


class Membership(models.Model):
    """
    Register the membership of a user to a club, including roles and membership duration.

    """
    user = models.ForeignKey(
        User,
        on_delete=models.PROTECT,
        verbose_name=_("user"),
    )

    club = models.ForeignKey(
        Club,
        on_delete=models.PROTECT,
        verbose_name=_("club"),
    )

    roles = models.ManyToManyField(
        Role,
        verbose_name=_("roles"),
    )

    date_start = models.DateField(
        default=datetime.date.today,
        verbose_name=_('membership starts on'),
    )

    date_end = models.DateField(
        verbose_name=_('membership ends on'),
        null=True,
    )

    fee = models.PositiveIntegerField(
        verbose_name=_('fee'),
    )

    def valid(self):
        """
        A membership is valid if today is between the start and the end date.
        """
        if self.date_end is not None:
            return self.date_start.toordinal() <= datetime.datetime.now().toordinal() < self.date_end.toordinal()
        else:
            return self.date_start.toordinal() <= datetime.datetime.now().toordinal()

    def save(self, *args, **kwargs):
        """
        Calculate fee and end date before saving the membership and creating the transaction if needed.
        """
        if self.club.parent_club is not None:
            if not Membership.objects.filter(user=self.user, club=self.club.parent_club).exists():
                raise ValidationError(_('User is not a member of the parent club') + ' ' + self.club.parent_club.name)

        created = not self.pk
        if created:
            if Membership.objects.filter(
                    user=self.user,
                    club=self.club,
                    date_start__lte=self.date_start,
                    date_end__gte=self.date_start,
            ).exists():
                raise ValidationError(_('User is already a member of the club'))

            if self.user.profile.paid:
                self.fee = self.club.membership_fee_paid
            else:
                self.fee = self.club.membership_fee_unpaid

            if self.club.membership_duration is not None:
                self.date_end = self.date_start + datetime.timedelta(days=self.club.membership_duration)
            else:
                self.date_end = self.date_start + datetime.timedelta(days=424242)
            if self.club.membership_end is not None and self.date_end > self.club.membership_end:
                self.date_end = self.club.membership_end

        super().save(*args, **kwargs)

        self.make_transaction()

    def make_transaction(self):
        """
        Create Membership transaction associated to this membership.
        """
        if not self.fee or MembershipTransaction.objects.filter(membership=self).exists():
            return

        if self.fee:
            transaction = MembershipTransaction(
                membership=self,
                source=self.user.note,
                destination=self.club.note,
                quantity=1,
                amount=self.fee,
                reason="Adhésion " + self.club.name,
            )
            transaction._force_save = True
            transaction.save(force_insert=True)

    def __str__(self):
        return _("Membership of {user} for the club {club}").format(user=self.user.username, club=self.club.name, )

    class Meta:
        verbose_name = _('membership')
        verbose_name_plural = _('memberships')
        indexes = [models.Index(fields=['user'])]