import os
import re

import uuid as uuid

from django.conf import settings
from django.contrib.postgres.fields import CIEmailField
from django.core.exceptions import ValidationError
from django.core.mail import EmailMultiAlternatives
from django.db import models
from django.db.models import Sum
from django.template.loader import render_to_string
from django.urls import reverse


class BaseModel(models.Model):
    class Meta:
        abstract = True

    created_at = models.DateTimeField('créé le', auto_now_add=True)
    updated_at = models.DateTimeField('mis à jour le', auto_now=True)


def phone_validator(value):
    regex = re.compile(r'^\d{10}$')
    if not regex.match(value):
        raise ValidationError(
            "%(value)s n'est pas un numéro de téléphone valide. Format attendu : 10 chiffres.",
            params={'value': value}
        )


class Teacher(BaseModel):
    class Meta:
        verbose_name = 'coordonnateur'
        verbose_name_plural = 'coordonnateurs'
        ordering = ['first_name']

    uuid = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    first_name = models.CharField('prénom', max_length=100)
    last_name = models.CharField('nom', max_length=100)
    phone_number = models.CharField(
        'numéro de téléphone',
        help_text="En cas d'urgence, 10 chiffres.",
        max_length=10,
        validators=[phone_validator]
    )
    email = CIEmailField(
        'adresse email',
        help_text='Utilisée pour vous transmettre votre lien personnel',
        unique=True
    )
    has_confirmed_list = models.BooleanField(
        'a confirmé les listes',
        default=False,
        blank=True
    )

    def get_absolute_url(self):
        from django.urls import reverse
        return reverse('list_books', kwargs={'pk': str(self.pk)})

    @property
    def full_name(self):
        return f'{self.first_name} {self.last_name}'

    def __str__(self):
        return self.full_name

    def send_link(self, request):
        dest = self.email
        link = request.build_absolute_uri(reverse('list_books', args=[str(self.pk)]))
        msg = EmailMultiAlternatives(
            subject='Gestion des manuels scolaires',
            body=f'Bonjour {self.first_name},\n'
                 f'Voici votre lien pour la gestion des manuels scolaires : {link}',
            from_email=settings.SERVER_EMAIL,
            to=[dest],
        )
        reply_to = [os.getenv('REPLY_TO')]
        if reply_to:
            msg.reply_to = reply_to
        msg.attach_alternative(
            render_to_string('manuels/emails_link.html', {'link': link, 'teacher': self}), "text/html"
        )
        msg.send()

    def send_confirmation(self, request):
        dest = settings.LIBRARIAN_EMAILS
        link = request.build_absolute_uri(reverse('home_page'))
        msg = EmailMultiAlternatives(
            subject="Gestion des manuels scolaires - Confirmation d'un coordonnateur",
            body=f'Bonjour,\n'
                 f'{self.first_name} a confirmé ses listes sur {link}',
            from_email=settings.SERVER_EMAIL,
            to=dest,
        )
        reply_to = [os.getenv('REPLY_TO')]
        if reply_to:
            msg.reply_to = reply_to
        msg.attach_alternative(
            render_to_string('manuels/emails_confirmation.html', {'link': link, 'teacher': self}), "text/html"
        )
        msg.send()


class Level(BaseModel):
    class Meta:
        verbose_name = 'classe'
        verbose_name_plural = 'classes'
        ordering = ['order', 'name']

    name = models.CharField('nom', max_length=50)
    order = models.IntegerField('ordre', default=0)

    def __str__(self):
        return self.name

    @property
    def non_acquired_consumable_count(self):
        return self.book_set.filter(consumable=True, previously_acquired=False).count()

    @property
    def non_acquired_consumable_price(self):
        price = self.book_set.filter(consumable=True, previously_acquired=False).aggregate(Sum('price')).get('price__sum', 0)
        if price is None:
            return 0
        return price

    @property
    def non_acquired_book_count(self):
        return self.book_set.filter(consumable=False, previously_acquired=False).count()

    @property
    def non_acquired_book_price(self):
        price = self.book_set.filter(consumable=False, previously_acquired=False).aggregate(Sum('price')).get('price__sum', 0)
        if price is None:
            return 0
        return price

    @property
    def non_acquired_total_price(self):
        price = self.book_set.filter(previously_acquired=False).aggregate(Sum('price')).get('price__sum', 0)
        if price is None:
            return 0
        return price


class Editor(BaseModel):
    class Meta:
        verbose_name = 'éditeur'
        verbose_name_plural = 'éditeurs'
        ordering = ['name']

    name = models.CharField('nom', max_length=100)

    def __str__(self):
        return self.name


def isbn_validator(value):
    regex = re.compile(r'(\d-?){10,13}X?')
    if not regex.match(value):
        raise ValidationError("%(value)s n'est pas un ISBN valide.", params={'value': value})


def positive_float_validator(value):
    try:
        value = float(value)
    except ValueError:
        raise ValidationError("%(value)s doit être un nombre décimal")

    if value < 0:
        raise ValidationError("%(value)s doit être un nombre positif")


class Book(BaseModel):
    class Meta:
        verbose_name = 'livre'
        verbose_name_plural = 'livres'

    teacher = models.ForeignKey(verbose_name='coordonnateur', to=Teacher, on_delete=models.PROTECT, null=True)
    level = models.ForeignKey(verbose_name='classe', to=Level, on_delete=models.PROTECT, null=True)
    field = models.CharField('discipline', max_length=200)
    title = models.TextField('titre')
    authors = models.TextField('auteurs')
    editor = models.ForeignKey(verbose_name='éditeur', to=Editor, on_delete=models.PROTECT, null=True)
    other_editor = models.CharField(verbose_name='préciser', max_length=100, blank=True)
    publication_year = models.PositiveIntegerField('année de publication')
    isbn = models.CharField(
        'ISBN/EAN',
        max_length=20,
        help_text="Format attendu : 10 ou 13 chiffres, éventuellement séparés par des tirets et éventuellement "
                  "suivis de la lettre <code>X</code>. La recherche sur Decitre ne fonctionnera qu'avec un code ISBN à "
                  "13 chiffres (ou EAN)",
        validators=[isbn_validator]
    )
    price = models.FloatField('prix', validators=[positive_float_validator])
    YES_NO_CHOICE = (
        (None, '------------'),
        (False, 'Non'),
        (True, 'Oui'),
    )
    previously_acquired = models.BooleanField(
        "manuel acquis précédemment par l'élève",
        choices=YES_NO_CHOICE,
        blank=False,
        default=None,
    )
    done = models.BooleanField(
        'Traité',
        blank=True,
        default=False
    )
    comments = models.TextField(
        'commentaires',
        blank=True,
        help_text="Ce message sera visible par la documentaliste."
    )
    consumable = models.BooleanField(
        'consommable',
        help_text="Exemple : un cahier d'exercices est un consommable",
        choices=YES_NO_CHOICE,
        blank=False,
        default=None,
    )

    @property
    def previously_acquired_text(self):
        if self.previously_acquired:
            return 'Oui'
        else:
            return 'Non'

    @property
    def consumable_text(self):
        if self.consumable:
            return 'Oui'
        else:
            return 'Non'

    def __str__(self):
        return f'{self.title} ({self.authors}) - {self.isbn}'

    def get_absolute_url(self):
        from django.urls import reverse
        return reverse('edit_book', kwargs={'teacher_pk': str(self.teacher.pk), 'pk': str(self.pk)})


class SuppliesRequirement(BaseModel):
    class Meta:
        verbose_name = 'demande de fournitures'
        verbose_name_plural = 'demandes de fournitures'

    teacher = models.ForeignKey(verbose_name='coordonnateur', to=Teacher, on_delete=models.PROTECT, null=True)
    level = models.ForeignKey(verbose_name='classe', to=Level, on_delete=models.PROTECT, null=True)
    field = models.CharField('discipline', max_length=50)
    supplies = models.TextField('fournitures')
    done = models.BooleanField(
        'Traité',
        blank=True,
        default=False
    )

    def __str__(self):
        return f'{self.supplies} pour {self.level} ({self.teacher})'


class CommonSupply(BaseModel):
    class Meta:
        verbose_name = 'fourniture commune'
        verbose_name_plural = 'fournitures communes'
        ordering = ('order', 'name',)

    name = models.CharField('nom', max_length=200)
    order = models.IntegerField('ordre')

    def __str__(self):
        return self.name