import django.contrib.postgres.fields as postgres
from django.utils.translation import ugettext_lazy as _
from django.db import models
from django.core.serializers.json import DjangoJSONEncoder
from common.models import Resource, Mark, Review
from boofilsic.settings import BOOK_MEDIA_PATH_ROOT, DEFAULT_BOOK_IMAGE
from datetime import datetime


def book_cover_path(instance, filename):
    raise NotImplementedError("UUID!!!!!!!!!!!")
    root = ''
    if BOOK_MEDIA_PATH_ROOT.endswith('/'):
        root = BOOK_MEDIA_PATH_ROOT
    else:
        root = BOOK_MEDIA_PATH_ROOT + '/'
    return root + datetime.now().strftime('%Y/%m/%d') + f'{filename}'


class Book(Resource):
    # widely recognized name, usually in Chinese
    title = models.CharField(_("title"), max_length=200)
    subtitle = models.CharField(_("subtitle"), blank=True, default='', max_length=200)
    # original name, for books in foreign language
    orig_title = models.CharField(_("original title"), blank=True, default='', max_length=200)

    author = postgres.ArrayField(
        models.CharField(_("author"), blank=True, default='', max_length=100),
        null=True,
        blank=True,
        default=list,
    )
    translator = postgres.ArrayField(
        models.CharField(_("translator"), blank=True, default='', max_length=100),
        null=True,
        blank=True,
        default=list,
    )
    language = models.CharField(_("language"), blank=True, default='', max_length=10)
    pub_house = models.CharField(_("publishing house"), blank=True, default='', max_length=200)
    pub_year = models.IntegerField(_("published year"), null=True, blank=True)
    pub_month = models.IntegerField(_("published month"), null=True, blank=True)
    binding = models.CharField(_("binding"), blank=True, default='', max_length=50)
    # since data origin is not formatted and might be CNY USD or other currency, use char instead
    price = models.CharField(_("pricing"), blank=True, default='', max_length=50)
    pages = models.PositiveIntegerField(_("pages"), null=True, blank=True)
    isbn = models.CharField(_("ISBN"), blank=True, max_length=20, unique=True, db_index=True)
    # to store previously scrapped data 
    img_url = models.URLField(max_length=300)
    cover = models.ImageField(_("cover picture"), upload_to=book_cover_path, default=DEFAULT_BOOK_IMAGE, blank=True)

    class Meta:
        # more info: https://docs.djangoproject.com/en/2.2/ref/models/options/
        # set managed=False if the model represents an existing table or
        # a database view that has been created by some other means.
        # check the link above for further info
        # managed = True
        # db_table = 'book'
        constraints = [
            models.CheckConstraint(check=models.Q(pub_year__gte=0), name='pub_year_lowerbound'),
            models.CheckConstraint(check=models.Q(pub_month__lte=12), name='pub_month_upperbound'),
            models.CheckConstraint(check=models.Q(pub_month__gte=1), name='pub_month_lowerbound'),
        ]

    def __str__(self):
        return self.title


class BookMark(Mark):
    book = models.ForeignKey(Book, on_delete=models.SET_NULL, related_name='book_marks', null=True)
    class Meta:
        constraints = [
            models.UniqueConstraint(fields=['owner', 'book'], name="unique_book_mark")
        ]


class BookReview(Review):
    book = models.ForeignKey(Book, on_delete=models.SET_NULL, related_name='book_reviews', null=True)
    class Meta:
        constraints = [
            models.UniqueConstraint(fields=['owner', 'book'], name="unique_book_review")
        ]