''' models for storing different kinds of Activities '''
import urllib.parse

from django.apps import apps
from django.db import models

from bookwyrm import activitypub
from bookwyrm.settings import DOMAIN
from .activitypub_mixin import CollectionItemMixin, OrderedCollectionMixin
from .base_model import BookWyrmModel
from . import fields


class Tag(OrderedCollectionMixin, BookWyrmModel):
    ''' freeform tags for books '''
    name = fields.CharField(max_length=100, unique=True)
    identifier = models.CharField(max_length=100)

    @property
    def books(self):
        ''' count of books associated with this tag '''
        edition_model = apps.get_model('bookwyrm.Edition', require_ready=True)
        return edition_model.objects.filter(
            usertag__tag__identifier=self.identifier
        ).order_by('-created_date').distinct()

    collection_queryset = books

    def get_remote_id(self):
        ''' tag should use identifier not id in remote_id '''
        base_path = 'https://%s' % DOMAIN
        return '%s/tag/%s' % (base_path, self.identifier)


    def save(self, *args, **kwargs):
        ''' create a url-safe lookup key for the tag '''
        if not self.id:
            # add identifiers to new tags
            self.identifier = urllib.parse.quote_plus(self.name)
        super().save(*args, **kwargs)


class UserTag(CollectionItemMixin, BookWyrmModel):
    ''' an instance of a tag on a book by a user '''
    user = fields.ForeignKey(
        'User', on_delete=models.PROTECT, activitypub_field='actor')
    book = fields.ForeignKey(
        'Edition', on_delete=models.PROTECT, activitypub_field='object')
    tag = fields.ForeignKey(
        'Tag', on_delete=models.PROTECT, activitypub_field='target')

    activity_serializer = activitypub.Add
    object_field = 'book'
    collection_field = 'tag'

    class Meta:
        ''' unqiueness constraint '''
        unique_together = ('user', 'book', 'tag')