''' base model with default fields '''
from django.db import models
from django.dispatch import receiver

from bookwyrm.settings import DOMAIN
from .fields import RemoteIdField


class BookWyrmModel(models.Model):
    ''' shared fields '''
    created_date = models.DateTimeField(auto_now_add=True)
    updated_date = models.DateTimeField(auto_now=True)
    remote_id = RemoteIdField(null=True, activitypub_field='id')

    def get_remote_id(self):
        ''' generate a url that resolves to the local object '''
        base_path = 'https://%s' % DOMAIN
        if hasattr(self, 'user'):
            base_path = self.user.remote_id
        model_name = type(self).__name__.lower()
        return '%s/%s/%d' % (base_path, model_name, self.id)

    class Meta:
        ''' this is just here to provide default fields for other models '''
        abstract = True

    @property
    def local_path(self):
        ''' how to link to this object in the local app '''
        return self.get_remote_id().replace('https://%s' % DOMAIN, '')


@receiver(models.signals.post_save)
#pylint: disable=unused-argument
def execute_after_save(sender, instance, created, *args, **kwargs):
    ''' set the remote_id after save (when the id is available) '''
    if not created or not hasattr(instance, 'get_remote_id'):
        return
    if not instance.remote_id:
        instance.remote_id = instance.get_remote_id()
        instance.save()