from django.contrib import auth
from django.contrib.auth import get_user_model
from django.core.management.base import BaseCommand


class Command(BaseCommand):
  help = 'Get a list of all permissions available in the system.'

  def handle(self, *args, **options):
    permissions = set()

    # We create (but not persist) a temporary superuser and use it to game the
    # system and pull all permissions easily.
    tmp_superuser = get_user_model()(
      is_active=True,
      is_superuser=True
    )

    # We go over each AUTHENTICATION_BACKEND and try to fetch
    # a list of permissions
    for backend in auth.get_backends():
      if hasattr(backend, "get_all_permissions"):
        permissions.update(backend.get_all_permissions(tmp_superuser))

    # Make an unique list of permissions sorted by permission name.
    sorted_list_of_permissions = sorted(list(permissions))

    # Send a joined list of permissions to a command-line output.
    self.stdout.write('\n'.join(sorted_list_of_permissions))