feat: allow managed local census easily from voting admin

decide/base/helpers.py

@@ -0,0 +1,22 @@
+from django.apps import apps
+from django.conf import settings
+from django.db import router
+
+
+def is_valid_app(app_label: str) -> bool:
+    return apps.is_installed(app_label) and app_label in settings.APIS
+
+
+def is_same_api(app_label_1: str, app_label_2: str) -> bool:
+    return settings.APIS.get(app_label_1) == settings.APIS.get(app_label_2)
+
+
+def is_same_database(model_1, model_2) -> bool:
+    return router.db_for_read(model_1) == router.db_for_read(model_2)
+
+
+def is_possible_connect_apps(app_label_1: str, app_label_2: str) -> bool:
+    if not is_valid_app(app_label_1) or not is_valid_app(app_label_2):
+        return False
+
+    return is_same_api(app_label_1, app_label_2)

decide/voting/admin.py

@@ -1,13 +1,28 @@
+from django.conf import settings
 from django.contrib import admin
 from django.utils import timezone
 
+from base.helpers import is_possible_connect_apps, is_same_database
 from .models import QuestionOption
 from .models import Question
-from .models import Voting
+from .models import CensusLocal, Voting, VotingLocal
 
 from .filters import StartedFilter
 
 
+try:
+    from census.models import Census
+except ImportError:
+    CENSUS_LOCAL_AVAILABLE = False
+else:
+    CENSUS_LOCAL_AVAILABLE = (
+        is_possible_connect_apps('voting', 'census')
+        and is_same_database(Census, Voting)
+        and is_possible_connect_apps('voting', 'authentication')
+        and is_same_database(Census, settings.AUTH_USER_MODEL)
+    )
+
+
 def start(modeladmin, request, queryset):
     for v in queryset.all():
         v.create_pubkey()
@@ -46,5 +61,28 @@ class VotingAdmin(admin.ModelAdmin):
     actions = [ start, stop, tally ]
 
 
+class CensusInline(admin.TabularInline):
+    model = CensusLocal
+    fk_name = 'voting'
+    extra = 1
+    autocomplete_fields = ('voter',)
+
+
+class VotingCensusAdmin(admin.ModelAdmin):
+    list_display = ('name',)
+
+    def get_inlines(self, request, obj):
+        return [CensusInline]
+
+    def has_add_permission(self, request):
+        return False
+
+    def has_delete_permission(self, request, obj=None):
+        return False
+
+
+if CENSUS_LOCAL_AVAILABLE:
+    admin.site.register(VotingLocal, VotingCensusAdmin)
+
 admin.site.register(Voting, VotingAdmin)
 admin.site.register(Question, QuestionAdmin)

decide/voting/models.py

@@ -1,7 +1,6 @@
+from django.conf import settings
 from django.db import models
 from django.db.models import JSONField
-from django.db.models.signals import post_save
-from django.dispatch import receiver
 
 from base import mods
 from base.models import Auth, Key
@@ -131,3 +130,39 @@ def do_postproc(self):
 
     def __str__(self):
         return self.name
+
+
+class CensusLocal(models.Model):
+    voting = models.ForeignKey(
+        'voting.VotingLocal',
+        on_delete=models.CASCADE,
+        db_column='voting_id',
+        db_constraint=False,
+        related_name='+',
+    )
+    voter = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        db_column='voter_id',
+        db_constraint=False,
+        related_name='+',
+    )
+
+    class Meta:
+        managed = False  # create to managed local census easier
+        db_table = 'census_census'
+        unique_together = (('voting', 'voter'),)
+
+
+class VotingLocal(models.Model):
+    name = models.CharField(max_length=200)
+    voters = models.ManyToManyField(
+        settings.AUTH_USER_MODEL,
+        through='voting.CensusLocal',
+        blank=True,
+    )
+
+    class Meta:
+        managed = False  # create to managed local census easier
+        db_table = 'voting_voting'
+        verbose_name_plural = 'Census local votings'