feat: multi tenancy support

app/apps/common/models.py

@@ -0,0 +1,84 @@
+from django.db import models
+from django.conf import settings
+from django.db.models import Q
+from django.utils.translation import gettext_lazy as _
+
+from apps.common.middleware.thread_local import get_current_user
+
+
+class SharedObjectManager(models.Manager):
+    def get_queryset(self):
+        """Return only objects the user can access"""
+        user = get_current_user()
+        base_qs = super().get_queryset()
+
+        if user and user.is_authenticated:
+            return base_qs.filter(
+                Q(visibility="public")
+                | Q(owner=user)
+                | Q(shared_with=user)
+                | Q(visibility="private", owner=None)
+            ).distinct()
+
+        return base_qs.filter(visibility="public")
+
+
+class SharedObject(models.Model):
+    # Access control enum
+    class Visibility(models.TextChoices):
+        private = "private", _("Private")
+        is_paid = "public", _("Public")
+
+    # Core sharing fields
+    owner = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="%(class)s_owned",
+        null=True,
+        blank=True,
+    )
+    visibility = models.CharField(
+        max_length=10, choices=Visibility.choices, default=Visibility.private
+    )
+    shared_with = models.ManyToManyField(
+        settings.AUTH_USER_MODEL, related_name="%(class)s_shared", blank=True
+    )
+
+    # Use as abstract base class
+    class Meta:
+        abstract = True
+        indexes = [
+            models.Index(fields=["visibility"]),
+        ]
+
+    def is_accessible_by(self, user):
+        """Check if a user can access this object"""
+        return (
+            self.visibility == "public"
+            or self.owner == user
+            or (self.visibility == "shared" and user in self.shared_with.all())
+        )
+
+    def save(self, *args, **kwargs):
+        if not self.pk and not self.owner:
+            self.owner = get_current_user()
+        super().save(*args, **kwargs)
+
+
+class OwnedObject(models.Model):
+    owner = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="%(class)s_owned",
+        null=True,
+        blank=True,
+    )
+
+    # Use as abstract base class
+    class Meta:
+        abstract = True
+
+    def save(self, *args, **kwargs):
+        if not self.pk and not self.owner:
+            self.owner = get_current_user()
+        super().save(*args, **kwargs)