further split of relations classes

ormar/relations/relation_proxy.py

@@ -0,0 +1,62 @@
+from typing import Any, TYPE_CHECKING
+
+import ormar
+from ormar.exceptions import RelationshipInstanceError
+from ormar.relations.querysetproxy import QuerysetProxy
+
+if TYPE_CHECKING:  # pragma no cover
+    from ormar import Model
+    from ormar.relations import Relation
+    from ormar.queryset import QuerySet
+
+
+class RelationProxy(list):
+    def __init__(self, relation: "Relation") -> None:
+        super(RelationProxy, self).__init__()
+        self.relation = relation
+        self._owner = self.relation.manager.owner
+        self.queryset_proxy = QuerysetProxy(relation=self.relation)
+
+    def __getattribute__(self, item: str) -> Any:
+        if item in ["count", "clear"]:
+            if not self.queryset_proxy.queryset:
+                self.queryset_proxy.queryset = self._set_queryset()
+            return getattr(self.queryset_proxy, item)
+        return super().__getattribute__(item)
+
+    def __getattr__(self, item: str) -> Any:
+        if not self.queryset_proxy.queryset:
+            self.queryset_proxy.queryset = self._set_queryset()
+        return getattr(self.queryset_proxy, item)
+
+    def _set_queryset(self) -> "QuerySet":
+        owner_table = self.relation._owner.Meta.tablename
+        pkname = self.relation._owner.Meta.pkname
+        pk_value = self.relation._owner.pk
+        if not pk_value:
+            raise RelationshipInstanceError(
+                "You cannot query many to many relationship on unsaved model."
+            )
+        kwargs = {f"{owner_table}__{pkname}": pk_value}
+        queryset = (
+            ormar.QuerySet(model_cls=self.relation.to)
+                .select_related(owner_table)
+                .filter(**kwargs)
+        )
+        return queryset
+
+    async def remove(self, item: "Model") -> None:
+        super().remove(item)
+        rel_name = item.resolve_relation_name(item, self._owner)
+        item._orm._get(rel_name).remove(self._owner)
+        if self.relation._type == ormar.RelationType.MULTIPLE:
+            await self.queryset_proxy.delete_through_instance(item)
+
+    def append(self, item: "Model") -> None:
+        super().append(item)
+
+    async def add(self, item: "Model") -> None:
+        if self.relation._type == ormar.RelationType.MULTIPLE:
+            await self.queryset_proxy.create_through_instance(item)
+        rel_name = item.resolve_relation_name(item, self._owner)
+        setattr(item, rel_name, self._owner)